I have owned many old mac amps, and when I acquire them, I send them to Mac for general servicing. I have NEVER had them do anymore than replace a burned out lamp. Ever! And I am talking about amps and preamps that were 15 to 30plus years old. Each one met spec. The same is true when I bought my harman kardon Citation 17 preamp and 16A amplifier. I sent them to hk on Long Island and they sent them back with a data sheet. They far exceeded factory specifications. It erks me a little when someone says 'oh I replaced the caps in this or that and now the unit sounds awesome' (caps are so easy to change and this seems to be the rage today) Capacitors do NOT DEGRADE over time, they FAIL. Which means if your amp is playing, your caps are fine.
So, I think that if a unit was manufactured using quality parts, you should be ok, at least that has been my experience.
Norman
So, I think that if a unit was manufactured using quality parts, you should be ok, at least that has been my experience.
Norman