PLAN B analog blog

I get this same problem with my Wiard Noise Ring and my ZO.  You can hear small fluctuations in the ZO that are in perfect time with the LED's on the front of the NR. Usually, my patches get so sonically messy that this doesn't matter, but I could see that it could be annoying in certain applications.

Bryan

>>> synth_freak_2000@yahoo.com 09/18/06 2:51 AM >>>
hello peter,    :-)
yes, you're right! one model 15 does not affect the
other model 15 of mine! only other modules affect the
model 15 pair of mine.
but, anyway, thank you for the info and i'll just set
the PWM knob to 0 or 10 when i am using other waves of
the model 15's.
regarding the pulse/ PWM waves, i will have to stick
with this cross-mod. but it is ok. it reminds me a bit
of my VCS3's that many modules affect other modules in
unknown ways...     :-)
many thanks,
best regards,
Bakis.



--- "(i think you can figure that out)"
<peter@buzzclick-music.com> wrote:

> Bakis,
> 
> As always., great to hear from a fellow Greek!
> 
> I have noticed this anomaly as well...when my M15s
> were in mounted
> close to my one remiaing Blacet VCO.  Please try
> this, as it fixed the
> problem for me (admittedly a bandaid of sorts):
> 
> Move the PWM pot of the module you suspect to be
> bleeding over to te
> M15'a to full CWQ or CCW - enough for that
> squarewave to be locked out
> of oscillation (held full pos or neg).  This takes
> care of it, atteast
> on my system. ,  
> 
> As far as what's causing it, is it terrible to say
> I'm not 100% sure?
>  How's that for honest?  One thing I do know, M15's
> do not cause other
> M15's to do this, and I've made special precautions
> to limit the
> amplitude of the square outs well short of the power
> rail of the op
> amps driving them. My suspicions are there are a few
> square wave
> vco/lfo's out there that are not attenuated - that
> run from rail to
> rail. This causes havoc on any power system, much
> like when LEDs are
> not properly current limited and I believe my VCO is
> especially prone
> to picking up on that.  
> 
> Most PWM circuits run on the same prinicple as a
> manual one shot
> comparator.  The PWM pot sets the threshold, and the
> incoming waveform
> (non square wave) goes into the other side of the op
> amp.  This config
> allows anything in the incoming wave which is
> greater in amplitude
> than the pot setting to pass to the output as a
> high.  Problem is, 
> unless you design it differently, that high will be
> at the rail - the
> same amplitude as the voltage powering the op amp. 
> this fluctuation
> in current then ricochets through the entire power
> system.  SOme
> istruments are sensitiive to this, some aren't.
> 
> The Model 1 power buss I think may take care of this
> problem.  The
> first run of these (50) are arriving in about a
> week's time form our
> PCB vendor.  I'll give you all an update at that
> time.
> 
> When tim allows, I will do some experiements with
> increasing the value
> of the two main bypass caps on the VCO engine bard -
> currently 10mFs.
> 
> - P
> 
> 
> 
> 


Bakis Sirros - Parallel Worlds
[Doepfer_a100] group owner
http://www.parallel-worlds-music.com 
http://www.myspace.com/parallelworldsmusic 
http://www.shimarecords.co.uk 
http://www.rubber.gr 
Athens-Greece

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One thing I have to add on this.

"in the olden days' when open architecture and cross polination (read:
 Frankensynths) weren't as previlent, we as designers only had to
concern ourselves with integration within our own closed systems. 
Things have changed, and many (such as I) release product that's
designed to compliment another format. In my instance, Doepfer.

While I do make every effort to intergrate with Doepfer products
seamlessly, I don't concern myself with proper integration with the
others.  It would pretty much impossible for me to do that.  What I do
do is make every effort that my own products won't become system
noisemakers (suuch as zener-limiting the am0litude of square waves to
be well under the rail voltages).

