AUDIO FORUMS >> Replacement Tubes >> Rectifier Tubes

Message started by JOMAN on 06/19/19 at 06:15:08

Title: Rectifier Tubes
Post by JOMAN on 06/19/19 at 06:15:08

I have gone in a Ďnewí or revised direction in trying to finalize a rectifier tube choice for my UFO-25 and CSP-3 and felt that it would be best to post regarding this in itís own topic.  Iíve rolled a lot of rectifiers, many NOS and some new production and ultimately ended up with frustration that could not be ignored.

Itís been a while since I had my Mullard GZ32/CV593 and circumstances forced me to put it in my UFO-25 if only temporarily.  In my CSP3 I had a AWV 5AS4GB.  That was the first time that I listened to that combination and the results were unexpectedly good, among the best.  This caused me to reflect on part of what I found to be frustrating.  As good as the results were in many cases I was always trying to work out the best trade offs.  This combination presented the best trade off so far but it was still the best Ďtrade offí.  At this point I decided no more trade offs.

I went all the way, so to speak, with my UFO-25, my ZR2 and will be with my CSP-3 when I get it modded.  I recalled some of the rectifiers that could be the all-the-way choice but had dismissed these because of the price that they were fetching.  These were the WE422A, U52, early GZ37 and the Mullard or Philips GZ34 metal base.

I still didnít want lay out the cash especially since the price of these has escalated significantly and the supply has decreased proportionately.  After some consideration, taking into account longevity and options that would give close to the same results as the ďultimateĒ options only one fit the bill... Mullard/Blackburn GZ34  fat base, smooth plates (no notches) late 50ís production.  I came across one the was made in 1957 and appeared to be NOS at a decent price... relatively speaking.

I got it a couple of days ago put it in my UFO-25 and the GZ32 in my CSP-3.  Not one previous rectifier or combination has even come remotely close to what Iím experiencing now.  At this point I revisited the possibility of getting a GZ34 metal base as this is supposed to be one of the killer rectifiers.

Evidently these GZ34ís were made by the Blackburn plant, Philips/Amprex and in Brussels and labelled under various names with the Philips usually getting the nod.  Typically these were well over $600.00 some ranging as high as $800.00.  Far more than I wanted to spend.  I just about dismissed that possibility especially considering the performance I was getting now with the Mullard GZ34/32 combo and then came across a ďreasonablyĒ priced Philips/Miniwatt GZ34 Metal Base, NOS, with the original box!  This one is slated for my UFO-25 once I get it.

I still plan to try combinations, GZ34 in both the amp and preamp as well as the GZ34 in the amp with a GZ32 in the pre.  This ought to be interesting.

One other very important factor that Iíll add.  Some components will not be able to take advantage of a tube like the GZ34 Metal Base.  For these components a tube like the Mullard Fat Base at lesser cost may be the ultimate, or, another consideration may be the Psvane 5U4G from Decware, very well priced from a solid company.

The UFO-25 on the other hand does warrant a tube like the GZ34 Metal Base as it will wring out the very last bit of potential in a tube of that caliber.  This has been clearly demonstrated to me.  Once I get the tube(s) Iíll post the end result, figure a month or two allowing for burn in time.

Title: Re: Rectifier Tubes
Post by alper_yilmaz on 06/19/19 at 14:31:53

Stop it, John!  I donít want to get onto the GZ34 route; that would break the bank!  :)



Title: Re: Rectifier Tubes
Post by Lon on 06/19/19 at 14:58:19

I'm with you Alper. I'm trying to wean myself off of NOS tubes. The Sophia Electric Aqua 274B seems the ideal tube for my rectification needs. I've replaced 8 Amperex 7308 with the rigorously tested and balanced 6N5P from Steve for input tubes, and his rigorously tested and balanced output tubes. Only voltage regulation tubes and the ZROCK2 tube are NOS in my main system now. And I'm getting glorious sound!

I can get different, not better imo, sound with a dozen or so NOS rectifiers I have on hand. . . . I have lots of backups, more than I need. My rectifier tube hunt is done.

Title: Re: Rectifier Tubes
Post by JOMAN on 06/19/19 at 16:00:34

Actually, I agree with you guys thatís why I didnít get into the details of the results.  Itís just my cursed OCD kicking in.  Canít ever leave weíll enough alone, so consider this an FYI... only.

Oh and a correction, the GZ34 that fired up my OCD was a 1958 vintage fat base, smooth plates not 1957 vintage.  The metal base is the 1957 vintage Philips/Miniwatt, which is on itís way. (See what I mean by OCD)  

Title: Re: Rectifier Tubes
Post by Rivieraranch on 06/19/19 at 23:35:24

I personally despise the Pissvane brand because of How they market tubes. They are deifying a vacuum tube as if it were jewelry. That is really messed up.

Title: Re: Rectifier Tubes
Post by orangecrush on 06/20/19 at 01:38:18

I am with you on using the best NOS recifiers. I have been using the Brimar 5R4GY, CV717 in my Torii Mk3 for a few years now, and I could never go back. Expensive? Yes, but not when you consider how long they last. The impact on the amp is tremendous.

Title: Re: Rectifier Tubes
Post by Lon on 06/20/19 at 01:52:56

I've never known Decware to send out Psvane tubes. . . Ruby. . . yes.  . . Valve Art. . .yes.

Title: Re: Rectifier Tubes
Post by JOMAN on 06/20/19 at 03:06:39

Decware is using Psvane 5U4G in the UFO-25.  Although these are not listed on the site I asked Steve if he would sell one to me and I got a price for one.  I will only buy these from Decware because I trust that they are giving me the straight goods when it comes to Psvane and any Chinese made tubes for that matter.

So with that statement a bit of qualification is in order so that it is not misconstrued.  If you go on to the Grant Fidelity web site there is an interesting commentary on the recent history of Chinese Tube production and why Grant Fidelity does what they do.  Combine that with the dynamics of Chinese production and marketing, you quickly realize that quality control and consistency is still a problem.  I know that Decware testing processes are rigorous and designed to meet high standards.  That means that tubes that do not meet those standards are not sold or supplied to their customers.

I have the same view of the way that the Chinese Tube producers market as does Rivieraranch.  Getting these from Decware helps me to look past that because they do make some good sounding tubes, itís just that I take some of their advertising statements with a ďgrain of saltĒ, a rather large one at that.

Eventually we will not be able to get NOS tubes.  Then what?  So I hope that someone manages to get their... process... together and start producing with a reasonable degree of quality control and consistency.  At that point Iím in.  

In the meantime as orangecrush pointed out the longevity of some of the tubes that Amprex, Mullard, Brimar and others produced canít be disputed. Itís not that they never had tubes that didnít fail.  Itís that their quality control and standards made these the exception.  A tube like the GZ34 Metal Base is known to last a very long time as are the non metal base late 50ís early 60ís production.

Iím not trying to pitch NOS over new production.  Iím just saying that we are all facing the same dilemma.  So some of us will opt to work with new production for good reasons and Iím glad when some of us do that and I follow their experience with interest.  Some of us will opt to go with NOS also for good reasons.  The combination of the two helps to keep some objectivity in all of this.  Thatís why Iím posting the ongoing results of my Ďrevised directioní.  Itís only an FYI...

Thereís a lot of good and valuable experience amongst us and all of it is welcome, at least as far as Iím concerned.


Title: Re: Rectifier Tubes
Post by Lon on 06/20/19 at 03:47:39

Okay, thanks for the info about the new tube with the Anniversary amps.

I think I'm pretty much done with tube-rolling and will stick with tubes from Sophia Electric for rectifiers. and Decware (NOS Russian) for power and input, and NOS voltage regulators, of which I have probably a life time supply of those that I like most as they last for a long time and I have about five or six replacement pairs. I also have on hand several dozen tubes I can use in my ZROC2s!--though in time I'll look for a new production choice for those. All the best to those who want to spend the big bucks on NOS but I've found great sound with the current tubes from Decware and Sophia and will continue to use those. (They also have just the right amount of "forgiveness" to allow me to listen to almost all my collection happily, something that was hard to accomplish affordably with NOS tubes). I'll probably sell a good portion of my NOS stash in time.

