Hattor Ultimate Power Amplifiers

Thanks tweak1. That is a nice deal on those monoblocks but it's still above my current budget. Luckily,  the Son of Ampzilla MK2 I am auditioning is for sale and it is more in the range of what I can spend.  I am going to listen for a few more days, but I am pretty sure I will be keeping this Son of Ampzilla MK2.

Underwood HiFi has a few Ampzilla amps/pres at great prices

Ampzilla 2000 Mk II for $5995 the pair

Select Specials and scroll down

hth

Class D is not an optimum match for electrostatics.

middlemass and  mijostyn are correct tomflynn OP , Class-D really dislike driving 1 ohm loadings in the highs, and that is what the Martin Logan ESL’s present, and a heavy negative phase angle –68.81º at 5.9 kHz together with 4ohms loading.

Cheers George

What's your budget for new amps and do they need to be Mono's?

By the way, I am thrilled with my Khozmo mostly passive preamp. Arek added a simple stepped  attenuator to it for me because I needed a little more gain in my system.  Arek at Khozmo was a delight to do business with also, just awesome customer service. I have had other serious preamps in my system, from Berning to Superphon,  and this Khozmo is my keeper. It is so clean and simple and it lets the music bloom. My original post was really about whether or not to go Upstream to the $3K to $5K class D amplifier level... and for now i have made my decision... A/B.

Thanks guys. I managed to borrow a Son of Ampzilla 2 from a friend. And just coming out the gate, barely warmed up, it is clear that stepping away from the Class D monoblocks is my direction.  

It’s ignorant to clump all class D into the same basket
It could be your passive Kuzma. I had the Hattor passive, and although I loved it, I think there was an Impedance mismatch with my class D amps. Upgrading to the advanced input buffer (~$350) + shipping back to Poland. If you’re handy you might be able to order them an install yourself

Depending on your budget there’s a pair of Merrill Veritas for sale < $5K
and PS Audio M1200s with tube input stage should be available now

I have a Audio Alchemy DPA-1 + PS 5 that I replaced the Hattor with. It made a big improvement. It's for sale on AA and USAudiomart

mijostyn nails it again. Class D is not an optimum match for electrostatics. It may "drive" them fine, but if you care about quality of sound, just say no.

tomflyn, you have ESLs and I think you are barking up the wrong tree.
ESL lovers generally shy away from class D amps because they have a tendency to sound harsh. I think you would be better served by getting something like the Parasound A21+. For the same money you could get two of them strapped. They are high bias class AB amps. I use ESLs and use the same type of amp. In the near future I will shift back to pure class A which I think is the ultimate for ESLs. The Amps that Sound Labs recommends most for its speakers are the Atma-Sphere MA 2 and the Parasound JC 1+.