In Reply to: A2 all the time posted by Chip647 on January 5, 2015 at 12:31:12:
Yes, agreed. I built a driver that would handle the requirements, which a scope and distortion measurements confirmed.
My last attempt at constant A2 was with 805s since I had everything I needed. Sound was good and I'm sure many would have thought more than acceptable, it just wasn't great like my 845s.
Many possible reasons. The curves for an 805 aren't fantastic and I'm sure that's why GNFB seems to be commonly used with this tube. I never use it but tried it for comparison purposes. The interesting thing is that although it certainly greatly assisted linearity it murdered sonics and I MUCH prefered the sound of zero NFB despite the increased distortion.
I still prefer biasing in A1 but designing with clean transition into A2 on peaks as necessary, generally brief.
Naz
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Follow Ups
- RE: A2 all the time - Naz 15:10:43 01/05/15 (4)
- Low Voltage 811A? - Triode_Kingdom 08:08:05 01/06/15 (2)
- RE: Low Voltage 811A? - tube wrangler 09:24:06 01/06/15 (1)
- Sounds like a DSP problem to me! - gusser 13:38:26 01/06/15 (0)
- RE: A2 all the time - Chip647 06:51:51 01/06/15 (0)