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

cheater00 . cheater00 at gmail.com
Thu Jun 6 10:30:25 CEST 2013


Looks like preringing, check all bypass capacitors. Also check voltage
rail buffer caps for high ESR with the Peak ESR meter.

Cheers,
D.

On Thu, Jun 6, 2013 at 1:24 AM, Michael Zacherl <sdiy-mz01 at blauwurf.info> wrote:
> 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 synth-diy.org
>> > 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
>
>
>
> --
> nonconform? noiseconform: http://blauwurf.at
> http://soundcloud.com/noiseconformist
>
>
>
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy


More information about the Synth-diy mailing list