Thanks for the tips, agdr!
Are there any high power dual op-amps available? Before I make new boards, I'd like to see if perhaps it's possible to use my current board.
A voltage doubler supply seems easy enough. Can I use LM series regulators to keep it steady? Would I need more than a 9V winding for the doubler then? because I need more than +/-24VDC to regulate it. What's the dropout voltage for an LM317 anyways? I'm on my phone and can't check now.
Are there any high power dual op-amps available? Before I make new boards, I'd like to see if perhaps it's possible to use my current board.
A voltage doubler supply seems easy enough. Can I use LM series regulators to keep it steady? Would I need more than a 9V winding for the doubler then? because I need more than +/-24VDC to regulate it. What's the dropout voltage for an LM317 anyways? I'm on my phone and can't check now.
I just remembered something. I've been restoring a vintage Elektronika PM-01 mixing console and I have two units. One I'm fixing up, the other is a parts donor. Since the second unit will be scrapped after I finish the first one, I can use any parts out of it. And it has a separate headphone amplifier board, pic related obviously.
A simple op-amp job with an output buffer. It runs off of +/- 12V but I think the voltage can be raised if the rail filter caps are high enough voltage. I'd say maybe +/- 20V? Depends on the op-amp. Originally uses a K157UD2 op-amp, which can go up to 18V per rail. Sound wise it's considered kind of a soviet NE5532. Output buffer uses KT815V and KT814V in push-pull configuration. Very simple circuit.
Replacing the op-amp is a bit difficult as the soviet part has a non-standard pinout. Filter caps on board should be replaced with something like 22uF with 100nF bypass on op-amp. Input caps can be replaced with film (I have 4.7uF K73-16V in stock
) Feedback capacitor should be replaced with a fresh on as well. R8 could be omitted since we're talking 600ohm output here.
KT814V is an equivalent of BD166 and BD168. KT815V is and equivalent of BD167, BD169, BD815 and BD817.
What do you guys think, does this have potential? What should I change in the circuit? The circuit is an exact tracing of the original, verified by the service manual.
A simple op-amp job with an output buffer. It runs off of +/- 12V but I think the voltage can be raised if the rail filter caps are high enough voltage. I'd say maybe +/- 20V? Depends on the op-amp. Originally uses a K157UD2 op-amp, which can go up to 18V per rail. Sound wise it's considered kind of a soviet NE5532. Output buffer uses KT815V and KT814V in push-pull configuration. Very simple circuit.
Replacing the op-amp is a bit difficult as the soviet part has a non-standard pinout. Filter caps on board should be replaced with something like 22uF with 100nF bypass on op-amp. Input caps can be replaced with film (I have 4.7uF K73-16V in stock
) Feedback capacitor should be replaced with a fresh on as well. R8 could be omitted since we're talking 600ohm output here.KT814V is an equivalent of BD166 and BD168. KT815V is and equivalent of BD167, BD169, BD815 and BD817.
What do you guys think, does this have potential? What should I change in the circuit? The circuit is an exact tracing of the original, verified by the service manual.
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