300b vs 845

I meant to make it clearer that the Chinese graphite plate 845s, both the A and B, are darker sounding than the vintage NOS, KR and metal plate variants, which are in turn quite different from each other. If you've never heard anything other than the contemporary Chinese graphite plate 845s, then the 845B sounds as you describe, David. The 845M does light up a room, but I don't experience any more heat output than the 845B. It's just that the glow is more shrouded by the graphite plate configuration. They both get hot but if you've dealt with the heat issues for the B tube, the M will be no worse.

By all accounts the Viva 845 is excellent. I haven't heard it.

Phil

Guys, Thanks for the responses. I hadn't thought about the heat issue and that could be a problem the way I am set up. My problem my be my amp and not the 300b tube, I just don't have enough experience with SET.
Thanks
Mike

no heat issue really. the 845 845B and 845M all put out similar heat, and not as much as many. My monos use 4 of them, and the room is not hotter in any appreciable way. The 845M's are brighter (as in more lumens) than the 845 and 845B, but not hotter.

If the power supply design is correct and of adequate capacity heat should not be an issue with a correctly designed 300b. My Audio Note Conqueror was a space heater; my custom 300b tube rectified amp runs warm but does not materially impact the ambient temperature.

My ASL 1009-845 drives avalon opus ceramique with great impact and dynamics in 24 x 14 x10 feet room. It was a surprise as speaker is 87 dB into 4 ohms. I would have cancelled my order of ASL hurricane if i knew ahead of time.