" Eesyore"


** The noise ( at 1.36 nV rt/Hz ) is just a little worse than for the
Project 66 schematic.

Note: that figure is for a shorted input rather than a 200 ohms source.

Current in the transistors is the same, but there is one resistor change
that adds a pinch.

The 33 pF caps produce an earlier HF roll off than project 66 does.

-3dB @ 32 kHz in fact. A bit low for my liking for sure. That'll be
intrusive at
20kHz too..



** In a recording or PA system there are very many amplification stages,
each one with a LF and HF roll off curve, and all of them ACCUMULATE !!

If the overall aim is a flat response +/- 1 dB from 25Hz to 20 kHz -
then each stage needs to be a whole lot flatter that that aim.

However, given the input device is a dynamic microphone, few of which have
good response beyond 15 kHz , a -1dB point at 16 kHz is not so bad.

The treble EQ pot can always be given a tiny nudge if the sound engineer has
a mind to .....




........ Phil