Yes, checked both filament and B+ and they are both good (1,4 v filament and 32v b+).
Another weird thing happened yesterday night: I removed the Quickie from the system and turned it upside down to inspect soldering once again. Everything was fine so I switched it on trying to ear any strange noise while gently touch components.
I was using the quickie as headphones aplifier for this task (I built Edcor transformer in a separate case).
No noises, no sizzling, just music.
Put the pre back into the system and...no more sizzling nor pops...
I will investigare further this evening...