Doepfer

Hi all,

Just wondering if anyone else has the combination of A-112 and R2M.
I've just discovered a potential problem with mine that I'm trying to
work out and was wondering if anyone else can replicate the problem....

Simply put, the Gate out of the R2M doesn't seem capable of triggering
the gate in of my A-112. I can trigger other things with it (eg. A-140
ADSR or A-198) but no joy on the A-112. On the other hand, I can
trigger the A-112 with an LFO. 

Perhaps I'm doing something wrong or perhaps the A-112 requires a
gate/trigger of higher voltage than the R2M can deliver ?

Any help or confirmation appreciated.

Cheers

Simon

> Hi all,
>
> Just wondering if anyone else has the combination of A-112 and R2M.
> I've just discovered a potential problem with mine that I'm trying to
> work out and was wondering if anyone else can replicate the problem....
>
> Simply put, the Gate out of the R2M doesn't seem capable of triggering
> the gate in of my A-112. I can trigger other things with it (eg. A-140
> ADSR or A-198) but no joy on the A-112. On the other hand, I can
> trigger the A-112 with an LFO.
>
> Perhaps I'm doing something wrong or perhaps the A-112 requires a
> gate/trigger of higher voltage than the R2M can deliver ?
>
> Any help or confirmation appreciated.
>
> Cheers
>
> Simon

Strange. From theory it should work. I'll ask Christian to try out this
combination (he is our R2M and A-112 "man").

Best wishes
Dieter Doepfer

> Hi all,
>
> Just wondering if anyone else has the combination of A-112 and R2M.
> I've just discovered a potential problem with mine that I'm trying to
> work out and was wondering if anyone else can replicate the problem....
>
> Simply put, the Gate out of the R2M doesn't seem capable of triggering
> the gate in of my A-112. I can trigger other things with it (eg. A-140
> ADSR or A-198) but no joy on the A-112. On the other hand, I can
> trigger the A-112 with an LFO.
>
> Perhaps I'm doing something wrong or perhaps the A-112 requires a
> gate/trigger of higher voltage than the R2M can deliver ?
>
> Any help or confirmation appreciated.
>
> Cheers
>
> Simon

Christian tested the R2M/A-112 combination and indeed it does not work. The
reason is that the Gate input of the A-112 has a load of ~ 10k to GND. This
reduces the +5V Gate voltage coming from the R2M so that the A-112 does not
trigger. Within the A-100 the problem does not occur as the A-100 modules
have more powerful outputs and the gate voltage does not collapse if the
A-112 is triggered by another A-100 module.

If you are a bit experienced with eletronics there is a simple solution:
replace the 10k resistor R15 on the A-112 board e.g. by a higher value (e.g.
47k or 100k). R15 is located near the Midi In socket between the 100n
capacitor C21 and the Z-diode D5/4V7.

As long as the A-112 is connected to a gate source (e.g. R2M or the output
of an A-100 module) R15 can be even removed (simply pinch it off on one
end). But without R15 the A-112 may trigger accidentially if nothing is
connected to the Gate input. If this does not matter R15 can be removed.
Otherwise I'd recommend to use a higher value as mentioned above.

Hope this helps

Dieter Doepfer