• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

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Spare NOS ham radio parts and Dyna Transformers

I built this pair of amplifiers from a Dynaco design. The diagram was included in an advertisement for there A-451 output transformers. I just happen to have a pair and also a pair of the power transformers to match. I have been a ham radio operator/repairman for years and had other parts like ceramic tube sockets and such. They may not be pretty but boy they sound good for a almost 50 year old design! I have since changed the output tubes to 4ea. EL34/6CA7's. They sound even better than before...
 

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Hi all,
I have built in new circuitry into older JADIS JA-30 monoblocks, which at original sounded boring, dark and no vivid.
Now it sounds much much better with very good details and dynamics, still with all basic parts kept as original (power supply and heating, output transformer, etc.)
Now it uses 2x ECC82 and 2x 6550C SE triode connected.
some pics, schematics and measurement is here: perys | perys - Jadis-JA-30_mk2012 ? rajce.net

An externally hosted image should be here but it was not working when we last tested it.