Modified Matamp S2000 cabinet the hard way

Over the course of the last year I have been acquiring tools here and there so I can be self sufficient in small scale production. The bare minimum I need for swift assembly is a brad  nail gun. I elected to buy an air powered model and a compressor as this came with a selection of tools that will be of use later (spray gun for painting the inside of the enclosure and air nozzle for removing sawdust from the work piece). I also have a sliding compound mitre saw which allows me to make square cuts for jig making cutting picture frame infills to size once cabs have been assembled and other general wood working tasks.

I’ve asked for assistance from Matamp in cutting boards but due to the small workforce and large amount of orders recently it has been difficult to fit in. To circumvent this I have approached the college construction department and they have been kind enough to oblige.

Recently I ordered three sheets of far eastern poplar ply. On arrival it turned out to be of lower quality than the Italian made product. For this purpose it is however fine. Ray the tech in the construction building ripped them into flat packs for two greenboy 15″ subs and all the woodwork for a Matamp S2000 head and cab.

The latter cabinet is what will feature in this post. I have had recent instruction on assembling Matamp boxes which enables me to push forward at home. As I have minimal tools and no jigs at home this will prove to be a very useful exercise. I have the ability to create straight, square cuts.

In order to ensure flush fitting of the Back panel and the baffle I have manufactured jigs to properly space the beading from the edges of the cabinet. Unfortunately my phone had run out of battery in the window of time I had to fulfil this task. There’s more to make though so there’ll no doubt be method pictures elsewhere in this blog.

As for cutting the handles on the side of the box I will utilise the method I saw Jeff use to create the handle holes on the Greenboy 15/6 seen in the build diary in this blog. Sadly it appears that I did not manage to document the process but it is straight forward and will be demonstrated in this blog post. To summarise, it requires the handles to be marked out on the side of the board prior to assembly and along the marked lines small off cuts with straight edges can be temporarily nailed to provide a guide for a flush cut router bit with a guide bearing. This way I can perform this operation at home.

Likewise cutting the baffle to accommodate the drivers will be a new challenge.  Circle cutting jigs for routers are easy to make and could consist of some of my stock of mdf and a nail as a low tech solution. See video below for tutorial. Luckily I have a Series 2000 anniversary 2×12 that I can derive the handle measurements from. There is a slight problem in that the originals and the limited run of anniversary cabinets were made of chipboard and the back panel of mine has swelled fast and cannot be removed. If subsequent efforts to release it fail I shall use the factory jigs for the baffle and back panel.  I will have used the circle cutter for the Greenboy subs in any case and it will be documented in that build diary.

https://youtu.be/QVzy5Th44H4

https://youtu.be/brq3wtKuv0Q

More to follow.

Matamp GT20 and 1×12. Non standard Coverings.

This post will document some of the cabinets that I have assembled, machined for a project that involves disposing of around £15,000 worth of dead factory stock.

A half hearted attempt to sell them at a clearance price and zero options failed miserably and the remaining fifteen amplifiers are piled up in the showroom and have deteriorated in their two years of storage. I`d originally offered to make some video demos for them but the amplifiers were just dumped onto the Facebook page with no fanfare or marketing. My tentative solution is to make them a little sexier and see if we can punt them as something more special than a clearance item.

To fudge the problem of turning clearance items into more expensive aesthetic one offs I intend to mix up the models of amplifier and sometimes offer the GT40, S3000 in various configurations to help direct these lower gain products to the correct demographic.

Matamp 1×12 two tone vinyl with gold string.

There’s quite often spare loudspeaker carcasses at the factory as enclosures and head sleeves are cut and assembled in batches. I’ve been after having a play with with covering boxes in contrasting colours for a while and this is my first attempt. The vinyl came from a massive box of mixed offcuts and the badge was an old one that’d been gathering dust on a shelf.

There are plenty of examples of amp manufacturers offering “two tone” coverings and as a custom shop it is another service that can be charged for at a premium.

The first step is to apply a water based glue to the edges of the box. This is then left to dry and aids the adhesion of the covering.

Sized with glue and left to tack up.

I’d cut the vinyl the previous week but not thought to take any pictures. Usually Matamp products have two string grooves machined 44mm from the front and back respectively. I decided to omit the rear groove as a nod towards Simms Watts a UK amp manufacturer from the 1970s. Subsequent boxes will have a mix of single and double grooves (double will have the contrasting stripe in the centre).

The most difficult section is applied first. The vinyl needs to be wide enough to cover the string grooves answer leave approximately 10mm to be trimmed after the rear of the box has been covered.

Again a 10mm overlap is allowed. It is at this point that you cut along the stringing groove.

There’s some difficult cuts to make on the back. I was busy concentrating and so there are no pictures to indicate the method. Easy enough to work out though.

