Mad Professor - Stone Grey Distortion  [traced]

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roseblood11
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Post by roseblood11 »

A friend gave me one of these pedals today. First glance: Based on CD4049ube, two 2n3819 Jfet's, one opamp. I´ll retrace it next weekend, I guess it will be easy as most traces are visible.
Sound is good, but not overwhelming...

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roseblood11
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Post by roseblood11 »

ups... typo: itś a CD4069ube

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roseblood11
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Post by roseblood11 »

Parts values:

r1: 4,7k
r2: 14,7k
r3: 470k
r4: 470k
r5: 200k
r6: 1m
r7: 1m
r8: 1m
r9: 1m
r10: 1k
r11: 100R carbon
r12: 10k

c1: 47n
c2: 47nF
c3: 100pF ceramic
c4: 100pF
c5: 100pF
c6: 15pF
c7: 2,2nF
c8: 100nF
c9: 10nF
c10: 100µF
c11: 4,7µF
c12: 22nF

d1: Zener, maybe 5,1V
d2: 1n4007

u1: tl051
u2: cd4069ube

t1: 2n3819
t2: 2n3819

p1 (distortion): 1m log (measures almost 1,2m), ("10A1M")
p2 (tone): 50k log
p3 (volume): 50k log

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ShortScaleMike
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Post by ShortScaleMike »

Excited about this one!

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Sikor
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Post by Sikor »

I've played one yesterday :)
I like it a lot, but it was very bright.
While playing through bright clean channel I had to turne Tone knob at least down to 9 o'clock.
Untill 3 o'clock at the Gain knob it was becomming more gainy, but still dynamic.
Turning gain more didn't really brought new gain, but mostly compression.
SGD has definitely my interest :)
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roseblood11
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Post by roseblood11 »

Done!

I´ll have to redraw the schematic before I can post it. Veroboard layout is finished as well, I´ll build it on friday to verify the schematic.

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Post by Lawnchair »

Irons hot.

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Post by ShortScaleMike »

Fast work! I was going to offer to do a vero layout but it seems you've got it all under control - nice work.

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roseblood11
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Post by roseblood11 »

pictures:
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mad prof stone grey board2.jpg
mad prof stone grey board2.jpg (40.16 KiB) Viewed 7793 times
mad prof stone grey board1.jpg

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roseblood11
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Post by roseblood11 »

schematic and veroboard layout.

UNVERIFIED!
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mad prof stone grey vero.gif
Mad Prof stone grey schem.gif

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WhiteKeyHole
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Post by WhiteKeyHole »

I wonder by how much, if at all, the Bearfoot Model H differs.

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roseblood11
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Post by roseblood11 »

Schematic and veroboard layout are VERIFIED!

I used a 1n5817 schottky for D2 (because of the lower voltage drop) and a OPA134 instead of the TL051. There´s only a subtile difference in sound compared to the original pedal, but I definitely prefer the clone.

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Post by muhd85 »

Hi! just to report that i've build that layout and i would say that it sounds marvelous! just like the video. but i used tl071 instead of tl051.. i like this much better than bjf DRD.. its worth it! :D

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Post by DimebuGG »

PCB...
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Source Gate Drain-stortion.pdf
(51.13 KiB) Downloaded 1030 times
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roseblood11
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Post by roseblood11 »

This is my pedal... I only had that big mojo carbon comp resistor for the 100R. It looks good, but it doesn´t fit into the enclosure... :slap:
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stone grey built.jpg

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euronymous0001
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Post by euronymous0001 »

roseblood11 did you try to sub the fet with other types (e.g. J201, 2N5457 and/or MPF102 )

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roseblood11
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Post by roseblood11 »

They are just uses as clipping diodes. You can sub them with whatever you want.

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Post by chriscustom »

euronymous0001 wrote:roseblood11 did you try to sub the fet with other types (e.g. J201, 2N5457 and/or MPF102 )

good result also with the type of BF245A

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Post by chriscustom »

DimebuGG wrote:PCB...
R4=470k.

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Kaos
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Post by Kaos »

Oh yeah!

You guys are my personal heroes of the day!
I just saw a demo( of the pedal and instantly wanted it. That'll beef up my Fender Supersonic.

Cheers
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