If you want to DIY a chassis, look on youtube for "metal brake" -- if you're just starting out it makes a lot of sense to make a drawing of the chassis on a sheet of paper (i.e. in one plane) and fold it up to see how the parts go together. Easiest is to make a clam-shell of two pieces which will fit together.
You can also DIY heat sinks with a metal brake.
You can also DIY heat sinks with a metal brake.
I have built several DIY Aluminum Chassis ..... I generally use 1/2in aluminum plate for the sides and 1/16in sheet for the top , bottom, front and back ..... I just drilled the holes and used self tapping screws to secure the top , bottom , front and back to the 1/2in sides which can also double as heatsinks ...
I get the metal shop to cut the sizes that I need and do the drilling and assembly at home ...... The last one I built was 6in tall, 10in deep and 19in wide and cost me about $60 and about an hour for assembly and is stronger and more durable than most any pre-built chassis I have seen ......
Cheers
I get the metal shop to cut the sizes that I need and do the drilling and assembly at home ...... The last one I built was 6in tall, 10in deep and 19in wide and cost me about $60 and about an hour for assembly and is stronger and more durable than most any pre-built chassis I have seen ......
Cheers
Aluminum
20 series is very pure aluminum, it can be bent without crazing and is soft. Not ideal for drilling and tapping if you want it to hold threads though many unscreweings and screwings.
30 and 50 I dunno.
60 series is 6% chromium. Excellent for everything except bending. It will machine like butter, hold threads and can be welded. Great for nearly all aluminum applications.
70 is 15% chromium. Harder than 60 but still machines and everything else beautifully. Cant be bent or welded. I've seen it welded, but I've also heard it depends a lot on luck.
All of them will polish and what not, 20 will just polish in seconds and 70 will take more arm effort.
Cool.
Srinath.
20 series is very pure aluminum, it can be bent without crazing and is soft. Not ideal for drilling and tapping if you want it to hold threads though many unscreweings and screwings.
30 and 50 I dunno.
60 series is 6% chromium. Excellent for everything except bending. It will machine like butter, hold threads and can be welded. Great for nearly all aluminum applications.
70 is 15% chromium. Harder than 60 but still machines and everything else beautifully. Cant be bent or welded. I've seen it welded, but I've also heard it depends a lot on luck.
All of them will polish and what not, 20 will just polish in seconds and 70 will take more arm effort.
Cool.
Srinath.
The face plate of a phase linear 400 is closer to 60 from my touch and feel, most vintage amps like pioneer etc are also 60 if I was to guess.
The abundance of 20 series is a relatively recent phenomenon. 20 also gets the highest prices due to purity. I'd say screw it and use 60. Common, cheaper and really strong. Or 70 if its the same $. In my hood 70 is pricier, 20 even more, 60 is the cheapest.
Cool.
Srinath.
The abundance of 20 series is a relatively recent phenomenon. 20 also gets the highest prices due to purity. I'd say screw it and use 60. Common, cheaper and really strong. Or 70 if its the same $. In my hood 70 is pricier, 20 even more, 60 is the cheapest.
Cool.
Srinath.
Here's what Krohn Hite used to hold their chassis together:
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An externally hosted image should be here but it was not working when we last tested it.
And 3003 -
3003 Aluminum Alloy contains Manganese as its major alloying element. 3003 Aluminum is an alloy with very good corrosion resistance and moderate strength. It is not heat treatable and develops strengthening from cold working only. 3003 Aluminum Alloy has good machinability and welding is readily accomplished by means of conventional welding methods. Commonly used in chemical equipment, ductwork, and in general sheet metal work. 3003 Aluminum is typically used in stampings and the manufacturing of pressure vessels, builder's hardware, garage doors, awning slats, refrigerator panels, gas lines, gasoline tanks, heat exchangers, drawn and spun parts, and storage tanks. All of our 3003 Aluminum Sheet is protected on one side with a protective vinyl film.
And 5052 -
5052 is an aluminium alloy, primarily alloyed with magnesium and chromium. It has good workability, medium static strength, high fatigue strength, good weldability, and very good corrosion resistance, especially in marine atmospheres. It also has the low density and excellent thermal conductivity common to all aluminium alloys. It is commonly used in sheet, plate and tube form.
Typical applications include architecture, general sheet metal work, heat exchangers.
