Matamp/Electric amp schematics

[Nutjob]

Has anyone tried to clarify the component values for that existing Matamp GT120 schematic thats been floating around since forever?

Also, has anyone come up with schematics for the Electric Amp USA amps, since they got gutshots galore all over their websites?

[Nutjob]

No one?

So it wouldn't be redundant if I did so and posted them?

I've searched high and low all over the Internet to find anything on either, and the closest I could find are the old schems floating around and alot of posts where people say they will draw them up, but never do. And those posts are quite a few years old.

[Nutjob]

Really? No takers? Regardless, I am almost finished with them and will post in the next day or so. The Electric Amp was a little bit of a challenge, but with so many gutshot angles on their website, was able to see just about all the component values, as well as discovering that their "presence" control is done in two different ways on two different but same model amps, and their "boost" control is simply a mid control. peculiar.

[Nyqusit5]

I haven't corrected yet the schematics I have put online (check out my website), nevertheless. As you have discovered, designs can vary espaecially for the PI and OP stage when it comes to Matamp GTs (judging from those I have had for repair).

[Nutjob]

I haven't corrected yet the schematics I have put online (check out my website), nevertheless. As you have discovered, designs can vary espaecially for the PI and OP stage when it comes to Matamp GTs (judging from those I have had for repair).

Also noticed the oddly different "drive" control setup on yours instead of the more common 3P4T rotary setup on others.

[Nyqusit5]

Yes, some have 5P switches, some have 3P. I guess it depends what they have in the parts bin...

[Nutjob]

here we go...



took a while, but I believe this is pretty close to what them blurry values actually are, after various attempts at cleaning them up in photo editors, cross referencing with known early Orange Matamp schematics, and squinting at many a googled matamp gutshot.

Electric Amp USA 120 Master Volume Unit schematics coming up next...

updated a couple components.

[Enzo]

Just a suggestion. If you want some input on a schematic that is "floating around" the internet, provide a link to it. otherwise we have to go hunt, and hope what we find is the same thing you are talking about.

[Nutjob]

My bad. All the known Ormat and Orange schems can be found on the Orange amps field guide site.
http://users.telenet.be/orangefg/orange_mods.htm
And the only known early Matamp Gt120 schem can be found by image googling "1973 Matamp GT120" it's pne of the first images that comes up from another site .
http://vintageamps.com/plexiboard/vi...hp?f=4&t=76954
Since early Orange/Matamps are followed by so few people (most musicians i talk to are rather bewildered by my White and Green Matamps when I gig them out, and I live and gig in LA), I assumed everyone that does, has done as much homework on them as I have. Not really needing input, just offering up a legible schematic that I'm confident is mostly correct. But if there is an error, by all means let me know.

[Nyqusit5]

Ooops, just realized I haven't got a link to my website like I thought I had. It is: The Quest for Tones | NICOSONIC
Sorry for the confusion.

[Nutjob]

oh, and the updated one is the one above, not the one under "thumbnails"... wouldnt let me erase it for some reason...

[lastcaress83]

any word on the EA schematic? I'm eager to see what those are cookin' with...

[Nutjob]

any word on the EA schematic? I'm eager to see what those are cookin' with...

Getting close. I'm actually just about done with with my EA clone build. Should actually have it fired up today. I need to experiment with the tone stack values to find which sound correct.

The basic block layout is:

first gain stage - "depth/fac/deep" control - "gain/fuzz" control - dc cathode follower - fender style tone stack (w/ mids being referred to as "boost") - dc cathodyne PI - Vox/Matchless stye cut control (presence) - ppimv master - output stage

The ptp layout is actually brilliant. They must have spent alot of time setting up a very logical star ground scheme, with each section segregated to it's own ground leg, very short signal path, minimal use of wire, and easy access to all components. I cant help but want to rip off the general layout for all my builds from this point on.

[lastcaress83]

Cool, I can't wait to see what you come up with. I thought about going into the internet wayback machine to see if I could dig up some older gut shots... Are you sure it's an FMV tone stack and not just a baxandall with a mid control?

[Nutjob]

Cool, I can't wait to see what you come up with. I thought about going into the internet wayback machine to see if I could dig up some older gut shots... Are you sure it's an FMV tone stack and not just a baxandall with a mid control?

Based on the gutshot on their website (the biggest one of the mv unit with the green chassis), I'm absolutely sure of it being the fender tonestack: