[sdiy] (OT) Doepfer MIDI-CV oddity

[Tom Wiltshire]

Do you have a schematic for this?
If it works from a Thru but not directly, it must be something to do with the hardware, mustn't it? After all, if the software was faulty, it wouldn't work at all, and it wouldn't act any different plugged into a Thru.
I did quite a bit of research looking for MIDI input circuits based on the 6N138/9 and found a large range of resistor values used. I'd assumed that since all MIDI circuits do the same job, there'd be a "typical" design that everyone just drops in. Not true. There was a wide variation. I expect some of the designs are actually fairly borderline and may well only work when driven directly from a logic gate (as would be typical in a Thru) rather than from a uP output pin. I suspect a few resistor tweaks would solve these problems, but I never found the "correct" values to use.

T.

On 19 Jan 2011, at 07:12, NSSINC wrote:

> 
> 	Not that this will be any help, but I have the same problem with a home
> made MIDI splitter driving an ESQ-1. Dropped notes etc. But if I patch
> it after going thru another keyboard's thru, it works fine. And I don't
> have any (intentional) ground connections in the splitter. Never looked
> into it more after I found the quick "fix"...
> 
> -Al
> 
> 
> Justin Owen wrote:
>> Hey all,
>> 
>> Apologies for the OT - thought some of you might have a take on this.
>> 
>> I recently acquired a Doepfer A-190-1 MIDI-CV module which, initially I thought was faulty. It regularly drops/misses/ignores MIDI Note On/Off/Gate info - or at least fails to output it at the Gate Out.
>> 
>> Today, just as a test, I ran out of my normal M-Audio MIDI interface, into another MIDI-CV unit, out of the MIDI Thru of that and then into the A-190-1... which seemed to fix the problem. Odd.
>> 
>> I swapped leads round - same deal. Won't work direct but will work out of another units Thru. I've never had any problems with this MIDI rig so far, the main lead I use is only a few meters long and it works with everything else I throw at it.
>> 
>> Clues?
>> 
>> Thanks - again, sorry for the OT.
>> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy