Patman's Plate Amp Box Construction Resource Page
The PAB (Plate Amp Box) Construction page.
This is a DIY (Do-It-Yourself) project. I hope to give you insight in the
overall construction process of the PAB (Plate Amp Box) that I built all by myself
over the course of weeks from May 25, 2002 to May 28, 2002.
I'm using the Parts Express 250W plate amp model
that is widely used to power DIY subwoofers for many bass enthusiasts. It's a very versatile
amp that offers many ways to tailor its
power output bass boost rumble filter
if you like to fiddle with amp behavior simply be either changing 2 resistor values (R26 and R27) or in
conjuction with 2 more capacitor positions C14 and C15 where caps are swapped for resistors.
Sometimes Parts Express offers this plate amp for $99 plus shipping (which is what I paid for it),
but it's still a bargain at $135 plus shipping. The model that Parts Express is currently shipping
has the bass boost removed.
Rudy (Viperoni) was nice enough to document one of the possible mods on the amp
a speaker/electronics guru named John K documents a few mods
here. Please remember that
you mod your plate amp at the risk of voiding any and all warranties, so be careful and understand what you
are doing if you decide to mod your plate amp. Currently, I've left the amp in the "No Bass Boost" condition,
but I've modded another similar amp (the MCM counterpart of the 300-794 plate amp) with very little trouble.
Just to recap the design specs for this effort:
- 1 Parts Express 250W Plate Amp
- 1 box (12"x12"x5") made out of MDF with t-nuts for the screws.
- 1 set of banana plug connectors to output the power to the subwoofer.
I was able to use the power tools from my previous Sunosub efforts, as well
as non-power tools:
- Power drill - Black-n-Decker 4.5A corded model ($35)
- Power sander with sanding plates/attachments - Ryobi 5" Orbital model ($35)
- Plunge router - Skil Plunge Router ($65)
- Router bit ($21) - 1/4" upcut spiral twist is what I used upon
recommendation from many members of the DIY HT community.
- Screw drivers (slotted and/or philips head)
- Drill bits ($13) - assorted sizes to make pilot holes and final width holes.
- C-Clamps ($4/each) - 4 of them as a minimum, but 8 of them as a maximum for
clamping down the glued endcaps if you don't have heavy bags of sand.
- 24" Clamps ($14/each) - 2 of them.
- PVC pipe hacksaw ($6)
- Saw horses or work tables ($13/each)
- Terminator crimper tool ($12)
Tool costs: roughly $125 - but I had all of these tools from my previous
construction efforts, so dividing among 3 sunosubs, box sub, center channel speaker,
2 sets of speakers, my tool costs were about $30/subwoofer project (including tax).
As a bare minimum you'll need the following in raw materials:
- 1 sheets of 24"x49" 3/4" thick MDF (Medium Density Fiberboard) from Home
Depot for the side of the enclosure (or scrap MDF - I have a 15"x48" piece that I used)
- 1 Plate amp (Parts Express had a nice sale on the 300-794 amp for $99 plus shipping, usually $125-$135.)
- Sand paper (80, 100, 120, various grit) ($6-$10)
- Speaker wire (used 16 gauge, but 12 or 14 gauge is fine ($0.30/foot), male spade connectors
($1/6 connectors), and small ring connectors ($1/6 connectors).
- Banana plug terminal connectors (2 for $2 at Radio Shack).
- Wood glue ($3)
- Machine screws (8-32, 3" $0.83/6 screws) for the driver, need 8 screws (I go to Lowes for philips heads).
- T-nuts (8-32, 1/4" depth, $0.83/4 t-nuts), need 8 t-nuts (I go to Home Depot because they are cheaper).
Material costs - roughly $125 (these prices listed are estimates from my sieve-like memory)
Panels (quantity and dimensions):
3/4" MDF panels:
- two 12"x12" (front and back panels)
- two 12x3.5" (right and left side panels)
- two 10.5"x3.5" (top and bottom panels)
But it might be a better idea to make the box 13"x13"x5" for everything to fit better:
- two 13"x13" (front and back panels)
- two 13x3.5" (right and left side panels)
- two 11.5"x3.5" (top and bottom panels)
As a bare minimum you'll need the following in personal protection -
wear them while using power tools:
- Safety glasses ($6)
- Ear plugs ($2)
- Mask to cover nose and mouth ($3 - cutting MDF results in lots of sawdust)
Hint: For faster navigation, when you click on your first picture link,
don't close that 2nd window, but resize this window and position it so you
can see both windows concurrently. I've designed it so that you can leave
that 2nd (photo) window open, and you can click to your heart's content in
this first window, and the images will only show up in that 2nd other
window. This should also speed up your visit here. If you want separate
windows, then right click of the photo links and select the "open in new
Day 1: May 25, 2002
I bought the scrap MDF, and took it over to the workshop of
my friend, Jeff, who helps me cut the MDF into the correct panel dimensions
that I drew up on a piece of paper.
- Photo 1 : Here are the cut pieces of MDF and the plate amp.
