Question for RS

[CYP2D6]

Since Lord Valve will not explain how a cathode follower works would you
mind explaining it? I read the links but I'm not sure I understand it.

[Lord Valve]

CYP2D6 wrote:

> Since Lord Valve will not explain how a cathode follower works would you
> mind explaining it? I read the links but I'm not sure I understand it.

http://www.youtube.com/watch?v=xvDCa1NJPz0

[???]

On Thursday, May 16, 2013 10:18:03 AM UTC-7, CYP2D6 wrote:
> Since Lord Valve will not explain how a cathode follower works would you
>
> mind explaining it? I read the links but I'm not sure I understand it.

RS certainly knows his stuff, maybe he didn't see this request.

This is a short explanation that somebody else gave online, and it matches my understanding:

"A cathode follower is a way to configure a tube gain stage where the signal output from the tube triode involved is taken from the CATHODE, rather than the PLATE, which is where most tube gain stages' outputs are taken from - hence the name. It has the advantages of a very low input capacitance, while also boasting a high input impedance. This means that it doesn't tend to load down the previous stage as much as a typical gain configuration. As such, this type of configuration is perfect as a buffer between your signal and a stage that normally would load down the input a LOT, such as a tone stack (AKA your tone controls). It is of note that a cathode follower doesn't ADD gain, it's usually close to a 1 to 1 thing; it's used for the advantages outlined above.

The simplest mechanics of it are that there is a resistor (or two resistors in a voltage divider configuration to the input, depending on how the stage is designed) on the cathode between said cathode and ground that sets the load. The output signal is then taken from the side of this resistor connected to the cathode. Typically, the signal then goes to a blocking cap (which removes the DC component from the signal), and finally on to the next stage - as I said above, most often the tone stack or an effects loop - something that tends to REALLY load your signal down."

So, it's the high input and low output impedance that makes it work so well between a gain stage and a tone stack. They aren't magic, they are still limited by the current of the tube. But they can maximize the gain at the input because they don't load down the previous stage, and the output is not as susecptable to being loaded down by the tone stack that follows.

RS can go into WHY it behaves this way.

[RS]

On Sat, 18 May 2013 11:46:08 -0700 (PDT), "???"
<lucky...@hotmail.com> wrote:

>On Thursday, May 16, 2013 10:18:03 AM UTC-7, CYP2D6 wrote:
>> Since Lord Valve will not explain how a cathode follower works would you
>>
>> mind explaining it? I read the links but I'm not sure I understand it.
>
>RS certainly knows his stuff, maybe he didn't see this request.
>
>This is a short explanation that somebody else gave online, and it matches my understanding:

....

>RS can go into WHY it behaves this way.

Hey, LS. Actually I had started to explain some of the operational
theory, but the thread (originally addressed to "Lord Valve" for some
reason) went the usual route. The usual flamers. So I'm gonna wait
till they burn themselves out. Kinda comedic, but still a
distraction.

I've actually been thinking about the best way to explain followers.
It would be difficult without some of the underlying concepts, even
basic voltage dividers. That in itself may be of interest to some.
Useful in bias circuits, and just about everywhere.

So I was thinking about how to best present that without too much math
or tech jargon. I may post a multi-part thing starting from
ground-level. That would be easier for me too, as I haven't had the
time to spend an extended stretch in any one post. (Boring patent
stuff to do with approaching deadlines. It was fun at first, now I'm
reading patent claims for hours....zzzzzzz.)

Thanks for your post, BTW.