Mad Professor - Snow White Auto Wah  [traced]

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Re: Mad Professor - Snow White Auto Wah

Postby Barcode » 06 Sep 2011, 21:21

Just posting as a placeholder so I can have the thread in my "Your posts" area.
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Re: Mad Professor - Snow White Auto Wah

Postby Seiche » 06 Sep 2011, 23:45

Barcode wrote:Just posting as a placeholder so I can have the thread in my "Your posts" area.

laaame *cough* *cough* [smilie=a_peek.gif]
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Re: Mad Professor - Snow White Auto Wah

Postby Barcode » 07 Sep 2011, 05:17

Seiche wrote:
Barcode wrote:Just posting as a placeholder so I can have the thread in my "Your posts" area.

laaame *cough* *cough* [smilie=a_peek.gif]

:lol: It's become my notepad for threads I want to keep track of!
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Re: Mad Professor - Snow White Auto Wah

Postby ckyvick » 07 Sep 2011, 09:14

Barcode wrote:
Seiche wrote:
Barcode wrote:Just posting as a placeholder so I can have the thread in my "Your posts" area.

laaame *cough* *cough* [smilie=a_peek.gif]

:lol: It's become my notepad for threads I want to keep track of!

Someone didn't notice the "subscribe topic" button :lol:
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Re: Mad Professor - Snow White Auto Wah

Postby Barcode » 07 Sep 2011, 16:34

ckyvick wrote:
Barcode wrote:
Seiche wrote:
Barcode wrote:Just posting as a placeholder so I can have the thread in my "Your posts" area.

laaame *cough* *cough* [smilie=a_peek.gif]

:lol: It's become my notepad for threads I want to keep track of!

Someone didn't notice the "subscribe topic" button :lol:

And I still don't. Where is it? I looked all over the place for it. (And I'm sure I'll feel like a bonehead once it is pointed out...) :slap:

EDIT: THERE IT IS!!! Wow, it's way down there at the bottom, in tiny little letters... Lame.

Ahem. Carry on.
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Re: Mad Professor - Snow White Auto Wah

Postby devastator » 09 Sep 2011, 16:26

John3 wrote:I just did the R18 and Cap mods, didn't do the diode, and it is a amazing change. I always liked the pedal, but this makes it breath so much more. It gets a better quack and the knobs seem to be much more responsive overall. Thanks for the tip. :applause:


looks intersting . I'm very unpleased with that box , too much weak and hard to set . The filter is barely acting.

Maybe I'll give a try to the R18 mod .
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Re: Mad Professor - Snow White Auto Wah

Postby coldcraft » 12 Sep 2011, 03:45

speaking of the R18 mod, couldn't you just change the sensitivity pot to log for smoother control of the lower range?
Black Dynamite wrote:you need to shut the fuck up when grown folks is talkin.
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Re: Mad Professor - Snow White Auto Wah

Postby jorgelopes » 24 Oct 2011, 05:30

devastator wrote:
John3 wrote:I just did the R18 and Cap mods, didn't do the diode, and it is a amazing change. I always liked the pedal, but this makes it breath so much more. It gets a better quack and the knobs seem to be much more responsive overall. Thanks for the tip. :applause:


looks intersting . I'm very unpleased with that box , too much weak and hard to set . The filter is barely acting.

Maybe I'll give a try to the R18 mod .


Hey, try the changes mentioned on the previous page, changing R8 for an 1u elet cap and D6 for an 1N34. It gave me a huge difference in the best possible way.

cheers

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Re: Mad Professor - Snow White Auto Wah

Postby Ripdivot » 14 Jan 2012, 02:55

Does anyone know a simple mod for the snow white the will reverse the sweep via a toggle switch? In other words the filter currently goes from closed to opened when you play a note but I would also like to be able to make it go from opened to closed. This would add a lot of versatility to the pedal and I think it would sound cool. :hmmm:
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Re: Mad Professor - Snow White Auto Wah

Postby Liquids » 14 Jan 2012, 12:47

You might get some insight if you compare the envelope section to the mutron/q-tron which offers this as a feature.

However, switching in/out an inverting op amp stage between the input buffer and C3 would work, even if crudely.
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Re: Mad Professor - Snow White Auto Wah

Postby ppluis0 » 06 Feb 2012, 02:56

What do you think about this... :roll:

http://www.guitarpcb.com/apps/webstore/ ... ow/1466721

Just click on the "SWAW Build Plans" hypertext to see a schematic, part list, board placement, wiring and so son.

