somehow, I have a small issue with the pitch bend signal going out of my midimuso: when I pull the pitch bend wheel of any midi keyboard fully up, the cv of the pitch bend jack reads +10V. But: if I turn the pitch bend wheel fully down, it only reads -7.6V. Hence, the lower limit is not an octave (I would expect -10V here)!
I have set the test point to 10.67V and also the pitch bend trimmer was set to 0V. Does anyone have a similar issue? Or maybe an idea what could be the issue here?
Thanks for your help!
-> the negative power supply at UC7, pin 11 is -12V
-> The voltage at C18 is 0V when the pitchbend wheel is max flat, 5.3V when in the center, and 10.5V when max sharp.
I have also noticed something strange: when I move the wheel from center to max flat, I measure -10V for a fraction of a second, before it rapidly sets to -7.6V. This is very wheel reproducible when starting from the center position.
I also checked the negative supply voltage with that behaviour: it constantly stays at -12V and is not affected.
Do you have any further hints or advices? Thanks a lot!
I hope to be working on a little project “module” to send the controller change signals… Only issue I foresee is not being able to verify the mode the 1007 is in .
Damn, you’re right: I measured in auto-ranging mode. I measure -7.6V straight when turned to fixed range. Hence, my -10V statement was wrong!
In the meantime, I have already exchanged the TL074 in UC7. The measured voltage doesn’t change…
I have also checked if I have wrong components for C18, R1 and R13: all are as demanded by the schematic…
I’m starting to think that it’s actually a design flaw, I measured my pitch bend output and it is also asymmetric (although not as bad as yours).
If I adjust the trimmer for 0V out with the bend wheel in the neutral position, I get -10V for maximum flat and +11.3 for maximum sharp.
I believe the the 1K values for R1 and R27 may be too small and exceed the drive capability of the opamp. Because these gain setting resistances are so small, the equivalent resistance of the voltage divider formed by the trimmer pot is of the same order of magnitude and so it also affects the gain of the non-inverting amplifier.
I would suggest trying to replace R1 and R27 by 100K resistors and see what that does.
EDIT: I changed R1 and R27 to 100K on my #1007 and now I get -10.66 to 0.000 to +10.44
Hello guys, so yesterday i noticed what i believe is a dysfunctionnement of my midi to cv module, but i am not sure because it might be that i didnt set it up right, either in my DAW or maybe i need to reprogramm the chip: CV and Gate 3 and 4 dont work. Like when i send midi information to channels 1 and 2 of my usb midi cable i have CV and Gate out of the CV1/2 and Gate 1/2 of the module; but when i send midi information to channels 3 and 4 of my usb midi cable , i have the « midi activity led » blinking on the module, but nothing out of the CV and Gate…
first off check the program you are on maybe you accidentally re programmed it to be the 2 channel mode??? check the manual for midimuso https://midimuso.co.uk/index.php/cv-12/
another thing could be U9. this is the only thing that differs between channels 1 and 2 and channels 3 and 4 however it doesn’t effect the gates so maybe not that.
another thing to do is double check its just the triggers by seeing if anything is comoing out of the CV outs. because maybe your not seeing the flash and havent checked the cv??? if this is the case then it might be around U11?
if none of those its probably something in whatever your sending the signals from!
Hey thank you, i think it is the chip or my cable then because i am positive i dont have any CV or Gate coming out of 3 or 4. But i wonder if it is plausible that i reprogrammed the chip « by accident » ?? I will Check this evening!
as I doubt it could be the cable or the chip. you’ll be please to know! unless the cable cut out every few micro seconds exactly in sync with when the channel 3 and 4 commands came along it haha
