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

Harbeth Super HL5+ speaker owners: Are you driving the Harbeths with a solid state amp? If so, what amp and how much power? Your impressions. I’ve been using a Conrad Johnson CA-150 (SS) integrated with my Harbeth SL5+ and the sound is nice but is underpowered at 135W@8ohms. Also, I would like a little more refinement with the amp. Bryston 4B3 perhaps? Thanks!
135 wpc solid state shouldn’t be underpowered for a harbeth hl5 unless the room is very large and/or you listen hella loud

that been said, i drive my harbeths with any of the amps below
-- audio research reference 110
-- audio research v70
-- primaluna dialogue prem hp
-- hegel h390
-- odyssey stratos
-- audiosector patek se
-- at times even a naim xs2 with teddy cap

harbeths are tolerant of many good quality amps, choice of amp depends on musical taste largely
I have not owned Harbeth speakers but heard this model at an audio show with a Vinnie Rossi LIO, only 25 watts but It’s one of those unforgettable moments. There was also a very expensive vinyl rig playing something incredibly well recorded that added to this unforgettable moment in sound.
I have used my Super HL5 Plus with Rogue Audio M-180 monoblocks (180 WPC) and currently ARC VSi55 integrated (50 WPC), both are tubed.  I use solid state with my Harbeth P3ESR - Simaudio 600i (125 WPC).  I agree that you don't need a ton of power. 

What exactly do you mean by "underpowered"?  If you want to have rock concert levels these may not be the right speakers for you.

I have to turn up the volume of my CJ CA-150 to almost half way to get to the level that I enjoy and it is not real loud. A lower output source can force me to put the volume slightly over half way. However, it does sound wonderful and I don't hear the sound starting to break up. The CA-150 integrated is equipped with a passive pre. If I mated the CJ MF-2275 power amp with my CJ ET-5 preamp would I receive more gain?
@routeman21 That's about where my listening level is with my Super HL5 Plus with my 180 watt tube momoblocks.  When I really crank it, it goes to about 3' o'clock on the volume dial.  That's with my Modwright LS 100 preamp, which goes to 11!

There's nothing wrong with that, in fact, it's a good thing, because you have smaller steps between each volume step, allowing you to have more flexibility in setting the volume.  Imagine if you only had to turn the volume to the 9 o'clock position.  The difference in volume levels between each turn of the volume dial would be much greater than they are now, giving you less ability to get the volume level exactly where you want it.
Jjss49, from the list, I have used the Nait XS to drive the SHL5 before. The amp is underpowered in driving the speakers and the result is underwhelming. If sticking with Naim, you need 282/250DR minimum for the SHL5+. Better still 252/300DR or higher but from that point it gets too costly.

The Harbeth SHL5+ sounds great with the 282/250DR a significant improvement over Nait XS. I know since I own the former.

you are conflating input sensitivity with power output, like how far you need to push the gas pedal down in a car to get it to accelerate... a car can have a more sensitive gas pedal... doesn’t make it more powerful at peak output


thanks... the lil is naim just used in my system in second system in smaller room... look at the list of amps... if i wanted naim separates i would have them... but i am glad you enjoy yours, naim is wonderful stuff
Isn't midway or just over midway on the volume control usually an optimal position for performance of the pot?

I don't know. I just assumed that turning up the volume too high (midway and above) gets that much closer to the clipping point of the amp rather than having more reserve to handle the harder to drive Harbeth's. On the other hand, I may be too fussy about the whole thing because if it sounds good, as it does, stop thinking about it.
I find this thread interesting because I went back and forth for a long time trying to decide whether high watt solid state would be necessary for the Harbeths. While more power will not go amiss, based on the benign impedance curve and the high impedance coinciding with the Harbeths one or two severe phase angles, I went for low watt class A: Pass labs INT-25 (XA25 power amp section). The volume topic is interesting because most digital tracks sound best to me at around 35 clicks (out of 63). In this range, the amp is wonderful, with a deep and wide soundstage (also a function of the Harbeths), smooth and detailed treble, and articulate bass. I love Jazz and this setup is amazing for it. 
Drawbacks: High volume listening can be a little “shouty”. I don’t think this is a function of increasing distortion, but rather a slight lack of cohesion from top to bottom where the mids and highs outpace the bass. I do this more for experiment and less for listening as it does get quite loud even though my room is on the larger side. 
I agree with your latest assessment and would try to not let the gear head in you bias your choice too much. Think about what kind of listening you will be doing and go with your ears. Hope this helps.

