Doepfer

--- In Doepfer_a100@yahoogroups.com, "E Karel" <eklkrl@...> wrote:

> --- In Doepfer_a100@yahoogroups.com, <hardware@> wrote:
> >
> > > Indeed, T&H works correctly but S&H doesn't. Initially I had both
> > > units in S&H mode.
> > 
> > I have checked the A-164-1/A-148 combo with A-148 in S&H mode. You are
> > right: this combo does not work. The reason is the AC coupling of the A-148
> > input in S&H mode in combination with the way how the gate signal is
> > generated by the A-164-1 (connection to +12V via protection resistor). If
> > the A-164-1 is not operated the output is open and the coupling capacitor of
> > the A-148 does not discharge. The T&H does work as in this case the input of
> > the A-148 is DC coupled.
> > 
> > I found a simple solution: solder a pull down resistor (about 100k) between
> > GND and the A-148 input. The resistor can be soldered directly to the
> > corresponding terminals of the socket on the bottom side of the A-148 pcb.
> > The 100k resistor connects the A-148 input to GND when the button of the
> > A-164-1 is not operated. Then the AC coupling capacitor of the A-148 is
> > discharged as necessary. I have tried successfully an 100k resistor but I'm
> > sure that any other value in the range 47k ... 220k should do the job.
> > 
> > Best wishes
> > Dieter Doepfer
> >
>

Hello,

I've just tried this solution, and I think I must be doing something wrong, because it still doesn't work.  I soldered a 100k-Ohm resistor (1/4 watt, 5% tolerance) connecting what I think is the input and GND on the top Trigger Input socket on the A-148 -- looking at the left (back) side of the board, these are the two top-right solder points.  Is that correct?  It doesn't seem to do anything.  It still works as S&H with other triggers, but not with the A-164-1.  What am I doing wrong?

Thanks,
Ernst