Project Enclosure

[jolic]

I want to make a transparent plastic enclosure for an amplifier I'm building. Will using a plastic rather than metal enclosure make the amp susceptible to noise and interference problems?

 

[audioguru]

Clear plastic does not last long. It scratches easily, turns yellow, gets hard and brittle then breaks.
The heat from the amplifier's circuit will accellerate the destruction.

 

[jolic]

Thanks, I hadn't thought about that.

 

[ericgibbs]

Thanks, I hadn't thought about that.

Look at this:
**broken link removed**

Almost bullet proof, used it for many years for equipment front panels.

Its not cheap.!

Whats your location.?

 

[jolic]

I'm from Indiana.

You're right, its not cheap, but its not incredibly expensive either. It looks like its about what it would be if I were to just buy some sort of enclosure anyway.

I'm looking into aluminum too. I could cut windows into it or something. I've never really done a project like this before, so I really don't have much experience to build on. If there are any other ideas out there, I'm open to suggestions.

 

[stevez]

Just some thoughts:

A. A metallic or plastic frame with a safe choice of glass - glass being somewhat more tolerant of heat. By 'safe' I mean tempered or otherwise resistant to breakage - and if it does break it results in less dangerous fragments.

B. On glass or lexan - are any of the metalized window films such that some sheilding effects are possible while still providing the visibility?

C. As compared to metals, many plastics are thermal insulators - you might need to plan for that.

 

[Menticol]

I don't know if your amp does, but some equipment like PC PSU's have certain points of the PCB attached to the metal chasis via screws. I guess the metal chasis is used as another conductor to complete the path, and for grounding purposes.

By this reason, and for improved mechanical resistance, I suggest you to use a metal box, with a window on the top and the front for example.

It's a lot easier to drill the window and glue the plexiglass piece, instead of making the whole box of plastic (making the cuts, mantaining the exact perpendicular angles while the glue dries, etc).

You have to remember that the box must have some means to open it again, for cleaning and maninteance purposes.

Also note that your friends will not see the bottom and the rear part of the box, no matter what material you choose, so don't spend too much money on that parts

Offtopic: This remembers me when I made the cardboard computer case hahaha

 

[rjvh]

Hi What eric sugested is very good stuf for it If we have out door panels we use boxes from the same matterial different colors then transperant thought

take in mind that the heat transfer properties are not that good so if you talk about a heat generating amplifier make sure that you have the majority of the heat sink outsie of the eclosure and it always works to put some forced cooling in the enclosure

if forced cooling is used remeber that what goes in must come out

I ve see quite a few cases that they put the magic fan on the eclosure for blowing fresh air in the casing but no exit holes in it

the only thing the magic fan whas doing was wasting energy

Robert-Jan

 

[Boncuk]

Hi What eric sugested is very good stuf for it If we have out door panels we use boxes from the same matterial different colors then transperant thought

take in mind that the heat transfer properties are not that good so if you talk about a heat generating amplifier make sure that you have the majority of the heat sink outsie of the eclosure and it always works to put some forced cooling in the enclosure

if forced cooling is used remeber that what goes in must come out

I ve see quite a few cases that they put the magic fan on the eclosure for blowing fresh air in the casing but no exit holes in it

the only thing the magic fan whas doing was wasting energy

Robert-Jan

Not quite. It pressurized the enclosure.

 

[rjvh]

Not quite. It pressurized the enclosure.

Yes you're right in that but if that is the goal you still have holes in the enclosure for heat removal and you install a bigger fan on it to keep a over pressure in the casing.

Robert-Jan

 

[Boncuk]

Yes you're right in that but if that is the goal you still have holes in the enclosure for heat removal and you install a bigger fan on it to keep a over pressure in the casing.

Robert-Jan

Holes have to be avoided under any circumstances. Requiring a bigger fan will result in the same amount of heat (not transferred) and more energy.

 

[rjvh]

Holes have to be avoided under any circumstances.

I am not agreeing with this

If you have a casing with certain hot spots on the PCB than you want to have a airflow that can transport the heat

sometimes that done with spot cooling (can be a heat sink or mechanical fan) see your prossesor in the computer

but in many cases there is a airflow path within the eclosure and also extra fans to get the volume displaced in a sertain time what of course also need an out put in the enclosure

the thing with over pressure is that if the input gives more than the output can handle you create an overpressure and keep dust out side (if the input air is filtered)

This is the same with buildings and pressurised fire emergency ways in buildings

of course the pressurising will take some energy to achieve but there will be defenetly heat transfer

Robert-Jan

 

[bassnut]

Is this for a doof car amp? (a guess, since you want it transparent)

 

[ericgibbs]

My feeling would be, if you want to see the amplifiers innards, why would you want to enclose it within a transparent cover.

You certainly dont want to hear a fan buzzing away in the background

Some of the early valve [tube] amps where used without any covers.


**broken link removed**