Alvarro, it's an original from the 60's. It still has a Dave OBrien Mac Clinic sticker on it. The free clinics were the most successful marketing tool ever devised in the HiFi industry. Dave wrote a little book about it and it's very interesting. He was a really nice man.

I took an amp to one in Portland once. Very gracious and considerate. They'd -*test*-('") any amp and if it was a Mac amp fix it for free while you waited. Then you got a chart showing all the specs and distortion levels.

Dave never once bad mouthed another mfgr's product. He let the -*test*-('") report speak for it'self. Which it usually did.

There's no such thing in Europe, free clinics i mean.
I never listen to a Mac like yours, but i know a few things about McIntosh sound...
As you know, most tube amps draw power only from the plates of the output tubes. In the McIntosh circuit, half the power is taken from the plates and half from the cathodes, so that power is drawn from both sides of each output tube.

Maybe the classical McIntosh reliability comes from this fact: Easier on output tubes than conventional circuits. You get high power with low distortion.

.....maybe some day, i'll have the "time" to buy a Mac....

Well, i'd check out the price of the MC 275 Commemorative edition of 94, not the original one like yours, and it costs only 3.500,00 €