Posted by alexz (A) on April 08, 2012 at 19:10:48

In Reply to: RE: L2 Phono with inductance volume control posted by Klassenfahrt on March 21, 2012 at 06:16:37

Hi,
Where you get this 7k7 number from ?
Firstly, your output stage has 33k plate R. Output impedance is aprox. Rp || ra that bring it to a value around 20k. That allow to conclude that 100k load is not too high. Higher load will be even better.
Also statement about 10k output impedance with thansformer load sounds a bit optimistic.
In any case by loading you common cathod amplifier with transformer you will have serious gain loss and low frequencies roll-off due to inductivity of the load.
Just google "common cathod amplifier design" and you may find a lot of interesting things.
HTH
Alex

Edits: 04/08/12