I'm using it with a Gigmaster 30 ENGL and a DSL15H Marshall. A lot of people seem to complain about the fact that the attenuation level not being variable, but I personally think it's enough...maybe because I'm not using man sized heads.
Anyway, the unit's features:
-20dB attenuated output and a bypass output, this one don;t need to be explained
-Line output, 1/4'' TRS Jack: this can be sent to an audio interface for recording, this output is dry so you'll need to use the wall of sound pluggin to simulate a cab (or any other IR pluggin).
Above it, there is a Out Level pot which applies to this output.
Note: if you use an unbalanced 1/4'' jack you will experience hum / noise
-Cab simulated output, XLR Cable: this one is self explanatory as well, I personally did not use it, but people claim it's better than expected.
-DC Jack: this is used to power the unit, HOWEVER, it seems to be needed if you use the Cab Sim, the Line output and the attenuation stage don't need to be powered in order to work, but I suggest you to power it up if you use it with high wattage amps because it also powers the cooling fan at the back of the unit.
The unit seems to be solid and well built, nothing to complain.
I did have a hard time figuring out what should I do to get my free cab impulses from Wall of Sound tho, so I will write down what you need to do:
-Get Torpedo WOS III for your operating system
-Open your DAW
-Load WOS III
-Register
-Log In
-WOS III will ask you if you want to test it with 2 Free IRs of if you want to activate your product
-Chose "Activate product", WOS will ask for a 30 digit code, instead, enter the product code that's placed near the "designed and engineered in france bla bla" sticker.
-you're good to go
In conclusion, I strongly recommend this unit, the only thing that could be improved about it would be a more comprehensive startup guide given with the unit.