Making Your Amp YOURS (D.I.Y. Part 1)

28 Feb Making Your Amp YOURS (D.I.Y. Part 1)

So if some of you out there are anything like me you customize or fix things to make them YOURS. Here I’ll attempt to show you how to build your own amp/speaker cabinet.  This will be part 1 of 2. The second part will deal with the covering (tolex) of the box. Keep in mind, also, that this is just my way of doing things. It’s not the only way. This will be a to the basics article.

Cab/Headbox dimensions are up to you. For the head I just copied the Marshall one that I was replacing.

This started out for me when I saw, for the first time, a Marshall special edition orange covered head and cabinet online. Soon I started on my own tone quest and started buying selling and trading gear to find my “tone” and look. It was only after I stumbled upon a dude named SoloDallas on the YTube, while trying to find a tutorial for ” Gone Shootin’ “, that I realized that tube amps were the way to go for meaty, crunchy raw power sound and tone. Naturally, like most of us, I don’t have money to throw around so I got innovative.

Being a carpenter it came easy for me to build my own boxes. So, the speaker cab featured below is of my own design. It is loosely similar to the Marshall 1936 cab. But I was able to slowly save and purchase all of the pieces until I could build the whole thing. (there are no build pics of the speaker cab. sadly after I started writing this I have come to find out that the flash drive they were on got SMASHED to bits!! :-( ).  I soon, also learned from Fil, about a guy named David Bray. (he did the mods to Fil’s 1987x head). Here in the US tax returns are a great thing. They allowed me to purchase a 1987x and send it to David for the now dubbed “SoloDallas Mod.” When I received the head from David his work was awesome but the head box was crap. (In NO WAY due to David’s work.) Finger joints separating, tolex tearing, dents, dings you name it. So what better way to fix this than to make a new box to fit the new cab.

But enough of my rambling let’s get to it.

(Just a small warning before I get to the pics and so fourth: You will need at least some background in carpentry to do alot of this work!!! If you don’t have the tools already the cost vs. benefit is not worth it. )

For Speaker cabinet building solid pine plank or 3/4′” birch select 11 ply. plywood are the two main choices for construction. In this case I already had some birch ply from another project. I actually prefer ply over solid wood because there is less chance of warpage due to grain pattern. For the head cab I used 1/2″ select Birch ply simply because that’s what Marshall used to build the original.

First is to make the simple outer box. After temp brad nails are in place next is to brad nail the corner gussets in.

First is to make the simple outer box. After temp brad nails are in place next is to brad nail the corner gussets in.

(Make sure to glue ALL joints. I use Titebond II)

After the glue dries, drill the holes in the corner joints for the dowel connectors. I prefer dowels because it is nearly impossible to separate the joint after drying. (corner joints can also be done with dovetail or finger joints) Also drill through the sides into the corner gussets. The general rule I use for doweling like this is go 1/4″ smaller than the plywood that you’re going in to.

Next is to insert the dowels. You can either buy pre-cut dowels at a store or buy a long dowel and cut your own custom lengths. Be sure before insertion, of the dowels, to thoroughly coat them in wood glue. These are the backbone of the box stability.

The next step would be to cut off the dowels after glue has had time to dry. I use a Japanese style pull saw. (very clean smooth cut)

After doweling comes routing.

Marshall regularly uses a 1/2″ or 3/4″ round-over bit for their cornering. (3/4″ in this case) Make sure to do the 4 corners before the face or the outer corner points will not turn out right. Do not rout the rear of the box. Just relieve these corners and edges with some 80grit sandpaper.

Note that around the face there is a temporary 2ndlayer around the inside. This is there for backing the router bit bearing.

This is what the corners should look like after routing and the temp 2nd layer is removed

Note the backing strips for the front and rear panels. These will need to be set back far enough so that the piping in the face panel sits flush with outer box once everything is finally assembled.

Now is the rough cutting of the front and rear panels. The outer dimensions of insert panels like these (the same would apply to a speaker cabinet grill) should measure about 1/4″ smaller than the hole they will fit into. This allows room for tolex and piping to properly fit in the finish product.

The same applies to this panel as with the box. You must put on a backing strip for the router bit for a 3/4″ round-over. For the rear panel, the edges only need to have the sharpness relieved with some 80grit sandpaper.

