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|27th August 2011, 07:44 AM||#1|
Join Date: Aug 2011
Capacitor Replacement Opinions? - Marcof PPA-1h MC Amp
Looking at doing a maintenance replacement of the electrolytic capacitors on this small head amp. It is over 30 years old, and has gone unused for several years. There are 11 Illinois Capacitor caps on (and under) the board. See pic below of what the board looks like. Here is a circuit drawing (graciously provided by another forum poster, xjwmcx).
PPA-1h Circuit Drawing
No idea on the specs of these 30 year old caps, but current general purpose IC caps are approximately as follows:
IC, 220 uF, -10/+50%, 10 V, ESR 1.5 ohms, DF 0.2, Ripple 250 mA
Here are three choices I've considered for replacement, considering physical size limitation. Also selected 270 uF +/- 20% over 220 uF, for tighter control and better match to original if available.
Elna, RFS, 220 uF, +/- 20%, 25V, ESR ??, Ripple 505 mA, Tan 0.1, $1.25 (CDN)
Panasonic, EEU-FR, 270 uF, +/- 20%, 50 V, ESR 0.023 ohm, Ripple 1,890 mA, Tan 0.1, $0.84
Nichicon, PL Solid Polymer, 270 uF, +/- 20%, 10 V, ESR 0.008 ohm, Ripple 4,900 mA, Tan 0.08, $0.87
Thoughts on the best choice of these, or another choice I've overlooked? Elna seems to get "golden ears" recommendations, but the specs don't seem to measure up to the other two. The solid polymer electrolytic seems to be the clear winner based on specs. Any reason not to use them in an audio circuit?
The board also has 0.1 uF film bypass caps. With a 1.5 ohm ESR they may have helped a little, but seem almost worthless with a 0.008 ohm ESR. I suspect they are polyethylene, but may just leave them, or replace them with a 0.46 uF metalized polypropylene just to keep the "look and sound mystic" intact.
All thoughts appreciated.
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