[sdiy] Glide Pitch Drop?

[Harry Bissell Jr]

Its likely you have a 10uF electrolytic, and it
has some leakage.  I'd use a much larger potentiometer
and a much smaller cap. Maybe a 100K and a 1uF or
(if you have one) a 1M pot and a .1uF capacitor. Once
you get to a .1uF you could get a polystyrene or
polypropylene cap, which would be MUCH better in
leakage etc.

Its possible to use a Tantalum if you NEVER have
negative voltages. If you do, avoid tantalum like
the plague.

slight possibility there is a bad TL074...

H^) harry



--- xamboldt <xamboldt at earthlink.net> wrote:

> Hi Everyone,
> 
> I'm modding a sequencer to add a simple glide out,
> so I copied the glide
> section from John Blacet's old "Digital Pattern
> Generator":
> 
> http://www.blacet.com/dpg1.jpg
> 
> I didn't use the 50k output attenuator, just took
> the CV out from the
> sequencer and fed it through the glide circuit
> exactly as shown in the
> schematic. I'm using a TL074 for the opamps.
> 
> If I have the glide set to 0, then the voltage out
> of the glide CV out is
> the same as the non-glide CV out. The problem is,
> once I turn the glide up a
> bit, the CV out drops a little. Not the greatest
> thing to happen if you get
> a sequencer set up to the right pitches, and you
> just want to add a little
> portamento, but in order to do so you have to reset
> all the sequencer
> controls to compensate for the voltage drop.
> 
> Any ideas on how I could fix this? Or is a different
> circuit my only hope?
> 
> Thanks,
> Chris
> 
>