It's amazing how many fantastic variations of wonderful sound can be put together with varied tube complements in these amps.

Title: Re: Rectifier Tubes
Post by orangecrush on 06/20/19 at 16:05:15

Lon, I also use Amperex 7308. Are you really happy with those 6N5P? I would like to try them, but I have spent so much money on over hyped tubes that suck, I am very leary now. Those Chinese tubes Steve hyped up were total crap. I threw mine in the garbage. So I am leary about these 6N5P that are being hyped up right now. But, I trust you and I get that you need allot of tubes, so $$$$$$$$ NOS is not realistic. But if you only go through one pair every 5 years or so, would you still choose the 6N5P?

6N1P distort way too early in my Mk3 and are too dull. Thanks in advance. †

Title: Re: Rectifier Tubes
Post by Lon on 06/20/19 at 16:52:45

I don't know who is 'hyping up" the 6N5P. I'm recounting my experiences with them, haven't seen a chorus of "Amens" or anyone else excited about them. There's more interest in NOS pricey tubes here.

I didn't like the 6N11 tubes either, though I didn't get any from Steve, just bought cheap ones from eBay. They were thin and strident. I couldn't leave them in long enough to "burn in" but I don't think they would have changed enough to please me. In comparison to the 6N1P from Steve that I have on hand, in my preamps and amps the 6N1P are warmer and a bit "slower" sounding; the 6N5P are a bit clearer and more open sounding.

The 6N5P I totally enjoy. These are the only tubes that unseated my 7308s from the ZTPRE and the 25th Anniversary Monoblocks. I confess that I don't remember how they sounded tin my Torii amps so can't comment on how they would fit there.

And when I first experimented with 6N5P it was from eBay buys and I didn't pay much per tube. And I wasn't too impressed. But when I received a pair from Steve of his selected and tested tubes they were very different and I fell for them. I ordered a sextet from Steve for my ZTPRE and really enjoyed them but kept thinking "I paid good money for a lot of 7308s and why aren't I using them." But in the long run as I updated my ZROCK2 with the mods and whole system seasoned in I found that I was bothered by the treble in the 7308 and put Steve's 6N5P back in, first in the amps, and I noticed a mellowing of the high end and a general "un-uptight" nature to the sound that suited my system and the less than stellar material I play a lot. So I put the sextet in the ZTPRE and there was a further sense of ease and a slight mellowing and loosening that I have to say I prefer. I've been back to Steve's 6N5P a few weeks now and they are not going to be replaced by the 7308s. I just prefer this sound.

Now if you find the 6N1P to distort early in the Torii then these are likely to exhibit the same characteristic as I think in the pertinent ways they are electrically identical. I didn't find that distortion to be an issue when I was running the Torii with 6N1P, but I know that it has been a problem in several systems. A query to Steve may be in order to see what he thinks about this aspect.

I've also been experimenting with 6N6P which work as a valid substitute in these components. I have one (expensive) pair touted as "rare and the best" that really do sound quite good. I'm using the pair in my CSP2+ with the Anniversary mods right now and will try them soon in the Monoblocks. These are bigger tubes--almost the same size as EL84--and they may not present the same distortion issue in the Torii, I'm not sure, and I no longer have a Torii (went from three to none!) to test that out.

Bottom line, if the 6N1P weren't working for you, though I think the 6N5P are a better sounding tube overall, these will likely give you the same problem.

I'm using 7308s in my second system right now . . . . I am still experimenting with tubes in this system and may end up with 6N5p and 6N6P here as well. These tube types seem to suit my needs and my aim is to find a tube complement that makes comfortable listening of as many of my discs as possible, rather than chasing "the ultimate sound from the best recordings." In some ways I wish I WEREN'T addicted to many different styles of music and artists--if that were the case I'd get a reel-to-reel and listen to a handful of great recordings that are the sonic SHIT. But alas. . .I care less about the ultimate sound quality than exploring music itself vigorously. The 6N family of tubes are helping me to that end.

Title: Re: Rectifier Tubes
Post by orangecrush on 06/20/19 at 17:13:47

Thanks Lon, thatís really helps me to decide.  I appreciate it.

They are been hyped on this forum and by Steve in the same way as that Chinese tube. :)

Title: Re: Rectifier Tubes
Post by Lon on 06/20/19 at 17:59:38

Well I disagree that they are being hyped. I see many other tubes being hyped more than they are. Including Amperex. Glad I could be helpful.

Title: Re: Rectifier Tubes
Post by Rivieraranch on 06/20/19 at 23:40:02

I don't get where anybody could conclude that Steve hypes tubes at all. He is not in the business of selling tubes. He chooses what sounds best in the equipment and supplies carefully tested tubes. If he decides to use Pissvane tubes in one of his amps what can we do?  We'll all be begging Cary Grant fidelity for replacements.

Title: Re: Rectifier Tubes
Post by orangecrush on 06/21/19 at 00:12:29

I donít mean just here. Everyone including myself gets excited... and we all want to find the holy grail for cheap. I am just more careful now before I buy tubes. †Instead of using the word hype, just go with enthusiastic recommendation. 😀 Again, I am the most guilty of this.

An example recommendation for the Shugang 6N11:

ďThese tubes work in all Decware amps that use 6N1P, 6922 input tubes, which is most of them. †In the TORII's, that being all versions of TORII, MK2, MK3 and TORII JR, I have not yet found a better tube. †Because TORII's are direct coupled (where the amazing transparency and speed comes from) they are very picky about the quality and matching of the input tubes that you use. †Using anything less than great tubes in a TORII input stage can result in a drop in power or an increase in distortion or both.Ē

Title: Re: Rectifier Tubes
Post by Lon on 06/21/19 at 02:46:55

Well some seem to have really liked the 6N11P--so much is system and taste and room dependent. And Steve seems to be saying the distortion issue isn't present with this tube.

Still there's not a lot, and not continuous mention of this tube--I'd hardly call that hype. †There's just as little or less mention of 6N5P. I'd say Mullard GZ32 and other NOS tubes get more mention here.

Months back Donnie was questioning rolling any tubes at all and I'm surprised to find myself now using a lot of Steve's choices--when I was then arguing for other NOS use. But then I had not realized what a difference Steves testing made, nor had I found using Steve's so suitable until I had made some very different rectification and regulation tube choices to anchor those foundations. Moving to the Sophia and to OD3 and OB3 for output tube regulation and OA2 for input regulation had a profound influence on my other choices.

Title: Re: Rectifier Tubes
Post by JOMAN on 06/21/19 at 06:22:57

I donít think that the comments that Steve makes regarding the tubes that he chooses to use in Decware components or his  comments regarding alternative choices to be hype.  He is passionate about what he does and what he makes and I donít take that as hype.

I spoke with him about the 6N11ís as I was using a pair at the time.  By the way I also found that given the right circumstances they could lean toward being shrill.  I was going to buy more from him but he was not able to supply because the recent batch that he had received were different from the first.  Thatís not his fault, thatís the result of poor standards of manufacturers.  I can imagine the frustration that he must have from time to time.

But whatís one to do?   The best one can under the circumstances and I do feel that he does that and conveys it in what he says without overstating it.  His comments about why he was using the Pissvane (thanks for correcting my spelling Rivieraranch) were anything but hype.  He merely stated that it was the tube that he found to be similar to the performance of NOS tubes.  Never did I take that to imply or mean that it was a WE422A, U52 or GZ34 killer.

Look at some of my comments about tubes.  I try to be as factual as I can and definitely do not recommend anything.  I am simply am commenting on what I find the results to be in my space for my tastes.  I made some very strong statements about the good results when I had the Sophia rectifiers in my UFO-25 and now am not using them.  If someone was to conclude that what I said was hype they would be wrong.  I still feel that they are a very good sounding tube.

Iím glad that others comment on their take on different tubes.  The VR tubes in my UFO-25 were obtained because someone commented on their experience (thanks Lon).

