Converting a closed-back Marshall 4x12 to open-back

[npfrs]

I snagged a JCM 800 4x12 a few months ago. It's loaded with 70's which, although everybody seems to hate, sound pretty good (being well broken in likely helps) but I never intended to keep it stock. Since I got such a good deal on it I was planning on converting it to an open-back cab with 2 blues and 2 golds and also wiring it for mono/stereo.

Has anybody converted a closed-back Marshall 4x12 to an open-back? I've found a few different ideas online...









I also thought this was interesting...

[whiskey_face]

ive never done it but with those greenbacks

edit: I would build a totally separate back for it, instead of hacking up a marshall one.

36 x 36 sheet of void free ply
+ saw
+ router (the circular cutouts are waaaaay sexy)
+ tolex
+ an afternoon


bam easy

[benjuro]

I would build a totally separate back for it, instead of hacking up a marshall one.

[npfrs]

I would build a totally separate back for it, instead of hacking up a marshall one.

Yes, definitely, but I'm wondering what back to make? Seems like Marshall themselves used to do 2 vertical side panels, and I've seen photos of EJ using a similar one. However there are some other great options out there...

[sonidero]

Just route out a huge I, L, and F...

[npfrs]

Just route out a huge I, L, and F...

[Decibill]

I agree, I'd make a new panel and not trash the original. The easiest option would be a simple full vertical or horizontal panel cut out, like the Marshal or Orange option. "Aesthetically" though, I like the full rear panel with the rounded rectangle cutaway.