First order: once the phantom power (48V) for the condenser mic was on, a constant unbearable background noise like a jackhammer. Tried all the configurations possible to be sure that the preamp was the problem and not something else in my home-studio. Well, the preamp was the problem. Sent it back and bought another one.
Second order: exactly the same problem this time after two days, so I'm about to send it back again.
The problem occurs only with the phantom power on, for a prolonged recording of more or less 5 minutes. So I wouldn't suggest AT ALL this preamp, at least as a mic preamp.
I used the instrument line to record a bass in my productions and I loved it. No problem with that because the phantom power was off. In that case, loved the attack of the compressor and the tube drive.
It's really a pity, but just a terrible experience.