Monday, October 5, 2020

The 2A3 Mono Amplifiers

 Hi!

In the last post I showed the making of the 2A3 amplifiers. Here photos of the finished set.



Each amplifier has an outboard power supply. Here we see one channel, amplifier and PSU:




4 chassis in total:






The power supply uses 4 TV Dampers in a full wave bridge configuration.




On these photos 6AX4 are plugged in.




Any compatible type can be used, for example 6DQ4, 6DA4, 6W4, and many others.






The power amp uses a 6N7 as driver tube which is interstage transformer coupled to the 2A3 output tube.







Of course all types of 6N7 tubes can be used, for example the 6N7G in shoulder type glass:




Or the 6N7GT, with straight glass bulb, here an RCA with smoked glass:




Or a Sylvania with clear glass:




Here a Tung-Sol with blacked glass:




Also the metal shell 6N7 is useable, here a Ken-Rad:




And as a bonus 6J5 can be used as well without any modifications. Here a Sylvania with metal base:




The 6J5 will give about 3dB less gain compared to the 6N7.






This set delivers about 3.5 single ended Watts per channel.





This amp uses DC filament supplies for the 2A3 for absolute hum free operation even on the most sensitive speakers.



If you are interested in such a set of amps or any other, send me an email.

Best regards

Thomas



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