I have driven my SHL5+ 40ths with:

  • Bryston BP26 pre > Forte1A (class A 50 wpc)
  • Bryston BP26 pre > Michael Yee Audio PA-1 (class A/B dual mono 100 wpc)

  • Bryston BP26 pre > Ampzilla 2000 2nd Edition (class A/B 300 wpc monoblocks)

  • Hegel H190

In my 14x17 room, even the wonderful sounding Forte1A didn't cause clipping when cranked up just below painful levels.

What size is your listening room?
Used my harbeth with Quad QSP... Alright.. Then ATC P1 effortless and neutral and lastly with Robson A class monoblocks (small custom Scottish maker) 

Anthem STR Integrated. I find the sound to be pretty neutral in a natural vs. dynamic comparison. Think acoustic guitars vs electric. If vinyl is your preference the phono stage in this amp is very good. 


My room dimensions are: 18.7 ft. X 13.3 ft. The speakers are along the longer side.
I use the Aesthetix Mimas for my SHL5+ now. Before that I used the 60 watt Ayre AX7e. My room is 12 x 20 x 9 and even with with the Ayre, I could not cause any clipping at volumes louder than I could stand. Both amps are balanced bridged designs. 
i would say, after using various harbeth models now off and on over the last 15-20 years - if i were to have just one amp to drive them, i would select a nice warm sounding solid state unit, in the 75-125 wpc range (i listen mostly to instrumental jazz / vocals / light pop, some r&b - so i value accurate timbre, imaging, top to bottom coherency, clean attack and decay most... )

reason being that i feel harbeths have an innate midrange warmth and texture already, so tubes usually magnify that quality but it is not really necessary, especially if it comes at the expense of bass control and solidity

furthermore, harbeths have a smooth sweet treble, so once again, the classic tube sound profile can sometime cross over into being ’too much of a good thing’ - yes you can certainly excite the harbeth tweeters into harshness, but this is easily avoided

conversely, tube amps that don’t control the bass drivers well enough will result in muddy bass out of the harbeths... which have plenty (except maybe for the 30 monitor and baby hl3) to start with, but sometimes can overload a room and muddy up the midrange if not well controlled

if a touch of tube magic is still desired for the signal chain, i would inject it earlier, in the linestage or dac for instance

my two cents

hope this may help others
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.
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.  
Using the SST Son of Ampzilla II with mine - 220W. LTA Microzotl MZ2 tube preamp. Tried the Benchmark ABH2 as well, didn't think it was underpowered at all at 100W (and I have a big room), but didn't like the sound as much. 
Looks like I missed something important in your initial post:

Your impressions. I’ve been using a Conrad Johnson CA-150 (SS) integrated with my Harbeth SL5+ and the sound is nice but is underpowered at 135W@8ohms. Also, I would like a little more refinement with the amp.

My impressions of the following (from my previous response):

I have driven my SHL5+ 40ths with:

  • Bryston BP26 pre > Forte1A (class A 50 wpc)
           - 3rd place in refinement.  
           - First in musicality (non clinical?)  
           - Not as open sounding at higher volumes driving my B&W                   801 Matrix S2s or Maggies.

  • Bryston BP26 pre > Michael Yee Audio PA-1 (class A/B dual mono 100 wpc)
         - Still kind of new to this one (less than a month of recent time               with it since the move.)
         - Sounds a bit clearer than the Forte1A.

  • Bryston BP26 pre > Ampzilla 2000 2nd Edition (class A/B 300 wpc monoblocks)
           - Close but clear 1st place in refinement but better than the                    rest all around.  Especially at very low and moderately high                volumes.             

  • Hegel H190
           - 2nd place. Very close to the Ampzillas in refinement.
           - Possibly best match for the SHL5+40s up to just over                         moderate levels where the Ampzillas can just keep opening               up to higher levels

These impressions are based on 5 months in the new listening space (14 x 17x 9 wall to wall carpet, bass traps in the upper corners and some other minor treatments).
I work from home in my listening room so average over 5 hours a day listening.
I am also still a bit new to this hobby but have been a classical piano student throughout my life.
I listen to jazz, some rock and mostly classical piano.

Flipping the direction here, the Harbeths sounded better with these different amps overall than several other speakers of different types I keep in rotation.

Hope this helps!
hegels do very well driving harbeths

in fact, alan shaw (owner and chief designer) uses the h360 as his main amp in his workshop/lab in doing speaker testing