Power soak attenuators

[thomasks]

Folks,
What' s the consensus on using a power soak attenuator like the Bugera PS1 Passive 100-watt Power Attenuator? Can it damage your amp? And can you run 2 in series to cut it down to 1/4 volume but sustain its tone?

[statorvane]

I picked up one of those a couple of years ago. Not a bad little unit - my most powerful amp is a JMP50 clone. As soon as it is cabled up it drops the signal by at least 3-4 dB. Very noticeable, I can dial it down much more, but the volume reduction comes with a proportional deterioration in the tone. That is, at 1/4 volume I don't think you would describe the resulting tone as sustained. Once plugged in, even at the least attenuation setting the feedback is practically eliminated. Without the attenuator, I can get the amp to continue to feed at a much lower lower volume that I can by attenuating the amp volume to the same level.

My primary use is to reduce the sound level in order to keep my wife from getting upset at the volume. When she's gone - it is out of the loop. It serves its purpose.

[Mark]

Here is a review of IR units and reamping units.

https://youtu.be/5mveCNZgNPI

[romberg]

Folks,
What' s the consensus on using a power soak attenuator like the Bugera PS1 Passive 100-watt Power Attenuator? Can it damage your amp? And can you run 2 in series to cut it down to 1/4 volume but sustain its tone?

When you cut an amps output power by half you only drop the volume by 3db. Half volume is -6db. So, to hear 1/2 the volume you need to cut the power by four. To get to 1/4 the volume, you need to cut the power to 1/16th of the output. Thus an attenuator on a 100watt amp will need to drop around 94 watts and only pass around 6 watts to the speaker.

The attenuator rated for 100watts will only have a 6 watt safety margin. And that safety margin only exists for clean guitar signals. A distorted (square wave) signal produced by a cranked overdriven amp contains roughly *double* the output power of it's clean rating. Amps are rated using a clean sin wave. So, a 100watt marshall may put out near 200watts when fully cranked up. That attenuator above will now need to dump 188 watts.

If you plug an amp into any attenuator which can not handle the *full* power delivered into it then it can/will fail. When this happens, the amp may then be running without any load on the output. This can quickly take out power tubes, output transformers and many other parts of the amp.

So it is a very good idea to make sure any attenuator you use can handle the power you are asking it to dissipate. If you don't you do risk burning up parts in your amp (and in the attenuator). Same logic applies to speakers.

Mike