Monthly Archives: June 2012

Blue Hawaii

I’ve been working on making a Blue Hawaii electrostatic amplifier (designed by Kevin Gilmore). I’ve spent a lot of work on the chassis which I built myself. I’ve been having some trouble with premature clipping in the amplifier which I still need to sort out, and also need to figure out why there seems to be bandwidth issues above 10khz. Other than that, the project is well on its way to completion.

Power supply board

To do toner transfers for double sided boards, I hold the papers up to a light and align them, then tape the papers together to form a sandwich, and slide the board in before transferring. I’ve never had it off by more than a quarter of a drill hole. Usually it’s practically dead on.

Amplifier board after populating

Constant current sources as plate loads

All the boards (bottom right is a slow warm-up for the filaments and a delayed B+)

Milling the heatsink for the back of the power supply to fit a mil-connector and IEC input

Heatsink after cleanup and painting

Since paint isn’t the best of a thermal conductor, I took the heatsink back down to aluminum where transistors will mount. Fastest way was to just mill the surface off.

Covers to go over holes for tubes to exit the chassis

The chassis is built by having bars at each corner that faces screw onto. These were milled to be exactly 90* angles on all sides, so just screw it together and it forms a perfect box.

Drilling mounting holes for the base plate. I laid out the parts in cad (something I rarely do) to get drill positions so I could get all this done before getting boards ready to position.

Power output and IEC

The nicest box I’ve ever made. All the aluminum panels were polished to near mirror finish with a slight texture

More to come as I put more work into the project.