Covering finished. Hardware yet to be fitted.

Gold will do nicely!

Not bad for offcuts and dead stock.

12/12/17

A small update on this side project at work. I collated all the parts necessary to build a pair of GT20 head boxes from waste wood. I assembled them at home over the weekend with jigs manufactured specifically for the task by myself.

The little blue sliding square is my favourite tool. It’s been so damn handy and have been set to make all of my jigs for this project. All I did to make the jigs was mark off the correct depth, and glue/nail a second straight edge piece along the line using the square to make sure the position is correct.

With the rear beading located on the top panel isn’t thought it prudent to start there so I could use the long horizontal piece of beading to set the second side panel correctly.

In the picture above the front of the box is facing the camera. The left side was attached first to the top. Next came the long strip of beading followed by the short vertical piece. At this point I attached the other side and the final bit of the rear bead. Finally the bottom was incorporated as was the front bead. Both boxes were then checked to make sure they were square and left to set. I will be taking them back to the factory for machining and covering on my next visit.

Test fit prior to machining.

15/12/17

A busy few days. This project is just waiting for a new faceplate and it will be ready for the photography. The second box in the last update has also been covered and will be ready within the next couple of weeks along with a matching 1×12 cabinet.

First job of the day was to machine a radius on all the exterior edges of the box on one of the workshop spindle moulders. These are then recut with a handheld router with a guide bearing on the bottom of the cutter. The new radii are then sanded with an orbital sander and the string grooves are cut.

The left hand box is to match the original cabinet, while the right is part of the next set in the sequence. The pictures for the latter can be found at the bottom of this thread.
The pics below are of the head box being covered. The method is the same as the 1×12 cab and doesn’t require repeating. Any minor deviations will be detailed under the relevant image.

The rear corners are a slightly different proposition to what I’m used to. The first attempt (below) was a little off. The second (above) was better.

Note the vertical strips of beading to the front of the box. These were a pig to do and I messed up a fair bit. I will fix this with some red paint which will cover it sufficiently.

In situ at home. To prevent the vinyl lifting you must wait 24hrs for the glue to set.

Trimming the head box.

When drilling holes for the chassis I made a mistake and had to drill a second set of holes. This isn’t a problem but to avoid further mistakes I used my set square to locate the correct set. I used a brad awl to locate and widened the holes with an 8mm bit. This proved necessary as the previous perfect fit was compromised slightly by the 2mm thickness of the vinyl.

To fit the string a couple of 15mm staples are used. The hammer is to push the string into the groove.

Corners next. I used my new air screwdriver which promptly broke! It was cheap and there is a lesson in that. I’ll go back and fit the corners better when the amp relieves it’s new front panel.

There’s a little bit more poking to do with the awl. On the top panel there are two pre drilled holes 5mm in diameter. Two M5 T nuts are hammered in to the internal side which retain two 25mm M5 countersunk bolts. The second screw is self tapping.Chrome covers push fit on top. See below.

Done.

The box was made for this amplifier. I bought the prototype of a short run without a box as I had one knocking about. There is a new faceplate on order which will hopefully be ready next week.
The above shows the completed makeover.

Greenboy 15 sub build diary

And off we Go!

These cabs are far more complex than I have dealt with before. I’ve dug out some mdf out of the loft so I can manufacture jigs for spacing the braces correctly. I’ve no facility to cut the handles at home and I’ve waited long enough to start this project so I’ll are a jig and use a hand held router with a flush cut bit and bearing guide (top) with some scrap mdf to serve as a jig. I’ll mark the handle holes out prior to assembly.

Spacers required: 9.5″ for the port divider, spine and top braces, 9.75″ for girdle brace, 8.75 (from back panel) for the pillar brace. Made using a chop saw and mdf.

It took about an hour to set the mitre saw. The blade wasn’t quite square so needed adjusting for an accurate 90 degree cut. I still a little mystified by the process but that will improve with practice.

Dry fit to are sure panels are the right size.

All parts laid out

Order of assembly of first five components: base,side, back, side, port divider secured with wood glue and Brad nails.

Top and port shelf added

Due to the 15/6 being the wider version to accommodate valve amps the 15 sub will be oriented with the port to the side.

Top and spine braces added.

Spacer used to position brace.

All the vertical braces have been installed in the below pictures. Just the horizontal pieces need  to be added before the baffle is cut and installed.

To fit the remaining bracing I must cut it to size. The plans call for notches to be cut into the braces to help locate the counterpart. I do not have the facility to cut these and trimming to size with a mitre saw yields the same results if carefully done.

I used the side of the box as a stop and marked off the waste area. I`d lent my powered saw to a friend over the weekend so I had to use a tenon saw and a mitre box to achieve nice straight cuts.

