DIY electronics chassis?

[cameronthorne]

I will be building some active crossovers and DIY power amps on a budget...

I know that most people use aluminum project boxes for housing active crossovers and power amplifiers, etc. While I would like to get some nice aluminum enclosures, and probably will some day, is there any compelling reason not to simply use wood for these enclosures instead? What are the safety or grounding concerns :storm: with a cheap/simple DIY wood enclosure vs. a $100 Hammond chassis? I would of course ensure adequate ventilation in either case.

-- Cameron

[JoshK]

Its done quite often. You still should use an earth ground, but tied to a star point instead of the chassis. Then again you can use a plate on top and wood sides and tie the earth to the plate adding some protection for the case. But wood isn't conductive so it in itself is a safety measure.

[Amphiprion]

Lack of EMI/RFI sheilding is one downside. Thermal issues a slight downside. Cheap + beautiful = major upsides.

[cjd]

I've done both. Stay away from BUD cases unless you know *exactly* what it is. Not bad at all, but ugly. To my good/bad fortune, the rather complex pre-amp I built into a BUD case gets that "too hot electronics" smell so I'm not sure what to do with it. The smell goes away after it heats up all the way and it sounds superb. So, probably fix it. It's got a sweet relay attenuator and the ability to switch balanced sources (2 balanced, 2 single-ended inputs). But in the mean time I'm doing one in a cute little 2x6.5x8 Hammond case that's very very nice looking. Will simply be 4 single-ended inputs. And for now a cheap carbon pot.

Both output balanced.

I have some wood cases. Very pretty. But they take a different workshop to make, so ironically are harder for me to make right now.

By the way, you know about Par-Metal right?

C

[Amphiprion]

cjd and I both have the same love for those extruded Hammond chassis Too small for a power amp I would think (maybe you could do a mono chip amp or something) but great for preamps, DAC's, etc. Cooling on them is one thing I haven't figured out, the one I used was for a single board computer enclosure and I just put a 40mm fan on the end panel (NOT audio-quiet).

They come in a variety of sizes and the largest (that cjd mentioned) is only ~$25 and is quite nice, not just for the price either. You can find the whole line here:

http://www.hammondmfg.com/1455ptblb.htm

They are also available black anodized, and with black plastic end panels in lieu of the metal ones (only black plastic though on either the natural or black cases).

Digikey and Newark both carry them I think, with Newark having a larger variety IIRC.

[JoshK]

Other nice sources of prefab cases...

https://www.lmbheeger.com

https://www.lansing-enclosures.com

https://www.diyenclosures.com

https://www.par-metal.com

https://www.sescom.com

www.atiresearch-anodized.com (I've ordered from them before, kinda a pain, but nice chassis)

https://www.protocase.com

http://mywebpages.comcast.net/ampbox/

http://www.contextengineering.com/cont_electronics.html

http://www.hexateq-av.com/standard_enclosures.html (super nice but expensive)


heatsinks:

https://www.conradheatsinks.com

https://www.mmmetals.com

Then there is making plates with wood sides, vintage style, that a lot of us tube builders do.
https://www.surfasonline.com/products/6427.cfm (industrial thick aluminum cake pans)
www.onlinemetals.com (got lots of plates from them)
hammond makes bottom plates for their cheap chassis

Well those are just the ones I could remember easily and doesn't include a host of chinese/taiwanese DIY sites that you can get cases from or wood enclosure cases sites.

[JonMarsh]

Suggest you take a look at Par-Metal.

Par-Metal





Several styles of aluminum chasis, built to order finishes, many sizes available of each style, rather reasonable prices, considering quality (good construction- captive PEM nuts, not sheet metal screws in aluminum products).

[JoshK]

Lack of EMI/RFI sheilding is one downside. Thermal issues a slight downside. Cheap + beautiful = major upsides.

There are a number of easy ways to circumvent these issues, like routing out venting in the cases to allow air flow. I've seen an all wood case that was a thing of beauty and had a nice pattern cut out of it with a router and then rounded over the edges. I've also seen people line their wood cases with copper foil or thin sheets for EMI protection. There are expensive shielding sheets you can use too.

For copper sheets of decent thickness, I have gotten old copper tiles off ebay dirt cheap. These can be polished up nice with some steel wool and some armstrong, then lacquer it to keep the nice finish.

[chasw98]

If you want to save some money right now and put a nicer case on later, go to the flea market and find an old used stereo receiver with the appropriate size face to it. Most times you can dissassemble the receiver, gut it, and take the faceplate off and replace it with a blank rack panel for under $30 total.

Chuck

[cameronthorne]

Wow. Thanks for all the suggestions guys. I was aware of Par-Metal and some of the sites that Josh linked to, but I'll look through the rest. Par-Metal and Hammond seem to be in the same ballpark price-wise. Is Par-Metal really that much better? I almost prefer the looks on the Hammond better.

Looks like my options (including cheap wood for now) are a lot more numerous than I thought. Thanks.

