Bill I have much experience with SET and audio design. Transformers mater as much as tube type not all 300b have weak bass rolled off hi. And as far as 45 50 SET as you say the best. Best for what? at 1.5 watts what can you drive? You need a loudspeaker designed to run off such low power and I have built many. And this low power doesn't drive woofers into low frequencies very well. Most of the loudspeakers I design for 45 SET etc have little bass below 40hz since 45 SET has little drive. If I want bass to 25hz or lower need biamping. So I agree 45 SETs best for biamping;) Its the transformer and amp design that gives extended range not the tube type. Bill with a bit more experience you will learn this. Take care and happy listening.
