Old Amps that can still Kick Butt

The Music Reference RM-9 Mk.2. THE classic tube amp, better than the Marantz 8b and 9, the Mac MC75, and the ARC D76.

For low impedance loads, the RM-200, "Class A" rated in Stereophile by Michael Fremer since 2002. The only tube amp I know of that puts out as much power into 4 ohms as it does into 8.

@bdp24 My friend has an RM-9 Mk2. It is excellent. But so are McIntosh 225 and 240 amps.
While this is a current amp, the Prana Fidelity Class D amp has no shortcommings. At the LA SHOW yesterday, I heard the $10K 400 watt 8 ohm amp driving the Prana two-way average efficiency speakers off of a Townshend Allegri Reference Autotransformer preamp, Silversmith cabling and EAR Classic CD player. Best in show sound (it was a limited size show with only about 70 vendors). Other than deep bass, it had superlative coherent sound, dynamic and involving. Better than a twice the price Harbeth 40.2 anniversary. Listened for 45 minutes (analog too). Never heard a autotransformer pre-amp with such slam/dynamics and colorful sound. I heard the amp several years ago and was impressed.  Our records and CDs, classical, vocal, jazz and rock.  Now, the entire chain of music was magnificent! https://pranafidelity.com/index.php/project/purnama-amplifier/

I use a combo of classic amps, EAR 890, radical modified Dyna ST70 and a pair of custom Altec 1459 (transformer and case only original parts). The Prana is definitely in the running to replace the custom pair and 890.

The Nelson Pass Designed an built Threshold SA-4e. 100w/ch of pure class A, and a ridiculous amount of current. Yes, it's a space heater, but I too will have it serviced in lieu of replacing it. It makes my Martin-Logans sing!

Nelson Pass improved designed Adcom 5400.

Back in the mid-1970's I was the second owner of a mint-condition McIntosh MC225 tube amplifier.  I didn't make that much money back then and was offered a huge price for the amp and sold it.  I wish I had that amp today!