I am currently working on changing the electrolytic capacitors in my
Quad 33/303 amplifier. After nearly thirty years of daily use, they
are probably at or beyond the end of their useful life.

So far, I have replaced the four large electrolytics in the power
amplifier. (Two are for power supply smoothing, connected in parallel,
and two are for decoupling the speaker output.) These were last
replaced in 1985 after the original components leaked and damaged the
amplifier board underneath. Renewing these parts has produced a marked
improvement in the sound quality. (The replacements have larger
capacities than the originals - from 2,000uF to 4,700uF for smoothing
and 10,000uF for decoupling.)

The next job is to replace the remaining 'small' capacitors in the
preamplifier and the earlier stages of the power amplifier. Having
spent a evening looking through the RS and Farnell catalogues I am
looking to use solid aluminium capacitors wherever possible. (Farnell
sell Sanyo SG series 'audio grade' devices.) Where suitable solid
aluminium devices are not available I am considering 'ultra low' ESR
electrolytics with low leakage, primarily intended for switch mode
power supplies. (Typical part numbers are 664-492 and 769-794
respectively.)

Comments on these choices would be appreciated.

Thanks,


--
Chris Isbell
Southampton
UK