I have not heard of VTL amps taking out power resistors when tubes fail, but this was clearly the case with an ARC VT130 amp I had. This was quite a hassle on more than one time but this amp was a wonderful sonic match with my Maggie 3.3s ...unfortunately it clearly ran out of power just as the Maggies were starting to sing their magic. I found the Counterpoint NPS400 amp, 400w at 4 ohms, worked incredibly well with the Maggies. I suspect nothing out there in the $2k range can touch this amp in terms of driving Maggie 3 series speakers. It truly worked so very well with neither being foward nor overly warm. But the Wolcott Presence mono amps at approx 275w bring together all of the strengths of the ARC and Counterpoint amps. You should look into the Wolcotts as they sell for about the same price on the used market as the VTL 450.
John
John