The Model 1160 Reducer Passive Power Soak for guitars and bass amplifiers, from SPL simply does as its name implies, it reduces the power output of a guitar amp. This means that all sorts of amps, especially tube amps, can now be overdriven, to get that sound, without the need of having to be too loud. It is placed between the guitar amp and the speaker.
At this stage, it converts the amp's amplified electric power into heat. Power reduction with resistors requires no additional power supply so this passive principle helps to guarantee an accurate sound reproduction without any influence on the frequency response curve by an outside power source. So the Reducer is neutral, providing just a volume control, and can be utilized without any batteries or the need for it to be plugged in electrically - somewhere. For the amp output, impedance can be set to 4, 8 or 16 Ohm. Reduction is stepwise in the first stages, but it can then be adjusted continuously.