[sdiy] Curious capacitor in Music Easel ring modulator

[harrybissell at wowway.com]

Any DC offset at this point would probably result in bleed-through.

I had a similar circuit with a coil feeding an integrator. SHOULD be no
DC, but system wiring etc made the grounds a little different... resulting
in drift. A really big cap (I needed low frequency response) in series
fixed the trouble. I used a non-polar electrolytic. NP electrolytics are
not so expensive and I use them for all blocking apps greater than 1uF.

H^) harry




On Mon, 25 Aug 2008 22:10:02 -0400, Aaron Lanterman wrote
> Totally hypothetically speaking, suppose one was breadboarding the  
> "balanced modulator" shown here:
> 
> http://rubidium.dyndns.org/~magnus/synths/companies/buchla/Buchla_2080_5_200.jpg
> 
> Should I - I mean, the hypothetical "one" - really put in C1, which 
> is  a 4.7 muF electrolytic cap? I see no particular reason to 
> believe the  voltage on one side of it would be consistently higher 
> than the  voltage on the other, which gives me pause and makes me 
> wonder about  it in the original circuit. (I've seen electrolytic 
> caps like that in  other Buchla stuff, where it looks like it's 
> meant as a DC block, but  I can't see any reason to assume one side 
> would be higher voltage than  another which feels dubious given that 
> it's an electrolytic. I have  heard that electrolytics can take a 
> bit of AC action as long as the DC  isn't going the wrong way, but 
> that feels dubious too.)
> 
> - Aaron
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva