Sorry not my amp, and If i did review it, it was a while ago.
However, Yamah to soem degree has a signature sound and this as I've discovered when speaking to to some people that use their musical instruments, tends to be a little brighter than some others.
Is this what you're talking about?
It seems natural that this would be the case if, for example Yamaha was voicing their amplification to their Grand Piano.
The stock speaker system in the Studio is an Atlantic technology sub/sat system that tends to sound quiote warm.
Didnt check on your location, but you're welcome to pop over to AVSA and bring your amp with too if you want to listen to it in a more controlled environment. We may have a competitor or two in the studio too that you could obviously listen while youre there.
And you could check out our new rack that was supplied by Soundstructures.
Hope this helps
Joel