DeArmond Bassist 2

[DPM309]

I have a DeArmond Bassist 2 bass guitar combo with a blown power transformer. There is very limited information out there on the web and was wondering if anyone had a schematic or knows where to find a PT?
I have attached a picture of the inside of the chassis.


Thanks,
Dan

[DPM309]

Here are a couple of pictures of the actual amp I am working on. The above photo was off of an ad on E-bay. Looks like it has been modded - PT etc.

[52 Bill]

I don't think that the other amp is the same as the one that you are working on. Yours is a smaller less powerful version, with one less control.

What is wrong with your power transformer? Open secondary, open primary or shorted winding?

[DPM309]

They both said Bassist 2 on the fronts. Maybe the other one is a newer version? As far at the PT, the owner wanted the PT swapped out in order to eliminate the hum. The amp does work as is but has an annoying hum. I am looking into other ways to take care of the hum but in the meantime, I am trying to get an idea of the availability and price for a new PT. I am getting 315 VAC on the secondary of the PT.

[The Dude]

Are we talking mechanical hum or hum out of the speaker? Do you hear hum with the speaker disconnected? It's more likely filter caps than the transformer if it's heard from the speaker.

[DPM309]

The hum is coming out of the speakers. Filter caps look good but it probably won't hurt to change them out, a lot less expensive than a new PT. What else should I be looking at for the source of hum in a solid state amp. I work mainly on tube amps and have not had a lot of experience with SS amps except for changing out boards, etc.

[g1]

I think you can mostly rule out the power transformer itself as a source of hum in the speakers. If it is a non-stock replacement, orientation or lead-dress of the PT could be contributors.
It will be very helpful if you can identify whether the hum is 60Hz or 120Hz.

[DPM309]

I am thinking 60Hz but I always get them confused. It is the same hum as when you touch the tip of your guitar cord plug when it is plugged into an amp.

[The Dude]

Making sure the voltage is at least as high as the caps in the amp, I would try clipping another cap of the same approximate value across those 2 big filter caps and see if that gets rid of the hum. The leads are right there. It might narrow down which is bad. You could also check each for ripple with a scope or ACV on your meter.

[DPM309]

Thanks Dude. This is actually a Bassist 1, not a 2. I didn't even notice it as the owner said it was a 2. That is why the pictures above don't match. I will try the cap trick.