What solid state power amp are you using with your Harbeth Super HL5+ speakers?

I run my Harbeths with a sixty watt tube amp after borrowing and trying a couple of ss amps.What I have found to clean up and tighten the bass is to use IsoAcoustic pucks between speakers and stands.The cabinets vibrate quite a bit which contributes to their warmth and smoothness,but can veer into smearing and too prominent mids.It surprisingly had a much bigger positive effect than the ss amps.Just something I stumbled onto that you might want to try.

jjss49,

Ceiling height is 7.5 ft.

I'm using a 60W Hegel H90 with my HL5+. The pairing produces holographic imaging, a deep black background, detailed midrange and well controlled bass that is deep and powerful when it needs to be. It sounds clean.

While it can facilitate some magical moments (the singer and band is in the room, etc), I find that it rolls off a bit of the high treble, hence the black background. This is apparent once I switch to another amp that is slightly  more organic but a bit more vague in soundstage (an Audio-gd Precision 1 amp).

Despite that, ambience and reverb are still very much present and immersive with the kinds of tracks that emphasize them.

They are also in a small room, 10' x 12'.

I have the Harbeth Super HL 5+ 40th Anniversary speakers and I'm running them through a Pass Labs int 250. Absolutely love the combination. Sounds superb.

Using a Parasound a21+ driven by a Rogue Audio tube preamp.
Sound is as good as I could ask for.  Super smooth and refined.