I originally bought this over a decade ago now from a dealer. Think I paid around £1250 for it.
Was running an Inca Designs ID75 at the time, which was superb, but the Toca was even better, and plays louder then the power rating would suggest.
Only a handful were ever made, and the ones fitted with the granite front panel (I've never seen another) should have had threaded bushes, and a soft touch start on the lettering, not the push switch in the middle which was fitted.
No idea why this one was different (Col was long gone)
I rebuilt the amp, and had the chassis power coated in dove grey (the heatsinks were bare ali then) and reglued the front panel on using a big threaded aluminium plate, but it's done the rounds since, been buggered about with, and got damaged in transit at least twice to my knowledge hence the latest rebuild. There are some pics over on chews of Cols work.
The circuit was published in wireless world, but the Pcb's were never made available for DIY.
I've only got some as I had a batch of 10 boards made up from the original artworks to build my own amps.
One of the best amps I have ever owned, and if I hadn't of recently built one of Colins newer EWA designs, I would probably still be running a lower biased version of this.