Analogue systems

--- In analogue_systems@yahoogroups.com, Arnauld Michelizza 
<am@z...> wrote:
> On Fri, 16 May 2003, adamburr1973 wrote:
> 
> > can anyone tell me, will the rs230 pass audio signals? or is 
it for
> > cvs only?
> 
It all depends on the module.  Some can handle DC or AC 
without any weirdness. The the purpose of this explanation, let's 
assume that CVs are DC voltages.  I need to make this 
clarification as control voltages can also be LFO outputs, which 
in fact are AC.

Some do not recognize signals that go under zero volts - so they 
come out half rectified (you only get the positive voltage out).  
This is very common in analog modules that incorporate digital 
chips, in that  they are designed to for zero to + volt operation.  
Anythng that goes below that isn't recognized.

In the case of the buffer, while I don't  have one, I would assume 
in that since the envelope generators do in fact output negative 
voltges, that  AC would be fine as well.

The inverse however does not always apply - MOdules looking 
for AC may not see DCs at all. through the use of a de-coupling 
circuit (an electrolytic cap is a good example of one type) signals 
that don't pass both directions of zero volts (AC) will have no 
effect. - they won't even make it past the cap.  There is an reason 
for this, as this type of signal conditioning is intentionally used to 
remove DC voltage offsets.  A perfectly good example of this is 
the new DSP Delay -  because of this type of filtering, you can't 
delay control voltages.

But getting back to the bufffer - while it may in fact pass ACs, it's 
probably not needed.  This buffer was desinged to amplify the 
current drive of control voltage generating devices. The AC 
signals coming from A Sys equipment is plenty loud and I can't 
see you loading it down so much that it attenuates to the point 
that you'll experience problems.

DCs are different.  As all semiconductors have a limit to the 
amount of current they can supply to something else, they can be 
overloaded if you attempt to suck more current out of them. Once 
you exceed their limit, the output starts attenuating or dies out all 
together.  The very worst case you will fry the output section.  It 
simply heats up and burns.  That's

The buffers  were introduced as a means to amplify the current 
carrying capabilities of the devices under heavy load - so it can 
be fanned out to more places without problems.

I hope this helps,

Peter