Anybody know what happened at JOB...

My zus are super efficient. I have a BHK pre that has tubes. The gain of the Nuforce is do high, I had to install a passive pre between the pre and amp due to tube hiss levels. I reality I have the wrong amp for my speakers (101 dB efficient- at least that is what is advertised). I would say the Nuforce is a perfect amp for speakers under 94 dB or so. 

I got my STA200 a few days ago. Driving Klipsch RP600m speakers, The source an Oppo 205 and pre a terrific little McCormack Micro Line Drive and an alternative pre, a Placette Passive linestage. The sound was superb. This despite a far less than ideal acoustic space. I did experience a loud hum, but bringing the system to another room eliminated that.
From comments above it would seem that the Job 225 is not really better, just more powerful?

abery, I have to disagree with you, my friend. You had the Rogue pre, prior to your BHK, and you needed to do the same with the Schiit passive. The problem is not with the Nuforce and Zu interface, but the pre’s and the Nuforce. If you eliminate the pre’s, and go passive, without signal playing, turning the passive volume up to max, you would not get hiss or hum ( if no grounding / wiring issues ). It is fine if you want to change the amp, but I remember mentioning a long time ago, the Nuforce, and Job 225, were designed to be driven passively. My Luminous passive ( awesome ), at max volume, without music playing ( dac is on ) shows zero hiss, or hum, through my more efficient speakers, when using the Nuforce. But I understand how much you enjoy tube preamps, so the Nuforce is not a good match, interfacing with your preamps.

adameos, in your 1st room, when you experienced the hum, might be because of a severe ground loop, or even a light dimmer, on the same circuit. Could be any number of things. But the amp is quiet, when used with better matched components, preceding it, in the audio chain.

For what it's worth,I had a STA200 with a Rogue tubed pre and it was dead quiet.But I do have a dedicated line and no dimmers in the house at all.I do have a friend with dimmers that cause hum unless they are turned off even though they don't share a circiut.