Phono preamp tube rolling.

Now we are getting into the “icky” realm of ascribing magical sonic qualities to this or that tube based on loose subjective evidence or on hearsay evidence.  Why I stopped rolling tubes at all, once I figured out what I liked, of course. Changing a capacitor, for one example, can have a much more profound effect on SQ.  I guess it’s fun.

It is very often the case that when dual triodes, like nearly all the tubes so far mentioned in this thread, are used in circuit, only one of the two separate triode sections is actually used.  But what is a BGRP? Thanks.

What’s a BGRP?

KenRad VT231GT is also my favorite 6SN7.
ECC33 is not the same electrically as 6SN7.

I tried the National brand 12AT7, and I did not like them compared to at least four or five other brands of European or US origin. In fact a Chinese made tube was the best of the bunch in my 12AT7 survey, but it had a very short lifespan which I considered unacceptable. The next best were GE gold star and Mullard. ECC81 is the Euro equivalent. ECC81= 12AT7.

Fortunately, these small signal triodes tolerate a lot of abuse and can still sound”good” while being abused, if you don’t measure anything and are subject to listener bias. Which is all good. But it’s best not to draw conclusions like A is better than B based on a blind substitution of one for another type. If you think it’s fun and rewarding to tube roll, I submit its even more fun if you do some reading to gain a better understanding of what you’re doing. The science is fascinating.

Yes, some “Japanese” tubes are re-labeled Mullards or other Euro or US brand, but there’s nothing wrong with that.

Surfmuz, You wrote, "…12AU7, 12AT7 and 12AX7 are pretty much the same tube with a little different gain settings." As mulveling already intimated, this statement could not be more wrong. The only thing these three tube types have in common is that all 3 can be run off either a 6.3V or a 12.6V filament supply, depending upon how the socket is wired, and all the other pin connections (to grids, plates, and cathodes) are cross-compatible. But that does NOT mean you can freely switch among them. Any listening impression you get or got by substituting one for another type is as likely due to harming the performance of the substituted tube by subjecting it to too much or too little current, or too much or too little plate voltage, or usually both, as it is to any inherent sonic differences between the types. As a general bit of advice, I would suggest that if you don’t understand tube electronics, you ought not to replace one tube type with another different tube type.
As to the 12AU7, I dislike the sonics of this tube when it is used for gain. If it is used as a cathode follower or as a phase splitter (in an amplifier), that’s OK, because those two functions do not add gain to the circuit. 12AU7 can be replaced by 6CG7, 6FQ7, 12FQ7, or even 6SN7, which requires a change of tube socket, but only if you know what you are doing and can re-wire the existing 9-pin socket (or replace it with an octal socket for a 6SN7) to suit any of those tube types. All of those tube types are very similar electrically, if not identical, to the 12AU7. But don’t just plug them in; you need to re-wire the socket.

Mijo, ARC products are notorious for driving the tubes "hard", which causes them to wear out faster than typical. So you are well advised to do what you do.

surfmuz, What I meant is that there are nefarious persons who change the markings on tubes that otherwise look very much alike, so as to make inexpensive versions look just like rare and more valuable NOS tubes.  So, before shelling out big bucks for a Telefunken or Amperex or etc, it is wise to equip yourself with the expertise necessary to tell them apart regardless of the labeling on the tube.  On the other hand, I would totally trust Upscale Audio, Jim McShane, RAM, and certainly others with whom I am not directly familiar.  I would NOT buy expensive tubes off eBay.  Also, there are current manufacture tubes that do sound excellent and are reliable, made by JJ  and Sovtek, for two examples.  There you have good quality at reasonable cost.  In my experience also, some of the Chinese made tubes sound great but have a shorter than average lifespan, way too short.

Tom, What is “pyseabo”? Is it another word for “placebo”? Or did autocorrect do damage to your intentions?

to the OP: I try to use high quality tubes. Once or twice I’ve paid extra to RAM or Kevin for matched or low noise tubes. However tubes age at different rates, so what are matched or low noise tubes today might not be so in a month or 6 months. Still it’s hard to argue not to start with low noise for the input and any other gain tubes in a phono stage. Beware that boutique or NOS vintage tubes sold these days are very likely to be fakes. I have some Telefunken and Amperex tubes that I bought in the late 70s; I believe they’re real but I have no gear that requires a 12AX7 or AU7. I don’t “roll” tubes with any expectation that SQ will improve because of the brand or provenance. I replace tubes that I suspect are near the end of their lifespan.I own a good tube tester, but the real way to test a tube is to measure how it is functioning in the equipment. To do that you need a knowledge of electronics and how to read a schematic.

In general, I am not a fan of tube rolling.  Listener bias makes it almost certain that you will be certain you hear differences right away.  (Because you spent money on the new tubes.) But those impressions tend to fade over time, unless you are replacing truly worn out tubes, in which case you will inevitably love any fresh tubes. Given the fact you have supplied no further information, that is about the extent of any response I can conjure.