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Rectifier Tubes (Read 7492 times)
will
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Re: Rectifier Tubes
Reply #50 - 07/08/19 at 16:41:37
 
Good to hear Lon.
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All Modified: Balanced Transformer-DIY Strip/Shunyata Defender-RevolutionMacMini/Amarra-KTE Singxer/Gustardx20pro-ZBIT-CSP3-OldChen 300B/845, Torii IV, Simple Wave 300B-HR1/SVS Micro3000sub-Pi PCs-DIY PCs, ICs, USB, I2S, Speaker-SR and aluminum w ball bearing feet
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JOMAN
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Re: Rectifier Tubes
Reply #51 - 07/12/19 at 04:41:20
 
It’s 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 “minty cool” and it also states that it can make bring solid state qualities to a tube system.  I would agree with “Minty Cool” but don’t take that to mean that it is somewhat cold sounding.  It is not!  While it isn’t ‘warm’ sounding it is utterly EUPHONIC!  Perhaps even more so than some ‘warm’ tubes.

If you are familiar with the ARC sound of the late 70’s, 80’s and early 90’s, 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, that’s 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 it’s 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 it’s 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 it’s 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 6N5P’s.  The sound was ‘warmer’ 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 don’t take this to mean that this should be the tube of choice for everyone.  There isn’t one tube for all just as there isn’t one speaker for all.  Budgets and tastes vary.  This  has been my experience and perhaps there’s something in all this that will be of benefit.
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JOMAN
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Re: Rectifier Tubes
Reply #52 - 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.

I’ve 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 it’s not about it being a need.

Regardless of the outcome, I will predict that after this my tube rolling will be over.
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JOMAN
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Re: Rectifier Tubes
Reply #53 - 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, ...is the best way to describe the results.  As for the bass... solid with impact and tuneful resolution... I had to back off the ZR2.  

It’s 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.
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pursuitofnow
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Re: Rectifier Tubes
Reply #54 - 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... https://www.ebay.com/itm/gz34-tube-5ar4-mullard-nos-nib-valve-metal-base-5u4g-6s...  ;D
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JOMAN
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Re: Rectifier Tubes
Reply #55 - 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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Showme
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Re: Rectifier Tubes
Reply #56 - 03/01/20 at 23:26:14
 
OK, I‘ve got a Mullard GZ34 metal base arriving Monday. Should I stick it in the Zen 25th which currently has a Sophia 274B or in the  CSP325 which has a fat base Mullard GZ34 at the moment? All great tubes. I’ve been  using the Sophia for a longtime, first in my Select and now the Anniv addition. I don’t know what would give me the most bang for the buck
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pursuitofnow
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Re: Rectifier Tubes
Reply #57 - 03/02/20 at 03:28:56
 
I'd try it in the Zen 25th first and then swap with the CSP325 w/fat base and compare between the two in amp and preamp. I'm betting either way is going to sound fantastic.
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VPI Classic Signature | Koetsu Urushi Black | Bob's Sky 20 | ZP3 | Swiss Digital Fuse Box
DirectStream DAC (APS nickel transformers, Vocm mod)
ZTPRE | ZBIT | ZROCK2 | SE84UFO3
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Showme
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Re: Rectifier Tubes
Reply #58 - 03/02/20 at 03:48:11
 
Do I just kick the Sophia to the curb? I guess it could go in the Select.
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JOMAN
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Re: Rectifier Tubes
Reply #59 - 03/03/20 at 21:58:02
 
I would try it in the 25th first and try both alternatively in the ZEN, the Sophia and then the Mullard Fat base.

I had the metal base in the 25th and then I tried the Fat Base Smooth Plate in my CSP3 switching it out for a French made Valvo GZ32.  I preferred the Metal base in the 25th and the GZ32 in the CSP3.  I sold off the GZ34 Smooth Plate and got a second Metal base which is in the CSP3 replacing the GZ32.

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Showme
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Re: Rectifier Tubes
Reply #60 - 03/04/20 at 19:06:48
 
I'm sure you/re right. I'll just roll them around until I hear what sounds best to me. I have a Mullard GZ/32 I can throw in the mix too.
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safebelayer
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Re: Rectifier Tubes
Reply #61 - 05/12/20 at 17:03:00
 
Great thread on rectifier tubes; obviously, the emphasis on the gz32 & 34 tubes. Given the variance in tubes, even among the same mfr and tube type, I have a request...I've made this before as Will can attest.

Is there any possibility of providing pics of the preferred tubes in the GZ32 & GZ34 types?

Thank  you
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JOMAN
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Re: Rectifier Tubes
Reply #62 - 05/14/20 at 18:18:19
 
I’m going to try to attach the photos but I may have to do this in successive posts:

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6BBBA882-80D4-4843-B347-5A26A0CFBD54.jpeg
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JOMAN
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Re: Rectifier Tubes
Reply #63 - 05/14/20 at 18:20:12
 
Here’s another:

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7B6ACF2A-8D28-487D-B9A2-CFEAB28F0327.jpeg
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JOMAN
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Re: Rectifier Tubes
Reply #64 - 05/14/20 at 18:21:15
 
And one more, one with the notched plates:

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CA6172E8-E16B-4B41-AC1F-92A3BED22204.jpeg
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JOMAN
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Re: Rectifier Tubes
Reply #65 - 05/14/20 at 18:32:07
 
Ok, so the first is of the metal base which, although it may share some characteristics with the  1958 smooth plate fat base, is in a completely different league.  I know that may be hard to believe but it is the case in fact I have tried a number of GZ34 and these have unique attributes that set them apart from all the other GZ34’s.  Whether they would be to one’s liking is another matter.

