[Ian Iveson]

"Ian Bell" wrote:

It likely depends on how close saturation is to 20Hz, *at
the signal level the OPT is likely to encounter*. If you're
willing to use feedback, and the signal is small, you may be
OK. An appropriate filter at the input should make
saturation impossible.

Patrick'll be along in a tick.

Twice the plate load? It *is* the anode load isn't it? 2 to
3 times ra, depending on whether you want power or fidelity
respectively, broadly speaking.

There is a tradition of not caring about head amps...as if
they are add-on extras to the main system. These days, they
quite often *are* the main system.

Ian