Handmade Electronics

Updated: May 7 , 2003


This circuit can be considered RCA's version of the WE91A. Commonly found
in the Radiotron and other technical manuals.

For the power supply use:
1) Hammond  270HX B+ power transformer
2) 166L2 filament transformers
2)158Q chokes
2) 125E's output transformers (5K tap)

You can build a nice
economy single ended amp.
I'd suggest even goosing up the B+ to 300-0-300 using the
272HX or our H841 for B+.

Several customers built this design and found it enjoyable. While pentode drivers
are considered undesirable by many, a pentode driver can add a nice touch of
snap to a 2A3 design, and by running pentodes less conservatively current wise,
(meaning run 'em hard) pentode sound can become more musical.
6J7's and it's cousin the 6SJ7 come relatively cheap and there
is a good supply of NOS around. 6J7's require a 1/4" plate cap.

Schematics- Morrison 2A3 direct coupled- Page 2
Schematics- Reichart 300b SE- Page 3
Schematics- Acrosound 6B4G P-P- Page 4
Grommes Linestage
RCA Cathode Follower Linestage
RCA RIAA Pre-amp

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