By popular demand, I give you the Mad Professor Snow White AutoWah. Now stop pestering me for it. ;) This was a pretty complicated circuit to fit on a single-sided board, so there are a few jumpers (one of which is super long–bugs me, but it was the only way to make it work), but if you play your cards right you should be able to squeeze it into a 1590B like the original.
finally, SWAW has arrived.
ReplyDeletehappy new year to you brother!!!
Thank you so much!!!! I have really been wanting to build this. YOU ROCK!!!!!
ReplyDeleteVery nice, tahnks!!!
ReplyDeleteHi, I found a difference between the layouts; pin 4 of the LM324 is connected differently, what is the correct one?
ReplyDeleteWhoops. I'll fix it. The PCB side is correct. Pin 4 of the 324 goes to the voltage rail. Thanks for catching that.
DeleteGood day sir do you have a update of this schematics or new diagram of this work
DeleteWould I be able to replace the 2N5457 with a BF244A as long as I correct the pin placement?
ReplyDeleteYou could socket and try, but the datasheets aren't all that similar. Probably best to stick with the 5457.
ReplyDeleteOk, thanks for the reply. I haven't been able to get my hands on a 5457 since they have been discontinued.
DeleteI guess I could try ordering some Chinese ones from eBay.
DeleteOk, so I did some googling, and the BF245A came up several times as a replacement for the 5457. Can you get those?
DeleteI had a hard time finding them on Tayda's website. I tried the BF245B and the BF244A. Not sure if it's the FET that's the problem, but there is something very off with my build.
DeleteHi, thanks you for your work.
ReplyDeleteMy Snow White work bad. My problem is that I hear only a continuous buzzing sound when I press the swich. The buzz up and down by operating the BIAS potentiometer, but also up and down a bit by operating the RESONANCE, but less. I've been looking for the solution reading post and watching the electric scheme, but I can not find it. I checked everything but everything seems fine. I have printed the circuit and I have followed it too and I have bought again the main components to check one by one but it is the same. Any idea?
I built this yesterday. i can't test it yet because I thought I had some LM324 chips but only have TL074 and LF347. Those both pull the rail down too much. Maybe if I bypass the 47R but I think I will just wait for my order to arrive and just install the LM324. I'm posting right now because it seems the 100uF cap is connected wrong. I believe it should go from + rail to ground. As drawn above it connects pin 13 of the LM13700. Can you confirm this?
ReplyDeleteAnd is it posible that by this I were hearing the sound of ground (my buzz)?
ReplyDeleteConfirmed. It was the incorrect positioning of the capacitor in PCB. The + of capacitor has to go in V + (red line of PCB).
ReplyDeleteThanks
Yes, that would be the problem. I'll fix that in the layout. Thanks for catching that and glad your sorted it out!
DeleteI have been taking information and in some webs is recommended to change some components (D5 1N4148, R18 47K, D6 1N2A4 and C8 1uf) because them improve the sound.
DeleteI have repared the error with the capacitor (C7) and I have added that changes and it sounds great
can you point out where D5,D6,R18 and C8 are?
DeleteIs the layout already fixed?
Deletewhich side of 2.2uf polarity?
DeleteHave any of you tried using TL074 for A1? I am still waiting for some LM324s to come in I have tried it with the TL074 and can't get it working. I see a few layouts that use a pair of TL072s so I thought the TL074 would work. Can it work with maybe some changes?
ReplyDeleteThanks, Terry
I have a TL074 in mine. I tried an LM324, and it was similar. I've seen some other layouts with TL074 too.
DeleteTank for share
ReplyDeleteDoes anybody build it? Works great?
ReplyDeleteConfirmada la ultima versión. Gracias por la información. Saludos
ReplyDeletelo pudiste echar andar solo con la imagen del layout actual o necesitaste corregir algo? gracias
Delete
ReplyDeleteHello, I have mounted this circuit but I have no sound, I have checked everything and it is corrector according to the design of the pcb, somebody help me ????
thanks and regards
Hi, i had trouble with the decay pot, it didn't worked 'til i changed the 4k7 resistor(r27 in schematic) in series with it for a 47 ohm resistor, like it shows in this schematich ttps://elektrotanya.com/PREVIEWS/63463243/23432455/egyeb/mad_professor_snowwhite_autowah_guitar_effects_schematic.pdf_1.png
ReplyDeleteI saw another layout schem. and layout with this value and changed my 4k7 for a 47R. That was just what I needed to get this working like the demos, thanks!
DeleteHello your blog is awesome !!! .... i see i don't have 2N5457, Lm324, Bc550c lol but i have J201, TL074 and Bc547/48/49 so if i'm replace that would be oke ??
ReplyDeleteWorth a shot! Be sure to use sockets
DeleteHello, how to modify it for bass use? like Snow White Bass Auto Wah.
ReplyDeletethanks in advance.
hello, I have the pedal working but improvised, I explain with the in normal PCB mode no sound comes, nothing is heard but the pedal is active and if I move the pots they act because the filtering is heard in the departure.
ReplyDeleteIn a casual way checking the copper and solder tracks I made a bridge between the in and the polyester condenser track of 220nf, in the positive leg that goes from the 1uf electrolytic to this capacitor, in this way if I have an input signal and the pedal works, can you help me find the problem because I do not get the signal for the pc in?
everything is ok, solders, components and copper tracks of the pcb, I have repeated the project twice and both have given the same problem.
Thanks in advance and greetings
I seem to have the same problem. However, I did not try jump that you described. Just active but no effect. Anyone else?
Deletehola, tengo el pedal funcionando pero de manera improvisada, me explico con el in de modo normal de la pcb no llega sonido, no se escucha nada pero el pedal esta activo y si muevo los pots estos actuan por que se escucha el filtrado en la salida.
