Refurbing/Modding Marshall Cab

[aclarson]

I just picked up an older Marshall cab (pre-barcode) that I'm redoing the tolex, grillcloth, and wiring on, and I had a few questions about the history of Marshall cabs and what aspects of cab construction in particular are desireable. If anyone has any info or opinions on the matter, that would be great.

I've been particularly comparing to some pics of classic pre-'72 Marshalls since they're so highly praised, like this '69:


...as well as a pic I found of the newer HW series cabs that are raved about:


Here's the things I'm thinking about specifically:
1. From what I've read, the originals and the HW cab have a plywood back, where as the standard 1960 cab has an MDF back. Is plywood preferable, or is there a preference/trade off aspect? Since I'm in the process of re-tolexing the cab, it would be pretty easy for me to replace the back with plywood since it's just one square piece with some holes.

Update: It appears that the plywood is desirable and I estimate I can get a piece of baltic birch for like $20.

2. As you can see in the above pics, these cabs both have a baffle support that runs from the middle of the back of the baffle to the back. This also sounds like an easy feature to implement since it's just a chunk of 2" x 2". How does this contact with the back panel? Is there some type of padding to prevent the baffle support from buzzing against the back? Maybe there's a screw that screws into the support from the back?

Update: I've looked around more and the support seems to be pretty common at least on the good ones, so I'm gonna add it. It has a screw that goes in from the back, no padding, with the consensus saying it should be perfectly centered.

3. Another thing that looks interesting to me is the four triangle shaped wood pieces on the baffle corners on the old cab pic. Looks like they're there for additional baffle support. This would be another easy add-on. Anyone ever seen this? Looks like they're stapled to the baffle.

Update: this may be unnecessary if you caulk the baffle as suggested in the Youtube video I posted below, not sure yet.

4. Why does Marshall use those crappy rivets on the corners and anti-skid plate instead of screws? Would there be any drawback to using screws instead?

Update: Still no definitive answer on this one, but I'm starting to think it maybe just for cosmetic reasons. I'm starting to think I'm going to leave off the corner guards, make it look like the HW cab.

Also, if anyone has any other general cab modding or tweaking tips or something I haven't thought of, please share.

Thanks!

[aclarson]

Interesting, I just found this video:

YouTube - Bob Molton's Marshall Cabinet Tone Secrets

It explains ways to tighten everything up an seal up gaps, seems like a nice cab mod.

[aclarson]

Wow, I also just found this forum thread:
Marshall 4x12 slant cab recover 101 - The Gear Page

It has a full, detailed, picture guided walkthrough on how to refurbish a Marshall cab, very impressive guide.

[tomdarude]

great topic!....and nice find

[Fletcher]

I found the biggest improvement I could make to my Marshall cabinets is rewiring them with heavier gauge wire. I'm using 10 awg. in them these days. Much less speaker fatigue... much more open tone.

As always... YMMV.

Peace.

[Kenny M]

Originally Posted by aclarson

Wow, I also just found this forum thread:
Marshall 4x12 slant cab recover 101 - The Gear Page

It has a full, detailed, picture guided walkthrough on how to refurbish a Marshall cab, very impressive guide.

Jim from Scumback Speakers is the OP on this thread. Pretty nice guy and seems very responsive to questions. He's also a wealth of info concerning Marshall cabs and speakers. You might try sending him an email.

[aclarson]

So I'm still working on this, but I'm pretty set on how it's going to go.

I ordered standard black levant for the tolex: Mojo Tolex and Tweed » Marshall Style Black Levant Tolex / 54'' W

And salt-and-pepper (basketweave) for the grill cloth: Mojo Grillcloth » Marshall Style Salt & Pepper Grill Cloth 57'' W

I also ordered gold piping for around the baffle and I'm routing the piping channels as suggested in the refurb shown above. By the way, he had a seperate thread where he shows how to do the channels: Marshall JCM 900 412 Slant "Makeover" how-to... - The Gear Page

I already have two Celestion G12T-75s that I'm going to put in an X pattern with two Celestion V30s (Hellatone) much like the Bogner Uberkab. Anyone know how the Uberkab is wired? Do they parallel both of the same kind on one side input, or do they put a V30 and a 75 in parallel on each side? I'm concerned that since the v30s have a 100 dB sensitivity that they'll totally drown out the 75s with they're 97 dB sensitivity, that's twice the volume! Obviously you'd want them running at a different input level to achieve equal sound levels. I can do this in stereo with my Mesa power amp, but then the cab won't actually be stereo since I'll be powering one on each side. See my conundrum?

Someone at another thread recommended this speaker wire, looks like good stuff for the price (it's factory direct), so I ordered the 12 gauge: Knukonceptz product detail for KLEAR KABLE BLUE 12 GAUGE SPEAKER WIRE

Anyway, this thread has mostly been me thinking out loud, but hopefully it will help others by putting a lot of good info in one place.

[Southbay]

So, you were the guy getting me to link you every thread I ever did on restoring/refurbishing an old Marshall cab! Hope you got enough information to finish. Good luck with your project. Here are a couple I just completed.

[matskull]

Originally Posted by Fletcher

I found the biggest improvement I could make to my Marshall cabinets is rewiring them with heavier gauge wire. I'm using 10 awg. in them these days. Much less speaker fatigue... much more open tone.

As always... YMMV.

Peace.

Where do you buy that?
Also, do you solder the wire or do you put some little clips on them?

[matskull]

Originally Posted by matskull

Where do you buy that?
Also, do you solder the wire or do you put some little clips on them?

bump

[aclarson]

Originally Posted by Southbay

So, you were the guy getting me to link you every thread I ever did on restoring/refurbishing an old Marshall cab! Hope you got enough information to finish. Good luck with your project. Here are a couple I just completed.

Hey Jim, yeah, that was me! Nice looking cabs, man, you're the master! The refurb has gone really nice, I have already redone the tolex and added the piping channels and the piping, so I'm in the home stretch. Turned out pretty good. Mojo has been backordered on the S & P for like a month though, irritating. I'll certainly post pics when I'm done though. Thanks again man.

[Southbay]

Originally Posted by aclarson

Hey Jim, yeah, that was me! Nice looking cabs, man, you're the master! The refurb has gone really nice, I have already redone the tolex and added the piping channels and the piping, so I'm in the home stretch. Turned out pretty good. Mojo has been backordered on the S & P for like a month though, irritating. I'll certainly post pics when I'm done though. Thanks again man.

Thanks for the kind words on my cab work, aclarson. You can get the real Marshall S&P cloth at Antique Electronic Supply if you don't want to wait for the Mojo repro (which isn't as nice looking/sounding, I might add). The cabs above were done with all Marshall tolex/cloth/piping. Looks right, sounds right. That's why I use it exclusively.

Glad to hear your restoration project is going well, too!