I like your style, if in a moment of madness I do decide to say sod it and switch them on I’ll get the wife to do 🤣
The only good audio engineer that I know is about 80 miles away, the amps only owe the cost of fuel to go collect them ( £50 )
IF I decide to break them for parts is there any value in the massive Drake transformers or the Sowter, there are the mosfets too I guess .
Like other posters have said, its important to check the integrity of the power cables to make sure they are properly wired and earthed. Also check the fuses. Are any blown? Then if all these tests pass, then I'd use the variac to wind up the voltage slowly and see what happens. Of course, do this in a workshop environment, not in your bedroom.
You definitely wouldn't plug these into the wall outlet. By simply looking at the photos, there are many things that show a very unreliable way of construction. Beside that, on the upper pcb there are 2-3 empty IC sockets.
On the other hand, these towers are a scenario for spending the whole winter for dismantling and trying to reverse engineer the schematic (if you are inclined to).
These don't seem to have any resemblance with JLH designs (output transformers for start, some 10-12 TO3 power cans, not all sharing the big heat sink).
All in all, a good source of components for future project.
George
On the other hand, these towers are a scenario for spending the whole winter for dismantling and trying to reverse engineer the schematic (if you are inclined to).
These don't seem to have any resemblance with JLH designs (output transformers for start, some 10-12 TO3 power cans, not all sharing the big heat sink).
All in all, a good source of components for future project.
George
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Thanks George, everything does seem to point towards stripping them for parts , might cover my expenditures of £50.
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A bunch of close up pictures of the circuit boards and internals might be helpful. At first glance this looks like it might be a single ended output stage amplifier modeled after a tube amp.
It would likely be safest to figure out what you actually have there first. Check out the power supply design. Is it single or dual rail? Are the two smaller transformers power transformers or audio output transformers ( do the output leads go to the output jacks)?
It would likely be safest to figure out what you actually have there first. Check out the power supply design. Is it single or dual rail? Are the two smaller transformers power transformers or audio output transformers ( do the output leads go to the output jacks)?
If you want to power up, use a 'variac' rated 500 VA or higher. Monitor the supply current with an ammeter and measure the output voltage (no speakers connected) Just take your time to do it. Always be ready to turn off supply immediately if required.
Regards.
Regards.
OP wrote they are Sowters. So most probably they are either output transformers or output stage loading chokes. How many wires come out from their bobbins?
George
Those big Drakes have two 55 volt windings on them. That would put the power supply voltage at +/-80 volts, or what’s needed for your basic 500W/4 ohm amplifier. Could be 1k into 2. It’s either overkill heat sinking (for audio use, but about right for sine wave), or the bias is set very high where it would operate class A at sane audio volumes and go take AB above that. Probably not enough to run full class A. Circuit Configuration is anybodys guess without further study. It could be anything from a basic front end followed by an EF3 to a circlotron. With two separate power windings that is a possibility.
The other transformers may just be for a separate regulated front end. The amount of overkill employed here suggests that the designer may have done that.
The other transformers may just be for a separate regulated front end. The amount of overkill employed here suggests that the designer may have done that.
@TheFinisher I agree with the people asking for a bunch of photos. Anything would be helpful. I particularly want to see the PCB on the top.
😳😳😳😳
Brian Powell (creator of Crimson) is on diyaudio, he is very nice and answers questions when he can, try to contact her, he will give you the origin of this pcb.
Brian Powell (creator of Crimson) is on diyaudio, he is very nice and answers questions when he can, try to contact her, he will give you the origin of this pcb.