Look at the words that we use to try to express what we hear.  They can be very colourful and someone could think that itís hype.

Title: Re: Rectifier Tubes
Post by Lon on 06/21/19 at 14:09:37

Okay, just to put a pin in this "hype" business at least as far as I am concerned, I did a search of the forums and the 6N5P was mentioned by only five persons on this forum in the last 13 months, three persons only mention the tube without comment (including Steve). This is hardly a "hyped up" tube on this forum! John and I have made comments on sound quality, no one else.

I've been playing with my second system tube complements the last 24 hours. At present I'm getting great sound with the expensive pair of 6N6P that I have on hand as input tubes for the CSP3-25 and the Taboo Mk IV-25. I have a pair of Steve's red-tipped 6N5Ps as the driver tubes in the CSP3-25. Sophia Electric Aqua 274B are in each component, and Steve's red tipped power tubes are in the Taboo. An RCA 5814A is in the ZROCK2. Wonderful sound for TV, blu-ray and DVD and music. I'm going to keep this complement in for a while.

EDITED TO ADD: I did a search and there was even less talk of the 6N11 tubes on the forum in the last 12 months. Can't really call the tube "hyped up."

I'm not being adversarial OC, it's just that language is important and I want to be sure we're using the right wording. I agree that it's expensive and tiring to keep trying tube after tube because they were successful for others. I don't spend my money on much of anything else besides audio and music so I'm probably freer to experiment but even so I find it frustrating and tiresome at times. And there's also the realization I came to last decade that any "recommendation" has to be carefully evaluated because our systems and tastes and rooms are so different. In my own experimentation I've learned that a tube sounds a bit differently in a component with different interconnects, power treatment and power cords for example. Different sources can lead to different choices as well. It's really hard to take any recommendation and find it matches your impressions exactly. That's the nature of the revealing character of this equipment. A blessing. . . and sometimes a curse.

Title: Re: Rectifier Tubes
Post by JOMAN on 06/21/19 at 14:31:39

Lon,  just have to ask... 6N6P.  My understanding of this tube is that it has the same pin out as the 6N1P but draws more heater current.  Before using it did you confirm that the CSP-3 25 can handle it?  My curiosity is piqued.

Title: Re: Rectifier Tubes
Post by Lon on 06/21/19 at 14:37:56

I didn't confirm anything with Decware. I was given a heads up on this by Johnny here on the forum who has used it and I've used it in the CSP3-25 and Monoblocks, over 100 hours on this pair and fewer hours on others (later production, cheaper) that I have on hand. No issues at all . . . seems too behave exactly like the 6N5P or 6N1P and nothing in its particulars leaves me worried.

I really like the family sound of the 6N tubes, always have liked their relaxed feel for the higher frequencies and the "spread" of the lower frequencies--all these mated with a very open and expansive midrange. These characteristics have seduced me away from European and US NOS tubes. . . at least for now. I hate paying the prices for those and will be glad to stop doing so.

Title: Re: Rectifier Tubes
Post by JOMAN on 06/21/19 at 14:43:58

Got it... thanks

Title: Re: Rectifier Tubes
Post by orangecrush on 06/21/19 at 22:28:49


Title: Re: Rectifier Tubes
Post by Lon on 06/22/19 at 00:10:16


Title: Re: Rectifier Tubes
Post by JOMAN on 06/25/19 at 13:16:28

Yes and another WOW...

Iím well into rolling GZ34ís and GZ32ís and certain things I knew have been strongly reinforced and perhaps a new take on which tubes to roll first.

First. The rectifier definitely influences how the input and output tube will sound.  One combination of a particular GZ34 in my UFO-25 and a  particular GZ32 in my CSP-3 has the effect of significantly elevating the performance of the input and output tubes.  Example: Prior to having this combination of rectifiers I had pretty much written off the National/Matsushita PCC88.  I tried it again with this new combo of rectifiers and was surprised at the difference.  It still may not be my input tube of choice in my CSP-3 but I really liked what I heard now and it could very well be a close second.  The existing input tube a Tesla PCC88 from 37 factory sounded far more refined.

So, my take on this is that if at all possible start with the rectifier.  

Second:  Donít assume that a particular tube from the same factory is going to sound exactly the same as another tube of the same type from the same factory and add to that, that unless you try the tube yourself reviews and comments will be a start point at best.

The Mullard GZ32/CV593 ring getter 60ís manufacture is quite different from the Mullard GZ32 D getter 1958 manufacture both in physical size and end performance, far more than I expected.  Add to that that a French made Valvo branded GZ32 DD side mounted getter 58 manufacture, so far has bested both of the above.  All GZ32ís do not sound the same or for that matter even close to one another.

The same holds true for the GZ34ís.  Of the three that I have tried, one NOS Mullard/Blackburn 58 smooth plate and two used Philips Sittard 60ís smooth plate G34ís, all three sound quite different with the Mullard/Blackburn being the one of choice, so far.  In fact, personally I wouldnít bother with 60ís GZ34ís.  The Metal Base GZ34 is still en route.

This has demonstrated the frustrations and rewards of tube rolling NOS or new production.  So far one combination has been a WOW, more on that at another time.  Once this session of tube rolling is completed I hope to do very little more if any at all.  If I do any I have concluded that any pricey tubes that I buy will only be bought if a return is possible.  If a return is not possible then I will buy used at a lower price that have a demand so that these can be re sold.  Secondly if I buy pricey tubes I will only buy those that have a track record of longevity otherwise I will select ones that are well in the sub $90.00 bracket NOS or new production, until new production tubes establish a track record of longevity.

More to come...

Title: Re: Rectifier Tubes
Post by JOMAN on 06/28/19 at 03:07:35

Today I got my Philips/Miniwatt Metal Base DD Getter 57 NOS New In Box GZ34.  I just shut down after 5 hours and will start again tomorrow.  I switched out a Mullard/Blackburn Eico Branded OO Getter 58 NOS Smooth Plate GZ34 on which I have about 30 hours.  I also have 2 used GZ34ís Sittard made 60ís smooth plates.

This posting is not about which is better or details about the sound, I will touch on that but more importantly about what I have learned about NOS tubes and hopefully save someone some money and frustration.

First the Metal Base GZ34, is it all itís cracked up as being? Some of you are familiar with the review of this tube in Head HiFi Massive Rectifier Comparison.  Even though I only have 5 hours on this tube I can assure you that it is all that it is touted as being.  I will also go so far as saying that this tube is in a category of itís own.  Do Not compare it to other NOS or new production tubes you will be in for serious frustration if you do.

Is it worth the price?  Depends.  The asking prices of these tubes varies. If NOS $380.00 to over $800.00 if New In Box.  What something is worth is subjective and personal.  I picked up this one for $370.00, new in box and with a nice shine on it.  Do I consider this worth the price?  At $370.00 considering the results and the track record of longevity... ABSOLUTELY!  This one is going no where but my UFO-25.

Now what if you were to get a GZ34 of similar construction but made in the 60ís, say for between $135.00 with some asking over $400.00 and you picked it up because of the reputation of the Metal Base?  On the basis of the two used GZ34 that I tried, that would be a mistake.  Not saying they're bad tubes but they sure are not anywhere remotely close to the Metal Base.  Some ads make it sound that they are ďcloseĒ to the Metal Base... well they are not.  Because of such implications you might spend way more than you should and be very disappointed in what actually is a decent tube.  

In that case I would say that longevity aside youíd be better off with a Sophia Aqua 274B or another NOS tube like an Type 80 or a RCA5U4G...  I think you get the idea.

As to the Mullard/Blackburn Fat Base 58 OO Getter... Another tube in itís own class but not a Metal Base for sure, really, really nice though in itsí own right.  This tube is also a keeper and will probably be my Ďevery dayí tube, itís that good and way better than the 60ís GZ34ís.  Prices vary if you can get one thats NOS...$200.00 and well worth it!  Shortly after I bought mine there were two like mine that came up on an auction and went for, I think, $135.00 - $150.00 each, those were a steal IMO.

