I thought it might be interesting to start a thread sharing little insights, tips, realities we have learned and encountered in using our tubed components.

I'll start out with this observation: I've learned it is beneficial to change output tubes earlier than I would suspect. Steve has given good advice about this by recommending substituting a new set of output tubes and comparing the sound.

I use my amps a LOT and with low wattage push them hard and I used to think after a year or so I may need to change tubes. Well, doing a comparison after about 9 months I realize that the upper midrange and higher frequency output of the output tubes suffers and the tubes need replacement. Accustomed to the sound and tweaking around it I don't necessarily feel the tubes would need replacement, but the direct comparison shows without a doubt a fresh set of tubes brings decided improvement, especially in clarity and dynamics.

So my advice: check the output tubes status periodically, especially earlier than you would normally expect to, if you want the very best fidelity.

My experience is that rectifiers last longer than any other tubes in the chain. I have Mullard 5AR4s that were used for 1,000 hours before I got them, used another 1,000 hrs by me, and still test NOS and sound great. Same for my 5U4s. I don't have as much experience with the 274b, but the one I have has unknown hours and tests and sounds great.

I've seen people claim 10,000 hours+ for rectifiers, and I tend to believe them.

What are some real pretty rectifier tubes that sound great , work well in Decware amps, and are relatively inexpensive?

Lon and all,
This is turning into a great reference post, nice job...
I just got my KT66’s back with a new matchup and a full set of originals of everything to have for backup. Almost ready to maybe take the “Sofia” plunge
Best,
Scott

From Tommy: What are some real pretty rectifier tubes that sound great , work well in Decware amps, and are relatively inexpensive?

EDIT: Sorry, I tripped up, calling a 5V4GA a 5Z4GA, close, but different...corrected below.

I think a "good sounding" rectifier is pretty relative depending on system synergy and where you want your sound to go. There are so many variations in design, vintage and sound. So choosing one that goes in the sonic direction you want, in comparison to what you are using, could make or break how much you like it. For a 5U4G setup, like the CSP3, Zen, Rachel, and big Toriis, there are a lot of choices in 5U4Gs, and many more that are compatible.

If you are using a stock Ruby, or Valve Art, these are two different variations of that 5U4G-ST theme. If you like these, not a lot of change visually, but generally with more refined sound, are earlier RCA 5U4G-ST. I find the older ones tend to be more refined, but they can be nice into the 60s in their own ways. As far as those I have go, those with the big/thick black plates tend to sound bigger darker/warmer, and those with the slightly less massive plates tend to sound a little cleaner and less balanced toward bass. The lighter plates with top getters were my preference, to me more open, balanced and revealing of nuance.

From them, if you want to tighten/clean things up, and increase dynamics with spaciousness and fine detail, I agree with Joman, that the GZ32 type or Type 80 could be a good path. Most Euro made GZ32s are nice tubes, but tend to be costly. Other than the Russian GZ32/5AQ4 Joman posted, I prefer the balance of England/Holland made GZ32s, but you have to be diligent to find good ones relatively inexpensively, and those Russians are quite nice tubes...just not quite as refined to me. Worth a try if the type is appealing to your needs though.

5V4Gs are sort of American GZ32 "equivalents," different, but also dynamic, open and articulate, they tend to be in the neighborhood. Especially old fat bottle 5V4GAs can be pretty nice, while looking interesting too, and relatively inexpensive. Especially the ones with rectangle getters might be worth searching Ebay a bit. They tend to be quite clean, open and detailed, the older square getter ones I have going deeper and warmer while remaining dynamic and clear...Depending on what they are with, some of the type can be a little too clean. But often for even better value than the Russian GZ32s, they could be worth a try if you are looking to open things up with more dynamic articulation.

I like type 80s too. I have been using one in my CSP3 for a really long time. For cool looking, globes are well worth checking out. They are sometimes pretty costly and others not-so, especially if you only need one. The one I am using is a Philco with engraved base, cleaner/more open sounding than the Cunnninghams I have, but the Cunninghams are a good choice if a little more warmth is needed. This is the tube type Steve currently pictures in the 25th Zen. I think they tend to be a little less fine detail and dynamics oriented than GZ32s, but have a very nice spaciousness with these qualities present in a relatively convincing, balanced way.

