John aka @chienmort tested a number of amps at the SW Bash Bash a few years ago. The Veyron was one of them. It had a completely flat frequency response, which is at least half way towards a transparent amp. I still have one and don't find the fan loud, although I think some may be louder than others. It works well with the Monza, I can say, and is the bargain of the century in bass heads. The amp I actually use is the Trace Elliot TE1200, which is superb - and does the 3D/projection thing very well. I know @Clarky has a Monza and a TE1200. Maybe he'll chime in if he sees this. The Trace is a bit pricey, unfortunately, and probably not as portable as the OP is looking for.