Question for tube aficionados

rvpiano, I want to congratulate you on taking the next step to audionirvana. You are in for some silly happy surprises, big grins, and perhaps even some giggling like a little girl-- like the rest of us -- when we find the right tube for the job!

I’ve used tubes for 10 years or so now in various uses in my audio chain. and like you, questioned the tubes abilities, and the higher costs of "better" tubes.

If you just wanted to jump into tubes and get something going soon, I would suggest just calling perhaps 3-4 tube sellers to ask them what they would suggest based on your particular unit (but make sure to call Upscale Audio- they are knowledgable, will help guide you, will ask you what you are powering, etc. In fact, when you buy tubes from Upscale on their website, you are required to type in the type of tube unit that you would be using the tubes for-- in order to make sure they match electronically.

Sovteks and EH are .... okay. But the next level up you will hear differences in sound... say to the Gold Lions, as they said above. But the next level would be like modern made tubes that are well-designed and manufactured with good Quality Control (like PSVane, modern Mullards, etc), then like the NOS tubes that dont cost an arm and a leg, at the entry level rung, and on upward. I always try to buy the entry-mid level NOS that have really "low microphonics" means that the tube should have been tested on a tube-testing machine to check its current condition. eg, Upscale does this, like tube depot, etc will write down the "matched" electrical voltages/etc of each tube. so you know you got a "matched pair", eg, when I bought 2 tubes for a preAmp, and when I bought 8 KT88s.
But what type of tubes are you looking to upgrade right now?

@elizabeth I hear what you are saying, and for some manufacturers this is fine, from Schiit (or is it iFi?) that have the sockets. But i think they might limit the quality the OP is after.

I’m not a purist, but I dont use the sockets that allow other tube types, b/c it is just another thing in the way of the audio chain. And the OP is looking for good tubes with good bang for buck. IOWs, I personally would not put a socket on a $75 NOS tube.

TBH, im not familiar with your CJ PV11, so i did a quick look up- this is from the 90s? and uses 3 different tube types? of course it is fine to have an older model, but that will tell us more about its general circuitry under the hood. Some amps can handle substitutions, some cant. Some pre amps now (LTA MicroZotl) have a choice of 6SN7 or 12AuX, b/c the circuit board and electronics inside support these different electrical platforms.

@rvpiano: i would like to make some recs on tubes, but it would help me/us to know:
1. Do you have a budget per tube or to replace all 6 right now? or replace just some? Whatever you do, swap out all the tubes of the SAME type. eg, dont replace one 12AU7, replace all of them at the same time. you probably guessed this, but some people dont.
2. I know the Nuforce class D amps you have, but what speakers do you have?
3. What particular aspects of sound quality do you want to change? more or less hi frequency? more or less mids? more ore less bass? more balance overall? a "sweeter" sound? a dryer sound? a colder sound? a bigger soundstage? a smaller stage? a more aggressive or laid back sound?  you get the picture....

@hedgehog gives good advice above about how and when to replace tubes: line stage first, then phono section, and make mental notes of the sound changes as you progress.

1. Line stage: 2 x 12AU7: I’m assuming
2. Phono: 1 x 5751 and 3 x 12AX7
https://conradjohnson.com/owners-manuals/pv11man.pdf

12AU7s: Lots of good opportunities here.
The NOS Mullards are end stage tubes for many, meaning once you hear it, you never let go of the tubes. I bought 4 matched of these tubes for about $125 each after shipping, taxes, matching, etc. from Upscale last year to try in my PrimaLuna tube integrated. I also needed a softer top end b/c I have ribbon tweeters in my speakers, which can burn your ears with more aggressive tube profiles.

The Mullards (specifically the M8136 model from Upscale) are expensive, yes, but everything they said was true: softened but very beautiful top end slightly rolled off. The soundstage is to do for, it puts the band in the room with you. Not many cons to this tube other than a slightly rolled off bottom end. RV, I think this would be an obvious choice for you.

The NOS Brimars are excellent too at $80 each, I have a pair, BUT it does not offer the softened top end you are looking for.

The RADIOTECHNIQUE 12AU7s: for $95 each, have not tried, but probably excellent+.

there are other NOS tubes out there. I recommend going to Upscale website, and watching the videos on each tube that they sell.

doing the CJ tube replacement for $310 would be a quick and easy way to get things squared away. Then, down the road, you could roll some tubes. But I'm sure part of that $310 is a fee for their special knowledge of the right tube combination. Maybe not the best value per se, but definitely a quick and easy way to clean the slate and start from a proper baseline. 

But i would have to agree that the Gold Lyons would be more of a lateral move. Absolutely nothing wrong with that, but i just try to make a little bigger move when I do an upgrade.

I'm not talking about exceeding the $130 budget either. But the sound quality gains will be significant, especially since preamps tend to have more influence on the final sound characteristics than amps (and yes, I know, I know, some of you will argue with that ... yeesh).

In fact, you may just ask yourself, "why did it take me so long to figure this out ... :)"