It works. The different DIP switch settings are pretty subtle (at least at low nighttime volumes). I didn't use the trimpot but instead did a B50K pot with P19 going to lug 1 and Q19 going to lugs 2 and 3--I think I've seen this called a "presence mod". Unfortunately, I don't have any mojo magical MA856 diodes so I tested out easily accessible 1N914s and BAT41s as well as some germanium diodes with 1N34As and 1N270s. Sound is not too bad with the germanium diodes but the volume drop is too much. 1N914s and the BAT41s sounded okay. Need to try out some other diodes and maybe even a different IC, but at least for now it's working fine as far as I can tell. A higher input cap like a 47nf or 100nf might be also be something to try out. Thanks for the layout, Fuzzhead.
Thanks for verifying and for the build report! As for the magical diodes, I think they have a slightly higher voltage drop than your usual 1N4148/1N914?
After throwing in a bunch of random diodes in for testing, I think I'm going to stick with some 1N4742A 12V Zener diodes. A bit of an odd choice but it sounds great paired with my guitar and amp. The DIP switches being on are much more noticeable with these over the 1N914s and BATs. Ready to box it!
Another mod that may be beneficial to some people would be to get rid of the DIP switches and add SPST switches externally (that may be what Mark's older layout does, not sure), but that might be an issue cramming all those switches into a 125B. It's also moving further away from the original.
Just build this one, sounds great! Although with all pots at noon I drop below unity gain. I don't think that's the same case with the original? There is a fair amount of volume and gain on tap though so it's not really a problem
Hi All, i might be having a dumb moment here, but just wanted to check the dpdt switch numbering. Do you count across each row (ie top left is 1, top right is 2, middle left 3 etc), or down each column (top left 1, middle left 2, bottom left 3 etc). Want to make sure before i start wiring in! thanks as always
Just built this and I have a problem where the pedal is really silent and oscillates a ton when you increase the gain pot. It's synth like oscillation. I checked the offboard wiring and everything seems to work as it should (LED turns on and off, clean guitar tone passes through when the switch is off, trim pot actually controls the treble, dip switch does its thing, pots react as they should and the 3 way switch also changes sound). Looking at the stripboard nothing seems out of place even the components are healthy. IC voltages are as following: P1 - 4,84V P2 - 4,57V P3 - 5,85V P4 - 0 P5 - 4,47V P6 - 4,47V P7 - 4,45V P8 - 8,79V
I also cleaned the flux on the board with IPA after soldering. I really don't know where to check anymore so if someone has any idea what to do next I'd appreciate it a lot!
I have the big one built from PedalPcb but i`m thinking of building this to check out the difference with the dips.Thanks man!!!
ReplyDeleteIt works. The different DIP switch settings are pretty subtle (at least at low nighttime volumes). I didn't use the trimpot but instead did a B50K pot with P19 going to lug 1 and Q19 going to lugs 2 and 3--I think I've seen this called a "presence mod". Unfortunately, I don't have any mojo magical MA856 diodes so I tested out easily accessible 1N914s and BAT41s as well as some germanium diodes with 1N34As and 1N270s. Sound is not too bad with the germanium diodes but the volume drop is too much. 1N914s and the BAT41s sounded okay. Need to try out some other diodes and maybe even a different IC, but at least for now it's working fine as far as I can tell. A higher input cap like a 47nf or 100nf might be also be something to try out. Thanks for the layout, Fuzzhead.
ReplyDeleteThanks for verifying and for the build report!
DeleteAs for the magical diodes, I think they have a slightly higher voltage drop than your usual 1N4148/1N914?
I've read somewhere that a 5817 and a 4001 in series gives about the same Fv as the 856. Just ordered parts to build this one.
DeleteAfter throwing in a bunch of random diodes in for testing, I think I'm going to stick with some 1N4742A 12V Zener diodes. A bit of an odd choice but it sounds great paired with my guitar and amp. The DIP switches being on are much more noticeable with these over the 1N914s and BATs. Ready to box it!
DeleteAnother mod that may be beneficial to some people would be to get rid of the DIP switches and add SPST switches externally (that may be what Mark's older layout does, not sure), but that might be an issue cramming all those switches into a 125B. It's also moving further away from the original.
Just build this one, sounds great! Although with all pots at noon I drop below unity gain. I don't think that's the same case with the original? There is a fair amount of volume and gain on tap though so it's not really a problem
ReplyDeleteHi All, i might be having a dumb moment here, but just wanted to check the dpdt switch numbering. Do you count across each row (ie top left is 1, top right is 2, middle left 3 etc), or down each column (top left 1, middle left 2, bottom left 3 etc). Want to make sure before i start wiring in! thanks as always
ReplyDelete1 4
ReplyDelete2 5
3 6
Thanks Tom, should have this finished today, then the task of road testing the ic's
DeleteHi guys!
ReplyDeleteJust built this and I have a problem where the pedal is really silent and oscillates a ton when you increase the gain pot. It's synth like oscillation.
I checked the offboard wiring and everything seems to work as it should (LED turns on and off, clean guitar tone passes through when the switch is off, trim pot actually controls the treble, dip switch does its thing, pots react as they should and the 3 way switch also changes sound). Looking at the stripboard nothing seems out of place even the components are healthy. IC voltages are as following:
P1 - 4,84V
P2 - 4,57V
P3 - 5,85V
P4 - 0
P5 - 4,47V
P6 - 4,47V
P7 - 4,45V
P8 - 8,79V
I also cleaned the flux on the board with IPA after soldering. I really don't know where to check anymore so if someone has any idea what to do next I'd appreciate it a lot!
Thanks!