Abbreviation Nomenclature

[defaced]

Where can I find explanations for what abbreviations such as "Rk' " and "Rl" are? For example, looking at a JJ tube data sheet is useless to me because I don't know what the variables mean.

[Bruce / Mission Amps]

Where can I find explanations for what abbreviations such as "Rk' " and "Rl" are? For example, looking at a JJ tube data sheet is useless to me because I don't know what the variables mean.

Try going through some of this material first:

http://www.pmillett.com/tecnical_books_online.htm

or

http://www.pmillett.com/hb-3_tube_manual.htm

[Don Moose]

Rk - Resistor, Kathode
Rl - Resistor, Load (plate)

There is often a Ck as well.

PI - phase inverter
PT - power transformer
OT - output transformer

The sources Bruce pointed to are actual explanations, though, so much better.

[Steve Conner]

Rk' (Rk prime) is probably the internal resistance at the cathode, or put another way, the output impedance of a cathode follower made with the tube. Either way it's just 1/gm. I'd have to see the datasheet to be more certain.

[defaced]

Steve,

Here's the context of the RK'. There are two amps, the VHT Deliverance 60 and Deliverance 120. The D60 uses a cathodyne phase inverter to drive 2 x KT-88. The D120 uses a cathodyne phase inverter followed by a cathode follower to drive 4 x KT-88. I have the schematic for the D60, I do not have the schematic for the D120. So from the following description, I'm trying to interpret how to wire the cathode follower and the RK' was throwing me for a loop:

It's an AC coupled Cathode follower. 1K Rk' 22K rk. input cap .022uf Rl 470K output coupling to taste. output loading resistors depend on what tubes you will use.

Tubes used: 12AX7 cathodyne phase inverter, 12AT7 cathode follower which drive.

[Steve Conner]

Oh, well in that case I guess he's referring to the method of biasing a CF where you use two resistors in series between the cathode and ground, and tap the grid to the junction of them. The one he calls Rk' will be the one between cathode and grid resistor, and rk the one between that point and ground.

It's just the same as the regular way of biasing a tube with a 1M resistor from grid to ground, and a 1k resistor between cathode and ground. But you're propping "ground" up on a 22k resistor and taking the output across that resistor.

These particular abbreviations aren't standard as far as I know: it's the first time I've seen them.

[defaced]

Thank you. That makes perfect since. The same scheme is detailed on the Valve Wizard site for AC coupled cathode followers, but the labels are different.

The wiring would be identical to this diagram, but with the 470R changed to 1K and 18K changed to 22K.
http://www.freewebs.com/valvewizard/...eFollower3.jpg

Source: http://www.freewebs.com/valvewizard/accf.html