50s Gibson GA-5

[ca7922303]

Got a guy sending me photos wanting to know if I will replace parts back to original on this Gibson ga-5. I don't have the amp in hand, but wondering what it looks like what all has been changed from original. Thanks.

[ca7922303]

Got a guy sending me photos wanting to know if I will replace parts back to original on this Gibson ga-5. I don't have the amp in hand, but wondering what it looks like what all has been changed from original. Thanks.

He's also trying to find out if new transformer is a correct replacement

[The Dude]

Please do the owner a favor and have him take the amp to a qualified technician.

[mozz]

Where are you gonna get a good firecracker filter cap? It needs to be repaired. Properly. You won't find original parts so he will have to use modern parts, you aren't going to hurt value that much.

[Enzo]

Well AES has made these for years

Capacitor - CE Mfg., Tubular, 450V, 10/10µF | Antique Electronic Supply (tubesandmore.com)

I usually replace the firecracker with a couple small terminal strips mounted to chassis with the needed axial caps wired between them.

[ca7922303]

Well AES has made these for years

Capacitor - CE Mfg., Tubular, 450V, 10/10µF | Antique Electronic Supply (tubesandmore.com)

I usually replace the firecracker with a couple small terminal strips mounted to chassis with the needed axial caps wired between them.

Thanks for your help. I forwarded the firecracker link. Any thoughts on the transformers. He might have the correct one in there now, don't know?

[g1]

Old Gibson amps that don't match their schematics is very common. There will be no way to really tell what is original or not unless you had drawn up a schematic of the original amp when new. You may end up replacing parts that are actually originals with non-original parts that match some schematic.

I myself would decline a repair like this.

[Enzo]

Clearly the taped up wad of caps took the place of the original firecracker cap. You can see the metal band that held the old part still there. That black beauty cap is likely leaky too, and the paper wrapped electrolytic in the corner. We may never know what was this thing's original configuration, but it is a simple amp and bringing it true to one of the schematics is as close as it gets, for me.

[mozz]

"That black beauty cap is likely leaky too"

If that cap is from 1961 like the amp, .022uf, Gibson guitar fanatics will pay enough for you to recap the entire amp. Thanks for the link to the firecracker caps, didn't know they were still made. Their can caps are a bit expensive, i was going to order one for a Premier to keep it original, all the disc caps and resistors are fine.

[The Dude]

I see it also needs a grounded AC cord and death cap removal. Beyond that, make it work. Make it safe. Make it reliable. I don't see any reason to be concerned horribly with keeping it original. Separate caps on terminal strips is fine.

[Enzo]

Agree, unless it is a museum piece, instead of the firecracker cap, I'd just mount a coule terminal strips and wire discrete caps.

[ca7922303]

Anyway to tell if the two photos of original and current transformers are a match for this amp? Thanks.

[Enzo]

Is there something wrong with the original part? It has GA5 OT right on it. The SKylark is a single ended power amp. It has one tube. The transformer is made for that. Your "new" transformer appears to me to be for a push pull output. (brown-red-blue wires) Which generally is not meant for single ended circuits. But it may be some special part, I have no idea where you got it.

[ca7922303]

Is there something wrong with the original part? It has GA5 OT right on it. The SKylark is a single ended power amp. It has one tube. The transformer is made for that. Your "new" transformer appears to me to be for a push pull output. (brown-red-blue wires) Which generally is not meant for single ended circuits. But it may be some special part, I have no idea where you got it.

Original part was replaced due to failure years ago and new one works but owner now(it was his father's and father was 1st owner and had new transformer work done) now says it distorts at about 2 volume.

[mozz]

24S04 listed in the 1965 Thordarson catalog.
Universal output transformer single or push pull.
PRI. 4000 to 14000
SEC .1 to 50
35ma
4W

Sounds like a generic replacement, you could probably do better with a dedicated single ended transformer.