Tube Circuit Gain Calculator

Tubes || AX84 version || RC-22/mu version || RC-22/gm version

This calculator is based on a standard gain equation from Circuit Analysis of a Legendary Tube Amplifier: The Fender Bassman 5F6-A, Second Edition by Richard Kuehnel. (A simplified form for a fully bypassed cathode resistor appears in many versions of the RCA Receiving Tube Manual).
                                      tube gain x plate load resistor
Circuit gain = -----------------------------------------------------------------------------
               plate load resistor + plate resistance + ((tube gain + 1) * cathode resistor)
Values may be any standard form (68400 or 68.4K, 1M or 1000000, etc.) Check the "Use comma for decimal point" box if you use a comma to designate a decimal point (i.e., opposite the way it's done in the USA). You may leave the cathode resistor as 0 if it is fully bypassed. If you aren't sure if it's fully bypassed, add a cap value and pick a frequency to compute the gain for. If you have cathode resistor and cap values and leave the frequency blank, it will default to 1kHz.

  Use comma for decimal point
Plate resistance :
from tube manual or spec sheet
Plate load resistor :
value of resistor between plate and power supply
Tube gain :
tube's gain (amplification) factor (a.k.a., mu)
Cathode resistor :
value of cathode resistor
Cathode cap[s] :
value of cathode bypass cap[s]-- multiple values allowed, separated by spaces
Frequency :
matters only with bypass cap; if you use this, try at least extreme values you care about. For guitar, this would be 60 and 6000. Unused if multiple bypass cap values are present.
Tubes || AX84 version || RC-22/mu version || RC-22/gm version

Tube Circuit Gain Calculator version 2.0 Copyright 2007 by Miles O'Neal, Round Rock, TX.
Miles O'Neal <> [remove the "XYZZY." to make things work!] c/o RNN / 1705 Oak Forest Dr / Round Rock, TX / 78681-1514