Marshall supa mk1 schematic?

[hobbyseason]

My ongoing obsession with the tonebender mk1 and related circuits has led me to this one. However my searches on fsb and the dam forum havent come up with much.

Does anyone know much about this circuit or have access to a schematic? I know its based on a tb mk1 with fixed fuzz and filter / tone control.

Thanks for all the hard work and info shared on this site folks!!

[Travis]

I dunno if anyone’s done an actual schematic but I’ve built it from the layout on turretboard.org

The layout there is a copy of the original layout on .15” pitch stripboard



Found the pic of my build from a few years back. Lemme know if you need help finding that info

[Sphere80]

I used this:
http://www.luciferstrip.com/fuzz/tbmk1proto-schematic.jpg
from:
http://www.luciferstrip.com/fuzz/

Forum user Anders suggested replacing the 47k off Q2 with an A50K as a fuzz control and raising the tone cap for more effect.   I still haven't settled on a transistor set though. That's a beautiful build, Travis.

[anders]

I built the Supa Mk1 a while ago. But I can't find the schematic in my hard drive but I recall that the schematic din't have a cap between Q3 and  the volume pot so I added a large cap there since I don't want currnet into the pot.  Here is the layout used, I added a trimmer for Q2. I also added a fuzz control lifted from Solasound TB Mk1.
I

[Sphere80]

Thats' the layout! Works well.

 Anders, I think you said you also built an NPN version ?  Any OC75 alternative ideas if keeping with PNP?

[anders]

Alex, thanks for the link for the schematic
And I agree on Travis build, looks stunning!

[anders]

Yes, I used russian GT404's for all transistors in my NPN build, sounds ace. japanese 2SD72 also sounded good. Bear in mind that this circuit want leaky trannies. Part number isn't important, more important is leakage and Hfe. I'll test the trannies in a couple of days for leakage and gains and report back.

[hobbyseason]

Travis that build looks on par with pigdog / dam. Beautiful!

Thank you all!

For those that have successfully built this circuit, would you say it was as tedious selecting transistors as is with the tonebender mk1?

[Travis]

I would say it’s less tedious because you don’t have to deal with the fuzz pot of the MKI. Getting that fuzz pot to behave is one of the most difficult things, so there’s one less thing to worry about in the Marshall.

I used CV7007 (I think Mil spec OC77) and an OC76 in mine. The CV7007 are leaky but nothing too crazy. OC76 has very moderate leakage

Anders suggestion of GT404 sounds like a great one for NPN Russian stuff

Thanks for the compliments. That build has mismatched caps, some tayda resistors, a bad paintjob, etc so it’s not all prestigious but sounds cool. I have 2 DAM pedals and they are outstanding quality. Don’t have any Pigdog but Steve is badass. His Buzzaround looks amazing. I’m a fan of both of them.

[hobbyseason]

Cool, i have a heap of japanese 2SB-xx as well as russian stuff but i havent had much luck with that.

Any more pics of your builds online?

[Travis]

I hear ya man!

I’ve posted tons of pics in the show your pedal guts thread. Hopefully I didn’t use photobucket for everything

[GrooveChampion]

Travis, serious question now. Is there any sound difference to using these caps and resistors you use?

[Travis]

I don’t think you would actually hear a difference, but there technically are differences when you use higher rated resistors

I got some of those WIMA TFM because I saw them for same and thought it would be cool to make a geeky MKII with some of the original caps (I also have Iskra film and polystyrene caps used in the TB)

It’s possible that a part can be higher quality without sounding different as well.

I will record a clip when I get a chance but yeah I wouldn’t say my pedal sounds the best cause I used ______ cap it’s really more about the transistors

Since we’re just making a fuzz box I’m just using these parts for fun.

If it were a pro audio or hifi unit the part types are more of a consideration

[Travis]

It’s also a lot about selling them for me

[GrooveChampion]

Sadly like in muscle cars of the sixties, numbers outrank functionality. People need to stop listening with their eyes. I mean it looks amazing and all but I cant help but think that people are listening to specs instead of the sound.

[hobbyseason]

Where do you sell these travis? Under what name?

[Travis]

I’ve sold TBs on eBay, no brand name. My eBay name is mastertrav3

I haven’t been actively building pedals for a while so my eBay store is currently empty. Still got more old stuff to sell but been busy

Just got some PCBs made under the name Milksack FX. Because I thought they needed a name.. I’m sure everyone will love “Milksack”

[hobbyseason]

Cool, what circuits have u had made up?

[tracer03]

I just built this with some Russian GT404s:
Q1 - 72/.10
Q2 - 82/.21
Q3 - 127/.39

After playing with the bias voltage, got it to 4.5 on the collector of Q2 and it roars like Godzilla.

[Travis]

hobbyseason wrote

Cool, what circuits have u had made up?

Nothin crazy just a Menatone Fish Factory kinda thing for my little brother.

Looking forward to more PCBs though


Tracer that sounds cool!