ReplyDeletede manera casual revisando las pistas de cobre y soldadura hice un puente entre el in y la pista del condensador de poliester de 220nf, en la pata positiva que va del electrolitico de 1uf a este condensador, de este modo si tengo señal de entrada y el pedal trabaja, pueden ayudarme para encontrar el problema por que no me entra la señal por el in de la pcb?
todo esta ok, soldaduras, componentes y pistas de cobre de la pcb, he repetido dos veces el proyecto y las dos han dado el mismo problema.
Gracias de antemano y saludos
whether i use a pcb or verolayout i still get the same problem. not enough effect. sounds more like a subtle cocked wah. filter dosent really open up.
ReplyDeletechange the bleeder diode (upper 4148 going to the 2.2 uF cap) to germanium
Deletewich germanium should i use i have the same problem?
DeleteGood evening! I need your help. I soldered the schematic, everything works, the effect is. The problem is the following: a too small signal at the output and when there is a strong attack on the strings, a slight distortion appears. Tell me what to do? I apologize for the googl translator.
ReplyDeleteI followed the diagram above.. it sounds Autowah, but there is some continuous bass hiss sounds like "woooooooovvvvvv" while the pedal is switched on.. can you help me. please..
ReplyDeleteI am using 1A 9v power adapter.
DeleteHELLO ! WILL IT WORK WITH A LM3600?????
ReplyDeleteLM13600 works pretty nice ;)
DeleteSilly question, Can I use a 7.5K resistor instead of the 7.9k?
ReplyDeleteYou can probably get away with that. Or google parallel resistance calculator and make a 7.9k resistor out of 2 other values.
DeleteThanks. And... Thank you for all of the great work that you do and share.
DeleteDidn't see the drill template in the list. Which drill template would you recommend for this project?
ReplyDeleteSince the pots aren’t board mounted drill layout is up to you.
Deletegotcha
DeleteAloha, according to the data sheet for the 78L05 it indicates that pin 1 is V out,2GND and pin3 Vin. I'm confused because on the layout it is reversed..Am I missing something here? Thanks.
ReplyDeleteI say reversed only in the shape (flat side, round side). IGO labled correctly. Hope that made sense.
ReplyDeleteOkay, after some more testing I've found that the data sheet is incorrect. I should never doubt you. :)
ReplyDeleteI found another data sheet and it is a match to the layout. Good Idea to breadboard 78L05 to be sure.
ReplyDeleteI've built this circuit twice (pcb) and still have no effect, sound but no wah. Followed layout exactly and same result. Signal is low volume through amp. Any ideas?
ReplyDeletedid you find the problem? I got the same problem
Delete125Signal, be sure to use a genuine 2n5457. I was building a different effect that uses this JFET and had the same issue - clean sound with pedal on, no effect. It may not be the same, but worth checking anyway. I got no results using 2n5457 from AliExpress, as they were obviously fake, but genuine transistor brought the pedal to full working order as soon as I put it in the socket. Good luck!
ReplyDeleteHi! I've bould it but I have a low volume when effect it's on. Solutions? thanks
ReplyDeleteill already make this circuit and the result is nothing soundz like a normal tone littlebit high prequenzy... please enginer give the right detail of this circuit true component please
ReplyDeletei play my guitar using this circuit after build... this auto wah pedal circuit is a big lie. cleantone only no wah wah effects only cleantone
ReplyDeleteBeautiful sound, guitar & bass, perfect for almost everything, easy build and of course SPERCLASS layout!! ThankS!!!
ReplyDeleteVerified, I made this board with the following mods:
ReplyDelete1 - Cap. 2.2uF -> 1uF (faster decay sound)
2 - Diode 1n4148 -> 1n60 near the new 1uf cap(increase range)
3 - Resistor 20k -> 47k near Sens3 (Humbucker's attenuation)
4 - Fet 2n5457 -> mpf102 (didn't found 2n5457)
5 - NPN BC550C -> BC550B (didn't found BC550C)
And i gotta say, WHAT A WONDERFUL SOUND, I'm lovin it. GREAT JOB AND MANY THANKS FOR SHARING !!!
En serio te funciona con esta pcb?
DeleteYo la he hecho y no funciona
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DeleteFunciona bien, no tuve problemas para fabricar el PCB (lo hice usando el método de transferir tóner a una placa de fenolita), pedí el CI LM13700 de aliexpress y el resto de componentes que compré en mi ciudad, las únicas modificaciones aparte de las mencionado anteriormente. De hecho, fue la primera placa que funcionó por primera vez. ¿Puedes decir cuál fue el problema que sucedió con tu PCB? ¿Podré ayudarte de alguna manera? (Perdón por el español, estoy usando un traductor, soy de Brasil)
DeleteI really enjoyed creating this pedal, recorded a simple demo.
ReplyDeletehttps://youtu.be/RfZ2kz-DI3c
Hi everyone, I can't find the C1M pot, can I replace with A1M/B1M pot? Or any idea? Thanks
ReplyDeleteVerified!i used 2n3904 and 13600 ,lf444 for the ic
ReplyDeletegud am sir jun?pde ba magpatulong regarding sa circuit po na ito salamat po sa reply niu distorted kasi sya pag napalakas kalabit sa string eh saka pag naka full volume gitara salamat po 2n5457 lm13700 2n3904 po gamit ko
Deletecan anyone help me i mad this circuit it works but theres a loud distortion when strong attack on single strings is made i use 2n5457 lm13700 and 2n3904 thanks in advance
ReplyDeletecan anyone know what is need to adjust to make it work perfect thanks
ReplyDelete