[sdiy] "Load" on power supply changes pitch of VCO...

[Mike Beauchamp]

Actually, I poked around more with my circuit.. and I noticed the
capacitors I had on the output of the voltage regulators were .01uF
and the datasheets call for .1uF for "increased stability and
transient response". So I swapped them out just to check, and it seems
like the voltage isn't dropping anymore and the regulators are
actually regulating. Not only that, but this odd buzz I was getting on
the very high frequencies is now gone and the output is
cleaaaaaaannnn.

I'm gonna go downstairs and run more tests to be sure that's the
problem solver.. but either way, thanks for all the repsonses thus
far.

Mike


On 2/22/07, tony Rolando <goldenechos at hotmail.com> wrote:
> Tried a 15VAC supply?
>
> TR
>
>
> >From: "Mike Beauchamp" <mikebeauchamp at gmail.com>
> >To: synth-diy at dropmix.xs4all.nl
> >Subject: [sdiy] "Load" on power supply changes pitch of VCO...
> >Date: Thu, 22 Feb 2007 01:07:45 -0500
> >
> >Paul Perry> If it helps, the powersupply I made for the XR-2206 VCO is
> >a 12VAC wallwart that gets rectified, filtered with .1uf caps and
> >470uF caps and fed into  7815 and 7915 voltage regulators to give me
> >+15 and -15V.
> >
> >My VCO is "stable" in that it doesn't drift, however the frequency
> >changes if I add more load (like an led or something) to the power
> >supply.
> >
> >Maybe I'm wrong assuming that using power from voltage regulator chips
> >gives me a "regulated power supply"?
> >
> >Mike
> >
> >On 2/21/07, Paul Perry <pfperry at melbpc.org.au> wrote:
> >>If you want a stable VCO using an XR-2206, then you need a
> >>regulated power supply.
> >>
> >>paul perry Melbourne Australia
> >>
> >>----- Original Message -----
> >>From: "Mike Beauchamp"
> >> > The first VCO I built was Thomas Henry's XR-2206 VCO
> >> > (http://mypeoplepc.com/members/scottnoanh/birthofasynth/id20.html).
> >> >
> >> > I'm noticing that when I experiment and add various things, the pitch
> >> > changes. It's as though the pitch is dependent on how much current I'm
> >> > drawing from the power supply.
> >> >
> >>
> >>
> >
> >
> >--
> >Mike Beauchamp
> >Cross Canada Project: http://mikebeauchamp.com/crosscanada
> >Personal: http://mikebeauchamp.com
> >Business: http://therevox.com
> >Windsor News: http://windsorinb.relyon.ca
> >
> >
> >--
> >Mike Beauchamp
> >Cross Canada Project: http://mikebeauchamp.com/crosscanada
> >Personal: http://mikebeauchamp.com
> >Business: http://therevox.com
> >Windsor News: http://windsorinb.relyon.ca
>
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-- 
Mike Beauchamp
Cross Canada Project: http://mikebeauchamp.com/crosscanada
Personal: http://mikebeauchamp.com
Business: http://therevox.com
Windsor News: http://windsorinb.relyon.ca