[sdiy] (OT) Doepfer MIDI-CV oddity

[Colin f]

> That's funny. In the lower trace, the first pulse comes 
> through just fine although it's short. The later pulses look 
> like there's a much larger time constant, as if the pullup 
> resistor is too high. Anyone have an explanation for this?
> 
> Which pullup resistor value did you use?

It would be 470 or 510 ohms.
 
> The ringing at high level at the end (lower trace) and the 
> undershoot on both traces at the beginning look funny too. 
> Did you use a 10:1 probe? Where did you connect the ground of 
> the probe?

It was a cheapo crocodile clip test lead, on a USB scope, so there may
indeed be artefacts of that, but the shape of the pulses should be pretty
accurate.
I see what you mean about the increasing time constant.

Cheers,
Colin f