<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div dir="ltr">Eric,</div><div dir="ltr"><br></div><div dir="ltr">Care to comment on the brand of x7r’s you observed this with?</div><div dir="ltr"><br><blockquote type="cite">On Jan 10, 2021, at 10:51 PM, Eric Schlappi <eric.schlappi@gmail.com> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><div dir="ltr"><div>my two cents on filter caps:</div><div><br></div><div>I have experienced piezoelectric effects with x7r caps recently, I now only use them for decoupling.<br></div><div><br></div><div>One of the bigger upgrades for my filters recently was upgrading from 5% C0G/NP0 to 1% C0G/NP0. I had previously considered 1% too expensive but they really aren't anymore and it can really make a difference as far as getting your filter to oscillate reliably in edge cases.<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jan 8, 2021 at 12:51 PM David G Dixon <<a href="mailto:dixon@mail.ubc.ca">dixon@mail.ubc.ca</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><u></u>
<div style="overflow-wrap: break-word;">
<div dir="ltr" align="left"><span><font size="2" face="Arial" color="#0000ff">I have the same experience. Poly film caps oscillate
much easier than C0G caps of the same value. I have replaced C0G with WIMA
polyester to get stable oscillation in filters.</font></span></div><br>
<div dir="ltr" lang="en-us" align="left">
<hr>
<font size="2" face="Tahoma"><b>From:</b> Synth-diy
[mailto:<a href="mailto:synth-diy-bounces@synth-diy.org" target="_blank">synth-diy-bounces@synth-diy.org</a>] <b>On Behalf Of </b>Tom
Wiltshire<br><b>Sent:</b> Friday, January 08, 2021 7:26 AM<br><b>To:</b>
ColinMuirDorward<br><b>Cc:</b> <a href="mailto:synth-diy@synth-diy.org" target="_blank">synth-diy@synth-diy.org</a><br><b>Subject:</b> Re:
[sdiy] VCF caps in modern synths<br></font><br></div>
<div></div><span style="background-color:rgb(255,236,179);color:rgb(0,0,0);font-size:12px"><span style="background-color:rgb(255,236,179);color:rgb(0,0,0);font-size:12px"><span style="padding:3px;line-height:1.6;background-color:rgb(255,236,179);font-style:normal;color:rgb(0,0,0);font-size:12px;font-weight:normal">[<strong>CAUTION:</strong>
Non-UBC Email]</span></span></span><br>
<div><br>
<blockquote type="cite">
<div>On 8 Jan 2021, at 16:02, ColinMuirDorward <<a href="mailto:colindorward@gmail.com" target="_blank">colindorward@gmail.com</a>>
wrote:</div><br>
<div><span style="text-transform:none;font-style:normal;text-indent:0px;display:inline;font-family:Helvetica;white-space:normal;float:none;letter-spacing:normal;font-size:12px;font-weight:normal;word-spacing:0px;text-decoration:none;font-variant-caps:normal">Yesterday
I did some very non-scientific testing of 3320 4pole BPF built using C0G vs
polypropylenes. The test may have been more about the tolerances of the caps
rather than the dielectric, since my polys are 2.5% vs the C0Gs at 5%. I
noticed that at lower frequencies, the polypropylene version would go into
oscillation before the C0G version. Any thoughts on
this?</span></div></blockquote></div><br>
<div>Yes, I think you’re right. That seems more likely to be an effect of the
tolerance to me.</div>
<div><br></div>
<div>Tom</div>
<div><br></div>
<div>
<div>==================<br> Electric Druid<br>Synth
& Stompbox DIY<br>==================</div>
<div><br></div></div></div>
_______________________________________________<br>
Synth-diy mailing list<br>
<a href="mailto:Synth-diy@synth-diy.org" target="_blank">Synth-diy@synth-diy.org</a><br>
<a href="http://synth-diy.org/mailman/listinfo/synth-diy" rel="noreferrer" target="_blank">http://synth-diy.org/mailman/listinfo/synth-diy</a><br>
Selling or trading? Use <a href="mailto:marketplace@synth-diy.org" target="_blank">marketplace@synth-diy.org</a><br>
</blockquote></div>
<span>_______________________________________________</span><br><span>Synth-diy mailing list</span><br><span>Synth-diy@synth-diy.org</span><br><span>http://synth-diy.org/mailman/listinfo/synth-diy</span><br><span>Selling or trading? Use marketplace@synth-diy.org</span><br></div></blockquote></body></html>