Model T problem

[Chas]

Hi,

My Sunn Model T (original type, from '73) has started making a kind of crackling noise when it's subject to vibration. At first I thought it was a microphonic tube, but looking at it, it seems like what's actually going on is the rectifier (?) or whatevers in the big silver can behind one of the transformers is loose - I can jiggle it slightly with my finger, and when I do, it makes the same crackling sound. Any idea how I can can fix this?

Thanks for any advice!
Chas

[Anonymous]

The rectifiers would be small blackish looking cylinders on the underside of the chassis.  You didn't state if this can looking thing was on top or underneath the chassis, and I can't figure out what you are talking about.

Hopefully you don't mean one of the can type shields over the preamp tubes???

[Chas]

I guess I wasn't being terribly descriptive.
A picture's worth a thousand word - in this picture:
http://www.classicamplifiers.com/images/SunnModelT_Rear_800.jpg
It's the silver cylinder with the white label on it, on the left.

[Isaac]

The big silver can is a capacitor. A multi-cap, actually, containing several capacitors. It might need to be replaced, or it could be that it has some broken solder joints. Any decent tech can tell you. They do go out. Mine did, years ago. Only problem I've ever had with my T.

They're also getting rare. It may be necessary to replace it with separate caps. Perofrmance shouldn't suffer, but it won't be quite stock anymore.

[Guest]

I believe Antique Electronic Supply has their reproduction of the multi-cap can capacitor in stock again. You'll need the 525 volt version (40/20/20/20 mfd). Or you can install separate capacitors inside the chassis and still keep the exterior looking totally stock. There is enough room to do this. Lethal voltages are present, so have a tech do this if you don't know what you are doing. But have the original cap checked first as it could be a loose solder joint. Then gently twist the mounting tabs on the cap with needle-nose pliers to tighten it to the chassis.
Good Luck!
Ryan

[suo]

hi,
just became the proud owner of a sunn model T amp,
can anyone tell me from which year it is by the serial number:
A 14581
mucho thanx in advance, jack