Paleo-Electronics Blog

So yes, I have removed the hum, and to a large degree the amp appears to be working well, but I noticed that bass notes got kind of farty sometimes and some specific notes would warble all over.
Weird…  I’ll be putting the output section up on the scope again soon to see if I can [...]

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But I have done it! The amp sounds great. Some contact cleaner, a 3 prong mod and then I’ll button up the cab and give it a final run through, but I think I finally got it.
I’ll save the final bit for last, because I want to do a quick walk through [...]

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As you’ll have probably guessed by now, I don’t really know what I am doing. The GA-5T had a nasty buzzing that was independent of volume. So I re-did the power filter caps and now I have a hiss/buzz that is dependent on volume. I have run through with a [...]

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So.. those of you following closely (both of you :-), will recall that I had last determined that an idiot had put in a couple of diodes in place of the 6X4 rectifier tube. Amazingly, this person may have owned a multimeter, because he seems to have recognized that the diodes [...]

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This is actually why I took the Paleoelectronics.com domain in the first place. I got tired of hearing how an amp tech had cut out the old 2 wire cord from a classic amp to make it safer.
You certainly need to get an earth ground hookup in these old two wire amps, but [...]

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Many of you are likely wondering what is that tantalizing thing called a “death cap”.
Let’s have a look shall we? If you’ll recall from my previous post, the rectifying circuit in the GA-5 looks like this :

The death cap, a .022 mF is there to help suppress hum. Have that [...]

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As noted previously, the amp had a loud hum with no inputs connected and the volume and tremolo turned all the way down. Nothing I could do for it, I was going to have to open the case.
So I took off the back to have a first look. And sure enough.. there [...]

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I’m finally going to write about the fun I’m not having debugging a 60’s Gibson Skylark. To be specific, this is a GA-5T Crestline. The Crestlines differ from the 50’s Skylarks in that they are almost a completely different circuit, using two output tubes in a push pull configuration. [...]

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I spent about 10 years doing all my playing direct into a computer or a headphone amp.
Finally, I crawled out of the shell and started looking for an amp I could play at home at night and also in a studio/practice situation. I settle on the “Lil’ Lanilei” by Tris at Songworks. However, [...]

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A bit of the mystery of the Sprague 102C84 is solved.

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