Brystons did USED TO BE a little hard, but I would not judge their sound based on a 3B or a .5B. Also, everything else in your system is a little bit on the "edgy" side, so maybe you should start with some lower priced Cardas or even good old MIT 330 cables. Those are the cables those Brystons were voiced with back in the day. The Rotel and denon are not known for their analog-like sound. However they both (I believe) have digital outputs, so if you can't afford expensive digital source equipment, then you might want to consider even a modestly priced but high quality separate stand-alone DAC like a used Wadia for instance wyich you can sometimes pick up for under a grand.
Before you decide Brystons sound shrill, you might want look elsewhere in your system, to make global remedies, because I don't think changing the amps will solve the problem. And just for fun, you might want to go hear some of Brystons current models. They're a lot cheaper than Rowland!