Phono preamp tube rolling.

@surfmuz
The 12 ax7/ ay7 / at7 aren’t really the same thing with different gain. They have very different plate resistances and drive capabilities, for starters. The Ares’ 12au7 slots are mu followers with a lot of flexibility - one element per tube used for gain and the other for output - so any of those tubes will work, but the 12ax7 is by far the worst choice here. It’s not a good output tube. That’s why I suggested at7 / ay7 / 12bh7.

I upgraded to a VAC Renaissance phono stage. Way more musical and organic, quieter, much better bass, and more detailed too. I used "way better" a lot because it’s all true - including the VAC’s sticker price! If I have one critique it’s that I actually like the CineMag blue-label SUT in the Ares Magnum more than the Lundahl LL1931 in the VAC (personal preference). But I bypass the VAC’s Lundahls with my choice of outboard SUT anyways - even sometimes with a CineMag Sky blue (great combo).

The Impact of an SUT or Head Amp on the downstream of the system can be just as impressive as a change to a certain Tube can offer.  

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.

By the chance, did anybody tried Japanese stuff? ….Hitachi 12AX7, NEC 12AU7, Toshiba 12AX7 or Matsushita 12AX7 ?

Vintage Japanese tubes are excellent and I will give you one unique example from my vaults (images taken by myself, use links below before they will be expired).


These are very interesting preamp tubes from Japan (new old stock from the ‘60s). The wonderful "sleeper" in the world of 12AT7s for me are old Japanese tubes. National is a trademark of Matsushita Electric Industrial Co., Ltd. If you’re set on the sources and still want more tubosity- nothing beats old National (Matsushita) with pinched waist glass and gold pins.

The most well known pinched waist tubes are from Philips Heerlen and Valvo Hamburg. They were made mid to end ‘50s and have the glass pinched around the top mica spacer. I assume this was done to fight microphony. Pinched waist tubes have an indented ring around the middle portion of the glass tube. They’re quite expensive, but not overpriced like Mullard or Telefunken tubes from the same era. I’ve noticed that tubes from 1958 and earlier have a bigger pinch then tubes from around 1960. Personally. I haven’t seen tubes after 1960 with a pinched waist.

P.S. Tube rolling was fun in my integrated amp (I do not use tube phono stages). I’ve been looking for the best 12AT7 type (but not the most expensive as I already had genuine ECC801S Telefunken with diamond glass base).

Japanese tubes are normally cheaper and cheaters do not try to fake them! Most people know nothing about Japanese tubes. If you want to find something use Tube Asylum forum.

Matsushita tube factory in Japan was set up by Mullard!  

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