kodera2tBy good chance, I made a audio push-pull power amplifier with very nice sound quality. But the previous implementation was done with external regulated DC power supply and of course it is not so handy. So this time I made the amp just in one enclosure with power supply.
As you see, one transformer is added. Actually it is not transformer but choke coil for power supply (gigantic 22H).
The schematic is exactly the same as in the reference circuit in the data sheet. I don't have exact center-tapped transformer for push-pull operation, so substituted 0-7-12 k transformer for output and input is Bogen T725 with white-violet-black. YES, it is zero capacitor nor resistor circuit.
I don't want to show the inside, because...
It is too dirty. (I would say in advance, I am not pious audio maniac...) In order to get heater voltage (2.0V), I just put tiny 3.3V switching power supply and 2.0V is obtained through ohmic resistor voltage drop. The plate voltage (around 130V) is obtained just rectifying 100V AC, through capacitor-inductor network.
This is the first time in my life to use 400V tolerance capacitor. I know it is not clean and never be some good example, but it is working well!
Actual operation can be found in the following movie...
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Cool! Your wiring is better than mine used to be. But it doesn't really matter, as long as it works. That's why we all need project boxes, to hide all the ugly wiring. 😁 I remember those aluminium cases for tube projects. I used to have an aluminium hole punch for the various sizes of sockets.
It looks like you are rectifying the mains voltage to supply the HV, but I suppose you have transformers on the input and output so nothing is directly connected to the mains.
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Thank you comment! Yeah thanks to enclosure, I don't need to see bunch of wires (and also no fear of electric shock ;-)
And yes,, HV is simply rectified AC 100V, a kind of trans-less with switching AC/DC power supply. Actually the circuit is same as in a reference circuit in the data sheet. I added the schematic in the project log!
Are you sure? yes | no