If you’re doing a Head or cabinet with the 1/8″ beading I recommend clamping a guide/jig in place. This will make sure that your channels are perfectly strait. This channel needs to be 3/32″ deep and 1/8″ wide. Although, as you can see on the face panel, when you use the wrong mark to set the strait edge with your router will follow and you end up with a strip of bondo through the face panel. (good thing nobody will ever see it right????)  :-)

As for the placing of the handles, chassis holes, foot holes and so on, this I leave up to you to carefully measure and determine. I have no idea if placement is the same for even an original 1987 vs. a 1987x reissue much less the dimentions for all of the othe varoius Marshalls alone out there. This is also the case with the beading channels. I actually moved these ones from the stock location simply for my own liking.

That’s it for part 1. If there is any ?’s feel free to comment or use the private messenger. Below are a few pics of the finished speaker cab to try to show some of the building techniques.

The Baffle was made with 1/2″ ply for the surround. Center bar and emblem backing plate are 1/4″ ply.

Speaker panel is 1/2″ ply. The rest of the box is 3/4″ ply. See the Velcro pads in the corners and center? These are for the baffle attachment.

(notice the front edge of the cab is double thick so the speaker panel nails on from the back)

 

This is the side handle cut out. These vary by the type used. Mine (unfortunately) are the Marshall plastic ones.

One day I’ll switch to metal.

As you see I used the individual foot cups. Easy to mount for whatever head size you have. Only a paddle bit is

needed for the countersink hole. If you’re going to use the “skid trays” you will need to carefully use a router with a strait bit for the relief.

Here’s how I stiffened the corners. Integrated the stiffeners into the rear panel backer. (again… when installing the backing strips make sure to account for any tolex or piping thickness so your panel will not stick out!!!)

 

Full cab rear view for construction clarity. This may not be necessary, but I caulk all of the interior corners of speaker boxes to help eliminate rattles and sound bleed.

I chose urethane locking casters for a bit of a padded ride and smooth operation.

So these little handy parts are for mounting the speakers. Note the spikes that dig into the wood so they’ll stay when the speakers are removed . These are available at any hardware store with a GOOD hardware section.

I chose for a 3 piece rear panel with a removeable center. My only reason is so I have the storage for cords and ect… when I’m transporting my gear.

(notice the wiring jack. Two out side jacks for single speaker or used together for stereo. 4ohm in stereo with the 8ohm speakers. Center jack is both speakers wired in series for a 16ohm load.)

Here’s the wiring for the jack-plate above. (Note the un-sleeved wire connecting the tip lugs of the left & center jacks)

Again if you have any questions fell free to ask.

Thanx.

avatar
Jon Saxe
ss327@comcast.net

Just here to learn and try to give something back. :) 2006 SG Standard (Heavily Modified) 1978 Marshall 2203 100w Head. (un-molested) Self Built 2x12 cab w/ G12-65's

35 Comments
  • avatar
    KyleSG
    Posted at 05:07h, 02 February

    Yeah it’s crazy as I bought a 1974 marshall slant cab a awhile back and the back had a piece cut out….which you can see in my article passion for gear on here but yeah I thought for it being a 1974 that all of the cab would be ply wood or something like that but nope the original back was particle board as well. I think when marshall stopped the metal on them in the early 70’s and changed stuff like the handles to plastic to save cost they changed the wood abit as well.

    • avatar
      06AngusSG
      Posted at 05:24h, 02 February

      I think you’re right. There are a lot of companies that “cheaped out” at one time or another.

      I know that Marshall does make some ALL plywood cabs still but you’ll PAY for them. Their $300-$500 cabs (MG, MA & MC’s) are ALL PARTICLE board. They sound terrible as well. I had an AVT cab (pre MG era) which was the same. The speakers and their tiny magnets didn’t deserve the Celestion name!!!

      Looked at you post. Nice Cab. (now that you fixed it) 😉

      BTW I bought the 2203 I was looking at. Freakin’ AWESOME. And……. 4Holes in the back, looked under the chassis and they ARE all factory. This is how the Anerican versions were made for sure!!!!

  • avatar
    AngusRudd1019
    Posted at 02:12h, 01 February

    Does the same rules apply for making a 4 x 12?

    • avatar
      06AngusSG
      Posted at 05:27h, 01 February

      I’m not sure what part you’re meaning by “rules” but the build technique would be, generally, the same.

      Having never dissected a 4×12 cab, and speaking from carpentry experience alone, the only thing I’d change would be to use 3/4″ ply for the speaker mount rather than 1/2″ for stability. Of course, there would have to be added the 2×2 support for the back panel as well.

