Puzzle? Amps now running cooler

I recently installed a Promi passive preamp and as a happy coincidence my Monarchy SMPro 70s now run much cooler. ALthough I am very happy about this, I am also puzzled!!!

I also changed my interconnects at the same time to balanced interconnects from Nicholas at Promitheous.

I am no sure of all the science involved but believe there must be an explanation somewhere. Can anyone enlighten me??

 

You probably had some DC on the pre-amp outputs. Now gone due to the new pre-amp and the balanced operation.

 

Thank you for that - makes good sense.

 

or.....the new pre is rolling off earlier at very low frequencies and blocking LF gunk from the TT (I assume you have a TT from your avatar).

Turntables often produce LF mush below 20hz because of the arm/cartridge resonance. You can't always hear it but you can certainly see it with a ported speaker as the cones flap wildly which of course eats amplifier capacity. Actually, looking again at your avatar I see Quad ESL63s and you wouldn't have seen a problem with those......

Might be worth checking the LF response of the Promitheous TVC as being a transformer there will be some roll down at low frequencies.
If there is - even if it looks quite severe - don't worry as you are doing the ESLs a huge favour by not pumping sub 20hz signals into their input transformers.