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What it is
The Lotus M3 is a reactive attenuator. It goes between your amp's speaker output and your speaker, and turns the volume down after the amp has done its work.
What an attenuator does
A tube amp's sound changes as it is turned up. Past a point the power tubes and the output transformer work hard: they compress, sag and break up. On many amps that only happens at a volume too loud for the room, the stage or the neighbours.
The Lotus takes the amp's full output, turns most of it into heat, and passes a set fraction on to the speaker. The amp works as hard as you set it; the speaker plays as quietly as you set the Lotus.
It is reactive: an air-core coil in the load makes the amp see something that behaves like a speaker, not a plain resistor. Five toggles give 18 settings, from 3.5 dB to 33.25 dB in 1.75 dB steps. With a 60 W amp that is about 27 W at the lightest setting and 0.028 W at the deepest.
How it differs from a master volume
A master volume sits inside the amp, before the power section. Turning it down lowers the signal reaching the power tubes, so they never work hard. You keep the preamp's gain and distortion, but not the power section's part of the sound.
An attenuator sits after the power section. The power tubes and the output transformer run as they would wide open; only the level reaching the speaker comes down.
| Master volume | Lotus M3 | |
|---|---|---|
| Where it sits | Inside the amp, before the power tubes | Between the amp's speaker output and the speaker |
| What it turns down | The signal going into the power section | The power going to the speaker |
| Power-section breakup at low volume | No | Yes |
| Works on any tube amp | Only amps that have one | Yes, with the model that matches the amp's speaker output |
The two work together. Plenty of players set the master volume for the sound and the Lotus for the room.
Do you need one?
Probably yes, if
- Your amp has no master volume and sounds best turned up.
- You want the power section's breakup at home, in the studio or on a quiet stage.
- You record or work on amps. The Lotus M3 can also be safely used as a dummy load for direct-to-DAW, board or bench testing an amp.
Probably not, if
- You already get the sound you want at the volume you play, from the amp's own master volume or gain.
- Your amp is small enough to turn up all the way in the room you play.
Whichever model you choose has to match your amp's speaker output: a 2, 4, 8 or 16 Ω Lotus for a 2, 4, 8 or 16 Ω output. Hooking it up shows how.