I'm running an older Mcintosh 420 off ebay in 3 channel configuration. It's enough for me so I'm going to install just one amp on a partial MDF box in place of the jack here:



I've got about 15 3/4" stanchion to stanchion and 12" wide to work with to accomodate my amp and connectors. So I have 3/4" MDF left over from my speaker baffle project and 1/4 inch MDF left over from the access panel project. Took one Sunday to finish up thru painting.

First step was to cut dimensions and test fit. Two short side panels and a partial top to cover exposed areas similar to a sub box but allow access for wiring and ventilation. Not too fancy. Hope to just paint with textured paint and that will be enough. Not sure yet.

 

MDF is great with glue, so I attach and tack the sides



Then glue and attach the front, tack, adjust side clamps and clamp front. I let this sit 15 minutes since it's MDF and I also tacked it together.

 

Next I'll make a top piece from my remaining 1/4" MDF to help cover the exposure from outside. But leave an open space behind and under the seat for ventilation. This piece needs to go on after I install my amp to the base since there isn't room to assemble the amp into it once I install from the bottom up.

I've cut the length to 15 1/4". There is 15 3/4" space between the stanchions.

 

I take a piece of 3/4" MD scrap that happens not to be the same length as my base board. I'll use this as a pattern to transfer the hole locations to my base board. The length needs to be less than the space, less enough so you can move the board to uncover the holes.

First I square the board off, then take it to the truck and place one edge hard against the outboard stanchion and as far back as I think the box back edge will go, and then mark the 'Y' axis of the inboard hole.



Next I put the other edge hard against the inboard seat stanchion and slide it up just far enough to uncover the inboard hole and mark the "X" axis of the inboard hole.



I then repeat the process similarly for the outboard hole.

 

Then I use a right edge to crosshair the centers of the two thru holes and drill a small diameter hole thru each. Just wide enough to slip a small drill bit thru to transfer the hole accurately to the box bottom.



I then drill thru just enough to leave a mark topside of the box bottom, not thru



After this I take the box out to the truck and verify that I generally have the correct holes transferred.

 

Then I thru drill the box bottom with a drill bit just large enough to pass a small screwdriver or hex key to verify the holes are properly located. If off then I've left a good amount of diameter to drill to correct.



In this case the pattern was spot on.

 

For this install I'm going to pass the long bolt from the bottom up because for me it's simpler to install things properly from the bottom up. This means I have to be accurate in my math to get the top bolt retaining the box bottom properly flush with the top of the box bottom so it doesn't contact the amp bottom.

In the case of my 2005 F150 KR S'crew the bottom bolt that held the jack bolts is 1/2 inch proud past the underside of the truck, then there is 1/4" of metal layers to pass thru, then 1/4" of carpet/felt, then I will have 3/4" of runners for the box, then 3/4" of the box bottom MDF itself, which I will counter sink.

When I go to Home Depot the nearest thing I found to my calculated 2.5" space was a 60mm length.

The holes themselves are 8mm x 1.25 thread and I'll use stainless steel since I'm grounding to one of these.

So I bought 2, 60 mm, 8mm x 1.25 bolts to use.

To install the inboard bolt is easy, but the outboard bolt from underneath contacts the right side box beam on its inboard side. I found I could use a screwdriver and gently 'bend' the thrubolt inward a little enough to get a box end wrench on to install the bolt. Then once it was past the box beam, I bent it back straight from the topside.

 

The 8mm X 1.25 is a thru bolt that I torqued down. I tested it as ground in full up configuration with my system, running windshield wipers and with cruise and there was absolutely no system noise.

So I've no Big Three. I'm not pushing as many amps as some people are though.

For the ground I just trapped the ground thru hole terminal below a washer, then a lock washer and a bolt. You need someone to hold the bolt head underneath while you tighten down the bolts topside.



On top of this I'll place a mechanical lock bolt with it's flat side up to use as an adjustment base to press against for the topmost mechanical locking bolt that will be countersunk.

 

Next I drill the final diameter of the thru bolts thru the MDF base. MDF doesn't hold a thread well, so I ensure my diameter is large enough to just pass the entire diameter of the 8mm x 1.25 bolt.



These bolts can bend a little if your dimensions are off, or your thru hole is not exactly perpendicular to the bottom axis.

Then I countersink the thru holes using a plunge router and adjust the depth iteratively to get a washer and locking nut onto the top of the thru bolt to be just below flush.

I have the box on two 3/4" MDF Runners so as to 'float' the box. It's just easier to match up irregularities this way vs. a flat board, and there is room for it. THere's also 'give' in that there's about 1/4" to 3/8" of carpet/felt that can be compressed to get a tight fit.



I'll post more once I get the amp in and the box painted.

DIYAugs

 

Very nice Augs.

Great way to tidy things up and keep everything hidden, I like

 

Thanks man!

Not too happy with the visible finish, so I'm going to add a shoebox like 'top' to dress it up a bit. I'll post it once finished.

DeWaltAugs

 

Now the box is textured with Rustoleum texture paint. Thought I'd give it a tray to see how it works. Then bolted in, the amp attached and the top kick panel glued on.



Now I'll make a box top to slip over the box bottom. This to hide the connector side and top. I'll leave it short enough not to cover the amp cooling tunnel at the back.

 

and now with the box top slipped over the amp base box

I didn't like the look of the Rusoleum texture paint, so I'll go find some carpet to match the OEM and carpet this over similar to the sub box.

 

Don't you think you should have a fan or something to help cool the amp? You've basically blocked all airflow over the heatsink now.

 

the back of the box actually isn't covered. it covers 3 sides and the top if i am reading the bxo right.