Mad Professor - Snow White Auto Wah  [traced]

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abfackeln
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Post by abfackeln »

In the great debate for the Tracer Fund projects, this pedal has come up a couple of times. There was even a cool demo posted (

) that really got my interest up, even though I've never really been into auto wahs. Well, I "took one for the team" and snagged one - just came in today.
Played around with it for about 30 minutes before I couldn't stand it anymore and had to open it up. It tracks really well, but it does take a little getting used to and you have to adjust the way you play to get the most out of it. Fun little pedal...
Anyway, enough banter - here's the first round of pics to get us started. It's a double sided board, but most of the bottom side appears to be ground plane and vias. This thing is tight... I'll be working on a layout (perf also/maybe?), but I think there's some folks around here that get it done way faster than I do.....

Image

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Greg
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Post by Greg »

Wow.. that's gonna be hard to trace without removing components i would think ?
culturejam wrote: We are equal opportunity exposure artists.

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Post by chicago_mike »

an lm324 and a lm13700 along with a couple npn or pnp's. very similar to the agent 00funk
Skyline FX 2013

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Post by Orkspalter »

...
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Post by Orkspalter »

How blue is blue and how violet is violet in term of resistors:-D I am giving up finding out the values by looking only at the pictures...

R1
R2
R3
R4 1M
R5 10k
R6 1M
R7
R8
R9 4,7M
R10
R11
R12
R13
R14 4,7k
R15 4,7k
R16
R17
R18 20k
R19 4,7M
R20
R21
R22
R23 10k
R24 20k
R25 1k
R26
R27 4,7k
E28
R29


C1 22n/63V 5% Wima MKS
C2 Wima MKS
C3 0,22uF/63V 10% Wima MKS
C4
C5 22N/63V 5% Wima MKS
C6 22N/63V 5% Wima MKS
C7 100uF/35V El.
C8
C9
C10 0,1uF/63V 5% Wima MKS
C11


IC1 LM13700N 16DIP National Semiconductor
IC2 LM324N 14DIP ST Microelectronics


D1
D2
D3
D4 1N00X
D5 1N00X
D6


Q1
Q2
Q3
Q4

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Post by abfackeln »

These should help.... I've been copying the layout into Pad2Pad, so I can get a better idea of connections and start a schematic, but it's becoming obvious that I'm going to have to pull the ICs because of all of the traces and through-board vias that are hidden under the chips.


R1 5K1
R2 330R
R3 330R
R4 1M
R5 10k
R6 1M
R7 330R
R8 4.7K
R9 4.7M
R10 20K
R11 20K
R12 330R
R13 330R
R14 4.7K
R15 4.7K
R16 4.7K
R17 10K
R18 20k
R19 4.7M
R20 47R
R21 47K
R22 47K
R23 10k
R24 20k
R25 1K
R26 7.9K
R27 4.7K
R28 100K
R29 1K


C1 22n/63V 5% Wima MKS
C2 0.068
C3 0,22uF/63V 10% Wima MKS
C4 F59 822J
C5 22N/63V 5% Wima MKS
C6 22N/63V 5% Wima MKS
C7 100uF/35V El.
C8 2.2uF
C9 1uF
C10 0,1uF/63V 5% Wima MKS
C11 1uF


IC1 LM13700N 16DIP National Semiconductor
IC2 LM324N 14DIP ST Microelectronics


D1
D2
D3
D4 1N4XX2
D5 1N4XX2
D6


Q1 C550C(?)
Q2 C550C(?)
Q3 LM78L 05AC2
Q4 K170
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Post by Orkspalter »

Thanks for the missing values! The two ICs are avaiable from futurlec, the LM324N for 0.25$, the LM13700N for 1,10$ if the ICs would be destroyed from unsoldering....but guess you are willing to sell it after cloning so be careful:-P

Thanks for putting your time and money into that cool pedal and making it available (pictures )for us here, that should be appreciated!!! The whole tracers found thing is going sooo slowly and though, so much talking and waiting, talking again etc....this here and of course the TECH21 British/Blonde degooping thread is like a breath of fresh air.

