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Guitar Cab Modification Questions
PostPosted:Fri Jul 23, 2010 7:52 am
by Rusty the Scoob
I have a guitar question for a change!
This 2x10" cab was purchased on Craig's list as a sealed cab, in the process of being converted to an open back. I want to tidy up the changes and finish it up.
Here's how it looks as I received it, and my proposed cuts are in yellow. I'll peel back the carpet, make the large opening with a circular saw and the small one for the input plate with a jigsaw, then glue the carpet back down with 3M spray adhesive.
Guitar Cab with Alterations.JPG
Then the speakers get wired in parallel, right? Not series.
This is the input plate - pretty straighforward.
Control Plate - Smaller.JPG
I should take out that baffle between the speakers, right?
Anything else that I should be doing that I don't know about?
Re: Guitar Cab Modification Questions
PostPosted:Fri Jul 23, 2010 7:59 am
by keirweir
Re: Guitar Cab Modification Questions
PostPosted:Fri Jul 23, 2010 9:01 am
by Imagined Days
It's already an open back! And any more cutting would be sacrificing structural integrity.
Chris
Re: Guitar Cab Modification Questions
PostPosted:Fri Jul 23, 2010 3:06 pm
by sants
I think if you take off that much you will have very little bottom end if you ever want it or need it!
Re: Guitar Cab Modification Questions
PostPosted:Fri Jul 23, 2010 9:04 pm
by ugly rumor
Looks like a crappy cab, Scoob. Bust-outs where the speaker cut-outs are, obviously speakers screwed into the board, no "T" nuts, who knows what kind of corner joints, whether dado, finger-jointed, or just butted, and then is it glued, screwed, tacked, or what. At least it is plywood. Looks like a somewhat amateurish home-made job. I'd look for either a Thiele cabinet or a solidly well-made manufactured one, or make one yourself. Sorry to burst your bubble, but I think you would prefer honesty over schmoozy. I've gotten junk on ebay, too.
Re: Guitar Cab Modification Questions
PostPosted:Sat Jul 24, 2010 7:26 am
by Rusty the Scoob
No offense taken... it's Keir's cab anyway.

I think it just has to be good enough so he can a/b his K120s. If I had to guess at it's origin I'd say it was probably originally a cheap subwoofer cab for car audio.
Looks like Hard Truckers cabs have small holes... so I guess I'll just tidy it up a bit and install the jackplate.

Re: Guitar Cab Modification Questions
PostPosted:Sat Jul 24, 2010 4:57 pm
by Rusty the Scoob
Well, it's not beautiful but it's done.
Peeled back the carpet:
Laid down some masking tape so my circular saw and jigsaw didn't bind up on the sticky wood:
Tidied up and enlarged the port hole, cut the round hole for the input jackplate. Interestingly it's the exact same size as the inside of a roll of masking tape.
Peeled the tape, glued the carpet back, reinstalled the hardware, hooked up the speakers with some 18ga speaker wire, and good to go.
I thought I read somewhere that the red terminal is negative on JBLs, unlike most speakers. Is that true? It's easy enough to swap them.
Re: Guitar Cab Modification Questions
PostPosted:Sat Jul 24, 2010 7:46 pm
by JonnyBoy
The cab has been butt jointed on all joints, which means over time it can cause it to come apart without any interior baffle support. You may not want to remove the entire piece of support inside the cab against the Baffle. Hard truckers and I do also, miter the side joint to give asurface to glue and snugly lock it in to nail and screw. It may be ok, depending on how well its all together, or good enough. That baffle gives the box even more strength. You may want to consider trimming in the front of the baffle with some 1/4 round real tight, that will make it rock hard. Good Luck man!
Re: Guitar Cab Modification Questions
PostPosted:Sun Jul 25, 2010 12:19 pm
by keirweir
Yeah, I got this cab for $65 bucks on ebay a year or two ago. Just a random impulse buy. I scored some K's and wanted somthing cheap that I could try different speakers in. I am playing through a twin now with Beyma Liberty speakers. Now I can try my E-120's, K-120's and Beymas much easier.
Thanks Scoob.. Looking great! (for a $65 cab)
Re: Guitar Cab Modification Questions
PostPosted:Wed Jul 27, 2011 12:22 am
by ndrewoods
keirweir wrote:Yeah, I got this cab for $65 bucks on ebay a year or two ago. Just a random impulse buy. I scored some K's and wanted somthing cheap that I could try different speakers in. I am playing to play guitar through a twin now with Beyma Liberty speakers. Now I can try my E-120's, K-120's and Beymas much easier.
Thanks Scoob.. Looking great! (for a $65 cab)
Hey cool. I wish I could build a cab like that. Where could I get a cab to play with my guitar that is not that expensive? $65 ain't that bad.
Re: Guitar Cab Modification Questions
PostPosted:Wed Jul 27, 2011 1:01 pm
by deadguise
thought I read somewhere that the red terminal is negative on JBLs, unlike most speakers. Is that true? It's easy enough to swap them.
The Scoob read right.
http://www.jblpro.com/pages/jbl_faq.htm