This is Wednesday. Into hospital tomorrow, surgery on Friday. They fitted me in about 2 weeks before I was expecting it. There's always the possibility they'll set me back if an emergency comes in.
I survived it before, I should survive it again.
Thanks again for all the good wishes, they mean a great deal to me, since this is how I get the majority of my human interaction now.
Here's what I have been working on recently, an amplifier and bias supply for electrostatic phones. Unfortunately I haven't had time to make much use of my newly acquired CNC mill, so I don't have a pair of phones completed yet.
The amplifier employs depletion mode MOSFETS, which are delightfully tube-like to design with. It has a simple supply using an isolation transformer arranged as a voltage-doubler on the UK 240VAC mains supply. I've chosen FETs that I can get easily and fairly cheaply. The CCS loading means that the amplifier should enjoy good a PSRR
Here you can see essentially the same amplifier simulated with the DN2540, THD is ~0.07%, quite respectable. V swing is ~350V, 500V is easily achievable with the DN2470, and even more with the IXTP01N100, although this requires a bit more tweaking of resistor values.
Better try and get some sleep...
w