Part 2 Problem and a challenge OPAMP Distortion

[sonofspy]

OK thanks to RG and Chocklitbrown, (and more practice with DIYLayout),

I have pieced together this:



I'm out of practice so I still need help connecting the dots.

PLUS What improvements can you guys come up with?

This was a good-sounding pedal and was probably unique

For further impetus here's what it sounds like: http://www.Paradiserenovations.com/ariseclipsmall.mp3

[circa 1987]
Signal chain: Gibson L6S-->Anderton compressor-->This Fuzz-->Digitech DD--> Crate 1 -->Crate Kicker


Your help is appreciated!

Son Of Spy

[slacker]

Interesting circuit, looks like it's using 2 inverting opamp stages and using opamp distortion to get the sound.
I drew up a schematic from your layout to make it easier for people to see what's going on.



This might jog someone's memory as to what it is.

Here's a guess at how the rest of the layout should be wired up. I've reversed the input and output as these were the wrong way round. 9 volts needs to be connected somewhere on the line where I've shown it, you might be able to see on the circuit board where it used to be attached.
The volume pot is wired up in the standard way so that's a safe bet, but the fuzz pot is a complete guess. It will vary the fuzz wired up like this but it might not be how the circuit was originally wired up.

I don't suppose you can see where any more wires were connected to the board or know what value the pots were?

[WGTP]

Sort of looks like an op amp muff fuzz.  Check out the Mockman at ROG.   

[sonofspy]

Yes thanx slacker and WGTP

I can see the similarities..

http://www.storm-software.co.yu/diy/layouts/mockman.diy

and in your gallery WGTP
http://aronnelson.com/gallery/WGTP/AlteredMuff?full=1

I think you mostly have the wiring correct, slacker, +9 definitely connects there...and the volume

Earlier when looking for the Mockman I thought I saw a variation with the fuzz control built off the volume,
can't find it now..are there other likely locations where the fuzz countrol could be attached, like at the input
between the blue .47 tantulum cap (labeled +47 Y5...Is that it's value? (Note to self:must do research on
tantulum) and the 10K resistor?

Will try this with a pair of 100K audio pots and post back tomorrow.

Thanks everybody!:D

Son Of Spy

[WGTP]

http://www.diystompboxes.com/pedals/mfuzz.gif

Check out Gus' mods.  That is where I started.  I'm not expert, but it appears the second op amp is open loop, which means MEGA gain.  Adding a pot, 1meg for example, across the op amp would add lots of control.  The gain on the first stage is only 3.3.

The .47uf/10K at the input set the impedance and frequency response.  There is a suggestion on the Mockman to replace the 10K with a 100K pot.  I would go 250K my self.  That will adjust both the input volume, but also the tone. For just volume, try pots in the feedback loops.  Also check Black Cat OD.  It is just op amp IIRC.

[sonofspy]

Been a busy week, so it was only yesterday that I found time to do the suggested hookup.

Using two 1Meg pots...
Volume works.
Fuzz control does not work. Instead it sort of does a reverse volume thingy, no distortion at all.
LED does not light up (will check for "Dead")
Battery Heats Up big time.

Suggestions for alternate fuzz pot location?

and hooking up 1Meg pot "Across IC" Where?

Best Regards,

sonofspy