[Eeyore]

Paul Stamler wrote:

"Eeyore" wrote

And how do you remove the transformer and still drive a 1200 ohm load?
The schoolkids want to know.
BTW, the 301 is a single package opamp.

Nice of National to provide the LME49710 !


The 460B uses a TI TL062 dual fet input device. Good luck getting a
single package device to work in there.

A TL062 ? That's as noisy as hell !

That may not matter, depending on the level it's being presented with. The
thing that makes substitutions tricky in this application is that the new
opamp has to draw no more current than the original; you're stuck with the
limitations of a phantom power supply.

It's not *that much* of a limitation. Just been discussing it earlier. Phantom's
good for easily as much as 5 mA !


I don't know what opamp Jim Williams substitutes for the 301 in that
modification, but I bet the choice was non-trivial..

I doubt it. Not with the modern devices to hand.

Graham