No reason you'd want either of these 2 over 60/70. You're not doing duct work inside your amp are you ? Then no.
Cool.
Srinath.
3003 Aluminum Alloy contains Manganese as its major alloying element. 3003 Aluminum is an alloy with very good corrosion resistance and moderate strength. It is not heat treatable and develops strengthening from cold working only. 3003 Aluminum Alloy has good machinability and welding is readily accomplished by means of conventional welding methods. Commonly used in chemical equipment, ductwork, and in general sheet metal work. 3003 Aluminum is typically used in stampings and the manufacturing of pressure vessels, builder's hardware, garage doors, awning slats, refrigerator panels, gas lines, gasoline tanks, heat exchangers, drawn and spun parts, and storage tanks. All of our 3003 Aluminum Sheet is protected on one side with a protective vinyl film.
And 5052 -
5052 is an aluminium alloy, primarily alloyed with magnesium and chromium. It has good workability, medium static strength, high fatigue strength, good weldability, and very good corrosion resistance, especially in marine atmospheres. It also has the low density and excellent thermal conductivity common to all aluminium alloys. It is commonly used in sheet, plate and tube form.
Typical applications include architecture, general sheet metal work, heat exchangers.
No reason you'd want either of these 2 over 60/70. You're not doing duct work inside your amp are you ? Then no.
Cool.
Srinath.
I don't know, do I? I have lots of tools so I don't know, I'm going to get the aluminum off here probably METAL SUPERMARKETS - Buy Metal Online - Small Quantity Orders for Aluminum, Stainless Steel, Hot Rolled Steel, Cold Rolled Steel for Delivery or Local Pickup so what do I need to attach a bunch of different rectangles together, to make it look nice?
Unless you want your circuit to oscillate, then I'd recommend a box that performs well in rejecting RFI and EMI. I can't find any specific guides on designing a good box, from what I've seen, there is usually a good overlap at each junction of the box.
If you don't want to buy a sheet metal brake, then you can use angle and rivet or screw them together. I buy from these guys:
http://www.speedymetals.com/
One requirement of chassis that shields from RFI and EMI is that all panels must be electrically connected together and grounded. This means that your fancy looking black anodized case is really a piece of crap when it comes to shielding RFI. Anodizing is not electrically conductive! Try it yourself. Set your DMM to "continuity" and put the probes on the anodized surface. You will see that it does not conduct. So, unless there is a separate ground wire bonded to each anodized panel, you'd might as well have no chassis at all. Bare aluminum is fine, as is alodined aluminum. You also can't have substantial holes in the case if you want it to function as a shield. You can use a special screen in larger holes to keep RFI out, but of course it has to be bonded to the chassis and to ground to function.
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Should I make it out of steel? I figured aluminum was better that's what I always see.
It is wonderful when folks without a clue offer advice.
2024T3 is the old aircraft standard for aluminum. Today it is used mostly for keys. It will polish up quite nicely.
3003H14 is crap. It is the cheapest sheet aluminum and is usually sold in rolls. Useful for flashing and decorative uses. The lowest strength on the list.
5052H32 is the standard for sheet metal use. It forms well but does form small cracks on tight bends. it is the material of choice for decent quality sheet metal.
6061T6 is the work horse of aluminum alloys. It welds well is decent at machining, but a bit gummy, so use a lubricant such as Tap-free for aluminum to keep it from sticking to your tool bits and slowing things up.
7075T6 is the stuff they really build airplane parts out of. It is the strongest and most expensive. It with a bit of effort will take a shine and look like chrome.
So use either 5052 or 6061.
Anodizing is a nice way to finish aluminum. If you are bolting the pieces you can use a bit of lye in water to remove the anodizing where you want electrical contact.
There are other finishing processes that leave a conductive surface, but they are not very common these days and a bit expensive.
The easiest way is to use an aluminum top plate and wood sides.
RFI is a problem with bipolar junction transistors, not so much tubes or FETs.
For a 19" panel 1/8" is the minimum thickness for looks 3/16" or 1/4" is better. 1/16 or .062 is fine for small chassis, but for larger ones or to support a heavy transformer go for .080." or there abouts.
Steel is a bad idea. You can actually measure the distortion introduced into an audio signal line when it is routed close to a steel chassis.
ES
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