<div dir="ltr"><div dir="ltr">The AS3340 has the problems with PWM. I use an external opamp to solve that.<div>The CEM 3320 can be replaced by the V3320 and AS3320 . The AS3320 has a slightly different frequency setting. </div><div>The 3280 used in a filter has the same effect , a slightly different frequency setting</div><div><br></div><div>JS</div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Op vr 29 jan. 2021 om 04:31 schreef Markus via Synth-diy <<a href="mailto:synth-diy@synth-diy.org">synth-diy@synth-diy.org</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:16px"><div></div>
<div dir="ltr"><div><div dir="ltr">Hi all,</div><div dir="ltr"><br></div><div dir="ltr">I built a module based on the AS3320 from scratch and the schematics looks exactly the same in the CEM3320 specification. so I would say you can replace these including the weird max. 2V resonance CV.</div><div dir="ltr"><br></div><div dir="ltr">side note:</div><div dir="ltr">as was said below between the AS3340 and CEM3340 the only difference seems to be the resistor on the PWM output pin 4 (AS 51k vs CEM 10k). you might also want to add some op amps and zener diode to get all waveform outputs up and down to the same level e.g. 0 - 10V...</div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr">gruss,</div><div dir="ltr">Markus</div></div></div><div><br></div>
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On Thursday, January 28, 2021, 07:07:46 PM PST, Jay Schwichtenberg <<a href="mailto:jschwich53@comcast.net" target="_blank">jschwich53@comcast.net</a>> wrote:
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<p>Yep, me bad, sorry.</p>
<p>Jay<br>
</p>
<div>On 1/28/2021 3:18 PM, ColinMuirDorward
wrote:<br>
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<blockquote type="cite">
<div>Jay is correct, but got his chips mixed up. The
PWM issue is definitely on the VCO (3340) chip! Tom is asking
about the vcf chip (3320) :)</div>
<br>
<div>
<div dir="ltr">On Thu, Jan 28, 2021, 4:12 PM
Michael E Caloroso, <<a rel="nofollow noopener noreferrer" href="mailto:mec.forumreader@gmail.com" target="_blank">mec.forumreader@gmail.com</a>>
wrote:<br>
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<blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Are you sure
the PWM issue is the AS3320 and not the AS3340?<br>
<br>
MC<br>
<br>
On 1/28/21, Jay Schwichtenberg <<a rel="nofollow noopener noreferrer" href="mailto:jschwich53@comcast.net" target="_blank">jschwich53@comcast.net</a>>
wrote:<br>
> I would go and read what's on Muffs about it.<br>
><br>
> With the original AS3320 there are issues with the PWM
affecting the<br>
> frequency. To resolve the problem it seems people had to
add negative<br>
> voltage regulator (think it's -5V if I remember
correctly).<br>
><br>
> Then CEM and new AS chips seem to be better.<br>
><br>
> Jay S.<br>
><br>
> On 1/28/2021 10:46 AM, Tom Wiltshire wrote:<br>
>><br>
>> Does anyone have any experience to offer having tried
this? Are the<br>
>> old and new chips close enough to be direct
replacements? Or maybe<br>
>> with a bit of trimming?<br>
>><br>
>> There seems to have been a lot of focus on the AS3340
as a replacement<br>
>> chip (and there are a few little differences) but I
haven’t seen or<br>
>> read much about the AS3320 as a drop-in replacement.<br>
>><br>
>> Of course, changing all the filters to maintain
consistency is a<br>
>> possibility, and then you have a few genuine CEMs for
the next repair!<br>
>><br>
>> Thanks,<br>
>> Tom<br>
>><br>
>> ==================<br>
>> Electric Druid<br>
>> Synth & Stompbox DIY<br>
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