foolswood.co.uk

CPU : Opteron 2423HE (6 core)
Ram : 8Gb ECC
Motherboard : Tyan
PSU : Silverstone Fanless
Soundcard : M-audio Delta 1010lt
Graphics : Passive ATI X300
Storage : 30Gb SSD, 1Tb Samsung Spinpoint f3

I was getting more and more annoyed about the noise of my previous computer. In terms of hardware it is fine, with large projects I have to use higher latencies, but it is about 8 years old. However the thing sounds like a jet engine, and working hard with the fans down heats up fast.

So the idea was born to make a completely silent music production computer. I had wanted for a while to use ramdisks for recording because they are silent and very fast. I also did not want spinning hard disks or fans while recording.

I want to apologise up front for the random photography, I have included most of them that show anything. There are things that I wish now that I had pictures of, but that's hindsight.

To get around the need for fans I decided to use low power components. It also required a different case design as standard cases require fan powered airflow in order to cool properly. I decided that big heatsinks and an oversize chimney shaped case was the way to go. I also decided that in order to get the quantity of ram I wanted I needed to use server components. The case was designed around the components and initially drawn in blender. The materials chosen were aluminium and wood. Aluminium because it was easier to cut and lighter than steel, both sheet (1.5mm) and T-section were used. Wood was chosen because it is easy to work with and to join at right angles, it was a familiar material to us, and we had some.

The curve in the design was put in to reduce the amount of cutting the aluminium that had to be done. As you will see in the subsequent pictures this was built in the garage at my parent's house, which is not wildly high tech. The large cutaways and the open top are to allow passive cooling.

Because of the weight of the heatsinks the motherboard tray had to be quite strong. In this case design the motherboard tray also holds the SSD so it had to be quite large. The tray was made of 2 pieces of sheet aluminium bonded by rivets. The sheet aluminium was cut using a jigsaw. This did result in a fair quantity of shavings and aluminium dust. Also the jigsaw scratched the metal beside the cut point. In order to work around this we took to putting strips of masking tape either side of the cut point. This also caught some of the dust. The bench was covered with newspaper to stop it scratching. The edges of all cuts were sharp after cutting, so they were filed and then sanded to smooth them. The parts were then vacuumed, wiped with a damp cloth and washed in order to remove the dust and shavings.

The CPU heatsinks are screwed into the backplate in this design to minimise strain on the board. Behind the processor there is a triangular cutaway in one of the sheets of aluminium resulting in a 1.5mm recess. In this there are 3 risers, these prop the cpu backplate up from behind. There are also 2 screws that go through the motherboard tray from the opposite side to the board, screwing into the back of the CPU backplate. This combination clamps the backplate to the tray.

The holes for the motherboard risers were located by poking a biro through the board onto a piece of paper. This was used as a template for an mdf prototype, the dots were drilled through with a pillar drill. When the risers were screwed into the prototype, it worked, the board could be attached. The positions weren't perfect, so notes about which ways they needed to be moved were made. The metal one was drilled with these adjustments and the board was tapped with a spare case screw. Amazingly, it worked.

The outer casing is made of 1 piece of sheet aluminum. This was a design decision to reduce the amount of cutting and joining required. I also quite liked how it looked in the model.

The shapes were created in Inkscape as bezier curves, printed and drawn around in permanent marker. The curve is different to that of the model in order to make it easier to cut, since going in at a shallow angle is difficult. After cutting the shapes out, again with a jigsaw, the edges were filed, sanded and cleaned with white spirit (to remove any remaining marker). Then the flat sheet was bent around a work bench by leaning on it. The mounting holes were drilled and top crosspieces were added at the assembly stage.

The base of the case was made of wood, since complex metal joins were not really feasible in the garage. Also there was plenty of offcuts from other projects that we had what was needed already.

The original design had a weaker base to reduce area, but as was pointed out by dad, there wasn't a lot of benifit compared to the risk of having it break. Therefore during building it was revised to be based around a piece of plywood.

The connections to the component holding parts were blocks of pine screwed onto the plywood base. The parts were painted black, screwed together and rubber feet were screwed into the bottom.

The supports for the motherboard tray were made of aluminium T section.