The second, 1958 smooth plate fat base is very very good but doesn’t have the same liquidity, finesse, and wonderful decay of the metal base.  If I hadn’t have heard the metal base this would have been a keeper. These are quite often branded with names of component manufacturers.  Mine was Eico if memory serves.

The others aren’t even close.
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safebelayer
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Re: Rectifier Tubes
Reply #66 - 05/14/20 at 19:16:36
 
Thank you for the photos. Metal base tubes are ridiculously expensive now. Nice to see the gems that helped grow your system and listening experience.
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JOMAN
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Re: Rectifier Tubes
Reply #67 - 05/14/20 at 22:18:02
 
Agreed, the metal base are getting crazy expensive.  Sometimes you can get a “reasonable” deal.  The 1958 Mullard Smooth Plates (2nd picture) are also very good and have a character that was lost by later production GZ34’s like the one in the 3rd picture with notched plates or those with a smaller diameter base that have smooth plates.  I have a couple of the small(er) diameter base smooth plates and these are not to my liking and no way close to the first two.
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piezoman
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Re: Rectifier Tubes
Reply #68 - 05/20/20 at 18:30:48
 
John is indeed right. The metal base is profusely expensive, the average asking price on ebay is about $350-$500 each. There's an Italian nutball out there who is so far out of the ballpark its far beyond insane, he's asking 2-3 times that amount!

In my case, I lucked out on the 1955 welded plate Philips Miniwatt metal base GZ34.....$285 each from one seller, I bought both that were available. According to the seller, pulled from a piece of industrial equipment after sitting for several decades. They tested very well, the lettering is mostly wiped.

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piezoman
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Re: Rectifier Tubes
Reply #69 - 05/20/20 at 19:01:16
 
And the Mullard GZ34 fat base averages $200-300.

Very high.

And the great tubes that matter are only going to get higher.
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busterfree
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Re: Rectifier Tubes
Reply #70 - 05/21/20 at 00:24:57
 
Psvane HiFi series 5U4G - I think this is the version that shipped with my SE84UFO25. I like it better than the Sophia Electric 274 Aqua. I would like to hear a metal base GZ34, but I trouble accepting the price of entry (less so when the seller’s credentials are not certain).
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will
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Re: Rectifier Tubes
Reply #71 - 05/21/20 at 02:26:17
 
Hello Busterfree,

Can you tell us what is it about the Psvane 5U4G that you prefer, and why you like the Sophia 274B less?

Thanks,

Will
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JOMAN
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Re: Rectifier Tubes
Reply #72 - 05/21/20 at 17:12:34
 
Here’s what i consider to be a deal:
https://www.ebay.ca/itm/MULLARD-GZ34-RARE-EARLY-f31-TYPE-1959-OLD-STOCK-BOXED-TE...

This is not a metal base but the also very rare, very good and hard to find Mullard GZ34 F31, Fat Base, SMOOTH Plates.  Forget about the notched plate versions or the skinny base smooth plates.

This is the one that peaked my curiosity about the metal base and had I not got the metal base it would still be in my amp.  At this price if you didn’t like it you could re sell it.  

Just an FYI for anyone that may be... curious.
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safebelayer
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Re: Rectifier Tubes
Reply #73 - 05/21/20 at 19:03:33
 
That could be a really good deal. My personal practice is to buy from eBay seller with a 100% rating or with one I've done business with prior to a lower rating. This individual has a 98.6% rating. Be careful.
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piezoman
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Re: Rectifier Tubes
Reply #74 - 05/22/20 at 00:13:20
 
Not a problem with me. I purchased from that seller recently with no issues. I just now snatched that fat base up for $155. The seller was aski g for $195.

As John says, forget the notched plates.....per my reseach, they only get spiral downward at 1960 and  onward become worse.
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busterfree
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Re: Rectifier Tubes
Reply #75 - 05/23/20 at 14:53:25
 
Quote:
Hello Busterfree,

Can you tell us what is it about the Psvane 5U4G that you prefer, and why you like the Sophia 274B less?

Thanks,

Will


In a well treated room with a good recording and all else equal, the bass is better. What is better? I feel it more, more texture, more real. I want play things louder and jam. I have to hold back. It is more of a felling than based on facts. I can recreate at different listening sessions.
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will
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Re: Rectifier Tubes
Reply #76 - 05/23/20 at 16:49:54
 
Nice. Thanks.
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Chester
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Re: Rectifier Tubes
Reply #77 - 09/25/20 at 23:03:51
 
Hi there,

Has anyone had any experience with a RK60 rectifier?  Specifically, I was curious about what adapter to use.  I have seen a few adapters online (with wires and caps coming out of them), but don't know if they are of good quality and would hate to damage my beloved Torii Jr.  Any info would be greatly appreciated.  Thanks.

- Chester
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CAJames
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Re: Rectifier Tubes
Reply #78 - 09/26/20 at 18:10:47
 
I haven't used one but you should be able to use a 596 adapter as long as the external connectors are the same size.
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Chester
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Re: Rectifier Tubes
Reply #79 - 10/23/20 at 02:17:49
 
Hi Everyone,

I just noticed something out of the ordinary (for me) and wondered if anyone else came across this.  I have been rectifier rolling in my Torii Jr. and noticed that for some rectifiers, I can't get the bias to 825 mA even with the bias set all the way clockwise.  Both an RK60 and another 5U4 only go up to 774 mA.  Does this mean my EL34 tubes are going bad?  Does it have to be close to 825 mA to sound good or can it just be over 600 mA?

Also (maybe unrelated) is when I put the original 5U4 that came with the amp, I could bias to 825 mA, but the top of one side of the rectifier was much brighter than the other.

Any thoughts/guidance would be appreciated.

Thanks.
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