Hi, as i sound wise my only ref is my marantz and it beats that, still using original chinese valves, i'm pretty sure they are a weak link in the sound quality too, so i'm expecting an improvement when replaced when they finally blow. Do use tube dampers as well, think they help too.
I was hoping someone on here had had one and then upgraded so i could have had an opinion against other valve amps, but it doesnt seem to be.
The 300b does look awsome was considering that one too when i bought my 100b, but it was something like £200 more. I wouldn't hesitate to get another Yaqin amp though. Other chinese equip seems to going down well too.
I personally havent found any weak links in sound, bass isn't the deepest but i think that's down to speaker position, which i'm hoping to solve soon.
Hope this has helped.
Chris