Regular readers (hahaha…. I kill me) will remember that I bought two Gibson Skylarks. One of which I fixed immediately and the other sat waiting. This is a story about the other. This is a Gibson Skylark in the “Crestline” series. It is one of the many amps released with the GA-5T model number. [...]
Entries Tagged as 'Amp Repair'
Rebuilding a Skylark
November 28th, 2009 · 2 Comments · Amp Repair, Amp mods, Gear, Skylark Rebuid
Tags: 753397
Debugging the GA-5T : A bit hasty…
February 21st, 2008 · 1 Comment · Amp Repair
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 [...]
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Debugging the GA-5T : I never thought I would write this…
February 19th, 2008 · 13 Comments · Amp Repair
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 all the [...]
Tags: Debugging·GA-5T·Gibson Skylark
Debugging the GA-5T : A new beginning
February 18th, 2008 · No Comments · Amp Repair
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 DMM and every voltage is [...]
Tags: Debugging·GA-5T·Gibson Skylark·HP 1725a·Oscilloscope·Signal Generator·Signal Suite
Debugging the GA-5T : Fixed Rectifier
January 19th, 2008 · 2 Comments · Amp Repair
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 increased the voltage out [...]
Tags: 6X4·Diode·Rectifier·Weber Copper Cap
3 Wire ground your amp without ruining it's value.
January 19th, 2008 · No Comments · Amp Repair, Gear
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 you [...]
Tags: 3 Wire Plug·Grounding
Death Cap? That sounds delicious!
December 31st, 2007 · 8 Comments · Amp Repair
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 removed!! It is [...]
Debugging the GA-5T (How not to rectify)
December 10th, 2007 · 4 Comments · Amp Repair
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 was something [...]
Debugging the GA-5T (Prelude)
December 10th, 2007 · 5 Comments · Amp Repair
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. Here is the schematic. The first [...]
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Background
September 30th, 2007 · 10 Comments · Amp Repair
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, that [...]