As above, purchased from Mark and been used exclusively for my K712's sat at the PC. Some light marks off a 3M pad which I'd applied to stick to the amp to underside of the desk, would come off with some ethanol or acetone I suspect, but not tried.
Funding a Fulla2 for a change in setup.
I'll also be selling a Seiko watch elsewhere - Dracula model monster SRP313, if anyone here has any interest in such a thing! Lovely watch but recently bought a turtle which sees more wrist time.
If it's the same amp I'm thinking of it was made by Head n Hifi (Switzerland) rather than JDS Labs, Joe. Should have their name printed on the back panel iirc.
Just to provide a bit more info for potential buyers....
This O2 is the 'desktop' version which imho is a far better option for home use than the standard O2. 1/4" rather than 1/8" jack, power input is moved to the rear (far tidier solution) and sees the addition of L/R RCA outs allowing audio to be fed to powered monitors etc. Desktop version CANNOT however be powered using batteries, mains only. Comes with a UK power supply but PSU's for other countries are available fairly cheaply from either JDS Labs or Head n Hifi.
Rather than the default gain settings this one has custom gain of 1x and 3x which I think is a far better choice than the default 2.5x and 6.5x (clipping ahoy!!). In my time with this amp 1x was used almost exclusively and powered most of my headphones without too many problems, but 3x is there if you need more juice. 1x gain also makes this amp a very viable option for fairly sensitive IEMs and provides a nice black background and good volume control.