Recommended 12au7/5814s for Atma-sphere MP-3

Rodman99999, or anyone else, will the 12BH7 tube work in the MP3 as a replacment for the 12au7? Is that a safe replacement? Ralph?

The Mullard is the one obvious pair I do not currently own that I do want to try. Are they all the same (CV4003 and the 12Au7s), any good sources? Does seem like Andy at VTS carries them. I agree that the Amperex would be great to own, but the prices and scarcity makes give up on them. The Mullard's seem to be more accessible. If I could find some strong matched GTBs I would also give them a try, if they are warmer than the GTBs it might work well with the Siemens.

What makes a bigger difference, the 12au7s in the MP-3, or the VT-231/6sn7s in V1 of the M-60s? That is, which would you after first? I also read somewhere that VT-231/GTs were prone to microphonics compared with the GTA/Bs.

So what 6sn7s have you settled on for the MP-1? I'm using the early production Sylvania GTBs - stick with this and focus on the 12au7s? - I'll be looking for some Mullards based on comments so far.

Thanks Tvad. I'm going to give the Mullards a try (either CV4003 or 12au7).

Is Blackburn the factory of choice for Mullard 12au7s?

Any experience with mullardtubes.com? I've seen them advertise here recently, but I've not heard them mentioned by any users, yet.

I popped in the Clear tops last night and love them (in this unit), I just bought another pair and Mullard 12au7s from the Blackburn factory - I should be set. I also bought some RCA 6sn7GT - grey glass from the 1940s for the MP-3. Thank you all for your advice. I could not be happier with my Atma-sphere pre and amp; an incredible combination with Merlin speakers (and others I'm sure).

While I understand that to some extent, every tube matters, do the 6sn7s make as noticeable difference in the MP-3 compared with the 12au7s? That is, are these slots worth spending NOS money on?

On the M-60s, do the front and back 6sn7s (V1? V2?)get equal billing for NOS upgrades, or are the V1 spots more sensitive in terms of impacting the sound? Additionally, my understanding is that the V2s in the M-60s in the back have to be GTA/Bs to handle the voltage.

When does the bidding start on the Bad Boys?

Well, it started with a question and now I have taken the plunge. I'll be using Mullard 12au7, RCA Blackplate 12au7, RCA Cleartop, RCA 5814, and Siemens 5814 and mixing and matching those with RCA 6SN7 GT Greyglass and Sylvania 6SN7GTA early on the MP-3 - all fun and games as I find the best combination for my ears. On the M-60s I will be using RCA 6SN7GTBs on the front tubes and Sylvania 6SN7 GTBs on the back tubes with GE 6AS7s matched by RAM Labs. Thanks for you comments and private e-mails. And by the way, the units sounded pretty darn good with the Chinese tubes the units came with.

Well, it has been some time, and I have tried all sorts of 6SN7 and 12AU7 combinations to get the sound the suits me best using the MP3 and M60s. I have tried Sylvania and RCA GT, GTAs, and GTBs on the amp. The best combination for me was two RCA GTBs in the front and two Sylvania GTBs in the rear with GE 6AS7s from Roger Modjeski. In the preamp, the best sound for was the RCA Cleartops with RCA GT Greyglass, but frankly all the RCA variations sounded good to me and I preferred them to the Sylvnias in the preamp - that might have to do with the fact that I am using Merlin VSMs and the "warmth" of the RCAs just suits the speakers, especially the tweeter, better than the tipped Sylvanias. That being said the system sounded mighty good no matter what I put in there and I would say triode balance and quiet tubes are as, if not more, important, than the brand I chose. Once that is taken care of, the hairsplitting and preferences can take place. I think I'm set for now, but I do think I've got the Atma-sphere setup sounding as good as I can get it, BUT, tomorrow or the day after, I will receive the Amperex 12AU7s, we'll see how they do compared to the Cleartop I have in the MP3 and the RCA Blackplate 12au7s. Thanks for all the advice. I just wanted to add that in my search for tubes (for my Music Reference RM9SEs as well) that you can't do much better than working with Roger Modjeski, Andy at VTS, Brent Jesse, Jim McShane, and Jim Sutter. All fine gentleman, knowledgeable, an perhaps most importantly honest.

I have Herbies on every tube for good measure. I did spring for the RCA GT (Grey Glass - 1940s)that are suppose to be very well matched and I'm keeping my fingers crossed, quiet. I think I'm going to stick with Sylvania early GTBs for the M-60s, though I might roll some GTs in putting them into the mix helps. Is everyone in agreement that GT/231s (assuming they are quiet and well matched sections) generally sound better than GTA/Bs?

Jtimothya, great reading on that link. Thanks.

If there is no "danger" I will give them a try in the 12au7 slot. Thanks.