Cheers,
Jose
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Re: Mad Professor - Snow White Auto Wah

Postby Seiche » 06 Feb 2012, 08:04

ppluis0 wrote:What do you think about this... :roll:

http://www.guitarpcb.com/apps/webstore/ ... ow/1466721

Just click on the "SWAW Build Plans" hypertext to see a schematic, part list, board placement, wiring and so son.

Cheers,
Jose

this has been discussed a couple of pages back. he (my7of9) has been of great help explaining the circuit and possible mods. i'm thinking about picking up a pcb to be honest.
http://freestompboxes.org/viewtopic.php?f=7&t=7012&p=160787#p160787
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Re: Mad Professor - Snow White Auto Wah

Postby ITO » 27 Nov 2012, 19:44

Hi guys! Sorry for my bad English - I'm from Russia. What voltage should go on pin 1 and 16 LM13700? I have changes in the range of 1,2 ... 1,3 volts, what should it be?
Thank!
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Re: Mad Professor - Snow White Auto Wah

Postby Ice-9 » 27 Nov 2012, 23:31

ITO wrote:Hi guys! Sorry for my bad English - I'm from Russia. What voltage should go on pin 1 and 16 LM13700? I have changes in the range of 1,2 ... 1,3 volts, what should it be?
Thank!


1.2v - 1.3v sounds about right for the control voltage at pin 1, it will vary a bit with the bias control and the guitar msignal.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?
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Re: Mad Professor - Snow White Auto Wah

Postby ziash » 04 May 2014, 19:19

Hello guys,

I am trying to build this pedal and I'm getting trouble with it.

I'm using a very board and the schematic you post in the previos pages. I've got the problem with the sensitivity part. When I check the signla out of the operational I obtain a 6 - 7 DC voltage signal and over it my guitar signal.

If I take the TL072 out and I check the inputs I obtain two signal without DC level. But if I plug the TL072 the negative input from the operational rises to 6 -7 V.

I think that the problem could be with the 220n capacitor that I have choosen. Does anyone could help me?

P.D : the capacitor is a 220nF 0.22uF 100V 5% Polyester Film Box Type Capacitor from tayda electronics.
http://www.taydaelectronics.com/capacit ... citor.html


Thanks in advance.
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Re: Mad Professor Snow White Auto Wah [gut shots,schematic,p

Postby 2lane » 20 Feb 2015, 16:49

riesling wrote:The update

I made some minor routing changes and replaced the 100µ/35V cap with a 100µ/25V

The archive contains one pdf with complete project information and two EAGLE files

WAW_v014.zip


By the way: NOT FOR COMMERCIAL USE

Have fun with it


i can't download.
file is missing
please share again thank you
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Re: Mad Professor - Snow White Auto Wah

Postby Lgs_1995@hotmail.com » 28 Oct 2015, 04:31

Hello everyone, I've built my own Snow White Auto Wah but it does not sound right (It does no go "wah"). I've checked the circuit with a tester and this are the results: Image
Could someone please tell me if these are correct? There a re no soldering bridges on my pcb (I've checked) so my best guess is a bad component (It seems weird that I have almost 3,8v in the base-emiter junction in one of the two BJT, but that's just a guess).
I really want this proyect to work, if someone could help me out I would really apreciate it.

I'm sorry for my english, it's not my first language.
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Re: Mad Professor - Snow White Auto Wah

Postby BJF » 11 Mar 2016, 10:45

Hi

If you do not get it working check sidechain and also that the Lm13700 is working

I will say I am flattered, this is a basic design and in case you wonder what the zeners do those are there to limit peak when powersupply is higher than 9V so for 9 V operation they do nothing but when you run at 12V or higher they keep the range.


Have fun
BJ
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Re: Mad Professor - Snow White Auto Wah

Postby Ice-9 » 09 May 2016, 22:53

BJF wrote:Hi

If you do not get it working check sidechain and also that the Lm13700 is working

I will say I am flattered, this is a basic design and in case you wonder what the zeners do those are there to limit peak when powersupply is higher than 9V so for 9 V operation they do nothing but when you run at 12V or higher they keep the range.


Have fun
BJ
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Hi BJF.
In the pedal I looked at there were no zeners placed in the circuit at all ?
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?
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Re: Mad Professor - Snow White Auto Wah

Postby Ripdivot » 17 Nov 2017, 19:32

Does anyone know if there is a way to add a switch to this pedal so the filter closes instead of opens? I love the "wah" tone but I would also like to get the "oye" sound.
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