Adapting cathode follower out for 10k loads

[k brown]

Brushing up this Ampex F-44 to start playing around with for live recordings.

The manual recommends a load of 250k ohm for the outputs; what changes need to made to make it happy with modern 10k line inputs. Not going to do a transformer; don't need balanced out.

Obviously, larger output cap, but what else? - build out resistor? . . .

Online calc shows out Z of this CF would be 615 ohms. I would think that would be fine with a 10k load if the cap were made appropriately larger.

 

[C.B. - Boudio]

You can try just a bigger cap first.
You could also redesign that stage, make the grid AC coupled and do a normal bootstrapped cathode follower, to get an ever lower output impedance.

 

[k brown]

You can try just a bigger cap first.
You could also redesign that stage, make the grid AC coupled and do a normal bootstrapped cathode follower, to get an ever lower output impedance.

Yes, I was a bit surprised to see such a 'crude' CF circuit.