However, before you spend your hard earned cash make sure that these have the sound characteristics that you want.  More on that after I put another 30 hours on the metal base.  Also donít buy the Metal Base thinking that it will turn a UFO-2 into a UFO-25.  As good as a UFO-2 is, and those are in a class of their own, thatís not going to happen.  Your money would be better spent on a good source or a ZR-2.  

Listening to the different GZ34ís has given me a new respect for the UFO-25 and an expanded or more objective understanding of NOS tubes in general.

Oh, I got to tell you this... I came across an add for a WE type 80 for a mere $10,000.00+!  No wonder people think that audiophiles are idiots.

Title: Re: Rectifier Tubes
Post by will on 06/29/19 at 01:07:28

Some interesting insights here that bring up thoughts for me about tube conversations.

As Joman points to, the rectifier does its sound thing based on how it effects the following tubes. Taken further, he also points to how the UFO2 and UFO25 will reveal tubes differently, which to me points to how everything before and after the rectifier, power, power supply design, connectors, cables, source, room, other signal path parts and tubes, etc....all effect the rectifier's effect. This variability alone could make a given really good rectifier great here, and not as great there.

No less influential on the sound of a rectifier, it takes a fairly worked out system/room to reveal tube qualities clearly and with relative accuracy, presenting a vaster labyrinth of variables in how "good" or "bad" a given tube can appear in different settings. Every single thing that makes up a system room, and how those parts, and components are tuned to balance, cumulatively effect what tube sounds better or worse in a given system/room.

Making it more complex, as Joman points to talking about different vintages and makes of types are not enough for serious tuning, but they can be a good pointer to certain characteristics. This is clearly not just rectifiers, but all tube type's have sonic characteristics that vary due to design, construction, parts, vintage, companies, and specific factories. †

That a rectifier can create a pretty profound change in a relatively revealing system/room remains true...but which is "best" or "worst" among good tubes will vary depending on how it fits into individual systems. Joman's experience with the National PCC88/7DJ8 going from not so good, to good with a rectifier change illustrates this. I have had similar experiences many times as my amps have refined, lately, about all decent tubes sounding great in the right company, but like Joman, still, I have my favorite combinations.

I think this points to part of how certain tubes rise to higher consensus, like Mullard GZ34s, especially late 50s metal bases. They are costly because they fit the systems and tastes of enough people that are willing to pay that much for a rectifier...Similar is Orange Crush's Brimar 5R4GY, another popular tube for that type. †

Yet we all find our preferred choices in tubes based on our system state of development and specific balancing needs in the moment of trying new tubes. And the particular progression that brought us to trying that particular tube, and how it works, is variable system to system...again, a given tube having characteristic qualities, but variability depending on setting.

As an example, I have yet to keep in the few late 50s/early sixties GZ34s I have (one Mullard with 5 notch plates and double O getters, one Holland Phillips, smooth plates, double D getters). I really like the tubes, dynamic, revealing, extended, great solid bass, pleasantly warm, textured, and complete sounding tubes....And they do sound pretty different, but both have Phillips-made GZ34 characteristics that are identifiable. Here, for all their beautiful qualities, without tuning carefully to them, they shift my balance a bit too much into slight heaviness, where GZ32 types, Type 80, 5Z4s (especially specific ones), Sophia 274Bs, and others fit more easily. This does not make the latter tubes better, just a better fit for me. Likewise, I have so far found early 60s Amperex 7308s compelling, but finally they have a bit too much "of a sound" in my setup....Very articulate and spacious in warm and musical ways, with great bass, really nice textures and space, mostly excellent balance....but.... I think it is the smooth top that goes too far into roll off for me, reduction in very fine detail making the midrange and top sound incomplete to me. I am pretty sure that more fine detail information would make me love the tube, but it isn't there. Yet, like good Euro GZ34s, the American Amperex is a very well liked tube by those who's systems and tastes they fit well in.

We could write this sort of thing off a lot to tastes, and there are no doubt cases where this is true. But I would suggest that many of us, given a chance to hear, say five really seriously refined Decware based system/rooms, we may well like/agree for the most part with these systems, though they would have developed differently to "get there." Even when we did not like some parts that make another system based upon how those components or parts fit in our own system development, we may well like how someone else made them work in their efforts toward beauty and balance.

Leading to my request. In the end we will likely choose different progressions of parts to make a system whole, each decision that sticks creating the foundation for how we choose to tune the system further. So at a given stage of development, one might use a tube to tune for a touch more warmth to reach balance, while another might be tuning for more transparency and neutrality to reach an ultimately similar balance. Opinions about these two tubes being "better" or "worse" in a given system, where their different emphasis could work very well for different balancing needs, could easily lead to conflicting information for others about how "good" the tubes are.

But, if the systems are revealing, describing the characteristics of a tube sound, and direct sonic comparisons, can be pretty telling for other's analysis in their pursuit of improving their own system. Regardless of system/room configuration, describing characteristics that cause us to prefer one tube over another can tell a story that can be more easily applied across quality systems requiring varying treatment. It can give a point of reference. Whereas, opinions without descriptors and comparators, can help at times, but may not be all that useful toward cost efficient ways to enhance a complex system/room with different focus or needs.

Even then, as all of us who have explored tubes have found...among really good tubes, what is great there, is not necessarily great here. But with†relatively complete information about the sound of a tube compared to others, hopefully we can make better approximations. Tubes are so fun!


Title: Re: Rectifier Tubes
Post by JOMAN on 06/29/19 at 12:21:04

Iím going to have to clarify a couple of things and hopefully can do so in a manner that is not going to be taken that I am disagreeing with certain things that Will stated because I am not.

Perhaps this will help... The GZ34 Metal Base was not my first choice.  I wanted to get a GEC U52.  I read the ďMassive Rectifier...Review/ComparisonĒ again because based on owning a couple of the tubes reviewed I felt that the comments were very accurate.

After reading some of the comments about the Metal Base I was put off a little, comments such as ďminty coolnessĒ and giving a tube based system some of the attributes of a SS system.  Yet when I HEARD the tube Those comments took an entirely new understanding. Also the liquidity of the Metal Base is pointed out as being one of itís a very strong suits.  After hearing it I would say that those comments, as strong as they are, still understate this attribute of the tube.

I decided to get the Metal base because of an important factor, one that is important to me that is common to all GZ34ís and most GZ32ís.  They will take cap value of up to 60uF.  I was not going to spend $400.00 plus to watch a brief fireworks display in a glass bottle.  I also wanted the longest lasting tube made.  The metal base is one such tube with a track record.  Those were a couple of factors that caused me to take the plunge

I agree that we use tubes and other components to tune a system and that what is great in one setting will not be in another.  This is one area that does not apply to the Metal Base, unless you have heard it you will not be able fully appreciate this, in fact this is something that really set me back on my heels when I did experience it.  It has a certain greatness that will be evident in any setting and I will go as far as saying unmatched.  However whether it will or will be to your likening is another matter so as great as this tube is in certain respects, it will not meet everyones tastes.  If only such a tube existed!

Another area in which the Metal Base goes against a given is that GZ34ís will have certain common attributes which will tend to give a certain common ĎGZ34í sound to varying degrees.  Trust me when I say this, that is not the case with Metal Base and in this regard the Metal Base is an exception to the rule.  The one that perhaps can be considered the closest is the 58 Mullard Fat Base Double O Getter.  Even then there is a chasm between the two when you actually hear them.

The point I wanted to bring out in this regard isnít about which one is better.  Rather, I have seen very high prices being asked for GZ34ís on the basis of similar construction and therefore being close to the Metal Base.  That simply is not the case and is very misleading.  That does not mean that the other GZ34ís are inferior or a bad tube, hardly!  They are just far more different from a Metal Base than what you would expect.  So if you do opt for one of the non Metal Base do so on the basis of what one of those is not on the basis of my comments of the Metal Base.