- Photo 2 : I do a test fit of all the of panels and port to get an idea of how things will fit together.
- Photo 3 : After I mark off a hole for the plate amp to fit into (9"x9.25"), I use my trust router to plow through the front panel and create a nice opening for the plate amp.
- Photo 4 : The plate amp is dropped in the opening for a test fit, and to mark off the screw holes.
- Photo 5 : Using my plunging drill press adapter, I pop in the holes for the screws (8 of them).
- Photo 6 : The machine screws (8-32 1.5") are inserted for a test fit.
- Photo 7 : On the inside of the front panel, I widen the screw holes slightly so that the t-nuts will fit, this means drilling only 1/4" deep.
- Photo 8 : Another test fit of the machine screws being screwed into the t-nuts.
- Photo 9 : Once I'm sure I know where the t-nuts need to go, I apply some glue underneath them, and hammer them into the MDF, hoping the glue will be enough to take hold of the wood. Normally I use plywood squares, but since I don't need a super-tight seal when I screw in the plate amp, I didn't worry about the plywood squares for the t-nuts.
- Photo 10 : The enclosure starts to take shape once I apply some glue on the side panels.
- Photo 11 : I only had 2 24" long clamps, so I had to glue one side at a time to get things to glue up correctly.
- Photo 12 : Then I glue up the other side panels together.
- Photo 13 : But of course, the t-nuts get in the way of the front panel mating with the side panel square, so I use a PVC pipe hacksaw to chip away to make room for the t-nuts, and even on screw that needed some more breathing room through one side panel. This is where if I made the box 13"x13"x5" I would not have to scrap off the edges of the side panels. Live and learn.
- Photo 14 : Finally the front panel fits flush with the side panels. You'll see the banana plug terminal connectors I use to output the power connections to the subwoofer. I mark off the spot where the holes need to be.
- Photo 15 : I then drill in the holes for the banana plug terminal connectors.
- Photo 16 : Since the banana connectors are too short, I have to route out a section of the front panel from the inside so I can use a nut to secure the connectors to the box.
- Photo 17 : Here's a close-up view of the banana connectors in place and the nut that holds it in place for each one of the connectors.
- Photo 18 : I then create an adapter to the banana connectors with some wire and male spade connectors and ring terminal connectors.
- Photo 19 : At the very end of the banana connector is a smaller nut which allows a ring connector to be screwed on to it to make the connection.
- Photo 20 : Finally it's time to glue the front panel to the side panel square.
- Photo 21 : The plate amp comes with female spade connectors for its power leads, and here the spade connectors are mated as the front panel is being glued on to the side panel.
- Photo 22 : I screw in the plate amp, all of the t-nuts and screws fit as planned.
Day 2: May 26, 2002
- Photo 23 : Overnight I test the plate amp, and thank goodness it works. Here's a shot of the innards of the plate amp and the connections/t-nuts. It's quite a tight fit.
- Photo 24 : Happy that the plate amp works, I begin to glue the back panel to the rest of the enclosure.
- Photo 25 : Here's a shot of the enclosure and plate amp all glued up. But that's not the end of the story...
Day 3: May 27, 2002
- Photo 26 : It's now time to sand off any irregularities for the panels and makes everything nice and smooth (and square).
- Photo 27 : This is the backside of the box after my initial sanding efforts show that I need to fill in some small gaps. I do sand off the edges so it's rounded over on every edge of the box.
- Photo 28 : This is the front side of the box, you see the connectors in place.
- Photo 29 : Wood filler is applied on all of the joints where the panels are butted together.
- Photo 30 : More sanding ensues as I fill in the gapes and sand off the excess wood filler. Finally the box is shape to be painted.
- Photo 31 : I first apply a couple coats of primer, and sand it smooth as possible (it's not super smooth, but I'm not too woried since it's just a box for a plate amp, for Pete's sake!)
- Photo 32 : Then I use some leftover black lacquer spray paint, give the box 2 coats as well. It's now drying overnight.
Day 4: May 28, 2002
Not quite done yet with uploading the pix...
- Photo 33 : Then the final coat is a clear coat of lacquer to seal in the color and protect it.
- Photo 34 : With the paint job now dry, I screw in the plate amp, and the project is now complete! Yay!
- Photo 35 : Here's one more view of this small little project that took almost 3 full days (nothing like waiting for glue and paint to dry...)
Comments on the plate amp
Here's some of my comments in regards to how the PAB performs in my Home Theater setup:
The power for the sub does well with both music and HT. I haven't stressed it out yet on the super-bassy
DVDs, but that will be forthcoming soon.
This is what the PAB looks like hidden from sight in my HT setup:
I hope you've enjoyed looking at how I created my plate amp box! I did it because it
was a relatively inexpensive project, around $125 since I made the box out of scrap MDF,
and the paint was from leftover paint from other projects, but I did spend money on the
machine screws, the t-nuts, and the banana plug terminal connectors. I had all of the tools I needed.
So how many have visited this webpage since 5-28-2002?
Back to the Patcave