12au7 tube?

Good news: since they’re going in an amp, not a preamp or phono, you have more options for 12au7 tubes & subs that would be too noisy / microphonic in those slots.

I’ve recently been using RCA 5963 (close 12au7 sub) in an amp - they’re affordable (beasue 5963 was not intended as an audio tube) and have a nice balanced sound. There are gray and black plate variants. They’re too microphonic for preamp / phono, but fine in an amp.

I’ve also liked GE 5814 (triple mica, gray plates), as a warm 12au7 sub that’s not quite as "wooly" as Mullard. Also affordable. 5814 is a very close 12au7 sub.

If your component’s PSU has a little extra heater current to spare, you can sub in 12BH7 (very close sub except for 0.6A heater current draw instead of 0.3A per tube). These tubes tend to be more dynamic sounding than 12au7. A power amp is more likely to have the heater current to spare, since the power tubes take up much more of it than small tubes. I’ve subbed them in a few different amps.

6189 is another sub you can do (12au7 equivalent). The Sylvanias and Philips ECG of this tube tend to be more "solid state" like in their sound. Cifte / Mazda / France made some silver plate 6189 that are very good, definitely not on the warm side though. Siemens also made some silver (nickel) plate 12au7 some people like - man, mine are microphonic as hell though - should be OK in an amp.

RCA cleartop 12au7 are everywhere (often rebranded - millions were made) and some people like them. They used to be pretty cheap. I find them "fine" but nothing really exciting.

I haven't tried Brimar or Amperex of 12au7 types - but based on their 12ax7, they should be slotting between Tele and Mullard sound, like you are looking for!

@mulveling I don’t know about that assessment as the 12AU7 is used in the pre section of the integrated amp... you definitely need to it t be quite or you will amplify it

Oops, missed that part of your amp; assumed it was power only. I did not consider they might create 845 based amps in a "space saving" integrated form factor lol. Yep you need quiet 12au7 tubes. Stick to 12au7, 6189, cv4003, and (maybe) 5814 types then.

Andy at VTS (recommended below) can very carefully select for noise, but I’m not sure how his stock levels are these days, other than RCAs. Upscale Audio used to have some great vintage options (Platinum or Gold grades); most of them long gone now. Other than that you can play the buy-and-try game on ebay, or try some of the new production tubes.

I’ve used Arizona Tube Supply in the past for some of these tube types, and I like him. They are generally used but good quality tubes.

@lowtubes

Man you’re speaking like a kindred soul here - I feel almost exactly the same way, and yeah, I also went way too far. On the plus side, my tube needs for life are easily filled. On the downside, it’s far too hard to liquidate these collections without a lot of give-aways and/or accepting pennies on the dollar. I'm just not into recouping funds 100 bucks at a time, for the effort involved here. So eventually, someone inherits the problem.

These days I spend less time tube rolling, because most vintage small tubes sound really good anyways, and your hearing just adapts to their nuances over time. If I want to change sonic flavors in a much more meaningful way, it’s easier to swap a cartridge or SUT (or components, or speakers).

Versus signal tubes, power tubes actually yield a more meaningful delta to shaping the sound IMO, but they’re mostly new (not vintage) and it’s pretty quick to hone in on which is the "right" choice for an amp. With small tubes you can easily get into a back-and-forth never ending hell trying to figure out which you actually like better.

@inna rumor is PSvane makes many of the Ray’s tubes.

Right, but these days who else could it possibly be? We could pretty much guess that every time, and be right :) 

• New Sensor is doing just fine with its own fleet of sub-brands, and probably doesn’t want to encourange new brands (beyond a simple re-screen of labels) to compete with those.
• JJ / Czech can do it, but you can spot their trademark spherical glass domes from a mile away, and many of us avoid them out of habit & experience.
• Western Electric is too busy trying to establish itself as a high end option, trying to expand its tube offerings (very difficult w/ necessary tooling), and pushing its amp line
• Shuguang is gone? TJ Full music has always been small scale.

Yeah, GTA / GTB variants aren’t as good sounding as most of the older 6SN7GT tubes. You would need a GTA / GTB for 2 reasons:

1. Your tube slot (usually preamp or phono stage) is particularly sensitive to noise and microphonics. GTA and GTB tubes tend to be a LOT less microphonic than older GTs. Especially quiet are Sylvania chrome tops with the angled plates.
2. Your amp slot specifically calls for a GTA / GTB because it’s running a higher plate voltage and/or dissipation than spec’d for GT or 5692 (this one is even lower spec’d than GT so watch out). Sometimes driver slots in amps do this - like VACs, which specifically label these slots "GTB". You can often "get away" with running a GT or 5692 past its spec’d limits, but they might not last as long. Adding to the confusion: New Sensor makes an Electro Harmonix 6SN7 without "GTB" labeling, and a Tung-Sol variant that is labeled "GTB" - but they both have the SAME datasheet specs. Fortunately, it’s the higher GTB spec, so these are both safe for use in strictly GTA/GTB slots.

If you find you really need GTA / GTB (these are the same for audio applications), you might look for older 1950’s Sylvanias with deeper chrome tops and (sometimes) tall bottles. Sylvania really started cutting corners on production costs & quality in the 1960s. Their tubes also lost their beautiful midrange, sadly. Then they became Philips ECG and at that point, they practically sound like solid state devices.

I remember conversation with Kevin of VAC and he said exactly the opposite.

I generally agree with what Kevin says, but we're all individuals and different in key ways. Anyways, he's almost certainly referring to rolling different makes of the same type. Meanwhile, I'm much more willing (than most) to play fast-and loose with rolling different types into power slots, as long as it's guaranteed safe. E.g. KT88 versus KT90 and KT120 or KT150. Depending on amp, you can even mix more different types in there, like EL34, 6L6GC / 7581A, etc. 

This will certainly make many cringe (maybe Kevin too), because the fact is an amp can only be "optimally" designed for the parameters of 1 output type. That's why I called it "playing fast and loose". But here clear as day, I can hear one of my VAC amps (450S) sounding far better with KT120 than the KT88 it was designed for - in THIS room, on THESE speakers. Meanwhile, another VAC amp (Master 300) sounds far better with the GL KT88 it was designed for, than those same KT120. The sonic difference from these KT88 versus KT120 rolls is far greater than any small-tube rolls. KT150 does the same again, but there I've always found the results too bass-heavy. 

Are you aware of who the OEM is for Ray tubes btw?

Not to blow their cover but it’s fairly easy to search and find on the internet. Think large manufacturer who batches their top % of tested tubes and puts a different label on it.. Perhaps the helpful part is they are supposed to be top matched triodes tested [and as good as a guarantee that Ray gives them] whatever that is at the time the warranty is needed fwiw.

@decooney Yep. There is nothing new under the sun here, and I have to roll my eyes when somebody uses marketing / branding to act like a new tube manufacturer. At least be more up-front: "here is who makes our tubes, and here is what we do to (maybe) make them better than the standard production"