Matamp/Electric amp schematics

[lastcaress83]

interesting... I'll have to check it out. Here's some more quality pics of the MVU
if your interested: Guitar Kit pictures by screamingdaisy_album - Photobucket

[Nutjob]

I have those, thanks. Those shots have the most legible component values on the net. That particular unit has the Orange/Matamp style presence circuit instead of the vox style cut control.

[Nyqusit5]

Sorry for being a bit out on the subject, but I thought I'd share with you the threatening email I have received from electricamp following my posts on this thread. (Sorry for including the swear words, I can remove them if needed)

Contact | NICOSONIC.COM[/url].

Hello Mr. Nicolas of France:
All of the schematics that you claim to be re-writing on the
music-electronics-forum.com regarding MATAMP / ORANGE
and ELECTRIC AMP, USA are already available online and
upon request.

The MATAMP GT-120 was redone in about 2001 and made
super clear and legible along with all of the other common
ORANGE and MATAMP schematics from the past.

The ELECTRIC AMP Schematics for both AMP UNITS
and SPEAKER CABS have also been available online
and upon REQUEST since 2004.

INSTEAD of being a GLOBAL infringement weasel by attempting
to redo other peoples ideas and hard labor, you should just
go to the source and kindly with respect ask for the information.

Your MATAMP GT-120 schematic redu looks like shit.

You will be contacted by the WORLD INTELLECTUAL PROPERTY
ORGANIZATION IN SWITZERLAND [ WIPO] for your fraudulant
activity.

Until then grow up and get your own ideas you wanker.

I spare you the flow of insult I have received following my (polite of course) response to this email, although it is quite funny in places. I know for a fact that there is no infrigement whatsoever in me publishing these schematics, but Electric Amps USA is not the first company to try and scare forumers from publishing this kind of material.

I'll let you all be the judge of this company's attitude and professionalism...

Moderators, if posting this makes you feel uncomfortable, I'll of course remove it.

[Nutjob]

The funny thing is, those guys have never responded to any of the numerous email requests I've sent over the years, ranging from schematic requests to parts ordering. Funnier still, they're contacting you about the schematics I'm about to post. In fact, this is so rediculous that they would respond this way, I may just post a full layout diagram with the schems. I mean, if you want something to be proprietary knowledge, wouldn't it be better to NOT post numerous gutshots all over the world wide web?

[Nyqusit5]

To be honest, nothing in their email really makes sense and nor do the following ones I have received (man, these guys know a lot of sexist, racist and downright incomprehensible insults ) . At first, I thought it was a joke since the email wasn't signed.

To add to your point, have you noticed that they even sell the Matamp spares parts to make your own Matamp on evilbay? Faceplates, proprietary boards and all...

Anyway, they are not worth wasting my time... Shame for the nice Matamp guys in the UK.

[Nutjob]

I know... I've seen the parts they sell on ebay. So be it... I will also post a full layout diagram as well.

[LabyrinthAudio]

Great thread, one of only a few I've found on the web on this topic. Nutjob, I actually did the same thing you did with the GT120 schematic. Being into heavier and fuzzy jams, I've always been stumped by the EA "fuzz" control, at first I thought there was some sort of oddball clipping circuit like the 2nd generation Ampeg V4's and V9's with the back to back LED "distortion" control, or the Garnet BTO Stinger/Herzog circuit, or maybe they even put a germanium transistor in there or wired a tube as a diode. Isn't it just an extra gain stage or something? That's what Branimir did over at diystompboxes, halfway down the page is the schematic and sound clips. matamp green schematic ?

Also, the EA Power Units are literally insane, I saw a band with one of those pushing two 2x18 cabinets. I wonder if those are like the slave units but with a pre-gain/voice control? The bass player was going straight in and getting distortion. Anyways, schematics and layouts would certainly be awesome.

[Nutjob]

I'm still working on it. I had actually posted a schematic the other day when i got my EA clone up and running, but pulled it when I encountered some high frequency oscillation with all the controls dimed. I managed to kill the oscillations by adding some grid stoppers, but I want to make sure I've got it perfect before I post it, without any unnecessary grid stoppers or feedback capacitors that aren't in the gutshot photos I have seen. So I've got it up on my scope now trying to suss that out. Here's the schematic missing the unknown values:

[LabyrinthAudio]

So it's Deep, Fuzz, TMB tonestack, Master, Presence? And what are you using for transformers? The oscillations could be anything from lead dress to grounding. Are you using the same star scheme with the turret boards?

[Nutjob]

Used some junk drawer transformers I salvaged out of other amps. If I can get this one spot on, I may splurge for some MM's. Tried to get the layout as close as possible, same grounding scheme, same wire routing, shielded wire:

[Nutjob]

So it's Deep, Fuzz, TMB tonestack, Master, Presence? And what are you using for transformers? The oscillations could be anything from lead dress to grounding. Are you using the same star scheme with the turret boards?

If you take a look at the gutshots of the EA's there's a buncha silver micas all over, likely to knock down any high frequency oscillations, theres some gain in the preamp, then theres that dc-cathode follower pushing the tonestack and PI really hard. Im pretty sure the unique sound of these amps are a summation of each stage pushing the next real hard straight throught to the power tubes. I've got my clone biased fairly cool w/EL34's - 475V plate - biased @ 29mA, though I havent had a chance to really turn it up, it does sound very good at low vol. I'll have to A/B with my OR120 and my GTV, and knock out some heavy psych riffing.
I also wonder if there's any grid stoppers possibly hidden in the shrink wrapped ends of the shielded wire runs to the preamp grids. Something to consider.
Of course, I could just a have a bad solder joint or bad cap somewhere in the first two stages.

[Nutjob]

Some further testing and I'm questioning the value of that 1M grid leak at the input. A lower value knocks out the hf oscillation, same as backing off on the gain pot just a hair, or backing off the treble pot as well. Disconnecting the NFB had no effect on the oscillation. This is all with master volume dimed. Im pretty sure this gain monster is designed within an inch of "out-of-control", but man It sounds good. Tomorrow, I'm draggin it down to the lockout to run it full volume with some Sabbath riffs.

[LabyrinthAudio]

I'm sure you've already checked it if it's in there - that cap after the 1M grid leak resistor?

[Nutjob]

I'm sure you've already checked it if it's in there - that cap after the 1M grid leak resistor?

Do you mean the silver mica cap in parallel with it going to ground? I had checked that, tried 120p up to 1000p with varying degrees of attenuation of the offending feedback, but not elimination.

Currently I've got a 1M pot clipped in place of the first grid leak, dialed in to where theres no oscillation. If it measures a reasonable value when I pull it, Ill replace it w/ same resistor value and call it good.

Im okay with it where it currently is, sounds good at low volume, hiss and hum are well within reason dimed with no input either, nothing sketchy on the scope dimed into a dummy load, but I'm going to put it through the paces at max vol once I get it to my rehearsal space before I post the final schematic.

[diagrammatiks]

interesting... I'll have to check it out. Here's some more quality pics of the MVU
if your interested: Guitar Kit pictures by screamingdaisy_album - Photobucket

are your pictures of a recently built matamp?

I wonder if the same guy is still doing the wiring.

doesn't look nearly as clean as the older stuff.