[sdiy] emulating bi-polar capacitors

[James Coplin]

Aren't they needed in crossover circuits? I seem to recall something along those lines but I couldn't say why that's the case.

James

⁣Get BlueMail for Android ​

On Feb 15, 2022, 2:37 PM, at 2:37 PM, Mattias Rickardsson <mr at analogue.org> wrote:
>Hej Danjel and others,
>
>I don't recall seeing any hard facts about non-polarized electrolytics
>performing better than ordinary polarized in audio circuits, but still
>they
>occasionally turn up in designs. Would be interesting to hear why they
>sometimes are preferred by audio designers, though! :-)
>
>I searched for "non-polarized" in Douglas Self's reference book "Small
>Signal Audio Design" and found a couple of applications where they
>actually
>do make sense - but it's a practical reason rather than an audio
>performance reason:
>DC blocking in inputs & outputs, where it's possible that the connected
>gear pulls the voltage way off ground level, and you never know in what
>direction.
>Douglas Self writes:
>
>"C2 is a DC-blocking capacitor to prevent voltages from ill-conceived
>source equipment getting into the circuitry. It is a non-polarized type
>as
>voltages from the outside world are of unpredictable polarity, and it
>is
>rated at not less than 35 V so that even if it gets connected to
>defective
>direct-coupled equipment with an op-amp output jammed hard against one
>of
>the supply rails, no harm will result."
>
>Any other good reasons for using them?
>And sorry, no - I don't have any better advice than what has already
>been
>said. :-)
>
>/mr
>
>
>Den tis 15 feb. 2022 20:43Barry Klein via Synth-diy
><synth-diy at synth-diy.org>
>skrev:
>
>> I used one in a typical dual op amp triangle oscillator on the phaser
>in a
>> Music Man amp design. It made a difference in extremely slow sweep
>symmetry
>> and also I had a function where you pull the knob out and could fix
>the
>> sweep wherever you wanted it. After I left the whole thing was
>redesigned.
>> Maybe I didn’t know what I was doing….  45 years ago… Self-taught by
>> Electronotes. What a fun job before work politics F’d it all up.
>>
>> Barry
>>
>>
>> > On Feb 15, 2022, at 11:32 AM, Mike Bryant
><mbryant at futurehorizons.com>
>> wrote:
>> >
>> > 
>> >> I've never bothered, I've never noticed a difference in just using
>a
>> 47μ instead of playing about with back-to-back capacitors even after
>the
>> thick end of 40 years the earliest stuff I built that way still has
>> capacitors that capacitate just fine.
>> >
>> > --
>> >> Gordonjcp
>> >
>> >
>> > Agreed.  Unless you actually have a reverse DC bias voltage (in
>which
>> case rotate the capacitor) I've never understood any need for the
>> non-polarised capacitors.  Most mixing consoles are full of thousands
>of
>> them either feeding the input or fed from the output of an opamp via
>a
>> resistor to ground.
>> >
>> >
>> > _______________________________________________
>> > Synth-diy mailing list
>> > Synth-diy at synth-diy.org
>> > http://synth-diy.org/mailman/listinfo/synth-diy
>> > Selling or trading? Use marketplace at synth-diy.org
>>
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>>
>
>
>------------------------------------------------------------------------
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at synth-diy.org
>http://synth-diy.org/mailman/listinfo/synth-diy
>Selling or trading? Use marketplace at synth-diy.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20220215/2430091f/attachment.htm>