X Aleph Project Down Under

[macka]

Hi guys,

I have been low profile of late on diyaudio.com but I have been busy building a chassis for an X Aleph project I am working on with a friend in Aust.

As always the box takes forever to make and I am still working on that. Bought a Makita Mitre saw and in process of building an overhead router table for finishing the alunium sheet stock.

For various reasons we decided to make the box square like the vintage Aleph. The idea was to make it more practical but I must say it was not very practical to make.

The amps will be about 100 watts (8 ohms), most of you know the drill, 16 IRF 240s, about 5.4 amps bias, 25 volt rails, 650 va toroidals that are oversize cores to reduce noise, 22,000uf / 22000uf +0.22R + 22,000uf/22,000uf + 0.22R + 22,000uf/22000uf/2000 50 volt per rail. Thats simulated for 17 millivolts ripple.

Ian

[macka]

Some other images

[macka]

In progress

[macka]

metal work

[macka]

Tools of trade

Router table in progress. After looking at alot of options for cutting and finishing square panels I decided to make a custom router table jig. More details to follow.

[macka]

The way the boxes in quite simple.

I used 32mm 4mm aluminium angle in each corner and tapped two m4 bolts into the Conrad heatsinks. To attached the top and bottom I cut 20 x 12 mm bar stock and drilled and tapped into the blocks at the top and bottom of the L angles. I propose to drill and tap m4 bolts to hold on the Lid and M5 or 6 for the bottom since that is where all the weight is.

Fitting out the inside it going to be interesting and I plan to build up the power supply on the 5mm base plate and assemble a minoi sub chassis to support the filter capacitors and the main driver pcbs. That way I just need to lift the heatsinks onto the base plate and do the final wiring to the driver pcb.

More later.

Ian

[macka]

Always my favourite aspect of any project ..etching the pcbs.

I bought an etching tank at last. Should have done this years ago, has a bubble agitator and a heater...great .

This really makes a difference.

Ian

[jacco vermeulen]

Originally posted by macka
bubble agitator and a heater really makes a difference.

Absolutely.
Please keep the info on your diy router table coming, Mackaroni.

(errr, any chance of posting a drawing and the router type you're using ? )

[macka]

Hi Jacco,

The problem I have with fabrication is buying sheet alumnium from the wholesaler that is chopped to size but not square or has rough edges.

I looked at the table saw but it is messy and I am not happy about the fillings going down into the saw motor.

If this works it will be a smoother finish than a saw cut. At the moment it is easier for me to get the wholesaler Capel Aluminium to sell me 1 square metre and they chop it up for a small fee.

If this table works we may adapt it for an overhead hand saw with an aluminium cutting blade. Mitre saws with a 300-400 mm travel are quite expensive. A good one with accurate movement is over AUD $900

The Router is American Porter Cable router, variable speed and we have bought a special down cut bit for aluminium.

From the the image I posted its hard to explain how it works.

But the space between two bars represents the sled for the router cutter travel. Shown to the left is a guide rail that will track the postion of the router along the rails. There will be spring loaded clamps that will hold the bars flat against the work piece on a wooden table top with some end stops to enable milling a straight edge and a square plate. It will be able to mill a 6mm plate. A spray lubricant with a fine mist ensures the cutter does nto get clogged up.

All this will help take the chore out of fabricatinng a nice enclosure.

[Luke]

nice work Macka. Im also interested in this router table. Would your solution be able to put a bevel on 8mm aluminium plate?