rvlt Posted June 27, 2009 Report Share Posted June 27, 2009 Hi everybody,I built two midibox cv interfaces with the "all-in-one" pcb that sonicwarrior offered a few weeks ago. I think I share my experiences since there are a few traps you might fall into:1. The print on top of the pcb for the LM385 is wrong! you have to turn the LM385 180 degrees, or you won't get 2,5V ..2. Since I used a LM385 (2,5V) instead of a MAX6007 (2,048V) I had to adjust resistor values for all R_y: 2,7k worked for me.3. R6 is missing in the BOM. It's 2,2k.4. C11 is listed twice in the BOM. Should be 100N (not 330N).5. You have to put a jumper at J3 if you don't have a separate 5V supply.6. There are two resistor networks (RN1 + RN2) around IC5. For RN1 the pin-1 marking is missing: Pin 1 is point away from the PIC. I got a really weird menu navigation when I got this wrong first ..======I have attached a few pics: the black one is mine, I added a Yusynth clock divider and a gate-trigger converter (small breadboard in the back) to trigger my moog & ms20. the silver one is for a friend: no clock divider, but a much nicer front panel (schaeffer)...cheers,rvlt. Quote Link to comment Share on other sites More sharing options...
sonicwarrior Posted June 28, 2009 Report Share Posted June 28, 2009 Thanks for informing me per email. I've updated the sdiy.de page:http://www.sdiy.de/de/projects/midiboxcv.htmlStill need to do the english translation of the documentation. Quote Link to comment Share on other sites More sharing options...
lemonhorse Posted June 28, 2009 Report Share Posted June 28, 2009 Thanks! + fascinating pictures :) Quote Link to comment Share on other sites More sharing options...
JargMarbin Posted July 2, 2009 Report Share Posted July 2, 2009 Looks great! Quote Link to comment Share on other sites More sharing options...
sonicwarrior Posted July 2, 2009 Report Share Posted July 2, 2009 Still need to do the english translation of the documentation.Ok, I'm finished. I've set up a translated page and translated the PDF documentation:http://www.sdiy.de/en/projects/midiboxcv.html Quote Link to comment Share on other sites More sharing options...
rvlt Posted July 18, 2009 Author Report Share Posted July 18, 2009 Ok, here's a list of synths that work with the midibox cv with no problem:- Moog Prodigy- Moog Source- Moog Rogue- Korg MS-10- Korg MS-20- Korg X-911- Roland SH-101- Sequential Circuits Pro Oneso, generally speaking, I guess all standard 1V/Oct and Hz/V (Korg) should be fine. Keep in mind that ...- it's a good idea to calibrate your synths before connecting it to your cv-interface. I did that with all of above (what a nightmare!), but it was worth it.- if you want to use synths with S-Trigger (Moog, Korg ..), you need to add a small circuit to the gate-out to make i work====I slightly missed a software fine tune control. Would be really helpful to adjust the mb-cv tuning to the internal keyboard so that you don't have to retune everytime you switch between mbcv and "real" playing. maybe in future software release??====the only synths I couldn't get to work with mbcv were two yamahas (CS-5 and CS-40m). They have a "kind of" Hz/V behavior (CV doubles with every octave), but control voltage starts real low (C1 = 250mV, C2 = 500mV, C3 = 1V ..), whereas Korg synths start at C1=1V, C2=2V, C3=4V ...I don't know, maybe the resolution of max525 is too low in that range? maybe someone could enlighten me..cheers,rvlt. Quote Link to comment Share on other sites More sharing options...
Futureman Posted July 18, 2009 Report Share Posted July 18, 2009 So you had no probem with your Moog Source?Mine has been a bitch to calibrate, and then after spending ages trying to get it right, I read in the service manual that it is not at 1v/octave?Funky synth tho!RegardsMike Quote Link to comment Share on other sites More sharing options...
rvlt Posted July 19, 2009 Author Report Share Posted July 19, 2009 So you had no probem with your Moog Source?Mine has been a bitch to calibrate, and then after spending ages trying to get it right, I read in the service manual that it is not at 1v/octave?Funky synth tho!RegardsMikeHey Mike,at least the source I have (actually, it belongs to a friend) works with 1V/Oct. I checked with the owner's manual page 49: "As an input, the CV jack sends any control voltage received to the oscillators, which track this incoming voltage at 1 volt / octave."but ...I had massive tuning problems before: as soon as I touched the case, the tuning got crazy. It took me hours to fix it, it was a loose contact at U12:The source I had was modded, someone put a resistor and a 1M trim between R65 and U12 pin 1. Don't know what this was for, but I left it in. I resoldered the contact between the trim and U12 and tuning was stable again.so, maybe that mod is necessary to get a 1V/Oct response? Don't know..===Ah, another thing comes to my mind: I calibrated two moog prodigys (my own and the one from a friend), and both synths had tuning problems due to bad CA3046s in the oscillator section (the ones responsible for temperature adjustment). Maybe you could try to put new 3046 in your source (U26 + U34) and see if that helps. ok, best regards,rvlt. Quote Link to comment Share on other sites More sharing options...
sonicwarrior Posted July 22, 2009 Report Share Posted July 22, 2009 I don't know, maybe the resolution of max525 is too low in that range? maybe someone could enlighten me..What exactly is the problem here?Wrong tuning in the lows?Maybe it's better to use the Oct/V curve and an analog Oct/V to Hz/V converter?(MS-02 schematic or something like that, perhaps the one from the ASM) Quote Link to comment Share on other sites More sharing options...
xarolium Posted January 23, 2010 Report Share Posted January 23, 2010 I would liket to know if i could use 1N4001 instead of 1N5817 for the PSU thank you Quote Link to comment Share on other sites More sharing options...
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