ampage
Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. The sunn still shines online!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  

What exactly is a cathode follower?


 :
9/28/2000 12:19 PM
DanR
What exactly is a cathode follower?
What exactly is a cathode follower? I've heard it used relative to tone stacks and elsewhere.  
Thanks,  
DanR
 
9/28/2000 4:19 PM
Liam

Have a look at the following:  
 
http://www.firebottle.com/ampage/schems/mvp.gif  
 
The second triode in the second tube is a cathode follower. The voltage at the output (RHS) will "follow" the voltage at the grid. This means the stage has a gain of (slightly less than) 1.  
 
Why would anyone want an amplification stage with a voltage gain of less than 1? It's basically a buffer. This means that it can supply current without loading the input very much.  
 
Summary: amplification stage with high input impedance, voltage gain of approximately 1, commonly used to drive tone stacks.  
 
Someone please correct me if any of this is BS. I've got a bit of a hangover.:D
 

  Page 1 of 1