Do you mean you need something that will give you those sounds at band volume as well as in the apartment, but weighs a lot less than the Heartbreaker?
I will tell you a story...
In the late 80s and early 90s I used big Marshall amps and cabs. My favorite was the Club & Country combo, which is a 100W 2x12" that probably weighs about 90lbs. I too lived in a second floor apartment, and one night after carrying the Marshall back up the stairs, slipping because I couldn't see where I was going with it held across my chest and hurting myself trying not to drop the stupid **** heavy thing and wake up the whole building, I swore I would get a smaller amp. I measured the power it was putting out at my normal band settings with the MV just under half... 11W!
So I sold it and went and bought a 15W 1x12" combo. For a while I was happy, because it was easy to carry and it was loud enough. In actual outright volume, anyway... but after a while I began to miss the beautiful big clean sound and the effortless power of the distortion, so I gradually got bigger and bigger amps until I was back up to a 50W widebody 1x12". Still not quite right. Finally, years later - and admittedly after I'd moved back to a house, so no stairs - I got fed up with small tone and bought a Tremoverb. And I *wish* I'd done it years before, 100lbs and stairs or not. There is no comparison in sound quality.
I'm not young any more and I'm not a big guy either, I weigh less than 140lbs myself! But I've made myself get used to the Tremoverb, and not swear at it too much for being heavy... it *is* worth it. Think carefully before parting with the Heartbreaker - and consider fitting decent side handles if it's still stock without them, they make a huge difference to how easy it is to move the Tremoverb, I don't think I could do it with just the top handle. The Tremoverb is actually easier to move than a Fender Twin, despite being around 15lbs heavier. I think it just keeps me in shape now
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And if you do still want a smaller, lighter amp - and one that isn't too expensive nowadays - try a Mesa DC-5. That was my last amp before the Tremoverb, and it's massively loud and full-sounding for such a relatively light amp... it was almost good enough.