Thanks Graham - have just been reading up about them. There is a 6 moons review here that is interesting but a bit on the wordy side!
He claims the model on review upstaged a $9000 Audio Research pre-amp!
This article was a bit more concise but still rather wordy.
Both articles well out of date now!
Eventually I found the manufactures web site that has current offerings. As you say they are not cheap!
However the baby classic with XLR inputs and outputs would probably meet my needs. My source is DAC with balanced outputs.
I have a digital switch upstream of the DAC that auto switches 4 digital inputs. I would need to use RCA->XLR adapters for my phono stage.
Definately worth thinking about. Would love to hear one in my setup before making any commitments though.
As I said, something double insulated doesn't need an earth, everything else does, although there are exceptions for stuff entirely enclosed in an insulated box, like plastic, but then it'll probably qualify as double insulated, but nit necessarily, depending on the mains transformer used.
With a metal box into which the mains connects, I would always connect the mains earth to the case as a safety earth, then whether the output zero volts also goes to case, i.e. earth or not, depends on the design.
Turntables are often double insulated for safety, but the turntable, and more importantly, arm wiring is connected to the amplifier or phono stage ground point, which may or may not be also connected to earth.
The important consideration is for there always go be a safety earth or double insulation and no earth/ground loop which causes hum.
Many of the problems around turntable hum is due to incorrect grounding and/or earthing, either not enough, causing possible safety issues, or too many causing hum.