Lexan Chassis for Aleph 2

BrianGT

diyAudio Moderator Emeritus
2002-01-21 2:42 pm
near Atlanta, GA
www.chipamp.com
I fear that the Lexan would detract from the cooling of your amplifier. I was considering using carbon fiber for the top and sides of my amplifier, but I realized that I wanted aluminum, since it makes more sense in terms of cooling. I really like the look of carbon fiber, and I might make a front fascia out of carbon fiber.

I would not think that Lexan would conduct away heat as well.

The high end, high power amplifiers that I have seen have been made out of metal, and the entire chassis usually acts for cooling.

Just my perspective on cooling. If you can cool the amplifier, it would be interesting to be able to see into the amplifier, and allow for interesting lighting. You could just make the top lexan also.

--
Brian
[email protected]
 
I kinda like the idea, myself. The heatsinks should be handling the heat dissipation chores; just don't run the amp super-hot to the point that the Lexan softens.
I've seen numerous display amps over the years that have one or more clear panels on them. It's neat to be able to see the parts, circuit board layout, etc.
The only downside that I can see is if you've got a circuit that's prone to RF problems or something of that nature. The plastic casing won't provide any shielding. However, the Alephs--at least here--aren't giving me any trouble along those lines. That could easily change depending on where you live.
Given that it's relatively inexpensive and easy to work, I'd say give it a try. If you do run into shielding problems you won't be out very much money. If it does work, you'll have a pretty cool looking amp.

Grey
 
I've also considered this type of mixed heatsinks/(glass or plastic) chassis for my Zen monoblocs, and made some tries. But they were not very successful, mainly because of the different dilatation coefficients of the materials that lead to some "moving" of the different pieces, particularly when they are tightly bolted together. One solution I can figure but didn't explore is to use fixing holes (in the low dilatation coeff pieces - glass for instance) for the screws that are larger than the screws diameter with a low screwing torque, in order to allow the pieces to slightly move during warm up ...

But in my opinion (notice, Grey, I didn't use IMO ;) ) an all-aluminium chassis extends the dissipation capabilities of the heatsinks, as the whole chassis is involved in this purpose.

Hope this helps.
 
Now, that leads me off in a different direction...given that Lexan (and Plexiglas, wood, etc.) aren't electrically conductive, then there wouldn't be any eddy currents induced by the magnetic field from the transformer. The eddy currents themselves induce their own magnetic fields that could arguably influence the signal.
Hmmm...
Could a plastic/wood enclosure actually sound better than a metal one? Granted, it wouldn't be a as strong mechanically, but most of us aren't going to be shipping our units anywhere; once they're installed in the system, they'll rarely move from that spot.
And I thought I was using wood for the Alephs simply because I've got a wood working shop instead of a metal working shop. Perhaps I was ahead of the curve.
I know Petter is keen on the idea of using brass mounting hardware for transistors instead of steel, since it's non-ferromagnetic. (No, I'm not going to suggest the use of plastic screws to mount devices...) This might be a step futher along those lines.
Yes, plastic can be tapped fairly readily. I did it as part of my fiddling for the water-cooled project. True, I abandoned that approach, but not because of problems with threading the plastic.
Lemme think on this a minute or two. This idea might have more merit than I first supposed.

Grey
 
The idea of using different materials for enclosures came to me after experimenting with the shelves on my rack to support equipment. I used mdf, granite, wood, epoxy based material, glass, lexan.... Each one sounded different with its own flavour. Something like comparing caps.
So I must conclude that the case made from different materials must also influence the sound of the unit. I just not take anything for granted anymore and I'm willing to experiment. I removed the wooden side panels from my CD transport because it sounds better without them
I've also notice that some Japanise equipment makers use a lot of copper screws in their products.
 
Don't rule out wood.... i made my case out of a 10mm plank of pinewood for the top & bottom and "lapacho" (a dark, dense local wood) for the sides, with two internal 20mm supports inside. Everything was glued together and it's STURDY, not to count the weight. Looks cool after a couple of varinsh applications too! :D
 
Not really... humidity can be an issue with cheap woods, but unless you drop it in a bucket of water, i wouldn't be that worried, trust me. The "good looking" woods have usually smal pore and are less subject to humidity also, and that's the kind of woods you want to show up. And don't forget, if you did a good job sanding and laquering/varnishing, the problem is even smaller.

For the record, i was rather concerned about the pinewood bending because of the heat (it has 4 heatsinks bolted to it running at about 50 degrees Celcius). I fired up the (final? :) ) version of my amp today to check some things out, and the wood didn't seem to mind at all.
 
nobody's scared

I've been thinking about wood for my chassis too because its easy to find and easy to work with. But I'm definitely going to stay away from soft woods like and plywood.. If something shorts out they are going to catch on fire much faster.. also watch out with the varnish you put on it. I'm confident in the quality of my work but not so confident as to put easy burning wood on top of it and cover it with flamable stuff

but thats just my opinion :)