Harbeth & VAC combo

Since you predominantly listen to vocals and small ensemble, the better tube amps might do a better job than your current Naim. I do not have experience with Sugden but have read about their smooth and warm sounding signature.

Which Naim amp do you own? Nycjlee gave some good recommendations on solid-state amplification for the Harbeth. LFD, Naim and Exposure are more on dynamics (I have experience with LFD and Naim). As for the Hegel and Sugden, my impression is these are smoother and darker sounding amps, less dynamic and fireworks. Best is to listen and decide for yourself.

FWIW I chose Naim separates (NAC 282, Hicap DR and NAP 250 DR) to match with the Harbeth SHL5 Plus as the Naims are able to deliver the pace, rhythm and dynamic swings in the music very well with the Harbeth. Ditto the LFD and Exposure (the LFD has a slight tube-like glow despite being solid-state). If you want more sweetness or tube-like warmth or glow in vocals, there will be other amplifiers, especially tube amps that may be better than the Naims or any solid-state amp for that matter, though there might be a slight compromise in areas of speed and dynamics. The Harbeth may sound slow and uninspiring with certain solid-state amps such as Rega and Plinius.

As usual, the above are my experience based on my system and preferences. YMMV.

Ryder,

I do not have a dedicated amplifier since I wanted to keep my system as simple as possible. Currently, I'm using Naim Unitilite and assume that a good dedicated  amp will be a step up. It's a 50wpc.
The Ulite will go to my wife's system (with P3esr) and I'll find something good for no more than 6k.

Adrianob,

Since you already have the Naim Unitilite for the P3ESR, best is to go with something else other than Naim. The C7ES3 is one of my favourite Harbeth speakers alongside the SHL5 Plus. I have listened to the Leben CS600 at a friend’s place driving the M40.1 (he also has the P3ESR). We compared the Leben with other amps such as Naim 32.5/135, Exposure 2010S and LFD Zero LEIII just to name a few (he has many solid-state amps). The transparency and detail of the Leben CS600 are exceptional, something which the other solid-state amps could not match. The Leben sounded leaner, lighter and more refined than all solid-state amps we have tried (which sounded darker in comparison). Ultimately the CS600 falls a little short in the power department for the 40.1s but it surely has potential.

Since you have listened to the Leben CS600, presumably with your C7ES3, that is the best experience that you can have. Best is to listen to other options such as the VAC before making the plunge. For the types of music that you listen to, I suspect a high quality tube amp will be more suitable for your application. Good luck.

For my office system I started out with the P3ESRs.  I then shopped for amplification.  I was focused on small footprint electronics, and SS.  I settled on Rega Brio-R, DAC-R, and Apollo-R.  I am very pleased with how these mate with the Harbeth's.

Just to clarify. I had the Rega Elicit Mk2 and Krell KPS-30i with the SHL5s. It was a subpar combination which sounded a little dull in my experience. I have read about the newer Brio-R and Elicit-R(Mk3) sounding more lively and forward than the older Elicit and Brio-3 models. Perhaps these newer Rega integrateds may have matched the Harbeth well.

I have now added a more transparent and analog-sounding DAC (Chord QBD76) to complement the darker sounding Krell CD player. It is amazing what a quality source can do to the sound. It surely helps to put a little emphasis on the source as it is equally as important as the amplification, in my experience.