I've spent a fair amount of time over the past week running various simulations with regards to constructing such a buffer with no output blocking caps and I have to say that I'm struggling due to the threshold voltage of mosfets - I haven't got a vbe multiplier to work properly yet.
I chose mosfets as I want a high Zi.
I'm gonna keep at it, but if anyone knows how to design such a thing I'd be grateful for a few pointers.
The other idea that I've had is to build a class A source follower and use a dc servo, is this feasible?
Any ideas on how to build a high Zi buffer that has no offset would be very welcome,