Harbeth SHL 5 amplification

A very impressive loudspeaker when powered by a Pass Labs 25watt Class A amp.

I owned these speakers and while they sound OK with tubes, they really need power and current.  

The SHL5+ requires some power to wake up. If going tubes I would recommend a stronger amp with 35+ watts. I’ve tried 30 and under and it simply wasn’t enough. The MastersounD BoX and Triode TRV-88ser did well powering them. I don’t recommend Single ended amps with these unless it’s a beefy parallel Single ended one. 

On on the other hand, the 30.2 absolutely sings with a modestly powered tube amp. 

I heard Harbeth P7se (2? 3?) at a T.H.E. show in 'Vegas around 2007. They were driven by Plinius SA 103 and were stunning.

Thats very helpful. My listening area is about 20 x 14.  We listen at mainly medium volume to music/ no home theater. I am currently driving a pair of Spendor SP-1 speakers which I believe have similar efficiency to the Harbeth speakers.  The amp seems to do fine with them; I am looking to modernize a bit.
Thanks for the insight

I am currently talking to a customer about this exact speaker with a desire to driver it with my Diavolo which is a 10W SET. Incidentally I am advising against that.

The issue is headroom for dynamics. The question is at what level do you usually listen and how much headroom do you need. My rule of thumb is that most people list at about 80dB for reference listening and you want 10-15dB of headroom for music. For home theater reference is 85dB and 20dB of headroom is essential. 10w will deliver 92.3dB of volume and most of the time, headroom will be adequate but every now and then musical dynamics are going to push the amp too far. 

For those speakers in a small to medium room, 18w will give you 94.9dB of volume 10’ from the listening location. For most music this is plenty assuming you are not turning up to 11. I chose 18w because that is the power output of my Carissa SET. 32w will deliver 97dB.  Fine for music.  

Alternatively, for home theater where you really need to be able to hit 105dB, you need 185w of power. That means a high power SS most likely or a high powered tube though I tend to prefer high power SS amps to high power tube amps. Musical Fidelity is an amazing match for Harbeth.

It comes down to how you are going to use it.  

It depends on your room size.  
Since I prefer tubes and have a medium / medium large room I use a higher powered tube integrated that uses KT120 tubes for a solid 100 WPC on my Harbeths and love the sound- plenty robust and dynamic.  

I think what is almost uniformly left out of these type of discussions are the listener's musical preferences and expectations.  If all one listens to is string quartets, solo guitar and other small-scale works, a low-powered tube amp may be absolutely fine.  But if one expects a significant amount of "bass and power" as Arthur Salvatore says, you need a larger amplifier.  

Deja Vu in Washington DC sell Harbeth and also specialize in lots of low-powered tube gear (Audio Note, custom, etc.).  Why not give them a call and see what they say will wake up the SHL5s?

As I said in my response to your previous post, you need to demo the speakers at home with your equipment.  Or at least bring your amp to the dealer.  That said, if you are looking for "power" the SHL5s will sound better, IMO with a robust amplifier. I had very good results with my Naim 250, which only had about 70 wpc, but with a heavy power supply.  Then again, you may love the sound with your Leben.  I understand that people want to gather opinions as well, but the only way to know is to demo.  If you are working with a dealer, use his services and demo the setup.  If not, just buy used and hope for the best.  Trust your ears.  

Lots of owners end up with Luxman / Harbeth combos.

I make my own speakers, but I can say I really like my Luxman integrated.

I had both amp and speaker. They have great synergy. Try using a good Solid state preamp and use the Leben direct input, it took the combo to another level. 

I've driven my 40.1's with a 32wpc VAC 30/30 tube amp.   Not optimal, but it sounded decent.