Yamaha A 500 Integrated Amp Modifications

Power supply capacitors do indeed degrade, and if they fail (as they will) they can destroy your speakers. Since modern ones are often physically smaller, you may be able to fit modern ones with a higher capacity into the same case, for more dynamic headroom. Avoid audiophile caps: those from mainstream manufacturers are often better quality and cheaper.
Price is relevant here, because at least in Europe you can buy this amplifier’s modern successor, the Yamaha AS 501, for only about 350 euro. It is more powerful, measures better, and also has digital inputs. See here for a test of the previous model, the AS500 without the digital inputs but otherwise identical: http://www.avhub.com.au/product-reviews/hi-fi/yamaha-a-s500-amplifier-review-test-395710
It measures better than many audiophile amplifiers costing sometimes ten times more. In particular, frequency response under varying realistic load is stunning (within 0.05 dB). This is a perfect straight wire with gain. So don’t spend too much on refurbishing the old amplifier.

Thanks for the detailed info.  Very helpful.  I noted the THD on the old unit is incredibly low compared to the newer amps.  Should still be a very quiet amp.  But I would have to agree that it is probably not wise to drop a lot of money into it considering the age.  But will be sure to have all the parts that might be close to failing or are failing replaced.  Capacitors included.

Just got the A 500 up and running.  Seems to be fine.  True to form it has a more neutral sound than the Denon PMA 520 that I also have.

Question.  Does anyone know where to find a manual for the A 500?  Can't seem to find one online that I can download.

Also, I am trying to determine what kind of speaker connection to use with the amp.  Won't take Banana's and I am not sure Pin's will work either.  Weird shape to the speaker connectors.

Actually any electrolytic capacitor can be replaced for an improvement.  Nichicon KZ Muse or Nichicon KW are the best I have used.

Thanks.  Will consider that.  Right now my primary concern is trying to find a way to get cables to connect the speakers to the amp.  Want to Biwire and would like to avoid spades or bare wire.