Thanks to AK
There's an active Directly-Heated Triode pre function of my 300B SET moulding the source signal to be presented to a Linear Regulated PSU fed, TPA3116 (audiobah) based power amp.
This combo runs a pair of Audio Nirvana 15" drivers in Shindo-spec'd cabs.
The tubes are Sophia Electric Princess mesh plates, NOS Sylvania chrome-top 6SN7s & a NOS RCA 5R4G rectifier.
I think the 300B SET alone had a little gas issue when running the 15" drivers on a very loud volume, especially when part of the signal is sent to the dual subs.
The addition of the TPA3116 provides that extra muscle to the amplification.
The source is Frankenstein of a turntable - Rega RB700 arm implanted on a Kenny KD750 QDD table. The cartridge is a Denon 301mk2 LOMC.
The signal is sent to a Jasmine phono pre.
The records are VAC'd using a KAB-EV1.
And the listening room is acoustically treated with the DIY absorption panels on first reflection points.
The AN 15"s in the oversized cabs can push some good LF into the air, but I have a couple of Wharfedale subs DRC'd by a DSPeaker 8133 Cinema for the necessary Distributed Bass implementation.