I also like type 80 STs (coke bottle shape) Joman mentioned, tending to be tighter and more focussed sounding than the mellower, more complex Philco globes, but definitely family and possibly preferable depending on needs. Looking a lot like Euro GZ32's, made tall by the necessary adaptor, depending on taste they can be pretty nice to look at too. I have one Pope labelled, made in Holland that is my favorite, a little more focussed than the globe, but still showing ambient space and texture very nicely. Similar, a step further into focus but still pretty complex, and a little less dynamic, is an old Tungsol Type 80 ST. The Westinghouse I have sounds pretty good, but is just a bit murky down low and rigid for me, lacking a little of the complexity the others offer. But these are tell-tale signs of a new tube. It may be true NOS, not burned in, so hard to say.

For GZs and 5V4GAs adaptors are not needed. Type 80s need them, but they are pretty easy to get.

You can search on Ebay with 5Z3 to 5U4G adaptor and see if any suit you, something like this: https://www.ebay.com/itm/1-PCS-gold-plated-Adapter-for-5Z3-5U4G-80-5Y3-tube-SUB-...

A word of caution on the square hole 5Z4 to 5U4G adapters. It is possible to feel like you are fitting the pins correctly and have them in the wrong position, and then fry the tube. Best to look carefully at the pin spacing and sizes in relation to the socket spacing and sizes.

People who want the spacious dynamics of GZ32s, but with more power/push often go for Mullard or Phillips Holland GZ34...a similar, but bigger/warmer, more forceful sound than its electronically more chill little brother, the GZ32. They tend to be quite costly too, but with patience occasional buys show up. Preferring GZ32, GZ34 are too big and warm for me, but folks who love GZ34 likely find GZ32 a little lean. They are pretty plain looking little rectifiers, so may not fit your request, but a very popular "standard" for sound.

With similar tight bass and dynamics as GZs, and generally with quite a big spaciousness and good fine detail, is the 5R4GY type. Warmer ones I have tried are Phillips 5R4GYSs, a tube I personally could never get, finding it a little veiled. A wild looking, and very reasonable, Chatham "potato masher," also a little warmish, and not quite as open and detailed as some 5R4s, it sounds natural to me, open without a lot of risk of going too far. Stepping out from stock 5U4Gs or 274Bs it could be a nice shift into increased articulation with dynamic spaciousness, but not as far out on that limb as some others. RCA 5R4GYs are widely variable in price, sometimes pretty inexpensive. Some love them and others find them too clean. I find it depends on everything else. If the balance is really clean, the RCA can take it too far. But if you want to open things up, they can work well. I like the old pair I have, in my setup, slightly warm, dynamic and clear, but for me it rarely stays in. The most balanced 5R4GY I have, while being super spacious, is a Fivre I got from an English seller, a nice, big and open rectifier. Of these, I would say the Chaham, if the look appeals, is a good one to dip a toe in with for the type.

In the Torii IV I just replaced some rare 40s Telefunken RGN1062 globes (need adaptors) I have been using a few years, with some Sylvania fat bottle 5V4GAs (square getters). And a Type 80-ST Pope in the CSP3 in the place of the Philco Type 80 Globe. Combined, it is fast, open and harmonically rich...deep, warm and dynamic...in this setting anyway. First impressions, I had to adjust gains a little, but once tuned, I find it a little warmer, focussed, and more dynamic than what I had...to me really good warmth, the darkening touch not overwhelming spaciousness and fine detail, but richening it, and the focus not overly combining fine detail and textures. Sounds great so far in my setup.

Thanks Lon. I have been tempted by yours and other's great reports on the Sophia 274Bs but just have not gone there. My tube interest has been on hold for modifications....Mainly due to wanting a consistent baseline while testing amp changes. Over more than 2.5 years of this process, I have replaced power tubes with the same tube type, and nothing else except to test how other tubes work with the changes. The amps more-or-less finished, the tube rolling door is opening up again! Thanks for the push. It might just get me off my butt to order some Sophias!

Thanks Will.  Very thorough.  What is the price range on those tubes?

I have RCA 5U4g and use them in my Torii.  But I think they are over $50 now.

will wrote on 05/07/19 at 02:23:33:


I don't believe I have Will. I would probably have gotten around to it had I not found the Aqua 274B, and probably will get around to that type if I bore of the Aquas in the future.

I mainly buy tubes from eBay as well, in a similar method. It's amazing how clearly different types and brands can show their "stuff" in these components! Such transparency and clarity!

Good point. I have not used 5U4Gs in years. But if I did, though a 5Z3 adds an adapter, the price difference and selection are interesting! Does it use the same pin setup/adapter as a 5Z4 and 5V4G? Do you have favorites you have found?

