Combo to extension speaker cabinet.
I occasionally see cabinetry that has outlived its’ purpose, as was the case with this Marshall 1 x 10″ combo in which the amp had fried and wasn’t worth fixing. I removed the amp, speaker and grille panel, and made a new grille panel to fit the whole space. It’s now a very portable 1 x 12″ Marshall speaker cabinet.
In these combo amplifiers, the cavity where the amplifier was mounted was covered with matching tolexed panels, again, turning them into extension speaker cabinets.
First is a Vox Valvetronix 1 x 12″ closed back cabinet. The 2nd picture shows the new back panel and the top rear amp cavity cover.
This is a Line 6 Flextone 1 x 12″ open back cabinet with the amp removed.
This one is a Fender Hot Rod DeVille 4 x 10″ open back with the amp head removed.