Dieselpunk Stereophonic Amplifier

Step 4 Make: the Connectors

The special connectors are plumbing compression joints. The joints are sold in packages with two nuts and a joint with threaded ends.

This project requires two sizes because the DC power jack and stereo jack are different diameters. 5/16 inch joint for the DC jack and 1/4 inch for the stereo jack.

Cut the 1/4 inch  joint in half with a hacksaw. With a drill, bore out the joint with a 3/8 inch diameter it. Next, take the headphone jack and grind down the diameter so that it will fit inside the bored joint. Solder the jack into the joint.

Repeat the process for the DC power jack.

Find a location for both connectors on the lid of the box. Centerpunch then drill holes for these new connectors. Solder these connectors onto the lid of the box.

The nuts (connector covers) are attached to the box via a chain and retainers that slip over the threaded brass joints. The chains come with a brass fitting. Hack saw off an end of these fittings. The fitting and nut can then be attached to the chain.

The other end of the chain is attached to a retainer that must be fab'd. They're made from plumbers strapping tape and are teardrop shaped. Cut out the shape and drill out larger hole with a stepped drill bit. Cut the chain to length then attach the chain to the retainer.

Next, to keep the chain retainer from falling off the threaded brass joint, fab a plastic washer. The plastic washer must tightly fit on the threaded brass joint. Find some thin plastic in the recycle bin. Using tin snips, drill then cut out the washers. Alternatively, a rubber O-ring can be used.

While working on the lid, now would be a good time to fab the bass vent. The bass vent is more decorative than functional. It consists of a flange and grill. The flange is a piece of "junk" found at a recycler store. It had a lip that was cut off. This particular flange will be near impossible to find/buy but there are substitutes. The first that comes to mind, is a cast iron plumbing flange. Or one could be fabricated from scrap masonite or sheet plastic.

The placement of the flange is not critical. Mark a spot on the lid and cut out a hole. The bass vent grill is cut out from the perforated sheet aluminum.

After making the bass vent, I thought it would be a good effect to back light it with a red LED. This simulates the glow of a vacuum tube. A daughter board was built from scrap perfboard. A 560 ohm was placed in series with the red LED on the board.