 

The spacers I cut at the start of this project are used again to install the bracing correctly. All that remains now is to is to cut the baffles and install it. The second cab is also just about ready also, and just requires the beading to be added to the inside of the front of the box so that I have enough material to screw the baffle to which will facilitate the repeated removal to add sections of bracing between readings. Below is a brief pictorial documentation of the construction of the second enclosure.

At the first opportunity these cabs will be machined and loaded, though crossovers are still yet to be procured.

 

More to follow.

4×12 construction promo clip Orange Amplifiers

https://youtu.be/Ni-60bX1xY8

This is a recent video By Orange giving a glimpse of how their cabinets are made. There are a few interesting details revealed and given the similarity in construction and aesthetic with Matamp where I work part time.

I will review this clip and add times and notes of the points of interest that will aid my professional development.

0:15 CNC machine cuts handles and rebates the edges of the sides. This performs two functions. It speeds up the process of assembly and provides a larger gluing surface than the traditional butt joints used by Matamp.

0:25 You can see a big pile of side panels being stacked. Notice the top to bottom groove on the left hand side of the left pile of panels. Initially I was unsure as to if this was the front or back of the enclosure. The next section of film confirmed that these are used to locate the rear beading that the back panel is affixed too. The ability of CNC to position locating grooves has the potential to improve accuracy and assembly speed.

0:32 You can see the rebate at the front of the enclosure this will help locate the picture frame inserts that give Orange and Matamp their distinctive look. In this clip the section of bracing that is getting glued also provides reinforcement for the picture frame corners.

0.35 Glue for the picture frame inserts being applied.

0:38 Picture frame fitted.

0:45 Note the picture frame is made of ply cut from the same sheet as the box.

1:00 Covering. Note that the box itself is the only component that has glue applied to it. This gives the opportunity to position your vinyl easily as you are positioning that rather than a large unwieldy box. This is definitely a method to try as Orange makes some immaculately covered boxes.

1:52 Corners hammered into a good fit. This is an angled cabinet and this step is required to fit the angle of the top front corners.

2:00 Wooden runners hide string ends.

2:17 The halves of the angled baffle are secured with screws and a retaining plate. Matamp use zig zag staples.

2:17 Nice big jig for fitting of branding.

2:57 Push fit connectors poor in relation to soldering.

 

Notes.

I have registered a long defunct amplifier brand who have in the past bought re-branded Matamp products in their own livery. It is my intention to relaunch White Sound Equipment to offer a small line of White branded, Matamp built amplifiers with the woodwork handled by myself.

In the event that this is a viable prospect, to circumvent the lack of a table saw I can outsource machining services. If I am able to find a suitable company I could have batches of cabinets CNC machined to spec with non original features such as dovetail joints to improve strength and rebates to help locate panels and beading.

This enables speedy accurate assembly with just glue and a nail gun making my bare bones kitchen table work shop less of an issue.

A willing volunteer must now be found to assist with the CAD files.

Hand Cut Dovetail practice.

This post will serve to document my progress in the above discipline.

Makeshift workbench.

Before I started there was a need to find myself somewhere to work and something to work on. Last winter I  had a stove fitted in my house. This arrived in a ply shipping crate which I could never be bothered to dismantle, remove the fixings and burn. Up until the weekend this served variously as a wood store a dumping ground and due to its location in front of a window it’s most recent duty saw it acting as a nursery for seedlings before they were planted outside. Time for it to become a workbench!

Easy as pie! A bit of mdf secured with brad nails and a cheap Aldi vise clamped to the “bench”. I used some rosewood offcuts from a guitar build to protect the work piece from the clamps.

It’s a proper dog but it doesn’t move about too much if you keep your feet on! Has the advantage of being light enough to rotate to get a better angle to work at. It’s far from ideal but will tick all the boxes required from this peripheral piece of work.

 

Introduction.

Prior to this first attempt (my very first) I have spent very little time with hand saws. I made sure to work slowly and for a first go I was extremely happy with the initial fit. Only after completion did I think that this exercise would be a worthwhile addition to my portfolio.  As a result consider this first report incomplete. The details lacking involve the process of marking out the cuts. The next try I will document the process as a separate entry below the this section. Also I will include in this section a brief overview of the tools used.

Attempt 1 15/11/17.

After marking the cut lines (scribed with a knife or a pencil) I started the cut around 1mm into the shaded waste areas using my thumb as a guide for the 8″Draper saw. I cut slowly and carefully to avoid sawing past the baseline. These came out pretty straight.

After a little clean up.

A reminder that Chisels are sharp.

Cutting out the pins.

Not a bad first fit. I got a little overzealous practicing paring and the final fit isn’t as good as the initial one. It was at this point however, that I realised that the wood grain was oriented the wrong way. One to consider on my next go.
Ggggg