The Retro225 7591A / 5B/255M > 0.1 % distortion , Switchable 15 watts Triode, Ultra Linear 25 watts, Pentode 30 watts ,very similar footprint to the Quad 11 Mono's .
Constant Current Source 6E5P input tube in triode mode or Western Electric Driver tube .
The 5B-255M is an STC/ITT British made Western Electric
The Retro 225 also has a Triode , Ultra Linear & Pentode Mode switch.
37 watt 5B-255M Option as output tubes
Available with Lundahl or Ultra Wide band Japanese R core Orient Steel Transformers. 6hz to 65Khz (-1dB), input=4V
Balanced XLR or RCA inputs.
MORE TO COME ON THESE !
Wide Band Japanese Orient Steel .
World renown manufacturer