HiJust for fun, I'm curious to know what is an acceptable level of hum for you guys. I mean, in real life, not only in term of specs and numbers, but in term of use. ie, if you can't ear any hum in normal tracking/mixing level, but to hear a tiny bit of it you have to crank your headphones/speakers at max, do you consider it like an acceptable result? I know there is a pletora of tricks to kill hum like using aluminium chassis, encasing power transformer into an steel box, external psu, dc heaters, trying an infinite numbers of tube and put on the cleanest one at V1, mu-metal sheet/can around power transformer, etc. but the goal is not to speak of all the possible maner to extinct hum, or to start an war over the hi-fi guys but in general use, what is your acceptable level of hum?