Sound less open after days

Hi all,

After days of playing music the sound becomes less open/smeared.
I found out it has most likely to do with my preamp (a Bryston BP25). When I switch of the device for a while and put it on again the sound is more open. (all the other stuff, like power amp, streamer, dac etcetera is much newer).

Can somebody explain this phenomena?

https://archive.org/details/bryston_BP25_SCHEMATICS
bryston_bp25.jpg


Thanks in advance
 
wait until its really damaged.

Often temporary faults are difficult to detect.

You can try this cheapo bluetooth preamp "Whuzi audio ZK-PT1" and give feedback how its performing. I use it and wonder how it compares to classical hifi gear.

Its below ten dollars

IMG_20250119_150659.jpg