@lanx0003 The KRELL Duo 175XD was used on my Thiel CS3.7 and also my RAAL SR1a earphone using the older amp interface box. Interestingly, the SR1a drew more power out of the amp. I knew this because when I used the CODA #8 in place of the KRELL I could see the meters on the amp flying for the SR1a but not move for the Thiel CS3.7. I had both KRELL and the CODA on hand.
When I used the KRELL as a earphone amp I had the amp about 1 foot from my seating position. I never heard the fans.
Here is something on both the KRELL and Westminster Labs amps that I posted about earlier. Class A amps that stay cool.
I now use the Schitt Aegir amp in place of the CODA and the KRELL using a new RAAL amp interface box. It is rather good, not as good as the CODA or KRELL, but I only need 20-watts Class A with the new RAAL amp interface box.
The Aegir is mechanically nosier than the KRELL with fans. The new Aegir 2 is supposed to remedy that mechanical noise.
The CODA #16 does get warm generating the first 100 watts in Class A, but it is not very hot.