Bootstrapped Driver- More

[John L Stewart]

For its A30 Amplifier Electro-Voice gives the following specs-

Loop NFB 13 db
Drive Plates (Bootstraped Stage) PFB 2 db
OP Circuit (Local FB Around Pwr Stage) 17 db

Cheers to all, John

[Patrick Turner]

On Mar 27, 1:21*am, John L Stewart <John.L.Stewart.
> wrote:
> For its A30 Amplifier Electro-Voice gives the following specs-
>
> Loop NFB *13 db
> Drive Plates (Bootstraped Stage) *PFB 2 db
> OP Circuit (Local FB Around Pwr Stage) *17 db
>
> Cheers to all, John
>
> --
> John L Stewart

The McIntosh also used bootstrapping to give a small amount of PFB.

In the Circlotron and McI the output stage gain is very low so any N&D
fed fack through a PFB network does not
get amplified much to increase itself, so the lessening of the THD of
the driver stage due to the bootstrapping
is greater than the increase in N&D by PFB, so a net reduction of THD
occurs. And all that is before global NFB is applied.

Patrick Turner.