Weber Mass 100w Attenuator - Used  From Other

Designed for use with 60w amplifiers and lower. If you have a Tweed Bassman or Super Reverb, this is the one you want.

This attenuator has a main volume knob and 3-position treble compensation switch which affect the signal to the speaker. It also has a 3-band tone stack and volume control for the line out signal only.

Impedance selector for 2, 4, 8, 16 ohms, 0, 3db, and 6db treble boost, MASS bypass switch, unbalanced line out, tone stack for line out, tone stack bypass, extra output jack, range switch. The MASS employs an actual speaker motor for the load to yield a realistic interaction between the attenuator and the output circuit of the amp. The attenuation is continuously adjustable from -3dB to over -70db using the speaker control and the range switch.

By turning the speaker control to minimum (maximum attenuation), the unit may be used as a dummy load for testing or for DI use.

Optional wings may be employed for rackmounting the MASS. Attach these wings to the sides of your attenuator, and you can mount it in a standard 19″ rack.  Uses two rack spaces. Must place the attenuator on the topmost spaces of the rack to allow proper ventilation.

There is an option to add a headphone output, and this adds an extra jack with an independent volume control. For the footswitch option, we install a relay which requires 7.5V external power. This only powers the relay – the attenuator itself is still passive. We include the power plug but the footswitch itself is not included. You can use any latching footswitch, including one incorporated in a multi-effect floor unit.

IMPORTANT NOTE ABOUT HIGH GAIN AMPS*: *if you have a Fender or similar amp, and play with cleaner tones, this part does not apply to you. High gain amps such as Marshall or clones (with heavy distortion) are hard on attenuators. Unfortunately, an amp’s volume dial is not a good indicator of how much power is being produced.  Many amps can reach full power at 3 or 4 on the volume dial, so it is a good suggestion to get an attenuator with 4x the power handling. For example, if you have a 50w high gain amp, you should opt for the MASS 200. If you have a 100w amp, you should still go with the MASS 200 but you should not crank the amp. 

1) do not attenuate too far down. this puts a lot of power through a very small section of the volume rheostat which can cause it to fail

2) also do not turn your amp all the way up.  even if you’re just knocking a little off the top with the attenuator, it’s a good idea to keep the amp somewhere in the middle at most.  it’s best to find the lowest volume on the amp that is the acceptable tone to you, and then use the attenuator to bring it the rest of the way.