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Powersonic

Started by Final_Form, April 06, 2013, 02:27:03 PM

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Final_Form

Hello everyone,
Just recently joined the board mainly because I haven't been able to find any information on a Powersonic amp I have. The only info I've been able to gather comes from a 2008 post from this board: http://www.ssguitar.com/index.php?topic=928.msg5902#msg5902. There weren't any pictures in that post so I decided to take some.


Supposedly some had a lightning bolt symbol that would light up in the grill, but as far as i know this one doesn't have one.
















I have no idea if the insides are all original.

If anyone knows anything about these amps I would love to hear it. Either way, I figured the pictures might be of use to someone. Thanks for taking a look!

Roly

#1
Welcome!

If you can slip the chassis out and take a few crisp well lit pix and post them I'm sure we can give you some idea of what you've got.  The type numbers on the power transistors would also help.

Just looking at the general style of the panel and case I would have dated it from the 60's or 70's, and with trem and reverb it will be for tenor guitar, most likely fitted with 12-inch speakers.

What condition is it in - working okay, working but with faults, not working?
If you say theory and practice don't agree you haven't applied enough theory.

mickmad

I agree with Roly, a few shots of the inner guts of the amplifier would be nice!
Btw, it looks like you could plug in two guitars, and one channel also has an integrated tremolo effect. Nice stuff! If it works, could you post some audio clips?

Final_Form

It works, but I think one or more of the volume pots might be going bad. It's very scratchy when I turn it and it jumps up suddenly and gets feedback if I'm not careful with it. I'm going to take it apart, clean it up a bit, and get those pictures. Afterwards I could post some clips. Thanks for the replies!

Roly

Well a scratchy pot or two is hardly surprising in an amp of this vintage.  While you have the chassis out you should put a few drops of metho or a squirt of contact cleaner (specific) into each pot and socket and work them a bit.  Anything that fails to respond will need replacement, but looking at its general condition I would say a bit of a freshen up will be well worth it.   :dbtu:

A thorough (careful) dust with a soft brush and vac is good too - amps sometimes accumulate quite a lot of odd crud inside, dust, insects, matches, bottle tops, broken china...

Before and after pix, eh?
If you say theory and practice don't agree you haven't applied enough theory.

Final_Form

I took it apart and cleaned the pots, and it made a big difference. Although, it seems that the reverb won't work. It could be anything, but I have a feeling it needs rewired, or maybe the spring reverb is damaged, I'm not sure. The "Speed" knob adds some tremolo but I don't notice any difference from the "Depth" or "Reverb" knobs. I took a few pictures while I had it opened up, but I guess I don't really know what to look for. Sorry.  xP










I believe these are the power transistors? There's a third one, but none of them are very legible. It looks like they're made by RCA and serial ends in "051" maybe?

Roly

Yup, those are the power output transistors, 40051 PNP Germanium 60V 10A TO-3 case, and it looks like a transformer-driven output stage, quite popular in this era.  Just guessing but the third one could be the reverb driver.

Quote from: Final_Formmaybe the spring reverb is damaged, I'm not sure.

Get the springline out and have a look.  It is very common for the spring suspensions to break.  They can be repaired if you don't mind a bit of mix and match watchmaking, but if the springs are missing or you don't have another tank to rat then you'll need a new one.  If it seems to be intact then have a very close look at the wires that go from the inside of the sockets to the driver coils themselves, these frequently break just behind the socket; reconnect and you should be good to go.

HTH
If you say theory and practice don't agree you haven't applied enough theory.

J M Fahey

If you have 3 power transistors, the 3rd one is probably the driver.

Roly

Quote from: J M Fahey on April 14, 2013, 06:17:13 AM
If you have 3 power transistors, the 3rd one is probably the driver.

Of course.   ::)
If you say theory and practice don't agree you haven't applied enough theory.

J M Fahey

Quote from: Roly on April 14, 2013, 07:39:58 AM
Quote from: J M Fahey on April 14, 2013, 06:17:13 AM
If you have 3 power transistors, the 3rd one is probably the driver.

Of course.   ::)
Just 3 posts above, it was suggested it might be the *reverb* driver  ::)

:P  :P

Roly

And of course you're right that it would make more sense in this case for it to be a Class-A output driver.
If you say theory and practice don't agree you haven't applied enough theory.

Final_Form

Thanks for the info guys. :dbtu: I'm gonna take a look at those spring suspensions and see what I find.