Rube Goldberg Stereo II

Thanks to my friend Arturo for finding the right power supply for this project! Arturo measured the voltage and current to make sure it was going to work.

After a preliminary test using my car’s battery for power, I had the presence of mind to test the receiver, speakers, and power supply again before building a plywood box for them. If there’s a problem, find out early while it’s easy to fix.

The CD radio was once in my 2007 Subaru Forester. It works fine but lacks a USB jack, so I replaced it in the car with a Sony. The antenna is from an old Sony TV – good enough for city reception. The Ford speakers I bought from JerryCo. They are oval instead of round, and must have fit perfectly in a Ford truck. Here they require custom-made plywood mounting brackets of a rather odd curved shape. That proved to be the most challenging part of the project.

IMG_0436_356
System test, to make sure everything works before I build the box.
IMG_0438_356
Temporary wiring connections for the system test.
IMG_0440_356
Buzzsaw cuts the plywood to size.
IMG_0441_356
Use a drill press to get the speaker mounting holes straight.
IMG_0442_356
Jigsaw cuts the rough shape of the mounting brackets.
IMG_0443_356
Coarse wheel of a bench grinder does a great job of chewing away plywood.

You wouldn’t think of a bench grinder as a woodworking tool. But man, it does a great job of chewing away plywood! After removing some more plywood I would take the bracket back to the speaker and see whether it fit. Do this repeatedly until it’s just the right shape.

The speakers are mounted with curved brackets on triangular gussets. I isolated the speakers from the plywood so they wouldn’t make it rattle.

IMG_0444_356
Just right.
IMG_6494_356
Placement of speakers and power supply.
IMG_6496_356
Cutting holes in the front panel for the speakers and receiver.

A hole saw and a Craftsman multi-tool got the holes the right size and shape. Start the hole saw on one side, then turn the plywood over and finish cutting the hole from the other side. Multi-tool makes the receiver hole even.

IMG_6497_356
The receiver sleeve fits.
IMG_6500_356
Use a shelf bracket to support the back side of the receiver.
IMG_6501_356
Two bolted pieces of plywood hold the antenna.
IMG_6502_356
Antenna extension cord has a Motorola plug.
IMG_6503_356
Five sides of the box drilled and primed.
IMG_6504_356
Protective grids on the inside of the the speaker and ventilation holes.

Metal grid material having ½" holes was cut to shape leaving little metal rods at the ends. Bend the rods down, lay the grid over the hole, and lightly tap the edges with a hammer to mark the holes. Enlarge the holes with a thin punch, then tap the grid down into place with a hammer. I also put a drop of Gorilla Glue in each little hole.

IMG_6508_356
Pony Clamp to glue the plywood pieces together.
IMG_6512_356
Receiver in place, half the box done.
IMG_6514_356
Wiring connections soldered.
IMG_6516_356
System test repeated before final assembly.
IMG_6518_356
Big Blue is finished.
IMG_6520_356
I’ll listen to it out here on the patio.

:) The sound is fine. My Subaru radio and Ford speakers get along tunefully.

I have a theory of car stereo: in your car there will always be road noise. Because of the road noise, you wouldn’t be able to hear the difference between sound that is good enough vs. the best sound that money can buy. So I listen to MP3 on a thumb drive in my car. Meanwhile, on the patio, I can hear car stereo at its best.

Yeah, I know, I could have just bought a table radio. But as a retired engineer, I like to do this kind of stuff. My next project, I’ve assured my wife Jacque, will be to give the patio a thorough cleaning.


 Home Page updated December 2, 2016