Need help with a Gibson Skylar GA-5

[sixstringhook]

Hey all, new member here. Was wondering if anyone can help me out. Last year, I picked up a Gibson GA-5 Skylark amp. I found it on the curb during city wide clean up. Looked like it had been sitting in a basement for a few decades, but after cleaning it up, it looks great. It does power on, and you can hear audio coming out of it, but it makes a horrible noise on top of it. I assume the old "toilet paper tube" caps are bad. I only left it on for a few seconds, after that I havn't really touched it. I do have a fair amount of electronics repair experience, and I want to move forward with getting this thing fully operational again. What I am needing help with is, what value of caps do i need to get? I know i want to swap the power cord out with a grounded cord, and i want to get rid of the "death Cap". Anyone have any suggestions or can help me?

[Mick Bailey]

Hi and welcome.

The death cap is just clipped out and the ground of your mains lead attached firmly to the chassis using a crimped or soldered eyelet and star washer. The bolt hole should not be shared with any other mounting - it should be a dedicated ground point.

The capacitors are 'stick of dynamite' Mallory types. The value and voltage is marked on each one - 20MFD is 20uf. Dual caps show two values and are just two caps inside one casing sharing a common ground. Most people will replace a dual with two single caps and you have to be inventive with the way you mount them. You can use axial or radial. I usually mount them on a piece of tag strip fixed through the original bolt hole. You can get dual section caps, but they're very expensive. Its also possible to mount modern (smaller) caps inside the original cardboard tubes to preserve the look and mounting method of the originals.

Edit; Note that modern caps use harmonized values - so the original 20uf will now be replaced with 22uf. While you're at it, replace the other electrolytics.

[Justin Thomas]

What Mick said. Antique Electronic Supply does have a small selection of dual caps that aren't HORRIBLY overpriced, but I would just use single caps. Modern parts will probably be much smaller, anyway, unless you stuff the in the original tubes.
The only time I'd use those dual-cap firecrackers is in the bigger Blackface Fenders, where there's a ton of leads in an eyelet already, and I don't want or have room for more. Anyway, sweet find for free!

Justin