In many aspects the Metal Base is an exception to certain valid Ďrulesí on which we tend to tune or build a system.  I suspect that tubes such as the GEC U52, WE422A, Osram GZ37 also are exceptions.  We tend to generalize.  NOS takes on a certain generalized perception and this is played upon in statements regarding New Production tubes.  ďThis new tube is LIKE the NOSĒ.  Which NOS??? Theyíre not all in the same category or bracket.  Some may never be duplicated.

Does that mean that you canít build a great system using other tubes and components.  Hardly, you can.  Understanding how certain tubes are exceptional can help to build a great system. After hearing the Metal Base my perspective has been expanded in a manner that I could now take what I have learned first hand and apply it to tube rolling, resulting in less frustration and in the process actually being able save money.

Title: Re: Rectifier Tubes
Post by will on 07/01/19 at 19:55:42

Sounds like an amazing new level with the metal based Mullard Joman. That some of a given type and vintage rise above others seems a given, but it sounds like this one goes well beyond that in your setting. I trust your conclusion that it is a brilliant and exceptional tube.The opinion that this tube defies type characteristics is harder for me to grasp though. I can get it to some degree, but considering electronics, design, and materials of the time, and how these influence the other tubes and system sonics, as refined as the metal base is, it is hard for me to conceptualize that it will not do GZ34 things.

From post #26: "I agree that we use tubes and other components to tune a system and that what is great in one setting will not be in another. This is one area that does not apply to the Metal Base" ....and: "Another area in which the Metal Base goes against a given is that GZ34ís will have certain common attributes which will tend to give a certain common ĎGZ34í sound to varying degrees. †Trust me when I say this, that is not the case with Metal Base and in this regard the Metal Base is an exception to the rule."

If "in my system," were part of these thoughts, I would be able to grasp them better. And I can imagine a very refined tube of a type doing a lot to defy its type character, but these thoughts as absolutes are far enough from my experience, they are hard for me to easily get. Here, some tubes fit my setup more broadly than others, but I have yet to find a tube that I can feel overrules type characteristics and the need for tube set and system/room synergy for optimal sound. I have had tubes fit right off many times, and tubes that are exceptional for the type, but when they really sing in a system, I still think this is notably influenced by synergy with the rest of the tubes and system.†

Also, I have loved GZ34s for periods, using them mostly in a SE34 years ago. But generally, GZ34s in my Torii and CSP3, are a little (or a lot) too powerful for the way my system has evolved. ....why I used toned down GZ32s for so long. And I think this is due to inherent electronic/material/design attributes.

None-the-less, curiosity stimulated by your comments, I tried some non-Mullard/Philips GZ34s I have, a Zaerix labelled Hitachi, and a Sylvania fat bottle. In my Torii, both are clearer than the Philips GZ34s I have, often too clear in the past. But after lots of amp and system refinement that can transform the occasional hardness into musical fine detail complexity, they are good!

The Hitachi is punchier, bolder, and very nicely thickness. Seductive, but finally I found it too dynamic, not for my tastes, but for natural sound that is not hyped in this system/room. But unlike the Philips, with things as they are set up, it is clean and fast enough not to go into thickness, having a believable solid bass. It reminds me of KT77s. Every time I try KT77s I am seduced by their clear, spacious, dynamic character, and tight bass. But it does not take long for the more natural (in my system) ways of spaciousness, speed, dynamics and clarity of good 807s to come back into play. The Zaerix are impressive, but finally overstated for me in this setup, but they do solve some issues I had with Philips GZ34s, so make your thoughts on the metal bases easier to imagine.

The Sylvania is warmer than the Zaerix, with more spacious and textured mids, contributed to by being less dense/thick down low than my Philips. Also, it is mellower, less dramatically punchy. Even so, the GZ34 push does cause this tube to go a little into the warm heaviness in the lower mids and mid bass that I experience more of from the Philips tubes.

Trying them in the CSP3, they sound more spacious and neutral, closer to clearing the low mid bump, especially with a bit more gain from the ZBIT before it. At this stage of my CSP3 development, the Sylvania reveals beautifully complex and seductive spacial information if that makes sense. This combination also tightens the bass a bit over the same tube in the Torii. Still powering the signal a little heavily in my system, the sound is quite enticing, but its low mid, mid bass can be a bit dominant. Also lacking a bit in low articulation, many recordings have really nice bass, but those tending to heaviness still thicken and muddle the low end a bit much for me, contributing to the soundstage becoming a little confused. Its sound otherwise quite good, not bigtime overstated, it does help me better conceptualize the metal base transcending GZ34 values.

Still, the Sylvania was a little more powered up and dynamic in my CSP3 than I tend to like, but close enough, so I wanted to try and leave it in for a while to learn and get used to it, as it does do some very nice things...But listening last night with the lights off, with many variations on gain balancing, and a few tube changes, the Sylvania was very beautiful on many recordings, but on others, the push in the low end was enough to be a little too domineering and I pulled it. †

Tube sound so complex, at first this sort of thing is often the best analysis indicator for me. Rather than emphasis on hearing things I like, I find it easier to identify subtle issues in balance, space and complex detail, and if I can solve them, the tubeís good stuff tells its story better. And since I could not easily bring the Sylvania into ultimate beauty across a broad range of recordings without deeper, system changing efforts that would reduce flexibility, I pulled it. Putting back the milder, Philco Type 80 I had been using, I was relieved with its sounding very good across recordings, fitting more fluidly into the system balance that has evolved here. This is definitely influenced by my system having evolved with GZ32s, Type 80s and similar tubes, but I initially started using these tubes because I liked how they balanced my system better at the time...And this is not to say this would necessarily be the case in other systems, but what has worked in my particular system complex.

I wonderÖ.even if I just had your speakers, rather than my HR-1s, my system balance may have developed in ways that these GZ34 issues may be less of a thing for me. Who knows.

All that said, I am splitting hairs for the ultimate sound, as I am sure you are. And from this exploration, I can imagine if I stretch, how the metal base refinements could solve some issues my Philips GZ34s bring to my system, and those of the Sylvania also. It is all so interesting, and thanks for the stimulus to look into these tubes after so long!

Title: Re: Rectifier Tubes
Post by JOMAN on 07/02/19 at 03:15:19

Hey Will,

The Metal Base GZ34 is a bit of an enigma.  I think that Iím starting to figure out what makes it so much different from itís siblings and other rectifiers.  Perhaps others have figured this out but itís taken 25 hours of listening for me to be able to solve the riddle.  I want to give this another 15 - 25 hours before confirming what Iím going say...

The attributes that set the Metal Base GZ34 apart are: transparent decay along with unbelievable liquidity, not fluidity but liquidity.  Not splitting hairs here, itís the only way I can put it into words and I think that your HR-1ís are up to the task.

First the transparent decay: The decay is by far the best that I have heard, in addition the texture of each instrument and or voice remains throughout the decay, right from the high frequency to the lowest of the low frequencies.  This tends to give a completeness to the sound of a given instrument or voice.  The ring of a bell is not cut short, the reverberation of a drum is not cut short, itís complete to the end.

Add to this, what I consider to be the itís strongest attribute: LIQUIDITY!  And I mean liquid, liquid, liquid, liquid!!!  Add liquidity to the above attribute and you get a certain ďtemperingĒ so that nothing is etched, harsh or thin.  It is far easier now to identify the effects of the room and not mistake them for a shortfall in a tube.  My room was renovated with acoustic properties in mind, nevertheless I still have some work to do to tame the higher frequencies.  Regardless, I am able to listen at higher volume levels than before and at low volume level everything is far more discernible.

Last night my wife and I listened to the Moody Blues concert At The Greek.  The clapping and whistling was, well, real, and our ears should have been ringing listening at the volume that we had it at, yet no pain, no fatigue.

Now please do net think that Iím saying that this tube will eliminate the need to do some room treatment.  It just doesn't seem to excite the room the way the other tubes did.  If that makes any sense.

My wife said a few times ďI feel like Iím really thereĒ.  At one point she commented ďI really like the sound of that guitarĒ. Thatís a Strat dear.  ďI think you should get me oneĒ.  (Wonderful!)

