Integrated amp: Component weight

The Marantz PM 10S1 would fit your requirements. It weighs about 42 pounds And has 200 watts into 8ohms and 400 into 4ohms.  S/N ratio is 106db on lone has MC/MM phono stage, dua mono design, toroidal transformer, 5 RCA audio inputs plus 2 balanced XLR inputs. Can also be bi-amped. It’s also fully balanced. 
The price is about $5,000 

I do not have one, but saw one being used as a reference amp in a Magnolia hifi store and. It was easily able to power everthing from Magnaplans to big  B & W’s without breaking up. It is also a class AB amp. I wish you well in your search for the proper “power to weight” ratio as I recently purchased a 65 pound MICHI X3 to power my B&W 702 S2 Signatures with ease. A great tank of an integrated amp but to me a class A, AB unit should have sufficient heft t

@cundare2 - I'm in the same camp; bad back and can't lift heavy equipment up steps.

Not everyone's cup of tea, but I'm driving 86 dB sensitivity Bryston Mini T's with my McIntosh MA5300 integrated amp.  Here are some specs:

38 pounds unboxed.

Preamp out and Power Amp in jacks / home theater passthrough

6 analog inputs including MM phono and 1 pair of XLR balanced inputs

Class AB amplifier design

Built in "DA1" DAC with 6 digital inputs that can be upgraded/swapped out to McIntosh's DA2 since the onboard DAC is a module.

Headphone impedance is listed as 100 to 600 ohms.

$6,000 sticker, but you can buy them for less at dealers in person.

McIntosh MA5300

A drawback based on your requirements is that it's 160 watts at 4 ohms.

You can get nearly everything you desire in a set of stacking separates

the naim nac 272 has a fantastic dac streamer headphone amp numerous analog and digital inputs.

combined with the high current naim nap250 it is 80 watts but very high current an drives Harbeths beautifully Naim’s punchy dynamic sound makes the Harbeths come alive.

and considering these pieces are separates the weight of each piece is manageable

and with  the newer naim 200 series dealers have this combo on sale for a liot less them what newer 200 series sells for.

Dave and Troy

audio intellect NJ

Naim dealers 

OP

200-300 wpc, 40lbs, SS, not Class D

Mono-blocks will divide the gross weight, but, it’s a near impossible ask.

That is why I said: sell those speakers (the source of the extra weight needed), get efficient speakers (which get moved once) and need much less power (smaller/lighter/less heat/less cost/more placement options).

that's why I called it a 'lifetime solution'. we get older, back/knees/shoulders fall apart.

Efficient enough, you could then try tubes. Mono-blocks probably to reduce weight.

Maybe I missed it, but which Harbeth's?

Lot's of opinions about amps that will sound great with your Harbeth's, without knowing the model, or perhaps an assumption you have a version of the 40's given the stated power requirement of 200-300 wpc.