[sdiy] Smith's Evolver Desktop's spikey VCO waveforms

[Michael Zacherl]

yeah, I think the triangle is the only shape where this glitch can be heard.
but the 'normal' notches on triangles I know are right on the tip of the wave and (IIRC!) symmetric on both halves.
thx - m.

On 6.6.2013, at 00:27 , Scott Nordlund wrote:

> There aren't any trimpots to adjust, and in fact I think the entire oscillator, including waveshapers and waveform selection circuits, is included in a single IC. But it's surface mount and I think not available outside of DSI. 
> 
> I've noticed a small glitch in the triangle wave of mine too, though not as dramatic as that one. I only noticed when using it for Lissajous figures. I think a minor glitch is normal.
> 
> > From: sdiy-mz01 at blauwurf.info
> > Date: Wed, 5 Jun 2013 23:53:20 +0200
> > To: synth-diy at dropmix.xs4all.nl
> > Subject: [sdiy] Smith's Evolver Desktop's spikey VCO waveforms
> > 
> > Hi, 
> > a friend's Evolver Desktop has a peculiar glitch in its VCO's waves.
> > First, from his description, I suspected a trim pot being not adjusted properly but now he sent me some pics of the screen of his oscilloscope, and I can't tell what it is. [1]
> > Of course it's audible.
> > 
> > Shipping for repair is apparently very expensive so I thought I give it a shot and see if I can find out anything about it. But alas, without a schematic or a service manual and already gotten a bit rusty myself it's a bit hard.
> > 
> > Strange, at the first glance, is that it's on both VCOs and given the digi scope's coarse resolution it also might be identical (which I'm not sure).
> > Smith's service replied laconically "it's broken, must be repaired" - so no big help from there, at first.
> > 
> > Any thoughts what that could be?
> > 
> > Thanks a lot, Michael.
> > [1] http://blauwurf.at/temp/EvolverWave-Glitches.png
> > 
> > --
> > keep your ears open: http://blauwurf.at
> > http://soundcloud.com/noiseconformist



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