That’s the transformer I use:
It’s an old thing that I had laying around…. Might be broken… however do you have any tips for a nice transformer able to drive two microbuses and preferably in a form factor to screw it in the back of the case? I really get crazy In just not finding something right to replace that old thing with 
the pitch bend pot is wired up to the +12v of the module to get a voltage offset to set the pitch bend. the fact is the power supply will fluctuate a bit. have you seen if it settles at all? or does it just keep on going down and down and down??? if it just keeps going down and doesn’t stop at all then its a problem elsewhere. however if you find the reading settles at a certain point then it should be fine. remember 0.01v is pretty tiny regarding the pitch bend amount, because after that the pitch bend amount is usually attenuated again on the oscillator you plug it into. so some fluctuation is ok. just set it so it settles around 0 volts +/- 0.03V I recon.
however if it doesn’t settle and literally keeps falling until it hits -12volts then its another problem entirely. at that point you’d need to check the soldering and any shorts on the board again and also swap out U7
It actually is the latter case and it doesn’t settle at all…. Thanks so much for now for your quick help… I’ll start looking over it again and start swapping some elements… hope it’s an easy fix 
I’ll keep you updated! Have a nice day!
yeah sadly it could be anything around that part of the circuit. check the schematic and follow it through around U7C
maybe check the voltage on the outputs on the other opamps on U7. if they are dropping too its a problem overall with the TL074 in the U7 socket… if they are not dropping then its a problem with either R1 or R13 or something around that aspect of the circuit… it could also be soldering on the trimpot itself. but I dont think that is as feasible
Hey together,
@wrasmussen09 have you fixed that problem if yes what was the fault? I just got the same magic smoke but only from R2
so after solving my power supply issue which actually is quite a different story I now got it sorted with a good old winded transformer….
So now I’ve got a stable and working microbuses power supply… however I plugged in the midi to cv module to test again and whoosh magic smoke exactly like wrasmussen09 had it back then….
Does anyone have a idea what could be the problem…? Checked the solder joints 3 times now and also polarity and orientation of all IC’s….
Are you sure your power header is oriented properly?
If that’s not it, and if indeed there are no reversed ICs, then it’s pretty definitely a short or other mis-connection on the +12 V rail. If you measure from the junction of R2 and C2 to ground (or conceivably to -12 V, at the junction of R3 and C3) you probably will see 0 Ω or some very small resistance. If so don’t replace R2 and power things up again until you’ve found the cause. (Even then, maybe power up first with the ICs removed.) No real shortcuts unfortunately, you just need to trace everywhere the +12 V rail goes and look for solder bridges etc. I don’t have the module but from what I see on the schematic that looks like the 5 V regulator, one of the headers connecting the boards (J29/J30), and the op amps. In fact you could check with the boards separated and depending on whether the short goes away or not you’d learn which board it’s on.
Okay just checked that and pretty much reflowed every solder point and checked if there are some wrong connection…
If I measure the mentioned junction of r2 / c2 and ground (of the power socket) I get about 6k ohms resistance…
In the end for me it was the orientation of one of the ICs-- I’m not in a place where I can look right now, so from memory I think it was a tl072 on the board that screwed directly to the panel (sorry I’m never sure how to parse mother versus daughter boards). I swear I checked everything 12 times…but…
Hope that helps
That should be okay. I guess if it were me my next step would be to verify there is no continuity between the +12 V rail (at R2/C2) and any of the IC pins other than pin 4 of the TL074s, pin 8 of the TL072, and pin 3 of the L78L05. Also verify orientation of the TL431 and L78L05. Then I’d replace R2, remove all the ICs, and connect power. See if R2 survives, and make absolutely sure it’s +12 V on the aforementioned pins, and -12 V on pin 11 of the TL074s and pin 4 of the TL072. (Carefully, trying not to short anything in the process!) Then I’d put the ICs back a few at a time (with power off while installing them).
Hey Ho Midimusoers !
I just started building mine and have to be sure that my jacks will work. I have 3 pin one, but theres only one orientation they fit in.
Will they work ?
If somebody could verify that and tell me how he/she did it id be super satisified
Best wishes !
the pin that is diagonal at a slant on the jack socket is the sleeve (ground) that goes in the hole with the square pad
Hey Sam !
That means mine should work ?
The one with the slant is in the square hole, as i tried to show it in the second picture in my reply
If you compare the datasheet for your jacks with the pinout in the post linked above I expect you’ll find they’re the same except yours lack the tip and sleeve switch terminals. If so and if those are not used in the midimuso (check the schematic) then your jacks will work.
yep what @analogoutput said. they are all pretty standard these if you look at the moulding of the black plastic of the ones you have you’ll see there are grooves where the other pins would be, like analogoutput says the 2 pins that are missing are switches that open and close depending if you have a jack in the socket… as for the midimuso there are no requirements for switched jack sockets so these will work. and to be. honest im trying to think if I make use of switched jacks in any of the modules.,… I don’t think I have… reason being is I prefer to plomp a switch on the front of the module for whatever purpose… nothing more annoying than having to have a jack hanging half out of the socket because you dont want the switched jack to switch ha
two questions:
what does the jack above the CLK put out?
is it possible to change the CCs from 1 / 71 / 74 to other values?
cheeers
so it all depends which mode it is on. each of the jacks are labelled to match the midi Muso table. so depending which mode it is will show what each of the outputs will do
the mode is 4MV, the jack above the clock output is not labeled at all…
and is it possible to change the CCs?
The labels on the panel correspond to 4MV, so the unlabeled jack would be A(uxiliary) Gate 1.
I don’t see anything in the manual about changing CCs, but maybe I overlooked it. If not, it’s closed source firmware, so it can’t easily be modified.
Thanks alot sam + analogoutput !
For clearing that up
It works just sweet !
