Amps from the 1980's -- What gear holds up sonically? Reliably?

I’m the original owner of a beloved SAE 2200 amp bought in 1977 that is still in use. In 2001 I paid the original designer James Bongioro to completely upgrade it. Every capacitor got replaced with poly & premium electrolytics. He replaced all the semiconductors (diodes, transistors) except the matched input transistors which he said were working well and had no better modern alternatives. The output power protection circuit was removed. And the final upgrade was his addition of an op amp servo bias circuit board that was not present in the original SAE design. He used an Ampzilla servo bias circuit board. Boy did he boost the bias voltage over the original factory set level, too! The unit now runs about 50% hotter (and sweeter) than it did all those years before 2001.

Recently I’ve added an Ayre AX-5 Twenty amp for daily use. But I still have the SAE 2200 hooked up. I’ve auditioned many solid state mid-high amps over the years and until I heard the Ayre, none were more musical than my upgraded SAE. Certainly nothing within an order of magnitude above the $400 paid to James for the upgrade.

James Bongiorno, a "pioneer of audio", passed on in 2013, sad to say. http://forum.audiogon.com/discussions/death-of-jim-bongiorno

I've had several models of Sumo amps through here in the past 20 years, of them 3 Nine Class A's including the prototype. None of them needed recapping (per James Bongiorno who I befriended in '98) and all of them sounded great. We did mod the Nines to a newer opamp and IEC socket but I also had an Andromeda, a NOS Gold, and a NOS Power, the Power especially took my breath away. I still have the silver-faced rackmount Nine plus a Rowland Model 5, a ML no.336, and a Bedini 250/250 working perfectly now as when they left the factories. Only my Mac 2105, probably 70's, needed new power supply caps (oversized ones definitely gave me better bottom end). I also use a Nak 420 power amp in my studio from that era. There's also a Yamaha P2200, BGW 750D, QSC USA 400, an Audionics PZ3, and a hunkering Crest 4001 in the garage, all still work fine. The only other amp I had to replace caps in was a Harmon Kardon Q50A from 1964, rather older than these. Quicksilver caps were a huge upgrade but we also bypassed all the junk stages (tone, filters, blend) and the thing sounds awesome. Only a Merrill Veritas monoblock pair ( here for review, $12K) exceeded these but I didn't have the Levinson then which is my daily driver. I can't believe some people feel all amps sound alike (AES!) but then I hear cable differences too, so sue me. ABX is deeply flawed. Go with your ears...after a reference check multiple times. Blah, blah...

The thing about Sumo's consistently is they sounded deep. Side by side with a Hafler, the Hafler's of that era would sound weak and thin and compressed.

Though for mid-range and treble transparency and quietness, I wouldn't trade my modern amps for them anymore.

Best,

E

Speaking of Ampzilla and Mr. B, I owned a Son of Ampzilla in the 70's. I didn't like the lack of on-off switch, and called Mr. B about it. He just said fine and sent me an outboard switch to install myself. -Never used the switch but liked the amp a lot. I traded for a used Naim amp and pre just to get the mc phono card in the preamp. Before it was over, I had a Linn-Grace707- Supex 900 E plus super set up. Those were the days.
-Sorry, but this stuff brings back fond memories.