I found a new schematic for the Crestline GA – 5′s by accident on ebay. I thought I was buying an original manual / schematic that came with the Skylarks, but instead I got a reproduction. Sigh. The good news is that the schematic is very different than any other I’ve seen. Some very exciting stuff in here.
Here is a link to the raw scan : 4 Meg PNG
And one in a more palatable 290K size
Smaller but very decent GA-5 Crestline Schematic
So where to begin? The first thing is details. This schematic is full of details that I have not seen on GA5 schematics before. Some are trivial (it includes part numbers) and others are very useful (the output tranny is 8k/8 Ω).
Secondly, topology. This amp is significantly different in some design details.
Third, local interest. This is GA-5 but the topology matches my GA-5T, so I have a better idea of what was original in the amp that I have on the rack at this moment.
I have slurped every GA-5 Schematic I could find and I don’t think I’ve ever come across one like this, so I am kind of excited to show this. Naturally, it is my scan of a very old document. This image is in the public domain. I didn’t even watermark it.
Enjoy, and I’ll be commenting further on the details shortly.
This schematic fills in some of the gaps between the early and later GA-5 Crestline Skylarks. I have four of them and none of them is exactly the same. On many of the forums these disparities are written off as “Gibson’s circuit of the minute”. But this schematic seems to indicate that there was actual planning behind the changes. I have to admit, the amp does not really open up and achieve its potential until some of the components are altered or removed. But that’s a topic for another day.
This schematic fills in some of the gaps between the early and later GA-5 Crestline Skylarks ?? How
3 lead Cap across vol ctrl on gibson skylark - what is its purpose? // Aug 15, 2011 at 1:14 am
[...] RC network with two caps and two resistors. 102C84 Awesome find! The schematic on that site: New Find : A Totally Different Crestline GA-5 Schematic Closely matches my amp (.0047 coupling cap, grid stopper on v2a, .1 bypass cap on v2a cathode, [...]