Passive Attenuation

What you are describing is known as an "L-Pad". They are available in various power ratings and impedance from suppliers such as Parts Express or Madisound. It's function is to maintain a constant impedance load, and dissipate the excess volume as heat. Marshall also makes some large models so that guitar players can push their amps at full power (distortion) into a 4x12 while only allowing a small amount of power to reach the 4x12 to keep the volume down.

 

My Gawwwd, why didn't I think of this.

I'm gonna get an L-pad and put it in a small metal case with both 1/4 inch jacks and speakon inputs/ outputs. Then I'm gonna chuck it in my gig bag.

The next time I get a case of guitarist De-Ja-Moo (ie I've heard this bullsheit before) regarding his tone/tube drive relationship, I'll pull it out and whack it between his amp and speaker, and turn the speaker down...... brilliant idea if it works. One way to find out.

 

I'm not sure if the L-pads will work with a solid state amp.

 

Yeah, but then you still don't have that special distortion you get from cone breakup on the speakers ... there's always a reason for guitar players to play too loud.

 

You're right, it will work either way.

Many many years ago, I had 2 speakers that didn't work too well together because one was way more efficient. I put an L-pad on the loud one and turned it down until the balance was right. I used it like this for years and was using a SS amp the whole time.

 

The problem with using an L-pad is handling all that wattage. It's not a problem with tweeters because the pad is wired in after the crossover, and higher frequencies take up very little of the overall wattage of a signal.

The biggest L-pads I've seen are rated at 200 watts, and those are pretty uncommon.

I suppose you could try it. It depends on just how much you want to attenuate the signal. An L-pad is just an adjustable resistor; you adjust how much wattage passes by, and how much is fed into the resistor and converted to heat. Since you're running two cabs already, the one cab will see no more than half of the i-amps output, or 400 watts max. So as long as you're careful and don't try to attenuate the signal too much, you could probably get away with a 200 watt L-pad. You just don't want to have a resistor rated for 200 watts trying to burn off the full 400 watts. Unless you'd like to contribute to the light show.

 

True but that's not usually what the guitarists argue. They talk about tubes and heat and driving the amp.

Marshall actually make a device that call the "Power Brake" or something like that, which is designed to to exactly what I want to do with the L pad. The difference is that an L-Pad will probably cost $40 Australian and the Marshall device was $900. You could buy a smaller amp for that