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modman
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Post by modman »

Great contribution, I had a look. Nothing's certain but

Wouldn't R18 etc be 200k?
R1 5k1
R2
R3
R4 1M
R5 10k
R6 1M
R7
R8 this look like a diode
R9 4,7M
R10 20k
R11 20k
R12
R13
R14 4,7k
R15 4,7k
R16
R17
R18 20k
R19 4,7M
R20 47k 10%
R21 47k 10%

R22
R23 80k
R24 20k
R25 10k
R26
R27 4,7k
R28
R29


C1 22n/63V 5% Wima MKS
C2 Wima MKS
C3 0,22uF/63V 10% Wima MKS
C4
C5 22N/63V 5% Wima MKS
C6 22N/63V 5% Wima MKS
C7 100uF/35V El.
C8
C9
C10 0,1uF/63V 5% Wima MKS
C11


IC1 LM13700N 16DIP National Semiconductor
IC2 LM324N 14DIP ST Microelectronics


D1
D2
D3
D4 1N00X
D5 1N00X
D6


Q1
Q2
Q3
Q4
Attachments
LM13700N.pdf
LM13700N datasheet
(635.22 KiB) Downloaded 195 times
STMicroelectronics-LM324N.pdf
LM324N datasheet
(826.23 KiB) Downloaded 141 times
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abfackeln
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Post by abfackeln »

modman wrote:Wouldn't R18 etc be 200k?
R18, et al is indeed 20K (red/black/black/red), and verfied with a DMM.
R8 is indeed an 1/8w resistor
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Post by IggY »

what`s standing there to the right of R3?

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Post by tube-exorcist »

IggY wrote:what`s standing there to the right of R3?
That´s a little secret which I will tell you, when you have finished (and posted) your tracing - before you won´t need to know it.
"I've noticed there's an inverse relationship between cost of gear and talent. If you need the most expensive gear to get decent tones, then you suck as a player."

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Post by roseblood11 »

IggY wrote:what`s standing there to the right of R3?

Looks like a resistor, maybe the same value as R16?

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Post by SPeter »

roseblood11 wrote:
IggY wrote:what`s standing there to the right of R3?

Looks like a resistor, maybe the same value as R16?
Me too!
:)

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Post by SPeter »

SPeter wrote:
roseblood11 wrote:
IggY wrote:what`s standing there to the right of R3?

Looks like a resistor, maybe the same value as R16?
Me too!
:)
But 0.125W!

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Post by roseblood11 »

SPeter wrote:
roseblood11 wrote:
IggY wrote:what`s standing there to the right of R3?

Looks like a resistor, maybe the same value as R16?
Me too!
:)

You look like a resistor? :D :D :D

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Post by abfackeln »

roseblood11 wrote:
IggY wrote:what`s standing there to the right of R3?

Looks like a resistor, maybe the same value as R16?
Yes, it's a resistor, and yes, same value as R16 -

Orkspalter - can you add another R label for this one in your reference photo?
Image

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Post by tomtom »

an lm324 and a lm13700 along with a couple npn or pnp's. very similar to the agent 00funk
At first I tought about a modded DOD FX25B

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Post by Orkspalter »

I can´t edit the first photo with numberings so heres the top view photo with the added resistor R30
Attachments
Snow wah top.jpg

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Post by Liquids »

I can't wait to see the schematic for this thing and breadboard it!

Hearing those clips a few weeks back was a real inspiration for me, and sent me working on filters when I've had a few spare minutes since then....

To top it off, now I've found this thread. I never imagined there was enough interest in this one to see the actual circuit so close to being traced so soon... :thumbsup :applause: Yeah!

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Post by abfackeln »

I'm about 2/3 of the way through with creating the schematic. It's been slow going - I had some other projects come up this week, and I'm using Eagle for the first time (thanks for the tip madbean!), so there's been a learning curve involved. I also had to remove one of the ICs, and the traces/pads are like rice paper. I'm hesitant to remove the second IC.... so I'll see how far I can get and then post what I have.....
Image

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