Dennis Had Inspire SET with KEF LS50s

Technically, Dennis Had's Inspire amps are SEP's not SET's, since they use Pentode tubes, not Triode tubes in the output stage.

The Inspire amps have great drive abilities, a lot better then a 300b SET.  What are your goals?  is this to be your only amp?  For me, I enjoy playing with this stuff.  I like to throw in a SET for a few days, and then go back to my Ref75se.  The great price on the Inspire amps allows me to play a bit...

I forgot to mention that I supplement the LS50s with a pair of Velodyne HGS-10s and SMS-1 bass manager, crossed at 100 Hz.

I'm currently driving the LS50s with a Parasound A 23, and have used an A 21 in the past.  I thought to use the Inspire as Zone 2 from a Cary Cinema 12 with the A 21 remaining as Zone 1.  It seemed an inexpensive way to try a tube SET amp.  A friend who is very knowledge about audio setups suggests the Inspire damping may be insufficient for the LS50.  I haven't used a tube amp since the mid-60s, although I hear my cousin's Cary 805s several times a year.

I have not, but I think you will find better pairings, especially if you listen at decent volumes. I am sure it will sound very pleasant, but if you A/B'd against against a more powerful amplifier you would hear a huge difference.

I lit up a pair of LS50s last week with a Musical Fidelity a1008 integrated that can swing 75 amps of peak current and it sounded far better than a Primaluna Prologue classic that was driving them prior. It was also a huge improvement over a Bel Canto c5i. You could tell they really responded to the additional power. 

The Kefs are rated for 8 ohms, but they have impedance dips that makes them mate better with an amplifier that can easily handle a 4 ohm load. They are 85db sensitive, which is borderline low. 

On paper it is not a great match, and based on my experience they really do like power.