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Old 6th Aug 2020, 5:51 pm   #34
Radio Wrangler
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Join Date: Mar 2012
Location: Fife, Scotland, UK.
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Default Re: Simple Op Amp RIAA preamp 1st lash up

Single rail versions of circuits have a side effect of putting bias voltages on some of the capacitors they need. This can cause turn-on and off thumps, but can be handy for keeping electrolytics polarised.

Dual-rail circuits can be lower in thump, but can leave you in a quandary of wanting some large-ish capacitors to roll gain off before DC, large enough to want to use electrolytics, but you can't be sure how much residual DC winds up across them, or what polarity.... a puzzlement. Some people solved it with little bead tants and we're now paying the price.

No one way is perfect, all have different mixtures of compromises.

David
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