The other GZ34ís do not have those qualities to the same degree.  The 58 Mullard Fat Base to a lesser degree and as I move to the GZ34ís that were made in the 60ís those attributes are significantly reduced.  It SEEMS that as production moved away from the Metal Base a good amount of the magic was lost.

Iím going to confirm and add to the above once I hit the 50 hour mark.  Having said all of the above, I am NOT suggesting that this is the tube that everyone will like.  But I do think that once it is heard the attributes that I refer to above will be readily evident.

I was so impressed with state of the tube when I got it and the initial results that I emailed the gent that I acquired the GZ34 Metal Base from to thank him.  He responded with the following...

Thanks for sharing! I'm thrilled that you're happy with your purchase. I agree with you, There is something magic about this rectifier. I've had my primary metal base GZ34 in my Supratek Syrah for close to 20 years now. There is just nothing better. And it's still going strong. I think it's going to outlast me! That's really why I decided to sell my spare. I honestly began to realize I probably wouldn't need it. Your tube will be the same way for you. And it'll only get better with break-in.

How in the world did they make the tube so that it can last as long as it does?  

Title: Re: Rectifier Tubes
Post by will on 07/03/19 at 01:12:15

Sounds like a truly great sound Joman! Funny, I have been playing with tubes in the CSP3, yesterday adding a "new" (1930's?) mesh plate AZ1 in the place of the Type 80, and I might have described improvements similarly. Not that it would sound the same, but it does good tube things. Coincidentally, I also got similar comments from my wife, out of the blue! This morning, playing Trio Medieval "Song of Songs" ....she said, "This is so beautiful. It always seems like they are in the room, but this is more real, easy, more like we are with the people rather than listening to them."

The things I notice (and seek) most with system refinements are when nothing sounds off, everything sounding more complete, discrete, fine detail and spacial information rich and fully integrated. Critical to me, space, fine detail, and decay are always primary reads. If these fragile aspects of presentation are there more fully, this always seems to indicate more complete retrieval of what is on the recording, leaving everything else a better chance of sounding right. I think it indicates reduced smearing, noise, distortion...stuff that fills the space becomes more complete, more spacious! I suspect, as much, when fine detail is more resolved and articulate, it leaves more space between the more refined edges of sounds.

Put together, a great final indicator of more resolution and space for me is the sound "slowing down." I often notice this with notable improvements in space.

Finally, better fine detail, in more open space, increases musical nuance, the magic of subtler things making the sound more real...breath, complex textures, longer trails, etc...captivating. This all seems to require a good spectral balance, without bass masking, or rolled off tops, but when all is "right," the music becomes visceral and transporting indeed.

It sounds like your new metal base supports all this beautifully! I hope it lasts as long as the guy's who sold you the tube!

I think I must have created the wrong impression in my posts on a few thoughts. I am not concerned about my HR-1s "being up to" the metal base. Especially with results from my modifications, they are very revealing, smooth, fast, and balanced. But I suspect they are somewhat slower, warmer and deeper than your speakers. So I was referring more to signature differences from speakers, components, tubes, rooms, etc, causing different system development pathways in order to reach similar ends, and this can make a system more or less of an easy fit for an exceptional GZ34.

Related, based on your impressions, I seriously believe I would "like" the metal base, but no matter how amazing it is, electronically, I still question whether it would work in my setting without a fair bit of work to make it fit... But I have nice rectifiers and other tubes that do fit easily here, so all good!


Title: Re: Rectifier Tubes
Post by bikehappy1 on 07/06/19 at 02:28:44

Sorry to change rectifier directions a bit but how long should my stock Torii rectifiers last? My amp is two years old now and I listen almost every night. It seems to be lacking a little punch.

Title: Re: Rectifier Tubes
Post by Rivieraranch on 07/06/19 at 02:47:41

I would check my power tubes first.  

Title: Re: Rectifier Tubes
Post by bikehappy1 on 07/06/19 at 03:32:35

Thatís interesting because another tube guy said my VR tubes would go before my power tubes. Iím running TAD KT66 that are about a year old. I put my stock 6N11 input tubes back in that are about a year old.

Title: Re: Rectifier Tubes
Post by will on 07/06/19 at 08:47:27

I have quite a few tubes and love to change them to shake up my musical experience, so am not an authority on longevity. But in the last several years, working on my amps, I have tried to keep the same tubes in as much as possible keeping a foundational reference. So I have some experiential reference.

I think it is probably better to think of average quality tube life in hours rather than years. If you play 1 hour a day it is way different than 5 hours... Last few years, when home, I seem to average more...guessing 7-9 a lot of days.

I have never had a VR fail and I think the ones I am using now have been in the amp 4 or 5 years. Conservatively lets say 320 days a year x 7 hours = 2240 hours a year, x 4 years = roughly 9000 hours without sign of trouble.

The last rectifiers in my Torii, I guess I used for 5,000 hours or so. Made in the late thirties, and testing NOS levels when I bought them, they showed some ware, so I am not sure how used they were. But they started getting a little more noisy recently, so I changed them. I didn't notice a sound change otherwise. Other than a few screw ups on my part, the times I have had rectifiers fail, they seem fine sound-wise, but shorted out at startup, blowing the fuse. And these seemed to be premature failures...not much use on the tubes, so guessing construction weaknesses.

Pointing to tubes being pretty variable, seems to depend on a lot of things, construction quality, parts, transportation safety, use history, how the electronics of the amp effects them... If your amp runs lower than the ratings of the tube, all else good, it will probably last a really long time. Whereas, if we run them hot, they wear out faster. Also, weaknesses that may not show initially can develop with heating and cooling, and with use, so it can be a little of a crap shoot. Good testing NOS tubes generally had pretty tight standards, and important functions a lot of times, many military, so they tended to be well made. But not definitely long lived depending on initial qualities and how a tube was handled and/or used.

As to tube specs, I don't know the intricacies of how the input voltage and current, and output voltage and current of a rectifier effect tube compatibility and lifespan in combination with the construction and design work together with spec tolerances in terms of longevity. But weaknesses in any of these obviously can effect longevity. As Joman suggested, limitations can be the "reservoir" cap tolerances. On the other hand, some tubes substantially underrated for our 47 uF power supply cap values can work fine. This makes me think potential issues based on reservoir cap ratings must be influenced by other things for better or worse.

For example, I, and others have used 5R4GYs extensively with Decware without issues, and as best as I have found, they have a max cap value of 4 uF! That is close to 1/12 the value of the 47 uF stock power caps in my Torii.

Also used a lot with Decware, and listed on some amp pages by Steve, the type 80 and 5Y3 family are rated at 32 uF, well under 47 uF. I have not use 5Y3s a lot, but had no problems with them when I did. And, if memory serves, on this forum they were a popular tube for many years, particularly in the CSP. Maybe it is a good one, but the Type 80 I have had in, I used for a few years with relatively high daily use, and without signs of flashing or failure.

So though reservoir cap ratings can be important, they must at times be effected by other things, in some cases making the rating less relevant. I hope someone who has a better handle on how it all works together will fill this in.

I agree with RRs suggestion about looking at power tubes as a cause of losing some punch. Seems losing power, clarity, and finally going into distortion are signs of power tubes going. The ones I have in now, likely have 2000 or more hours, and still sound good to me. But longevity seems pretty variable with the power tubes I have used, especially with some of the newly made ones. These are true NOS 807s, and have lasted pretty well I think.

It has been a while, but my recollection is that input tubes seem to get noisy, sometimes intermittantly, and then start distorting, sometimes getting a little crackly or "whooshy" with warmup. Quality input tubes are supposed to last a while. I would guess the early sixties Holland Philips ECC189s I recently replaced had over 6,000 on them, and still sound good, but I wanted a change.

I love it that tubes are so "alive" and "characterful," but it makes these matters of longevity a little vague for me.

Title: Re: Rectifier Tubes
Post by bikehappy1 on 07/06/19 at 19:25:10

Thanks Will and RR. Iím guessing that I have about 2000 hours on my amp but only 100 hours since the 25 upgrade + new caps. I also try and remember that some recordings are just not very good.

Title: Re: Rectifier Tubes
Post by JOMAN on 07/07/19 at 12:52:06

A recent catastrophic rectifier failure caused me to re-evaluate how I was choosing the tubes that I would roll.  Based on my objectives I established guidelines that I would use when choosing tubes.  Interestingly the failure(s) that caused the re-evaluation met the following statement in the CSP-3 Manual:

The CSP3 uses a 47uf 500V capacitor in the first section of its power supply, so many 1940s rectifiers and remakes are not compatible since they want to see less than 10uf 500V capacitors. When buying fancy rectifier tubes always be sure they will be compatible with 47uf 500V capacitors.

So I did some research and came to certain conclusions...

First: the catastrophic failures were strictly due to extremely poor manufacturing processes.  In such cases not every tube produced will fail, but an unacceptably high percentage of the manufacturing output will.

The resulting guideline for me:  Stick with producers or suppliers that have high standards of production resulting in very low percentage of failure.

Next:  How will not following the recommendation stated in the manual effect longevity and performance?  More research, even considering such things as the effect of mixing directly heated tubes with indirectly heated ones.

To sum it up the conclusion that I came to was that while not following the manufacturers guidelines may not result in immediate failure it WILL, not may, but WILL effect not only tube longevity but also associated component longevity and performance.  

Now, some of us will go to significant lengths to ensure a clean and stable power supply, grounding rods, dedicated lines, specific circuit breakers, not so inexpensive power regenerators and power conditioners.  The rectifier is a part of that chain.  Taking that into consideration my conclusion and guideline is:

Follow the manufacturers recommendations when choosing tubes.   However those are only the guidelines that I have established for myself.  

Title: Re: Rectifier Tubes
Post by mark58 on 07/07/19 at 13:48:47

So for a non techy like me, what rectifier tubes are compatible with 47uf 500V capacitors.  Is this the same in all the Decware Amps too or just the about the ZP3?  Mark.

Title: Re: Rectifier Tubes
Post by JOMAN on 07/07/19 at 14:21:41

What I do before I purchase a tube now is simply google the specific tube and data; ďGZ34 tube data sheetĒ etc.  Iíve actually come across some interesting information on the development of a particular tube over a period of time.  Usually you can find the information that you need, sometimes with a bit of effort.

As far as the other Decware components the information should be in the instruction manual.  And the guidelines that I refer to are only ones that I have elected to establish for myself.

Title: Re: Rectifier Tubes
Post by Archie on 07/07/19 at 17:37:22

Mark, I was asking the same thing in a different thread: †

There might be some helpful information there.

Title: Re: Rectifier Tubes
Post by will on 07/07/19 at 18:46:17

I search like Joman suggests, "google" the tube type name and the words tube, and data or specs. Interesting references can come up, and some not so useful to me, but usually interesting. I particularly like the Valve Museum site if it comes up for the tubes I am searching. It is easy to read the tube pages with nice layout and being in English. They also have lots of information in general about tubes. Like these pages:

Other nice references, the radio museum pages, and the frank.pocnet data sheets cover loads of tubes, well worth looking, though some pages are harder for me, being in languages I don't understand.

Check this page out:

If you look at the index across the top, wanting 5 type tubes, I clicked "5." Then just below the number/letter index across the top, you see choice refinements, where I clicked 5UP in order to get to tis link with 5Y3s, 5V4s, 5Z4s....

Amazing collections of information!

Title: Re: Rectifier Tubes
Post by Archie on 07/07/19 at 20:58:40

what rectifier tubes are compatible with 47uf 500V capacitors

Can someone point out where this information is obtained?

Title: Re: Rectifier Tubes
Post by JOMAN on 07/07/19 at 22:46:01

Hereís an example of what came up after I googled GZ32:

This gives some history for the GZ32 as well as a data sheet.   Unfortunately not all the information shown here always is shown for every tube that you will try to find a data sheet for and add to that the information is really for electronic engineers/designers and so not always easy to follow unless you are one, but not impossible.  So you may have to check two or three sites to get the info you need.  At least this way you can make an informed decision and if your spending a good amount of cash, protect your investment by minimizing the risk.

Recently Will got my curiosity going on the AZ1 Mesh Plate.  So
I tried to find a data sheet and after checking two or three sites I found that the TFís are compatible in fact they can take a first cap value of up to 60uF 500V.  (Damn!)

Title: Re: Rectifier Tubes
Post by Archie on 07/07/19 at 23:02:52

I see the data sheet but not being an electrical engineer (probably need to be an OLD school EE!) I can't interpret it. † :-[

Title: Re: Rectifier Tubes
Post by will on 07/07/19 at 23:08:04

OOPs sorry, answering Archie's question at the same time.

Joman, You will see a funny part on the AZ1 spec...not 5 V but 4 for the heater! I got adapters that are supposed to have a resistor to take the voltage down, but with language barriers, I am not sure of this. Funny we both responded with a GZ32 and some of teh same info.


The pages often have the max "reservoir" or "filter" cap value listed and often not. If not, I cross reference to another page or site. If your amp filter caps are 47 uF, and you want to adhere to this spec, you would need a rectifier that has a max reservoir cap tolerance of 47 uF or greater.

If you search google for say, a GZ32 and go to one of the sites I mentioned, you will see the specs on the page.

This is one for a GZ32:

In the middle of the page you will see a max reservoir cap of 60 uF, and near the bottom, voltage and current info: 5 Vh, 2.3 Ah, 500 Va and 125 mAa. In these figures the h stands for heater, or the tube filament. The a stands for anode, or the plate. So this tube has a max reservoir cap tolerance of 60 uF and 500V plate voltage.

If you look at this 5Y3GT page: you will see that if you have been using them, by these standards they should not have been working or lasting, the 32 uF max reservoir cap tolerance well below 47 uF, and the plate voltage 350V, well under 500V.

Or here: the type 80, same reservoir and plate voltage specs as the 5Y3GT, also not fitting these standards.

Got me, I have been happily using a type 80 in my CSP3 for a few years with high hours daily.

Title: Re: Rectifier Tubes
Post by Archie on 07/07/19 at 23:31:45

Thanks Will, very helpful.  Funny though, the CSP3 page specifically recommends the 5Y3GT but the specs don't measure up.  Also, while not a listed tube, I and many others have been running the Type 80s with good results.  Are these tubes just tougher than their specs?

Title: Re: Rectifier Tubes
Post by JOMAN on 07/07/19 at 23:48:57

Thereís another factor that might explain to some degree why we can get away with using tubes that do not meet 47uF 500V.  

The quality of a tube and how rugged it is.  

One of the reasons that for quite a while Iíve been using AWV made tubes/rectifiers that do not meet the recommendations is that they are built like the proverbial brick outhouse.  Based on my understanding of metallurgy, and in this I do have some background, I felt that tubes of this type could withstand the stresses of the on - off cycle far better than ones that are not as rugged.  The shorter that cycle is the more often the tube is subject to the stresses.  The longer the cycle is, that is the tube is on longer, the tube is not subject to those stress as often.  So IMO, while the tube may not fail immediately the life span will be shortened.  Your guess is as good as mine.  I could use a variac to power up or leave the component on 24/7, but thatís not an option for me.

So if Iím going to spend what to me are major $$$$, Iím going to follow the recommendation of the manufacturer.

Many NOS tubes were built with standards of production that I wish were still used today.  So now when I buy new production tubes - $40.00 - $50.00 is the max., as I do not believe that they are made as well as the NOS were - IMO.

Title: Re: Rectifier Tubes
Post by Archie on 07/07/19 at 23:52:17

And voltages might not be that high in practice.

Title: Re: Rectifier Tubes
Post by will on 07/08/19 at 01:06:03

From Joman: "So if Iím going to spend what to me are major $$$$, Iím going to follow the recommendation of the manufacturer."

Makes sense to me, though as we know, reputation and specs have anomalous outcomes at times. Always a risk, I generally just don't spend big bucks on tubes. If I can buy a nice pair of NOS tubes I really like for say $60-100 give or take, that gives a fair bit of leeway for longevity compared to the cost of one pair of metal base GZ34 (or similar rare and popular tubes) at many times the cost.

