My Small Box Plexi: A re-creation

The Speaker Cabinet

I also eventually ordered a matching speaker cabinet from Jeff Swanson.

I installed one Celestion G12H and one 12" Weber Ceramic Silver Bell speaker.

This cabinet has a convertible open/closed back. Here's the closed view:

Here's the open view:

I haven't done enough extensive play testing yet, but so far I'm preferring the sound open.

The Weber Mass

Each speaker is rated at 25-30 watts, so a cranked 50 watt head is a bit much for this setup. I have a Hotplate, but I didn't want to be tied to always using it. My solution: add a Weber MASS speaker load (tedweber.com).

A MASS is basically a speaker motor without the cone. They connect a second spider in place of the cone to keep the compliance the same, and use the smallest possible frame (a 6 inch) - it's the perfect silent speaker load.

By adding a 16 ohm MASS rated at 50 watts, I get a 100 watt cabinet rating, and this arrangement allows me to keep the cab impedance at 8 ohms, which matches the other oddball 4x10 and 4x12 cabs I have. Here's a wiring diagram:

Here's a picture of the whole thing:

Isn't that cabinet just gorgeous, inside and out? Here's a closeup of the wiring and MASS unit mounted on the bottom of the cabinet:

When the MASS is switched in, I have a slightly quieter 100 watt 8 ohm cab, which just looks like a bunch of speakers to the amp. When switched out, I have a normal 50 watt 16 ohm cab. The 50 watt MASS unit only weighs about four pounds, so it does not make the cabinet significantly heavier.

Here's the rear panel switch. I selected and mounted it so that the cabinet can be laid on it's back without the switch touching the ground.

 

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Introduction

Turret Board

Chassis

Wiring

Completed Chassis

Head Cabinet

Speaker Cabinet

Sounds

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