Anders, I must thank you for challenging me to draw this. It was the push I needed. Also - I most likely would not have been able to complete this were it not for the clear and concise schematic that Madbean put up for their "Rainbow Puker" project. The 'dry kill' switch addition was Brian's idea and, should any of you want to fit this circuit into a 125b-sized box, head over to Madbean's shop and buy a PCB!!!
From a design standpoint, I am blown away by it. So much cool stuff that EQD got out of the FV-1 without needing an additional algorithm chip to tell the processor what to do. But as far as the actual sounds that come out of this pedal? I admire what Nick Reinhart is able to do with it, but I doubt that my build of it will have a home on my board... if you do attempt to mod yours (I've never looked inside one of these so I don't know if they are SMD or not) check out Madbean"s schematic first - you will see where the dry kill switch is placed between the output of the 1st TL072 op amp channel and the input of the other one.
Just me commenting on my own layout... again. For anyone out there besides me that is foolish enough to attempt this one - the EXP jack mod works. And also, I'd recommend increasing the value of the tracking pot to at least 50k in order to get a longer delay at fully CCW. The tracking is tied to an external clock IC function that is provided by the CD4069. Normally this is done with a digital watch crystal and 15pF capacitor but this way allows you to control the clock function with a potentiometer. Bigger value = longer delays, but at a point (probably above 100k or so) the FV-1 starts to get really glitchy and staticky. Which can sound cool... or not?
since Anders published the slightly modded layout I sent him, I must now explain a few things on it. 1) the 1uF coupling caps - I originally built this with film box. Which, as there are A LOT of them in this, it gets pricey and crowded on the board pretty quickly. I since have subbed for MLCC 1uF caps and I feel like I notice a slight difference in clarity but I could honestly just be imagining it... 2) the modified pot values: in addition to upping the resistance of the magic/feedback pot from 25 to 50, you may also want to try a C/rev log taper. And for the Pitch, it is REALLY convenient to use a center detent potentiometer since that allows you to find the "chorus" setting really quickly.
Most FV-1 circuits utilize an additional 8 pin IC with an effect algorithm to tell the processor what to do. However, every FV-1 chip comes preprogrammed with 7 different effects in the 8 available slots: 3 different modulation+ short reverbs (chrorus, flange, tremolo) 2 pitch effects (one with a short delay) a blank or "test" slot, and then two rather long, spacious reverb patches. You access these by simply grounding pin 13 of the FV-1 - and this is what the Rainbow Machine does. The wackiness it creates is actually just the built in effects being manipulated and fed back into each other.
Eventually friend of mine found small solderbridge and after removing it, pedal started to work. I learned that it's good practice to go through gaps between copperstripes with a small knife or similar. Thanks for sharing this!
Hey there - I've built about a half dozen of these from this layout and I've definitely encountered some bugs but none like the one you are describing. There is a lot going on with this circuit so, at the very least I would suggest checking all your connections for solder bridges and such around the both the output section of IC2 (which is the right side of the TL072) and the output section of the FV-1 (which is the upper right corner of that chip). I salute you for even attempting this one, as I am one of the only folks I know that enjoys stuff that is this complicated.
I think that the voltage divider anomaly sounds plausible. Also - I used the Madbean schematic to draw this so hopefully you can get it lined up and working. Best of luck to you!
Anders, I must thank you for challenging me to draw this. It was the push I needed. Also - I most likely would not have been able to complete this were it not for the clear and concise schematic that Madbean put up for their "Rainbow Puker" project. The 'dry kill' switch addition was Brian's idea and, should any of you want to fit this circuit into a 125b-sized box, head over to Madbean's shop and buy a PCB!!!
ReplyDeleteI bought a rainbow machine during covid and just can't connect with the thing. Fun I guess but useless. Maybe I'll mod it with the dry kill.
ReplyDeleteFrom a design standpoint, I am blown away by it. So much cool stuff that EQD got out of the FV-1 without needing an additional algorithm chip to tell the processor what to do. But as far as the actual sounds that come out of this pedal? I admire what Nick Reinhart is able to do with it, but I doubt that my build of it will have a home on my board... if you do attempt to mod yours (I've never looked inside one of these so I don't know if they are SMD or not) check out Madbean"s schematic first - you will see where the dry kill switch is placed between the output of the 1st TL072 op amp channel and the input of the other one.
DeletePitch shifters don’t have a rich history in music for a that reason?
DeleteSure. I mean, who's ever heard of ANY important, innovative, or influential guitarists using a digitech whammy? ;)
DeleteThanks for the good ideas here. I modded my RM with a 100k tracking pot and and a blend/kill pot. Now I love it.
DeleteCheck it out
https://www.instagram.com/reel/C9N84hDSgm8/?igsh=MzRlODBiNWFlZA==
I'm so happy to have been the catalyst for this!
DeleteJust me commenting on my own layout... again. For anyone out there besides me that is foolish enough to attempt this one - the EXP jack mod works. And also, I'd recommend increasing the value of the tracking pot to at least 50k in order to get a longer delay at fully CCW. The tracking is tied to an external clock IC function that is provided by the CD4069. Normally this is done with a digital watch crystal and 15pF capacitor but this way allows you to control the clock function with a potentiometer. Bigger value = longer delays, but at a point (probably above 100k or so) the FV-1 starts to get really glitchy and staticky. Which can sound cool... or not?
ReplyDeletesince Anders published the slightly modded layout I sent him, I must now explain a few things on it.
Delete1) the 1uF coupling caps - I originally built this with film box. Which, as there are A LOT of them in this, it gets pricey and crowded on the board pretty quickly. I since have subbed for MLCC 1uF caps and I feel like I notice a slight difference in clarity but I could honestly just be imagining it...
2) the modified pot values: in addition to upping the resistance of the magic/feedback pot from 25 to 50, you may also want to try a C/rev log taper. And for the Pitch, it is REALLY convenient to use a center detent potentiometer since that allows you to find the "chorus" setting really quickly.
Arg! Now I gotta crack mine open again...
Deletedoes the FV-1 need to be programmed?
ReplyDeleteMost FV-1 circuits utilize an additional 8 pin IC with an effect algorithm to tell the processor what to do. However, every FV-1 chip comes preprogrammed with 7 different effects in the 8 available slots: 3 different modulation+ short reverbs (chrorus, flange, tremolo) 2 pitch effects (one with a short delay) a blank or "test" slot, and then two rather long, spacious reverb patches. You access these by simply grounding pin 13 of the FV-1 - and this is what the Rainbow Machine does. The wackiness it creates is actually just the built in effects being manipulated and fed back into each other.
DeleteThanks Chris for the thorough explanation.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteEventually friend of mine found small solderbridge and after removing it, pedal started to work. I learned that it's good practice to go through gaps between copperstripes with a small knife or similar. Thanks for sharing this!
DeleteAwesome news! Seriously - this is a mind-scrambler of a build. I'm still wondering just how I pulled it off! -Chris
DeleteHey there - I've built about a half dozen of these from this layout and I've definitely encountered some bugs but none like the one you are describing. There is a lot going on with this circuit so, at the very least I would suggest checking all your connections for solder bridges and such around the both the output section of IC2 (which is the right side of the TL072) and the output section of the FV-1 (which is the upper right corner of that chip). I salute you for even attempting this one, as I am one of the only folks I know that enjoys stuff that is this complicated.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteI think that the voltage divider anomaly sounds plausible. Also - I used the Madbean schematic to draw this so hopefully you can get it lined up and working. Best of luck to you!
ReplyDelete