I bought off eBay and think I got a lower price.  So far, no issues.

I think from here:  

https://www.ebay.com/itm/Sophia-Electric-Aqua-274B-tube-replacing-5U4-G-Western-...

I bought one from Sophia, and three from eBay. After the first I learned to trust them and went without warranty.

Will,

I bought both my 274B and 5U4G direct from Sophia with the 30-day warranty.  I did not check eBay for it, but no tube bailed on me within the warranty period so far, so my experience is relatively positive.  Therefore, I would not pay more for additional warranty unless its was only a few bucks on top of the price.

Cheers,

Alper

Thanks Alper and Showme, I appreciate the input.

It is hard to imagine things getting better than the rectifiers I have been using, but I have yet to have that thought hold true with my system. I think, how can it get better, and no matter how good it has gotten, it always can get better so far! With so many of you loving the Aqua 274Bs, I broke over and bought a slightly used pair today from a 100% liked seller who had used them a while himself in his Sofia amps before changing to Sophia 5U4Gs. A good buy, and already burnt in, even so, I would not have gone there had it not been for all of your comments liking the tubes and their reliability. So thanks!

Showme, have you played with VRs other than stock and the OD3Ws in your 25th? A bit different setup in the Torii, but I suspect similar effects, as the OD3W you tried showed, you sure can do a lot to fine-tune these amps with VRs.

Is it cool in the 25th to adjust with the OA3s, or is it recommended to keep them as is?

Finding stock OA3s (setting up and cleaning the power tubes in the Torii) too forceful for my tastes, I ended up with 40s Hytron OC3s (nicely transparent) and 40s-50s Sylvania made OB3s. Once I got the amp opened and speeded up to my tastes with other tubes etc, I liked the relatively mild, but meaningful OB3 level of toning back the OA3 best here and have used them for years. But obviously there is no right VR, each system/room and tastes being different, a nice tuning tool though in my experience. I also found I preferred Euro variations of OC2, 75C1s, this VR tube in the Torii cleaning and setting the voltage drop to the input tubes.

Anyway, maybe you've already explored this, but if not, like inputs, rectifiers, and power tubes, I think you will find different makes, vintages and shapes of the "same" VRs can be used to tune the sound, and more obviously, different voltages.

I love how Steve's amps offer so many tuning abilities!

Thanks to this thread, I recently bought the Sophia Electric Aqua 274B rectifier.  What a nice upgrade this is over my Phillips R4GYS.  More transparency and a blacker background.  Needless to say, this is going to stay in the system for a long time.   I had also used an early 40s RCA rectifier to good effect but the Sophia Electric tops everything else I have tried.

At some point, I may try replacing the OD3 voltage regulator tubes on my 25th Anniversary Zen.  Does anyone have any recommendations on replacements and where to buy them?  Thanks.

Lon, thanks for the note.  I enjoy your contributions on this forum as well as your listening to jazz and conversation thread over at the Hoffman forums.

I will give that tube a try this Summer and will report back on this thread.  I have never tired rolling the voltage tubes  so I am sure there will be some trial and error.

I thought I would report back on rolling the OD3W tubes.   I bought some Raytheon OD3W tunes off eBay.   They were a definite improvement - cleaner sound and blacker background than the stock tubes.   The change was not nearly as dramatic as with the rectifier but definitely worth trying and not too expensive.

It never hurts to try something new.

I used OC3Ws for quite a while in my Torii III. My favs were Chathams over some later Raytheons I tried, the Chathams more complex and subtle. I liked how it was a little warmer and smoother than other OC3s I had tried, presumably a lot because it is so well damped by design. Then I ended up liking 40s Hytron OC3s, also an especially good tube. At the time, the OC3W influence had become a little too smooth and warm for the tube set I was liking, and the Hytron was more lively with space, textures and nuances.

A filter for the "signal" tubes in Steve's amps, I guess it is not really surprising how much effect a specific VR can have.

Thanks for sharing Lon.  I have to look to see what I I am running for VR in the back.

My up front combo de jour is Mullard input, Steve’s power tubes, the OD3W you recommended and Sophia rectifier.

Okay, I'm back to Steve's red-tipped 6N5P as input tubes and RCA 0B3 as voltage regulation tubes. There's just a hint of warmth and "romance" that a lot of the material I play use very well.

Now I'm leaving things as they are. Yeah, right. . . .