Old SS amps

I am running a pair of MacIntosh MC2100 SS Amplifiers that were built in the early to mid 1970s... one has been fully recapped; the other is (I believe) all original. They are fed by a PAS3 Tube Preamplifier that was built in 1968 I believe. The PAS3 has had a new power supply installed, and new tubes. Other than that I believe all the caps and transistors are original. 

Sound quality is pretty much identical from each amp. The only issue I have found is that the all-original amp runs a little warmer than the recapped unit. I will be recapping the original unit within the next few months, just to be on the safe side.

I think there is a certain 'charm' and sound quality to the vintage stuff that the modern units just don't have... but that is just my own opinion. I do think, objectively, that if you have a desire to run the vintage equipment you should try it. In reality, if you start by purchasing good quality brands that are still in good shape - you shouldn't run into anything that would be any more difficult to remedy than if you had an issue with a modern unit.

@devinplombier  yes, some amplifiers are not worth putting too much money into repairing, the better built ones like many of the old Krell amps is a different story. To buy a modern class A/B amplifier built like the old Krell amps would cost tens of thousands.

Still using my sunfire amp from late 90s in my second system. Sounds pretty darn good but not quite up to my Triode Lab PSet 45 monoblocks in my primary system. I’ve swapped them several times not and keep going back to the TL. There’s also a 10x cost difference so I probably shouldn’t be that surprised.

In 1980 I bought a Yamaha M2 Poweramp 240 w. Of channel weighs 70 lb. To purchase a 240 w amp today that's built as well as this one would cost me $5 to $6,000 or more. This amp was sold by Yamaha is a high-end home amp and also as a power amp for PA systems and concerts. I had a local tech that specializes in '70s and '80s amps only take it apart. Change relays that had corroded contacts because it had relay protection in several areas. Cleaned all the pots. Checked every capacitor. Checked all all transistors for proper specifications. All the parts that are inside these amps are subject to changing their specifications over time because of heat abuse, high voltage, low voltage spikes, whatever we're talking thousands of parts in these amps. Yes they will run perfectly for years and years and years. But if you want it to run like it was from the factory going through and and replacing the Hi-Spec parts that Yamaha put in with the high spec parts that are available today is the cheapest thing you can do. In the end I put $750 into the amp that I bought for $1,000 and it still is better than a $5,000 amp today. The amp is such a sweet piece of equipment. I purchased a second one because I'm going to buy at my speakers cost me a little more cuz it was having a problem when I got it. But now it sounds just as sweet. 

Yamaha is one of those engineering companies that just likes to do things top notch when they're selling a top-notch piece. If you look at their current offerings they have three levels of basically the same power amp. They're all supposed to be 100 w a channel but the quality of the construction as you move up becomes apparent as to why some of these ultra expensive amps do Excel at their craft. I've been an audiophile since 1975 and I've watched the industry grow up. I've been watching these companies grow up and it's always the company that goes to the nth degrant engineering that'll last today's modern high-end amplifiers are very well built. Use quality components. My choice is for the vintage because they just look cool. Enjoy whatever you have and enjoy upgrading it 

I’m still using a Reference Line Silver Signature amp that I bought new in 1999. Class A, so it runs hot. Still sounds fantastic, although it did blow out a couple of transistors over the years. Fortunately, Roger Modjeski (RIP) lived nearby and graciously agreed to fix it—twice. And this was after another highly-respected tech said no way. So my advice, if you’re considering a decades-old amp, is to have a great tech nearby, one who digs a challenge. :) If this amp blows again, it’s a 100 lb boat anchor.