Frontend ribbon gainstage. 7-pin tubes

[BluegrassDan]

Hey folks,

I have a stash of 7-pin miniature tubes, and I started thinking. How might one incorperate a 3HA5/6HA5/6AU6/12AU6/6GK5 as a ribbon mic booster? For example, putting it into a switchable "ribbon mic" feature.

Just after the input transformer and before (for example) a first 6072 gain stage? Or should it come after the second 6072 gain stage? Somewhere else?

Thoughts?

 

[ruffrecords]

Tubes got used in condenser mics because of their high input impedance and also the capsule output was high enough that the noise of the tube did not matter much.

A ribbon does not need the high input impedance and has a much lower output than a condenser capsule so the noise of the tube is a real problem. That is why all tube mic pres start with a 1:10 step up transformer..

Cheers

Ian