But as an example of the point I make, Blacet is designed to run off
of 15 volts as is Cynthia product.  The fact that one can get the
boards to fit behind a Eurorack faceplate is not the end of the
compatibility required, especially in regard to VCOs.  Blacet probably
didn't concern himself with that - his stuff is made to run off of a
format which is 15 volt (frac). These may work together great in that
environment, but put them against modules fomr ot of that family (such
as Doepfer) and all bets are off.  Grant Richter possibly had the best
possible solution with his 300 series instruments - running each
module off it's own wallart. This is a splendid way of thwarting off
the potenial of noise making as it really cuts down on the
traffic/current of the ground bus within the system. 

- P 



--- In PLAN_B_analog_blog@yahoogroups.com, "Bryan E Cornell"
<bcor@...> wrote:
>
> I get this same problem with my Wiard Noise Ring and my ZO.  You can
hear small fluctuations in the ZO that are in perfect time with the
LED's on the front of the NR. Usually, my patches get so sonically
messy that this doesn't matter, but I could see that it could be
annoying in certain applications.

> 
> Bryan
> 
> >>> synth_freak_2000@... 09/18/06 2:51 AM >>>
> hello peter,    :-)
> yes, you're right! one model 15 does not affect the
> other model 15 of mine! only other modules affect the
> model 15 pair of mine.
> but, anyway, thank you for the info and i'll just set
> the PWM knob to 0 or 10 when i am using other waves of
> the model 15's.
> regarding the pulse/ PWM waves, i will have to stick
> with this cross-mod. but it is ok. it reminds me a bit
> of my VCS3's that many modules affect other modules in
> unknown ways...     :-)
> many thanks,
> best regards,
> Bakis.
> 
> 
> 
> --- "(i think you can figure that out)"
> <peter@...> wrote:
> 
> > Bakis,
> > 
> > As always., great to hear from a fellow Greek!
> > 
> > I have noticed this anomaly as well...when my M15s
> > were in mounted
> > close to my one remiaing Blacet VCO.  Please try
> > this, as it fixed the
> > problem for me (admittedly a bandaid of sorts):
> > 
> > Move the PWM pot of the module you suspect to be
> > bleeding over to te
> > M15'a to full CWQ or CCW - enough for that
> > squarewave to be locked out
> > of oscillation (held full pos or neg).  This takes
> > care of it, atteast
> > on my system. ,  
> > 
> > As far as what's causing it, is it terrible to say
> > I'm not 100% sure?
> >  How's that for honest?  One thing I do know, M15's
> > do not cause other
> > M15's to do this, and I've made special precautions
> > to limit the
> > amplitude of the square outs well short of the power
> > rail of the op
> > amps driving them. My suspicions are there are a few
> > square wave
> > vco/lfo's out there that are not attenuated - that
> > run from rail to
> > rail. This causes havoc on any power system, much
> > like when LEDs are
> > not properly current limited and I believe my VCO is
> > especially prone
> > to picking up on that.  
> > 
> > Most PWM circuits run on the same prinicple as a
> > manual one shot
> > comparator.  The PWM pot sets the threshold, and the
> > incoming waveform
> > (non square wave) goes into the other side of the op
> > amp.  This config
> > allows anything in the incoming wave which is
> > greater in amplitude
> > than the pot setting to pass to the output as a
> > high.  Problem is, 
> > unless you design it differently, that high will be
> > at the rail - the
> > same amplitude as the voltage powering the op amp. 
> > this fluctuation
> > in current then ricochets through the entire power
> > system.  SOme
> > istruments are sensitiive to this, some aren't.
> > 
> > The Model 1 power buss I think may take care of this
> > problem.  The
> > first run of these (50) are arriving in about a
> > week's time form our
> > PCB vendor.  I'll give you all an update at that
> > time.
> > 
> > When tim allows, I will do some experiements with
> > increasing the value
> > of the two main bypass caps on the VCO engine bard -
> > currently 10mFs.
> > 
> > - P
> > 
> > 
> > 
> > 
> 
> 
> Bakis Sirros - Parallel Worlds
> [Doepfer_a100] group owner
> http://www.parallel-worlds-music.com 
> http://www.myspace.com/parallelworldsmusic 
> http://www.shimarecords.co.uk 
> http://www.rubber.gr 
> Athens-Greece
> 
> __________________________________________________
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> Tired of spam?  Yahoo! Mail has the best spam protection around 
> http://mail.yahoo.com
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