Tough One: Gallien Kruger 210G SS Guitar Amplifier

[Sleet]

I have searched high and low on the internet and done the obligatory request directly to G&K support (with no love).

Gallien Kruger 210G, manufactured 1978.

This thing is built like a tank, tone wise not so sure

Thanks.

Gerry

[J M Fahey]

Hi.
Hope this helps:
GK210 a, b, and c. (attached)
I'd *love* to have a couple pictures of the output transformer, the iron size and if possible some resistance measurements (although I guess they will be around 1 ohm or less)
Good hunting.

[Sleet]

Thanks so much for the schematics. As it happens G&K just responded to my email request with (I think) nearly identical scans of a schematic for my amp.

I'm just curious as to why you're interested in the transformers?

[J M Fahey]

Hi.
Good for you, now you have two.
I think the answer is obvious: I'm curious and want to build one of them, It's a very original design.
The schematic says all .... except the transformer data, but with the Iron size (at least) and maybe some resistance measurement, or the turns ratio (Simply deduced from Spk AC voltage Vs Collector AC voltage) I can design and wind my own.
Good luck.
PS: what was the problem on your amp?

[Sleet]

My amp was just old and tired. All original components as near as I could tell, with a build date of about '78 or '79.

There was power supply hum, dirty pots, loose speaker connections, some out of tolerance resistors. Very stout build quality, puts the current build quality to shame. I also like the fact that this amp is easy to work on and repair. Three individual "modules" for power supply, power amp and preamp. No SMT or really tiny parts.

I will attempt to take a few readings and get back to you. Life is about to get a bit busy in the near future.

Thanks.

[J M Fahey]

Thanks in advance to you.
JMFahey

[Sleet]

Hi.
Good for you, now you have two.
I think the answer is obvious: I'm curious and want to build one of them, It's a very original design.
The schematic says all .... except the transformer data, but with the Iron size (at least) and maybe some resistance measurement, or the turns ratio (Simply deduced from Spk AC voltage Vs Collector AC voltage) I can design and wind my own.
Good luck.
PS: what was the problem on your amp?

I now have a little free time. I can take a few pictures if you like of the transformers. I'm under the impression that to take resistance readings of the windings, I will need to unsolder all of the leads from the PCB's?

[J M Fahey]

Thanks a lot.
please do not unsolder anything, don't want to complicate your life and probably it is not necessary.
First of all: the iron core is made of stacked "E" and "I" shaped laminations, the "I" closing the free, open side of the "E" making a full rectangle with two windows in it.
If you look at it sideways you will see it clearly.
I need the long and short side of said rectangle, as in, for example, 8cm x 6 cm or some similar proportion (4"x3" for example)
That gives me the lamination size with sufficient precision to look it up in a normalized lamination size table.
Those thin sheets are stacked, I need the thickness or height of that stack, it will probably be around 1 1/2" to 2".
As to the winding resistance , don't worry too much, the value is probably way under 1 ohm, too low to measure easily with a multimeter.
A couple pictures will help.
Thanks again.

[Maddo]

Hello, could please someone reupload the schematics for this amp? Thank you

[Sleet]

Here you go.

[Maddo]

Thank you very much!