Opinions on Graaf Amps

Does anybody have any expereince with Graaf OTL amps? I'm especially interested in the little GM 20 but don't have a chance to listen to it where I live. Has anybody heard it? In my search for a new amp I have listened to the Carys (572s) and found them overall too bloomy. I don't like tube amps that try to sound like solid state (i.e., Audio Research or BAT) but I also don't want the tubes to color the sound too much. I've tried the Atma-Sphere S 30 which sounded terrific in my system, open, airy and very musical, but it just runs too hot. So now I am considering the Graaf or perhaps an Air Tight. Any thoughts would be appreciated.

My system:

Joule Electra LA 100 MK-III
Merlin VSM + BAM
Audiomeca Keops as transport and Audio Logic 2400 DAC
JPS Super + speaker cables, FX interconnects, and Power Cords

Many thanks,

Dr V
Thanks a lot Atmasphere.
Got feedback from Graaf. There should be no jumpers between output terminals and no "Y"-adaptor on the input. Everything is taken care of by the internal mono-kit.
QUOTED from Theo

.....You also have to replace the large electrolytics resting on top of the amps every other year. They last for about 3-5000 hours. Better replace them in advance in the summertime, before the listning season begins.....

Are you sure? Because it is rather expensive and gard to live with if true. Many tube amp need not change of this during its whole life....

You are correct, most amps dont. The problem with the GM-20 is the heat from the tubes gets the caps very hot, and so the caps don't last that long.

Hi , I have 2 Graaf Gm 20 used in biamp ( two stero amp one for the bass and one for the tweeter ) with a Graaf 13,5 bII and a Graaf Gm 70 phone stage.
I owned first only one Gm 20 with the same pre and i was absolutely wondered for the fastastc sound. With two Gm 20 the sound became amazing: detailed, terrific. Try it if you can, buy one and keep it .