Originally Posted by mordy
The 6AS7 tube draws 2.5A with an amplification factor of 2. It seems that it is possible that you could use this tube as a driver tube, but only with an external power supply since the LD MKIII cannot handle such high current with it's built in power supply. The socket adapter for octal tubes should work for the 6AS7 tube.
I am not sure if anybody has used the 6AS7 as a power tube in the LD MKIII. This setup would require external power supplies for both tubes. Then it seems to be a question if the internal electronics match this tube - could be that the amp would be damaged.
A low amplification factor means that you have to turn the volume up higher than what you normally do. I am running a 6BX7 octal tube as driver with an amplification factor of 10 (draws1.5 amps) without any problems.
I cannot say that I understand well the relationship between all these factors. In the past I tried to use 6FQ7/6CG7 tubes as power tubes but that did not work well. However, using the adapters and 6SN7 tubes works beautifully, and they sound better than the 6N6P-IR tubes that were my previous best power tubes.
First off I heartily agree with you re 6SN7 tubes as powers...the more I listen to my Sylvania VT231s (with the C3GSs as drivers) the more I am liking them - they are absurdly good for the money. They really are giving my MUCH more expensive Psvane CV181-T IIs a run for their money (and that's before I make my own silver wire adapters!).
Secondly, just for interest's sake, I am awaiting a Tung Sol 7N7 - the loctal version of the 6SN7GT...more adapter-making!! Looking forward to seeing how they compare to the Sylvanias...
And thirdly - don't ask me why (perhaps iluvmusic's pioneering spirit with 6AS7s has lit a fuse in me!) - but I have just bought some very nice-looking RCA "coke bottle" 6AS7Gs...wait for it...to try as power tubes. I know, I know...I am putting it down to early onset dementia! Whatever, I am determined to at least see if it is a complete no-no.
As for heater power, I am wondering if it is possible to have one tube fed by the LD, with the other fed externally...suppose a peek inside would show if each is fed separately or not...
And I would need to take off the front panel and stick my finger inside to test for excessive heat...NO, ONLY KIDDING!! - the dementia isn't that far advanced?? A thermometer - carefully positioned! - should do the trick.
You could try to dissuade me, mordy, but I am all fired up at the moment!...Still, I have probably a fortnight to reflect on my madness...This rolling game has become too addictive, lol...