Schematics for Guitar Combo ST-100 (100W)

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Joined: 2008-02-04
Schematics for Guitar Combo ST-100 (100W)

Hi all,

I have a guitar combo ST-100 (100W) with 4 tubes and 2 speackers (12" I guess). One speaker is from ESR and the other is from Fender. I think this is a modification of one of the former owners.

More details see attached pictures.

The combo has 2 channels, one for normal and one for bright. This is similiar to old Fender amps like todays "57 twin amp combo".

Now the transformer is blown and I need schematics for the repair. I searched the whole Internet, but there is no site, notice or even a hint about my combo.

So, maybe a person who knows this ESR combo with access to schematics can help to reanimate this fantastic amp.

I read that ESR amp are mostly copies of Peavey amps. Maybe one of you all can identify the corresponding Peavey model. This would be also very helpful.

Thanks in advance.

greetz from Germany...

Earth ST100 front.JPG66.1 KB
Earth ST100 top.JPG68.34 KB
Earth ST100 inside.JPG203.59 KB
Joined: 2008-05-19
Earth ST-100

I just bought a Tweed Revival 212 yesterday and found your post while doing some research on this amp. In the pics it looks like you have EL34 tubes in your ST-100, rather than the original 6L6GC. If this is true, it could explain why you fried your power transformer: EL34 draws 1.6 amps/tube, while 6L6 draws about .9 amps/tube. It could be you overloaded the transformer.

My amp looks exactly like that of "setayj", and says Earth Sound on the chassis, but "Product of ....NY" on a small plaque on the back. Works fine, but i can't resist the temptation to mess with it...

Good Luck!


Joined: 2008-02-07
hope this helps

I have an tweed Earth Revival 100W 2x12. Your amp looks similar on the inside. I got this schematic for my amp from someone else on this site. It is not for your amp, but it might be helpful anyway.
This is my amp
Here is the schematic

Joined: 2008-02-04

we will checks this. Nevertheless it will help to understand the design of my amp.

According to your picture, your amp seems to be a copy of a Fender amp. My amp seems to be a copy of a Peavey amp. But I heard that Peavey also copied amp from Fender. So I assume that there are some similarities, but the corresponding Peavey amp is still of interest.

However, as soon as the schematic is finished, I will update this thread.

greetz from Germany...

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