There is an error in this build. The 220n that connects to the output is connected to the wrong side of the 100n, it needs to connect on Row J instead.
On the Park Auto Wah when I made that I left the rate led positive leg on the board where indicated but attached the ground to the 3pdt as I would normally for an LED. And it switches the ground off to it so it can be both rate and an indicator LED. Assuming that would work here as well, I'll find out once I build it and get it boxed up I guess.
awesome thanks, the ldr's I have have don't hold in sockets worth a .... Leads are too thin I guess, I'll just use the same type I used on the shoot the moon.
I've been messing with this circuit quite a bit trying to get it to sound right and I thought sharing my work here might be of use to anyone who is doing the same. First: the biggest factor in getting this effect to vibrato with decent depth is the LDR. The designer's website claims they only build them when they can get "proper" LDRs, and so they only produce these pedals in limited quantities these days. I had the best results with the widest sweep I could get: some Juried Engineering-made GL5549's - which have about 150k light and 10m dark resistance. I also used a superbright LED. As far as the speed is concerned, the range is limited and if you want slower, you will lose top speed - but, per the discussion over on an old Madbean forum thread, if you swap the 1uF electros - the ones that connect to the base and the collector of Q2 - for 2.2 uF, it moves the overall speed range back to a slightly more pleasing sound.
I'm having another crack at this and have ordered the recommended LDR. Re. Slowing down - is it just the 2 electros at 2.2uf or the one on the far right as well?
Hey Ian - I just revisited this post recently and noticed that you had asked me a question about it, like A YEAR ago... sorry I never got back to you - try as I might to get notifications from this blog to go to my email, I just can't seem to make it work. I have a highly modified layout I can send you for this that I am quite happy with. You can hit me up at capitalistdeathculteffects at the gmail dot coms and I'll send it to you if you want. I've finally gotten it to where I like the sound of it.
Tried building this last night, wasn't working, spotted a the leg of a capacitor (220nf) was in wrong row. Spotted two microscopic bridges and sorted them. Went over it all with a fine toothed comb and can't see anything out of place. I'm getting a bypass signal and when the pedal in on I'm getting a guitar signal, but no effect, all be it with a slight change in tone.
Traced the circuit with an audio probe, the first part of the circuit that goes through the LDR traces the whole way from input to output. The second part doesn't have any signal going through it, but the LED changes how it's supposed to when the pots are turned.
My guess is the LDR isn't reading the LEDs properly, I used a GL5528 because it's what I had in stock.
One thing I noticed was I'm getting continuity between both side of the cut on the last row underneath the 2.2m resistor. Should this be happening? I can see how it would from the layout, I also can't see anything that would be causing a bridge.
I've never been able to get the rate LED to function properly on this layout so I came up with a fix. 1) add a cut to G11. 2) move the Depth 1+2 leg to G17. 3) remove the jumper on H-J 16, add a jumper to G-H 14. 4) keep the rate LED+ on H17 but move the rate LED- down to the now vacant J17 pad. This puts the rate LED in series with the LED that is facing the LDR. It will not only follow the speed pot, but dim in brightness as you turn the depth pot down- giving you a much more effective modulation indicator LED.
This is definitely a super fickle circuit Chris, I have achieved the results you mentioned above just by using 2 matching green LEDs... I'll post a video shortly
Just watched the video, Ian - I've made quite a few of my own mods to this over the years to try and get the warble just a bit more pronounced. But it totally sounds like a green LED is doing a lot of the heavy lifting in that department! What LDR do you use?
The one you recommended! I wonder if it's more about having the LEDs match, because previously I had a clear one on the board (with a green one for indicator) and it was very very dim... The clear one barely lit up and I had to have the depth maxed or it would disappear. As soon as I put the green one on the circuit it was really bright. So strange!
Made this on tagboard years ago, fab vibe effect!!!
ReplyDeleteI've got all the parts in for this hoping to have it done soon....
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteThere is an error in this build. The 220n that connects to the output is connected to the wrong side of the 100n, it needs to connect on Row J instead.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteJust move the LDR 2 holes to the left and move the lower 220n leg to row J and it's verified.
ReplyDeleteThanks for catching that. the layout is updated and tagged.
DeleteCheers
ReplyDeleteHere's mine.
ReplyDeleteAs stated I think it should run a second off on LED alongside the permanently out of indicator...
Lovely effect.... not too much, not seasick... Just a nice bit of warble.
Thank you!
https://youtu.be/2mWaPhik-Oc
https://photos.app.goo.gl/QwT1MqWEXS6CQbjt7
ReplyDeleteHow did you put in and on/off led and the rate led also? Struggling to work out how I would do it!
DeleteHi mark.
DeleteIt's easier than you probably think just wire up an LED as you would any other pedal, and use the rate LED wires off the board to your second LED.