After hearing so much about them from you and others, when I bought a pair of Sophia 274Bs with roughly 300-350 hours on them for $210, even at this "value" for these tubes I felt squeamish. But I figured I could sell them if needed. I like the sound of the tube just fine, interesting character...but not more than others I have that are much less cost with careful shopping. And though its specs fit 47uF filter caps, its construction and weight seems light to me, perhaps part of why yours did not last as well as you would have liked.

The cool thing for me, after working so long and carefully to tune up my amps, all the tubes I used to like, I like much more, and many I did not listen to, I love now. I think optimizing amp internals has done much more than tube balancing and refinement ever did for me, and tube rolling has been a powerful tuning tool for me. So I always really enjoyed tube rolling, but†is a total joy with easy success and my tube "collection" has much broader and greater value to me.

Title: Re: Rectifier Tubes
Post by JOMAN on 07/08/19 at 01:29:37

The other thing to note is that the caution in the manual refers to 40ís rectifiers that want to see less than 10uF 500V.  As pointed out 5Y3ís, 5U4G and 5AR4 are shown as alternatives.

5Y3ís are I believe 32uF and 5ARís are 60uF.  Thatís a spread of about 30% either way.  To me that was an indicator of donít go to large or too small a cap value as both will have a negative effect, but there is some tolerance either way.  Again that was my conclusion.  

When I did look at the data sheets of NOS tubes I found more rectifiers in the well below 32uF cap value, some VERY EXPENSIVE ones to boot.  Got to admit that put a scare into me.  

In all this I would say if your not sure, email Steve.

Title: Re: Rectifier Tubes
Post by Lon on 07/08/19 at 04:47:52

I count myself lucky that my Aqua 274Bs are considerably more to my liking than other types and have been truly reliable for me. I'm going to continue using them as my rectifiers and tuning around them.

Title: Re: Rectifier Tubes
Post by will on 07/08/19 at 16:41:37

Good to hear Lon.

Title: Re: Rectifier Tubes
Post by JOMAN on 07/12/19 at 04:41:20

Itís time for a follow up on the Philips Miniwatt Metal Base GZ34.  It is now THE permanent rectifier for my UFO-25.  Before I get into some of the specifics, a bit about the tube set in the UFO-25 and the cabling.

UFO-25 Tube set
The rear VR Tubes: Raytheon (CEI Labeled) OA3 GT Bottle
Front VR Tube:       Sylavania OD3W
Output Tubes:        6P15-EV (Decware Supplied)
Input Tube:            Telefunken PCC189

The cables are all Decware except the Coax which is a Snake River Audio, Boomslang:

ZSTYX Speaker cables (connectors Furutech Gold), DSR Silver Reference w/standard connectors, DHC1 Power cables with a mix of Furutech and Neotech Connectors.  I have had these cables for some time so that I would have a base line to work with when tube rolling.

The amp was fast, dynamic and transparent from the outset but the Metal Base GZ34 has really shown what this amp is capable of.  

The outstanding attributes of the Metal Base are Speed,Transparency, Resolution, Decay, and LIQUIDITY.  A review of this tube refers to it as ďminty coolĒ and it also states that it can make bring solid state qualities to a tube system.  I would agree with ďMinty CoolĒ but donít take that to mean that it is somewhat cold sounding.  It is not!  While it isnít Ďwarmí sounding it is utterly EUPHONIC!  Perhaps even more so than some Ďwarmí tubes.

If you are familiar with the ARC sound of the late 70ís, 80ís and early 90ís, when Bill Johnson was the designer, when components such as the Classic 30, VT50, LS5, and the SP series of amps and pre amps prior to the change to the 6H30 tubes, were competing with CJ and McIntosh, thatís the type of sound that I relate to as cool and euphonic, and certainly not solid state like in any way.

That statement was made in the review to try to explain the type of bass that this tube produces, which is another of itís very strong attributes, in fact the best of any other rectifier that I have had.  Punchy, detailed but nothing that would make me relate to the bass of SS gear, at least not in the UFO-25!

The sound stage is also interesting in that itís really not so focused on imaging.  It is expansive and deep depending on the recording.  If the recording is of a live event and well miked you will feel that you are in the audience, I mean REALLY there.  The acoustic qualities of the venue will be very evident because of the incredible layering.  If the recording is of a Jazz Trio, they will be IN YOUR ROOM with you.  It just seems so REAL.  The only other time I felt this to this degree was when I first auditioned an ARC/LP12/Magnapan Tympani system.  That feeling of REAL is what started me down this path and stayed with me all these years.

The other attribute that I found surprising is itís transparency when it comes to the signal that is being fed from other tubes and components. In my CSP-3 the output tubes are Siemens E88CC Grey Plates which sounded far more refined when feeding the Metal Base GZ34.  I wanted to check myself on this so I rolled 6N5Pís.  The sound was Ďwarmerí but with added emphasis on texture, with out any frequency being rolled off.  I related it to the CJ sound, which was the runner up to ARC for me.  Far better than the last time I had these in the CSP-3.  I feel that the Metal Base GZ34 allows all the attributes associated components to come through, at least more so than any other rectifier I have had.

In summary I would say that the Philips Miniwatt is a rectifier with some very special qualities and it is quite unique.  However donít take this to mean that this should be the tube of choice for everyone.  There isnít one tube for all just as there isnít one speaker for all.  Budgets and tastes vary.  This  has been my experience and perhaps thereís something in all this that will be of benefit.

Title: Re: Rectifier Tubes
Post by JOMAN on 08/13/19 at 20:57:39

Well, here I go again...

The GZ34 Metal Base in my UFO25 has impressed tremendously, so much so that I just have to try one in the CSP3.  So another is on the way.  This one is a 1956 vintage but otherwise the same as the one in the UFO25.

Iíve been trying to resist getting another because up till now I have not liked the results of using the same rectifier in both the CSP3 and the Amp.  But I have a hunch about the GZ34 Metal Base that I have to explore.

My fall back is the stubby fat bottle Valvo GZ32 made in France in the CSP3.  In fact this combo is so good that I had to wonder why I would need to explore any further.  I guess itís not about it being a need.

Regardless of the outcome, I will predict that after this my tube rolling will be over.

Title: Re: Rectifier Tubes
Post by JOMAN on 09/02/19 at 21:09:44

The second Philips Miniwatt GZ34 Metal Base has arrived and has been in my CSP3 for the past hour.  I was reluctant to get another as up till now I have yet to be satisfied with the results of the same rectifier in both my amp and pre amp.  But I had a gut feel about the GZ34 Metal Base after experiencing what it is all about.  And...  the tube rolling has stopped!

To detail what it does would take a very long time so to be as brief and to the point as I can I will say that it hits ALL the attributes that we can talk about and nails them like no other rectifier that I have tried, ALL OF THEM NO EXAGERATION!  Like the UFO25 it is in a league of its own.

The whole room has become the stage with detail and layers that I did not expect to be achievable.  Everything is so real, so liquid, the best way to describe the results.  As for the bass... solid with impact and tuneful resolution... I had to back off the ZR2.  

Itís a real shame that the prices of this tube continue to increase as this will be a limiting factor and many music lovers will miss the experience.

Title: Re: Rectifier Tubes
Post by pursuitofnow on 09/02/19 at 21:22:36

Based on the feedback I will have to try some of the metal base ones in my monoblocks. You weren't kidding on the rising prices...  ;D

Title: Re: Rectifier Tubes
Post by JOMAN on 09/02/19 at 21:49:06

I would hold off a bit.  I got my first one, a NOS New in Box for $370.00 USD (which I consider to be a deal), and the second for $320.00 USD.  The second is probably used although hard to tell by a visual inspection and by listening, it was a good buy.

Recently there was a NOS new in box Amprex BB branded Metal Base that went for around the $400.00 mark.  I suspect there will be more at a more reasonable price.  

I just finished listening to Santana... I was 18 again.

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