fine tuner(volume) control for a tube amp attenuator

Discussion in 'The Projects Forum' started by secretagentman, Aug 15, 2012.

  1. secretagentman

    Thread Starter New Member

    Aug 14, 2012
    secretagent here.

    Greetings to all !

    I am working on an attenuator to be used to attenuate the maximum(or fully "cranked') output of a vacuum tube guitar amplifier.
    It is a frequency re-active design, which is designed to have a "linear' output. In practice, the amp should "see" an 8 Ohm impedance. however, I need to provide a fine tuning volume control. The amp used to prototype the attenuator is 15W.R.M.S. output at full volume. Although the attenuator will greatly reduce signal strength, I believe that the usual potentiometers used as volume controls will not be able to handle enough
    power, or watts,output of the attenuator. I am not yet well versed in a great deal of theory. I do believe that a rheostat will be in order. I wish it to be as small a load on the amp as possible. The attenuator is connected to the output of the amp, and after attenuating the signal, will connect to the amps own speaker(which is 8 Ohms as well. I do not yet have a scanner, and can't provide a schematic. I hope the above information will be sufficient. The question is : How to best chose a value(Ohms) of rheostat, which allow volume cut-off when turned "completely down", and allow the maximum attenuated signal to pass when turned "completely up" ? Any advice or opinions are always welcome. Thanks in advance.
    Have a great day, secretagentman.
  2. #12


    Nov 30, 2010