I'll take a photograph when I get home and link it here
https://photos.app.goo.gl/V3hapjfQLnnQCG2X6
DeleteAh I see now, thats pretty easy to do now I get it. Thanks for the photo, I really appreciate it!
DeleteAnd rehoused with twin LEDs....
ReplyDeletehttps://youtu.be/JNupkM3vsnI
On the Park Auto Wah when I made that I left the rate led positive leg on the board where indicated but attached the ground to the 3pdt as I would normally for an LED. And it switches the ground off to it so it can be both rate and an indicator LED. Assuming that would work here as well, I'll find out once I build it and get it boxed up I guess.
DeleteDid you end up trying the rate LED as you mentioned? Thinking of making this when I have time this weekend and not sure how I would do it.
DeleteGetting ready to build this, curious what LDR has there been good results with?
ReplyDeleteI tried a few different ones and noticed very little if any difference. In the end I used some generic Tayda LDR and a 3MM orange LED worked for me.
ReplyDeleteawesome thanks, the ldr's I have have don't hold in sockets worth a .... Leads are too thin I guess, I'll just use the same type I used on the shoot the moon.
DeleteI've been messing with this circuit quite a bit trying to get it to sound right and I thought sharing my work here might be of use to anyone who is doing the same. First: the biggest factor in getting this effect to vibrato with decent depth is the LDR. The designer's website claims they only build them when they can get "proper" LDRs, and so they only produce these pedals in limited quantities these days. I had the best results with the widest sweep I could get: some Juried Engineering-made GL5549's - which have about 150k light and 10m dark resistance. I also used a superbright LED. As far as the speed is concerned, the range is limited and if you want slower, you will lose top speed - but, per the discussion over on an old Madbean forum thread, if you swap the 1uF electros - the ones that connect to the base and the collector of Q2 - for 2.2 uF, it moves the overall speed range back to a slightly more pleasing sound.
ReplyDeleteI'm having another crack at this and have ordered the recommended LDR. Re. Slowing down - is it just the 2 electros at 2.2uf or the one on the far right as well?
DeleteCheers
Ian
Also did you remove the 27k resistor and try a 50k pot for the speed?
DeleteHey Ian - I just revisited this post recently and noticed that you had asked me a question about it, like A YEAR ago... sorry I never got back to you - try as I might to get notifications from this blog to go to my email, I just can't seem to make it work. I have a highly modified layout I can send you for this that I am quite happy with. You can hit me up at capitalistdeathculteffects at the gmail dot coms and I'll send it to you if you want. I've finally gotten it to where I like the sound of it.
DeleteTried building this last night, wasn't working, spotted a the leg of a capacitor (220nf) was in wrong row. Spotted two microscopic bridges and sorted them. Went over it all with a fine toothed comb and can't see anything out of place. I'm getting a bypass signal and when the pedal in on I'm getting a guitar signal, but no effect, all be it with a slight change in tone.
ReplyDeleteTraced the circuit with an audio probe, the first part of the circuit that goes through the LDR traces the whole way from input to output. The second part doesn't have any signal going through it, but the LED changes how it's supposed to when the pots are turned.
My guess is the LDR isn't reading the LEDs properly, I used a GL5528 because it's what I had in stock.
One thing I noticed was I'm getting continuity between both side of the cut on the last row underneath the 2.2m resistor. Should this be happening? I can see how it would from the layout, I also can't see anything that would be causing a bridge.
Any suggestions?
Sorry, the continuity is actually between the cut on either side of the 27k resistor
DeleteI've never been able to get the rate LED to function properly on this layout so I came up with a fix. 1) add a cut to G11. 2) move the Depth 1+2 leg to G17. 3) remove the jumper on H-J 16, add a jumper to G-H 14. 4) keep the rate LED+ on H17 but move the rate LED- down to the now vacant J17 pad. This puts the rate LED in series with the LED that is facing the LDR. It will not only follow the speed pot, but dim in brightness as you turn the depth pot down- giving you a much more effective modulation indicator LED.
ReplyDeleteThis is definitely a super fickle circuit Chris, I have achieved the results you mentioned above just by using 2 matching green LEDs... I'll post a video shortly
Deletehttps://youtu.be/35B8znhQq0w?si=Ve7CLARaNRbOksD2
DeleteJust watched the video, Ian - I've made quite a few of my own mods to this over the years to try and get the warble just a bit more pronounced. But it totally sounds like a green LED is doing a lot of the heavy lifting in that department! What LDR do you use?
ReplyDeleteThe one you recommended! I wonder if it's more about having the LEDs match, because previously I had a clear one on the board (with a green one for indicator) and it was very very dim... The clear one barely lit up and I had to have the depth maxed or it would disappear. As soon as I put the green one on the circuit it was really bright. So strange!
Delete