Handling Heavy Amps

...and finally, I am in tune with your concerns.  I am back two days now from having two (more) discs replaced and bone spurs on my spine removed.  Music is my nervana, and I am appreciative to have had great help assembling my system!

I was looking at the Westminster Labs Class A amps, but the price was too rich for me. At that time, I ended up with the KRELL Duo 175XD. It was about 70 lbs I think, but it is big and ugly. It is similar to the implementation of the Westminster. I believe the Westminster designer, or the USA distributor said the same words to me on the WBF thread. 

The KRELL Duo 175XD sounded great. Buttery smooth, powerful, with detail. It is all Class A (up to 175 watts if needed) and runs cool. It has fans but I never heard them come one, even when it was beside me as a headphone amp. I normally used it to drive the hard to drive Thiel CS3.7 speaker.

Duo 125 XD Stereo Amplifier Technical Specifications – Krell (krellhifi.com)

The lower watt, Duo 125XD is even lighter than the amp I had (60 lbs). The looks are not pretty but the sound is gorgeous.

I have dealt with sciatica for around 9 years. I was using a 65lb. amp from Odyssey Audio, the Stratos 3 channel model (my rig is combo 2-channel and home theater). When it needed repairs, I lugged it to a UPS store for packing and shipping. It was not easy for me, even with a hand truck, especially since my system is down a flight of stairs in my basement. Well, the unit came back damaged by the shipper, so I had to lug it again. Got it back after a while. It worked a few months, then failed again. I was at my wits end. Then I remembered that erstwhile NJ resident and fellow audio society member Mike Kallelis of Arion Audio makes really good switching amps that I have heard numerous times. I called him and ended up with the Arion Audio S-500 ($2500 retail at the time in 2019). I was out of work then, but I can’t live without my music, so I got the amp. 500 watts per side of very clean power in a shoe-box size case that weighs about 22lbs. I have been thrilled ever since. Maybe a tad less warm than the Odyssey, but it is quite neutral, clean and my speakers love the huge reserves of power. Highly recommended.

+++1 for the CODA S5.5, though I don't know how it would pair with the Harbeths. I would reach out to Doug Dale founder and CEO of CODA, he is really a great person to talk to....I spoke with him twice before buying the S5.5 and once afterwards. 45 pounds, full class A, reserve power for days.

I've only had mine for less than a week, but it is already producing magic. I have it connected to my Buchardt Audio S400 MKIIs right now (87 db 4 Ohms) and the CODA is owning those speakers. Also had it connected to a pair of Clayton Shaw Caladans, but they were really easy to drive at 93 db.

There is a thread right now started by Jonah5 who is reviewer Terry London, who has one in house for a review. He thought so much of it that he posted an early "heads up" post here on Audiogon......check that thread out.

I bought mine from Audion Archon, and Mike Kay could give you some thoughts as well on the CODA