[sdiy] Circuit purpose?

[David Ingebretsen]

Hi Ove,

Actually, one was a J. Haible circuit. His Moog 914 FFB clone. That one was what made me the most curious.

David


>> -----Original Message-----
>> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
>> bounces at dropmix.xs4all.nl] On Behalf Of Ove Ridé
>> Sent: Monday, March 17, 2014 8:17 PM
>> To: John Henson
>> Cc: synthdiy diy
>> Subject: Re: [sdiy] Circuit purpose?
>> 
>> On 18 March 2014 02:55, John Henson <synthnerd at eircom.net> wrote:
>> > I have seen similar circuit topologies over the years in many areas,
>> > but this looks like an audio line out circuit which is one component
>> > more complicated than it needs to be. The 680R resistor represents the
>> > 600 Ohm output impedance (it's the cheapest nearest value) the back to
>> > back Electro Caps to behave like a Bi-Polar, and the obligatory 100k
>> > to Ground to stop charge on the last Cap causing clicks and bangs when
>> > plugging connectors in and out.
>> > If this is something you want to work with, go with 680R resistor from
>> > the Op-Amp output connected to Bi-Polar cap and 100k to Ground after
>> this.
>> 
>> A non-polarized electrolytic capacitor is really two polarized ones
>> connected back to back internally, so it's really two components, even if you
>> can't see it. :) I'm guessing those weren't made, or at least weren't cheap
>> enough when the circuit David is looking at was produced.
>> 
>> --
>> /Ove
>> 
>> Blog: <http://blog.gg8.se/>
>> 
>> "Here is Evergreen City. Evergreen is the color of green forever."
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