New project, small cab from old amp box?

[The Dali]

I have an old Marshall MG30FX that doesn't work. The PCB where all the pots sit is fried by previous owner so the "amplifier" part of the combo is pretty much shot. It got me thinking of what I could do with the box. It is a 10" box right now, but I'm thinking I could make it into a 10" or 12" stand-alone cab. I really only need to get a new piece for the front baffle and some grill cloth, new speaker and input wiring.

Anyone do this? Lots of home-made cab boxes out there, wondering why people haven't used old combo amp boxes instead? This one is built with pressboard so isn't the highest quality materials, but it IS a Marshall product and with a little modding could be a pretty cool little cabinet.

Created a short video overview!

 

[ehdwuld]

Re: New project, small cab from old amp box?

I had one of those as well
the solid state amp part failed
not sure what it was but not worth repairing

curious as to what you come up with
I have speakers both 10 and 12 for projects

 

[The Dali]

Re: New project, small cab from old amp box?

So I finished this project. Sounds pretty good but still tweaking. It was little more work than originally envisioned but not terrible. I’ll have a blog post posted soon with overview of the project.







Sent from my iPhone using Tapatalk

 

[The Dali]

Re: New project, small cab from old amp box?

I went with a 10" Celestion Greenback Made in the UK. Figured I'd keep it pure Marshall tone. Was originally thinking a 12" speaker but I don't think the box is deep enough to accommodate a 12". I may build a back to the box and make it a full closed-back box, not sure yet!

 

[GuitarStv]

Re: New project, small cab from old amp box?

Looks great!

 

[ErikH]

Re: New project, small cab from old amp box?

Nice work.

 

[DankStar]

Re: New project, small cab from old amp box?

Looks very useful now!

Maybe do a panel that could be removed for open/closed option?

 

[The Dali]

Re: New project, small cab from old amp box?

Looks very useful now!

Maybe do a panel that could be removed for open/closed option?

I probably will just make a third section for the back & re-paint them all. It was a little bit of comedy of errors - I should have just bought a new piece for the front baffle, but I was trying to build this without going to the hardware store. LOL

 

[The Dali]

Re: New project, small cab from old amp box?

Here is the full blog post that outlines the process.

https://hammersandchords.com/building-a-marshall-extension-cab/

 

[Jeffblue]

Re: New project, small cab from old amp box?


I had made a deal on a Carvin Bel Air amp that wasn't working. The power section PC board arced/fried. I removed the amp chassis, installed a Peavey Rockmaster in it's place and removed and replaced one of the two speakers with a JBL MI 12 inch speaker. Sounds excellent.

 

[ehdwuld]

Re: New project, small cab from old amp box?

View attachment 104267
I had made a deal on a Carvin Bel Air amp that wasn't working. The power section PC board arced/fried. I removed the amp chassis, installed a Peavey Rockmaster in it's place and removed and replaced one of the two speakers with a JBL MI 12 inch speaker. Sounds excellent.

sweet
don't chuck that old Belair chassis
I have one and the company doesnt do repairs anymore
I may need parts

what would you charge for the chassis?

 

[Jeffblue]

Re: New project, small cab from old amp box?

sweet
don't chuck that old Belair chassis
I have one and the company doesnt do repairs anymore
I may need parts

what would you charge for the chassis?

I had started to convert the Bel Air chassis to octal sockets and hard wired for a quad of 6V6 tubes. Of course, it is a little more complicated than just switching the tube types. I haven't found the correct resistor values to dial in close to a proper bias point. I punched the chassis for the tube sockets for a partial point-to-point wiring. If I can get back to this project, I believe it will sound amazing and more Fender-like.

 

[ehdwuld]

Re: New project, small cab from old amp box?

I love mine
it sounds fine stock to me

but I am curious as to how it turns out

I have read of some Hasserl Mods and was reading up on those last week
but seems like you have a more ambitious mod in mind

 

[Jeffblue]

Re: New project, small cab from old amp box?

I don't really care for EL84 tubes in an amp, but that's just me. It is a huge undertaking and not entirely positive I can pull this off. This project has been sitting around for years and I keep getting distracted by other projects, especially when I haven't resolved the issues. Hopefully I can do this. I also have a Mojotone Studio One amp kit that is nearly finished but has a huge decreased volume issue that I cannot seem to rectify. I have to get that project going again.

 

[The Dali]

Re: New project, small cab from old amp box?

Good stuff. Nice to be able to re-use this stuff.

 

[The Dali]

Re: New project, small cab from old amp box?

Added video to the top of the thread.