      Hope that answered your ❓

      • avatar
        AngusRudd1019
        Posted at 14:19h, 01 February

        kind of…After reading this, I am really interested in making my own cab…Do you have any plans on making one and doing a Part 3 or know where I can find a tut on one?

        Would you say building your own is cheaper than buying one?

        • avatar
          06AngusSG
          Posted at 04:38h, 02 February

          SO, I’ll apologize right now for being long winded here. 😉

          1) I don’t have plans to build one because I don’t really need one. My 2×12 serves me just fine. (especially with G12-65’s as of today!!!!!) And I wouldn’t know where to direct you for a tut. If it were me I would go to a guitar shop, measure the dimensions and build it my way…. but that’s just my stubborn way. 8)

          2) As for being cheaper to build your own???? It depends on what you’re going after??? Marshall 4×12’s go from $399 – $1299. The lesser being CRAAAPP in my opinion. (particle board box, crap speakers, ect, ect…)

          That being said YES it’s cheaper only if you compare your own cost to the HIGH quality Marshalls. I did some counting today and I could build a replica of the $1299 Marshall 1960BHW cab for $265usd. (for the cab only) This includes: Plywood, Tolex, Grill Cloth, Piping, Logos, Handles, Corners, Casters & wiring.

          Now for a couple of examples: if you loaded the cab with G12h-30’s total cost would be $825. ($150 cheaper than the 1960AV/BV cabs) Loaded w/ G12h-65’s it would be $965. (About the same as a AV/BV but cheaper than the 1960AHW/BHW) This would be for All new. If you already have speakers or find used for a good deal you’re set even better for savings.

          So you see it’s kind of a “relative Question. You could use the cheap Chinese Celestions or mix different types to change around the cost. Even if the savings were only $50 I would still do my own just for the fun and pride factors. Also, I like to know exactly what I have and how it’s done.

          Some other determining factors would be: Do you have the carpentry experience to do it? Do you have all of the necessary tools? If you don’t it’s NOT worth it. The tools alone would kill the cost.

          Anyway, sorry again for the long wind. I like to try to be thorough. If you do end up doing it I’d be glad to help you out if needed. If you have any more :?:’s feel free to ask anytime.

          Jon

          • avatar
            AngusRudd1019
            Posted at 05:42h, 02 February

            well my cousin is into construction and my bass player was a carpenter so tools wise and help wise, I can ask them but we would need to look at your tut for a guide as to what we need. I found a guy selling 2 G12-65’s for $125 on craigslist and that made me think of building my own cab. It sounds like fun and I would love to do it with my cousin but I’m not sure if he wants to.

            • avatar
              06AngusSG
              Posted at 06:52h, 02 February

              Well I hope they do help you out. For me, there’s nothing like making my own stuff. It leaves me with a sense of accomplishment!!!! (no different than tackling a new song.)

              I don’t know if you’re in a hurry but I could look into measuring a 4×12 Marshall and trying to come up with some simple plans to post. (They would be with my building style rather than Marshalls though) I couldn’t promise anything soon because I’m busy as hell right now but I’ll see what I can do.

              • avatar
                AngusRudd1019
                Posted at 22:44h, 02 February

                well before you go through all that work let me see if my dad and cousin want to do it because they might just say, buy one lol

  • avatar
    odgeuk
    Posted at 22:12h, 31 January

    Absolutely superb. Would love to see more pics of the finished head cab.

    • avatar
      06AngusSG
      Posted at 01:29h, 01 February

      Look for part 2 of my article. It covers the Tolex part of the build and shows more pics of the head. Or you can go to the link for my Flikr page for waaay more pics.

      Sadly I just sold this head 2 Weeks ago. But…. I just recieved my 1978 (year) 2203 Marshall master model. 8)
      WELL WORTH THE TRADE OFF!!! I’ll be building and covering a new box for it to mach the cab!! 😉

  • avatar
    rugster
    Posted at 18:12h, 01 March

    That really Is a work of art. Fantastic job.

  • avatar
    Angusrocks
    Posted at 16:47h, 01 March

    Fantastic !!! Beautiful !!!

  • avatar
    nitroangus23
    Posted at 23:21h, 28 February

    Fantastic post man,

    Love the detail and quality,very nice and the finished product speaks for itself.

    Seems you’ve also opened a door for new stuff here,now we can have a DIY section :)

    • avatar
      06AngusSG
      Posted at 23:30h, 28 February

      That’s kind my plan. Fil, seems o.k. with it to. I’m not big on the strutting my stuff with videos, so, I figured I could contribute this way.

