Supro Drive

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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pb+j
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Post by pb+j »

I just got one of these and I'm impressed but kind of on the fence, because it's WAY too gainey for me and only work for my playing style with the guitar volume way back. It's from Pigtronix/supro and it claims to be based on the power amp section of a supro and to make use of a transformer for saturation, which I'm skeptical about but I'm just a liberal arts major with only the tiniest of clues

I'm wondering if it's radically different from a Supreax Duex? Supro says it's an all new design, no diode clippin




Here's a picture:


Image


The little trimpot is for controlling the gain range when you use it with an expression pedal

Off the top of my head, I can see two electrolytic caps where the Supreaux only calls for one (?) and there's a Cmos down there in the lower right, possibly to control the expression pedal. If there is any interest I can take it apart further, to see the other side of the board, but only if there's interest because I don't want to F up the pedal
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bancika
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Post by bancika »

interesting, attiny13a? maybe they use it for switching.

I'd like to see the schematic, but wouldn't risk your pedal for it. Can you see the transistors? Is it silicon output stage, sounds like silicon on demos.
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pb+j
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Post by pb+j »

I've never traced a circuit to draw a schematic.

But I can probably loosen the pots, and then get a hot of the other side of the board.

They say no diode clipping in the little manual it comes with

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thesmokingman
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Post by thesmokingman »

re the bypass: http://www.muzique.com/schem/bypass.htm

if I had to guess, probably supreaux deux or similar with a small audio transformer to "saturate" with the final jfet stage. would know more with better pictures of both sides of the PCB

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Post by Dirk_Hendrik »

thesmokingman wrote:re the bypass: http://www.muzique.com/schem/bypass.htm
Thanks for the link.

Why would I want this!? The major reason for implementing a uC in my bypass scheme is to have it analyse my incoming signal and do switching on exactly the 0-crossings. Therefore avoiding pops.... but that seems to be the thing that is not there.
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Post by pb+j »

Ok I took it apart.

I really like this pedal--it has a quality I haven't seen in other pedals where it feels more like an amp. also it really has that kind of grunt you get from the power amp section, and it's got lots of "sag," even at low gain.

Just from looking at it with my totally non expert eye, I don't think it's a Supreax clone--I see compenents that aren't in the Supreax schematic?

Here are some shots of the board==they are bog so you may need to open them in a new window to get the full shot




And here are some shots of the chips, best I could do with the iphone
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pb+j
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Post by pb+j »

one thing that puzzles me is that line of pins on the bottom--made for jumpers of some kind?

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Post by blackcorvo »

I'm pretty sure the white-package device on the backside of the board is a DPDT Relay, so that's probably what does the bypass switching (the pedal's switch seems to be either a momentary one or an SPDT, so that would make sense).
The pins are probably for accessing the ATTINY chip for debbuging. No idea what it's purpose might be, tho.
Without side-view pics around the transformer, it's pretty impossible to know exactly where it's connected to.

My guess: It's a low-power MOSFET amplifier made to match the tone of a Supro amp.
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Post by jalmonsalmon »

Myy my, what a spammer :slap:

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Post by jalmonsalmon »

Thank you for removing that spammers crap! :applause:

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Post by thehallofshields »

Anyone have a clue what the Transformer is doing?

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Post by thehallofshields »

The designer is claiming he has actually achieved magnetic saturation of the transformer. I'm beyond skeptical.

No other pedal sounds more like a real Supro amp than the Supro Drive. This groundbreaking analog pedal re-creates the circuitry of a Supro amp, from end to end, including an actual output transformer. As the Supro sound has gained widespread popular recognition as a pillar of classic rock guitar tone, numerous amp and pedal companies claim to have captured our coveted sound by cloning the original Supro preamp, in stompbox format. They all got it wrong! The real tone of a genuine Supro amp has everything to do with the unique phase inverter design, Class A power amp section and the magnetic saturation that occurs via the old-school transformers found in these vintage tone machines. In short, the iconic sound of a Supro amp being pushed into overdrive has everything to do with the POWER AMP.

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Post by thehallofshields »

I bought one of these used. I hope you all will help me dissect it when it comes next week. :P

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Post by thehallofshields »

thehallofshields wrote:I bought one of these used. I hope you all will help me dissect it when it comes next week. :P
I'm not bonding with this pedal and struggling to find motivation to trace it.

What are all of your opinions?

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Post by efe »

No love for Supro Drive ?

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Post by Belanger88 »

I’d love to see it traced
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Post by monfi »

Belanger88 wrote:I’d love to see it traced
Me too :applause:

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Post by roseblood11 »

Sure
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@pb+j: if this pedal has too much gain for your needs, build the Supreaux Deux. It's perfect for lower gain sounds.

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