I want to announce I am out of business I will no longer be making any attenuators. I am proud of the fact that I got everyone's attenuator shipped out in a week or less and that I owe no one anything. I am back sorry for the short delay my chassis supplier had some family issues and wasn't able to fill my order on time. All new units are now black face and black lids all aluminum. My attenuator is a passive reactive load which maintains a load very near that of a speaker. By doing that this attenuator is extremely transparent. The limiting factor ends up being the response curve of the speakers at low volumes more so than any fault of the attenuator. In an attempt to compensate for the speaker response I have included a variable treble compensation switch. My attenuator will handle a 100 watt Marshall Superlead which can put out a 170 watts or more at full throttle. That is a lot of heat which means the unit will get warm. The handles don't get warm because they are isolated from the case so the handles are an extra cost option as not everyone will have to move the unit while it is hot. If you would like post an comment or question please do it here as this post won't get deleted after 90 days. I am happy to answer question sent to me via email or PM. You can find my email address by clicking on the forum name above left. Basic instructions: The Bypass switch has to be off for the unit to be in the circuit with the speaker. When the bypass is on the unit is bypassed using a true bypass topography so that no parts are connected to the amp or speaker. The -3db/-12db decibel knob has to be in the -12 position before the center knob does anything. For full load both knobs have to be counterclockwise. The treble knob only comes into the circuit when the db knob is in the minus -12 position and becomes more noticeable as the volume is turned down with the center knob. The bypass switch has to be off for the attenuator to be on. The line out volume feeds off the input so the attenuator controls have no effect on it and it only controls the signal at the line out plastic jack on the back. For purchase info click on my forum name 908ssp in the upper left hand corner and follow the prompts to email me. Thank you Jack Zucker for the demo.