[sdiy] High Voltage Opamps ?

[Michael Buchstaller]

>Add a Tube output stage to your opamp !

Good idea. But simply adding the tube´s grid to the opamp output will invert the signal,
not ?
Assume i want a non-inverting amplifier with a gain of 50. What will i have to do ?
Just wire the Opamp as a unity-gain buffer, and then use feedback from a 490K/1K divider
somehow ?

>You will need some extra compensation of the opamp because of the extra gain of
>the tube stage.

What kind of compensation ? A Cap from the output to GND ?

>I've seen headphone amps like this. While I wouldn't really want an opamp in a tube
>HP amp, it should be ok for static and low frequency measurements.

Hmmmm.... I remember some old Philbrick schematics, where they made an opamp building
block from 2 ECC´s - i built that once and made a simple (but working) Twin-T resonator with it...
Maybe i could just use *that* as my opamp....


-Michael Buchstaller