Bought this a year ago because I was too stupid to remember I don’t really get-on with headphones - for just the third time in 20 years… 
Consequently it’s minty and had f-all use: just enough to discover it sounds much better without a valve in it (unless you like the warm, mushy, lo-fi sound of dad’s radiogram for which it has been deliberately engineered).
Sans valve, it sounds amazing - helped in no small part by the relay-actuated discrete-resisitor volume control, which clatters-away enthusiastically when you use the remote or knob to adjust volume. It’s a very clean, clear, uncoloured sound.
It has two RCA line-level inputs, and one RCA volume-controlled pre-out. There are two different gain levels to help with matching sources and headphones or power amps. Everything is remote-controlled.
If you want to bung a 6SN7 into it, ebay is awash with them - I ordered it without one, and it will be supplied without one.
Currently retailing for £690 (the silver finish is a £40 option!) - and unobtainable due to each batch instantly selling-out - this is yours for £300 (the last one sold on ebay went for £450). This includes basic shipping to UK mainland destinations, or you are very welcome to collect from PE11.
PM if you want more info.