Roland System 100m

My impression is that the manual isn't sure what sources you might be
trying to add together with the multiple jacks (audio or voltages) and
therefore issues a general warning not to do it...

I agree with Scott's comments.

Besides, this is the function that the Dual CV/Audio Mixer & Voltage
Processor module is suppose to fulfill...  it is a very useful module,
especially if you are interfacing with another make of synth.

Bill



--- In RolandSystem100m@yahoogroups.com, Scott Juskiw <scott@...> wrote:
>
> In general, most (if not all) op-amps do not like to have their 
> outputs directly connected together. However, most op-amp based 
> output circuits contain a protection resistor to guard against this 
> happening. Otherwise, there would be far too many broken synths being 
> returned for repair (most people will unintentionally patch two 
> outputs together at some point in their life). As long as a 
> protection resistor is present, then it's not a problem. I've had a 
> quick look at the schematics for the 100m. Some of the outputs have 
> protection resistors, some don't. But not all outputs are directly 
> off an op-amp either. I think they are being a bit overcautious, I've 
> not yet managed to fry anything in my 100m, but use a mixer if you 
> have any doubts.
> 
> >On page 47 of Roland's "Practical Synthesis for Electronic Music" 
> >(which is basically the
> >Roland System 100M 'manual') it states
> >
> >"The multiple jacks cannot be used in place of a mixer.  If two 
> >outputs are connected to
> >the same multiple jack set, the result will be what is effectively a 
> >short circuit to both
> >outputs which could cause damage."
> >
> >The first part I buy (obviously) -- it's not a mixer.
> >
> >But I never thought that accidentally connecting two outputs to a 
> >multiple could cause
> >damage.  It happens -- that one puts two outs into a multiple -- 
> >even if you try hard not
> >to.  (In fact did it last night -- didn't get the result that I 
> >wanted, I tracked down problem
> >and corrected).  I've never noticed any damage, never worried about
it.  
> >
> >In fact the manufacturer of my other modular (Blacet) says don't 
> >worry about that sort of
> >thing -- his machine can take it.  Is the 100M a delicate beast?
>