-- Cameron

[---k---]

Other nice sources of prefab cases...

https://www.lmbheeger.com

https://www.lansing-enclosures.com

https://www.diyenclosures.com

https://www.par-metal.com

https://www.sescom.com

www.atiresearch-anodized.com (I've ordered from them before, kinda a pain, but nice chassis)

https://www.protocase.com

http://mywebpages.comcast.net/ampbox/

http://www.contextengineering.com/cont_electronics.html

http://www.hexateq-av.com/standard_enclosures.html (super nice but expensive)


heatsinks:

https://www.conradheatsinks.com

https://www.mmmetals.com

Then there is making plates with wood sides, vintage style, that a lot of us tube builders do.
https://www.surfasonline.com/products/6427.cfm (industrial thick aluminum cake pans)
www.onlinemetals.com (got lots of plates from them)
hammond makes bottom plates for their cheap chassis

Well those are just the ones I could remember easily and doesn't include a host of chinese/taiwanese DIY sites that you can get cases from or wood enclosure cases sites.

Josh,
Thanks

Thomas,
That looks like a good addition to the list of Referance Websites Sticky.

[cameronthorne]

Here is one more that I've seen recommended as well:

http://www.tekoenclosures.com/enclosures/19.htm

And some ideas for screening:

http://www.frontpanelexpress.com/

http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=82859

[cameronthorne]

What do you all use for hole punching the back panels for connectors on these nicer chassis? Those Greenlee punches are spendy! Most step drills and nibblers don't seem to be rated for larger gauge aluminum as is used in some of these links. So what do you use? What about squarish holes for IEC power connectors, etc?

If I wanted to borrow a few Greenlee punches, what sort of places should I look at in the yellow pages for a local metalworking shop that might have that sort of thing on hand?

You guys are so much help! Thanks.

-- Cameron

[JoshK]

I use drill bits in my drill press from here. I sometimes use step drill bits too, but I find them a pain. Aluminum is soft, so even if it is thick, just go slow and you'll be fine. I recommend you get a deburrer to make the holes look nice after.

Since I am into DIY, I don't use IECs. I use powercon connectors from Neutrik. They are really nice to use and you can drill round holes! Reterminating power cords with powercon connectors is a few minute job at most. I also like that they lock into place.

[Amphiprion]

We have DB-9 and DB-15 metal punches here at work. You wouldn't believe what those cost (>$400 each).

Actually you might believe that, I think they are in fact Greenlee brand. Not sure...

For power cord connectors, I holler at one of the system integration guys and have him mill me out a square hole on the milling machine.... I too need a solution so I can do that on my own.

[chasw98]

What do you all use for hole punching the back panels for connectors on these nicer chassis?
-- Cameron

Go to a local machine shop with a mill and see what it would cost to have them cut out to spec. Should not be too much. We have several milling machines here at work and they work real well for any work like that.

[cameronthorne]

Yeah, a few quality hole saws and and a small, used drill press would probably cost less together than just two Greenlee punches. Even the small round ones I have seen are $40ish each. Less work deburring with a punch, but that's just elbow grease. I was thinking about SpeakOn connectors instead of binding posts already, so PowerCon would fit right in.

[JoshK]

I just use one of these for example to debur. Cheap and effective. Hard to make work with steel, but aluminum is soft and easy.

My first drill press was this one. I think I got it on sale for $80. Worked well for a while. It is nicely made and heavy, but still small. The limiting factor was spindle to pole clearance making it limited to how far into a piece you could drill. I then found a big floor standing rigid drill press cheap on craigslist and jumped on it.

I use my drill press a lot! Almost as much as my tablesaw, but then I do a lot of electronic projects.

[cameronthorne]

Par-Metal looks quite reasonable. Do you guys usually install additional panels in the bottom of the chassis to mount PCBs to, or simply use standoffs directly on the bottom panel?

[Amphiprion]

Standoffs direct to the bottom panel for me.

[spasticteapot]

I have some metalworking and jewler's experience, and bodged together a few quickes a while back for the heck of it.

All you really need is some big sheets of sheet copper (20ga or so works nicely), and rivets - the trick is to fold the copper into the shape of the box, and rivet it together.

It's actually much easier than it sounds, and with a little work, you can have some absolutely gorgeous enclosures.

[JoshK]

That is a cool idea. My wife is a former jewelery designer and has a pinchant to sculp with metal. She is always saying that she will buy her tools to start up again if I stop spending on audio and then she'll show me how to make cool looking stuff for my amps.

[spasticteapot]

That is a cool idea. My wife is a former jewelery designer and has a pinchant to sculp with metal. She is always saying that she will buy her tools to start up again if I stop spending on audio and then she'll show me how to make cool looking stuff for my amps.

Sell some stuff, buy her tools. Trust me on this one.


As a side note, I can comment that jewler's files (which are just really tiny files) and a jewler's saw (essentially a tiny coping saw - you can get 'em for $20 at stores that sell Warhammer accessories) can do a very nice job if you're careful. While not as easy as a good milling machine or laser cutter, they also cost a lot less.