      The second part of this, for tolex covering, is waiting on review. I believe it’ll be posted soon.

      My next one, planned, is the ’50s wiring everyone has been asking about.

      Thanx for the kind words, by the way. :-)

  • avatar
    headwhop26
    Posted at 22:17h, 28 February

    I love how this website is going from what it started out as (lets learn more about AC/DC and become better guitarists) to bringing the AC/DC detectives, tone seekers, writers, carpenters, and electricians from out of the dark.

    While I must admit that the breadth of my woodworking experience included building birdhouses with my grandfather when I was little and several semesters building chess boards and mantle clocks in high school, I find this fascinating. This is the kind of thing that makes me want to start a bucket list (I hope that term isnt just an American one).

    • avatar
      rjofig
      Posted at 15:09h, 01 March

      I agree, it is neat to see how the site evolves and the different things people contribute.
      This is very nice work, 06AngusSG; I must say my skills on this go as far as being able to put basic IKEA furniture together, so I probably will not venture such a project myself, but if I change my mind, it’s here.
      The color is very 70s, reminds me of my dad’s station wagon back in the day :)

      • avatar
        06AngusSG
        Posted at 16:54h, 01 March

        You should look at part 2. You get the whole picture there. And thank you!

  • avatar
    ar2619Rob
    Posted at 18:13h, 28 February

    Your end product is stunning. It’s as least as robust as an original, I think probably more so. It’s a great article, it makes me want to have a go but I should just stick to skirting board and architrave I think, lol.
    You must feel proud to have something unique and of your own hand too. :)

    • avatar
      06AngusSG
      Posted at 18:49h, 28 February

      Thank You!!! 😉

  • avatar
    Ant
    Posted at 17:52h, 28 February

    Cool, nice work very impressive 😛

    im looking to do a custom build SG from a mahogany kit online
    anyone attempted this before?

    i have tried looking for vintage bodies but cant find any on the cheap :(

  • avatar
    banane
    Posted at 15:45h, 28 February

    Great article. Being a carpenter myself, I would say this work is done with a lot of passion. A lot of people just screw their cabs together, but this is the right way. Well done, 06AngusSG!

    • avatar
      06AngusSG
      Posted at 17:10h, 28 February

      Thanx, Franz? Right?

      I do all of my carpentry with alot of passion. Especially when I do furniture oriented, or finish work.

      • avatar
        banane
        Posted at 18:01h, 28 February

        Yes, I’m Franz, right :) Yeah, same for me. I loved to work as a carpenter, now as I’m working in the IT, I’m missing working with my hands sometimes. Having a small room with some machines and a workbench is another litle dream of mine :)
        What type of routing machine did you use for the corners?

        • avatar
          06AngusSG
          Posted at 18:48h, 28 February

          I have a Porter Cable 1.75hp router for the big stuff and a Bosch laminate trimmer for the small. :)

  • avatar
    TheBrowling
    Posted at 15:41h, 28 February

    Really good, I made a 0,5 watt amp some months ago, it sounds quite well for what it is (it cost me around 6€ and works with a 9v battery).

  • avatar
    Dries
    Posted at 13:15h, 28 February

    Does someone has dimensions of a marshall style small box head ( 1987X etc. )? I’ve searched for a while now, but haven’t found any blueprints..

    • avatar
      06AngusSG
      Posted at 17:13h, 28 February

      The head I did here is a 1987x. I’ll have it apart soon to do the Tolex post. I could re-take the dimentions and send you some hand drawn prints if you like?

  • avatar
    jakesg61
    Posted at 10:31h, 28 February

    Fantastic work there, like mentioned at the top of this post, Baltic Birch Plywood is the exact same wood type the marshall use to build their own heads and cabs. When i built my cab, i didnt use any glue, cranked my head up and nearly shook it apart haha, going to re-build it stronger
    greatly detailed post 😀
    thanks

    • avatar
      06AngusSG
      Posted at 17:15h, 28 February

      Glue is the KEY. :-)

      It’s the backbone of carpentry that many people overlook.(including myself)
      I find that I have to remind myself often to do it.

      • avatar
        banane
        Posted at 19:34h, 28 February

        Yeah, thats right. Too much things today are only screwed together and not as solid as they could be.
        Thats another reason why I love Marshall. Their cases (either amps or cabinets) are really solid.

  • avatar
    SoloDallas
    Posted at 09:49h, 28 February

    Terrific. People please welcome 06AngusSG’s great Contribution!

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