Bottlehead Forum: Re: Extended Foreplay III questions by Paul Joppa

First, my apologies for the error in the upgrade schematic, which should show the value as 3.0uF. I'll send the corrected schematic to Doc for future manuals.

Second, the value is not critical. The capacitor should be large enough to serve two purposes, adequately extended bass and maintaining a low line impedance to minimize certain kinds of noise pickup. Both are adequately served with anything more than 1.0uF, while more than 10uF is clearly overkill (IMHO). There are various precise calculations that could be made, but they all depend on vague and/or arbitrary assumptions on the criterion to be used so I don't see much point in fussing with them. It's more important to get a good-sounding cap.

Experimentally, you might try paralleling the Auricap with your existing PIO cap - tack it in, or even just use clip leads, to see if you like it. (Remember, if it seems promising, to leave it in for at least 50 hours of music before making any final judgements.) Since both caps are highly thought of, it's going to be mostly a matter of your taste and system synergy.