Selling my Weber Mass 100 Watt Attenuator since I sold my high wattage amps in favor of 5W champs. I'm the original owner who bought it straight from the Ted Weber Website. It is in excellent condition since I only used it for a few months before getting a champ and then it sat in my closet for a few years before I realized I probably won't be going back to high wattage amps anytime soon. I bought it with the headphone jack add-on which was extremely useful for playing at night or in an apartment without disturbing people. If you're attenuating very low, it gives you the option to add the lost treble back in. One of the best features is impedance matching your amp to almost all speakers/cabs so you can plug your Champ into a Marshall stack if you wish :).

Official description from the Ted Weber Website:
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.