JTM30 cab rebuild

[davidkerr82]

Hello, first post here, had a few marshalls over time, lastly a jcm600 head and 4x10 cabinet that I regret selling. I have recently picked up a jtm30 1x12 combo for a song that is in average condition but sounds amazing.

As a woodwork teacher I am planning to make a new 1x12 cabinet and a head cabinet for the amp. A quick question for those experienced with the edge radius of cabs, I am measuring a 1" radius on the existing combo, are all marshall corner protectors currently this 1" radius or are there different sizes? I don't want to route roundovers to find I have cut wrong sizes for the marshall protectors.

Marshall have been great in providing me info regarding the corner protectors but don't want to talk to me about radius's if things!

Any help is gladly appreciated.

 

[Dogs of Doom]

Hi, to the forum...

Yes, but the rear of the cab gets no roundover, so the rear plastic protectors are specific for that. Member @fitz has made a somewhat replica, of the JTM style cab's. The tolex is pretty much unavailable, but, he found one pretty close.

maybe he'll pipe in shortly...

 

[Resident 217]

I dont know for sure. But In having done a few repairs to old ones, it looks that Marshall assemblers do the corners by hand. I would say after the cab has been assembled. The corners are rounded over to fit the caps. It looked sometimes to be done very crudely like with rasp. A least thats the way it appeared to me. Sometimes underneath the corner, the tolex was rough and messy. Not really very uniform. The edge radius would depend on the style of cab.

 

[fitz]

to the forum.
I've always used a 3/4" roundover on my cab builds.
Not sure what the exact radius is in metric that Marshall uses, but once the tolex is on, the Marshall corners (or generic equivalents) fit just fine.
Tolex I used was black cherry from Tubes&More / Amplified Parts - a bit darker than the JTM, but that stuff is just unobtainium.

 

[davidkerr82]

Thank you so much for the replies so far from everyone, really helpful information. Fitz, you hit the nail on the head with the details I was looking for. I will go 3/4" roundover as I think the 1" looks too big visually. Good to know the Marshall corners fit 3/4" roundovers well.

Fitz I have read through all your builds, outstanding workmanship on display and I hope my build get somewhere close to yours. Bravo!

Thinking ahead to tolex and grill cloth, I know that the jtm original stuff or anything like it are impossible to get. I have a valvestate 1997 anniversary in blue tolex picture below that I really like. I am thinking along the same lines for the jtm30. Does anyone know the name of this style of grill cloth?

Thanks again for all the input and the welcome to the forum.

 

[fitz]

Does anyone know the name of this style of grill cloth?

Looks like re-issue pinstripe.
Possibly the backside like they did with the Origins.

https://www.tubesandmore.com/products/grill-cloth-marshall-bluesbreaker-32-wide

Here's a front/back pic of a scrap I have.

And here's the tolex I used on the JTM cabs.

https://www.tubesandmore.com/products/tolex-black-cherry-bronco-material-54-wide

 

[davidkerr82]

Great info, thank you. I have been going back and forth on Rolex and grill options, still not decided yet. In the mean time I have been putting together the amp head and cabinet. Happy with the dimensions and added the top grill like the jcm600 for cooling.

All has been roundovered and filled