6sn7 tubes for Atma Sphere amp

1Kitch, this may be obvious but Ralph knows anything you want to know about his amps. 
In terms of reviving the thread there isn't a great deal more to add than what was already known about tubes from earlier eras.  The RCA and later Sylvania tubes are still used and in reasonable supply.  6SN7s were made by the bazillion so decent old stock tubes are easy to find with a couple of exceptions.  The only 6SN7s I can think of that are new since 2010, are Psvanes and the Russian Tung Sol.  I don't know how either of them would work well in an Atma Sphere amp. Ask Ralph he might know.

Congrats from me too...belated. The Atma amps are great and rise to the occasion. Some tweaking helps.
.Contrary to preconceptions that the input tubes are all that matter I changed all the output tubes to rca nos. 28 tubes in my ma1. Very good investment. While changing driver tubes has been so-so. But then i started from nos sylvania to begin with.

Does anyone know the respective 6sn7 tube cascode function relative to their positions for the MA-1 Mk 3.3 amps?

This is a super old Thread if possible I would like to revive it?

I would say change out all 6. Compared to the new production (affordable) Russian and Chinese tubes, the old tubes and Shuguang tubes sound more 3D and less glarey. The stock tubes should sound very nice, but specialized tubes should adda lot of depth to the soundstage, and a more natural timbral balance. I didn't find any one tube position that didn't affect the sound, be it gain stage, CCS, or driver. You could argue that some affect it more than others, but it's hard to tell. If I had to say, I'd say the CCS tube has the least impact, but it does have noticeable impact. Or I'm delusional.

I would ask Ralph this directly to get his views as well.

I have a pair of MA1s, and after much rolling and agonizing, I have settled (for now) on RCA smoked glass for CCS (first tube), Sylvania WGTAs for second part of cascode (Not sure if it's top or bottom), Shuguang Treasure for first part of cascode, and Tung Sol GTBs (or are they GTAs?) for drivers. The Shuguang Treasures are every bit as good as the old tubes, but you still need to mix them all judiciously to get the best results. Too many Shuguangs were too bright, too many WGTAs were a bi tplodding, etc.

Congrats Glory! I have the Zu Definitions and use M60's. You are going to love the S-30!

In the past I've tried older (1950's) NOS Sylvania and RCA, preferring RCA's in the top and bottom half of the cascode voltage amp positions (V2,V1 respectively). These are the two most sensitive positions to affect sound.

Don't even bother spending good money on the constant current source tube (V3); I've never noticed a difference in this tube.

The 3rd most sensitive position is the output section driver tube (V4). This must be a GTB or GTA tube due to higher voltage. I have noticed an improvement with old (1950's) Sylvania GTB's here, but it would be the last place I'd upgrade. Talk with Andy and Vintage Tube Services...he's very helpful.

Good luck and enjoy!!

Jordan

I have heard the Sylvania 1960s GTB and RCA GTs in the 60 watt Atmasphere monos. I think Ralph likes the RCAs but I found the Sylvania richer and more pleasing. The W and TS are two that I use in my preamp,which is an AES AE3. If you have these costly tubes, then roll them, and see how they appeal to you. There is quite a bit of variance among tubes even if they are the same type. I own multiple pairs of Ws and TS RPs and only one pair of RPs is really any good. Some of the Ws are worldbeaters and some ...well they are..real losers, that are terribly microphonic. Expensive lessons in tube rolling.