Weber MASS 100W Attenuator

Up for sale is a Weber MASS 100w Attenuator, purchased brand new in January 2026. I have used it very scarcely at home and it is in absolutely mint condition, both cosmetically and functionally.

This specific unit includes the factory Headphone Output upgrade, making it the ultimate tool for silent practice. It is the perfect device to tame powerful and reactive tube amps—like a Super Reverb or a Bassman—allowing you to push the power tubes to their sweet spot without bringing down the walls. Since the item is already in Italy, EU buyers will save significantly on US shipping and import taxes!

Main Features:

• Real Speaker Motor: Employs an actual speaker motor for the load to yield a realistic interaction between the attenuator and the output circuit of the amp.
• Selectable Impedance: 2, 4, 8, and 16 ohms.
• Attenuation: Continuously adjustable from -3dB to over -70dB (can be used as a full dummy load for DI/Testing when turned to minimum).
• Tone Control: 3-position treble compensation switch (0, 3db, 6db treble boost) for the speaker out.
• Line Out: Unbalanced line out with a dedicated 3-band tone stack and volume control (with tone stack bypass switch).
• Upgrades included: Headphone Output with independent volume control.
• Note: Cables are not included, as per original factory specs.

Feel free to message me for any questions!