From the fuse (10A), the transformer must be big enough for class-A amp. I predict it is a 150W amp.
You have +/-24Vdc (or 48V single ended high voltage, or 24V high current), enough capacitance, not so big heatsink. The output transformer I don't know what for, but choke supply is possible. I guess 7W class-A is possible. Higher wattage (JLH) is also possible if there is room for fan (may be externally).
You have +/-24Vdc (or 48V single ended high voltage, or 24V high current), enough capacitance, not so big heatsink. The output transformer I don't know what for, but choke supply is possible. I guess 7W class-A is possible. Higher wattage (JLH) is also possible if there is room for fan (may be externally).
Get a real audio amplifier. A PA amplifier with an 8R monitor winding on the output transformer (like this one) does not make it suitable for music. Believe me, there are thousands of similar PA amp designs that were fine for that purpose but compromised on bandwidth and fidelity at every other stage.
IME, trying to open up the bandwidth of these old machines is more expensive and ineffective than a simple substitution of a cheap chip-amp as suggested in #5. If you can afford it for the sake of having a discrete design, then buy a kit of a basic 50-80W amplifier like Ebay NAP140, L6 etc.
IME, trying to open up the bandwidth of these old machines is more expensive and ineffective than a simple substitution of a cheap chip-amp as suggested in #5. If you can afford it for the sake of having a discrete design, then buy a kit of a basic 50-80W amplifier like Ebay NAP140, L6 etc.
People are saying to simply replace it. But what is the application? This looks like it is used for voice amplification in an auditorium. In that case you might do better thinking about acoustical treatments and speakers as that will improve the sound more than anything you could do to the amplifier.
The amp was never intended for use as a home HiFi. If you are trying to use it for that purpose, it would be mostly useless in that application. But the power transformers and chassis might be the start of a new project.
I would say that this is great amp now.
The people are building the amps with bjt or fets with similar technology instead of tube amps.
If the output transformer is good enough this amplifier will win with the sound quality with most project on this forum.
Try at first to check if old electrolytes are OK.
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That is a very very big "if". Constant-volatge output trafos used in small PA amps just aren't in the same league as the ones being used in the Susan Parker style amplifiers. You could do it, but you won't get the results. It takes a primo transformer and carefully matched and biased FETs. And that front end is probably a noisy POS.
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