Actually, I think Trevor is using them to his powered monitors so he's got attenuation options at both the Violectric and at the monitors themselves - kind of like using the Violectric as a preamp...correct, Trevor? Fried also told me not to do that (Trevor and I had a conversation about it - glad it's still working out, Trevor - I can't recall Fried's reasons but have that email somewhere). Instead Fried suggested I use the internal DIP switches to alter my rear-panel RCA's to line outputs, which I have been doing for my own powered monitors. It's a bit of a compromise from going direct from DAC via balanced to the monitor (this sounds the best), but it's still quite good and no serious compromises.
Indeed all of my monitors are powered monitors, I am basically using the V181 as a preamp. I know this will sound strange but when I do my recording/mixing I prefer the sound out of the v181 to directly out of the Zodiac+, at least for my secondary monitors. But I swap between the two to compare as well. I never actually tried hooking my mains to the V181 as they are in a separate treated room, but I might experiment. Needless to say the V181 has been excellent value for the money and I am really happy with the purchase. Fried was a great guy to talk to as well, very willing to answer any questions you may have.
Here is what he had to say in regards to the risk of using the 1/4" headphone jacks to your active monitors:
".. I see some issues because our V181 is able to output far more than +25 dB.
Of coarse V181 is very well suited to drive even longest balanced lines.
It is quiet, it is low impedance, it is powerful, it is adjustable.
But you have to take care about the overall circumstances ...