"Andy Evans" said:

I'm building a PP 2a3 amp right now and haven't decided on the input
stage. I'd like to use 6J5G and/or 1626 valves. Open to other
suggestions, but like to keep to octal or UX5 types (I also have 76,
37, 56, 27). I'd also need a differential first stage for the option of
balanced or SE, and I have CCSs. 2a3 needs about -50v of bias. Ideas?
ANdy

In my 2A3 PPamp, I use a 6SN7 as input amplifier/cathodyne, followed
by a 6SN7 driver in common cathode.
Supply voltage for the driver and PI stages is ca. 350V, derived from
a separate winding on the transformer.
The output stage gets about 300V with a 5 k Raa transformer.
Atthe output, I get about 13 watts @ 1 %, mostly third order
(obviously!).
This is without GNFB, I added about 6 dB of that, which makes the
distortion about 0.5 %.

I know, I could at least skip one stage and get rid of 1 or 2 coupling
caps, but this sounds very good to me already.
Maybe in a future upgrade I'll use a LTP with CCS in the cathode path.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005