06-07-2017, 12:57 AM
(05-07-2017, 07:32 AM)pwdrive Wrote: Is it similar to this one?:It's on page 265. Headed as speech amplifier and driver. Uses two 12AX7's as speech amplifier, a 6C4 triode and two 2A3's in push pull. I noticed these latter have a filament winding of 2.5 volts only. Rectifier has 5 volts and the other valves 6.3.
http://www.arizona-am.net/PHOENIX/NA7RH/4x1625_sch.gif
Lawrence.
Thus, rectifier supplies HT and microphone allows amplification. The push pull is listed as the driver for the final modulator stage. Yes, this is a bit new for me. I was swatting up generally on AM modulation but was forced to look at the process. I am doing plate modulation first. I had a look at valve prices online and the push pull were around 70 quid. Personally I think you can drop on valves dirt cheap sometimes. My X78'4 are worth a lot but I got them for a tenner.
