AC power help for component box

Okay folks. I'm building a home docking component box or whatever you wanna call it. I've got all the parts, and I need a little help on the power part. As you can see here:

I've got the ethernet and AC plug working great with the sled. Now for hooking the power up. I want to use the power brick inside of the box. So, i went to the electronics store today (Electronics Plus in San Rafael... they have EVERYTHING) and picked up all the parts.

The AC power will come into the back of the box with this connector:

(fuse at bottom is optional)
and here's the back:

and run through this rocker switch:

here's the back:

(spade 1 to the left, 2 to the right)
and end up with this socket:

where i'll plug in the power brick.

SO...
Only having the most basic of knowledge about all this (which should probably answer my question... but alas...) and not wanting to fry myself or anything else... Can anyone tell me what wires to connect where on each connector? If this were DC i think i'd have it... but i've never worked with AC. Or would it be the same hookup?

Help! =]
Thanks all.

Loren,

I went throught the same process when I built mine. The ground in the middle position was a no-brainer. You can also get by without strictly observing polarity of those North American (forget the name) AC plugs...but what I did was to use my multimeter to make sure that the +/- plugs on the AC feed lined up consistenly (i.e.- the power cord feeding the back of the box had one larger blade -- I made sure that it matched up with the larger blade on the DC transformer that it was connecting to. Make sense? If not, give a yell and I will try to make this plainer). For $15 or so, you can get a basic polarity tester at Radio Shack or Home Depot but, assuming your house wiring is OK, it is probably simpler to just make sure that your plugs line up. Plus, I don't think that the DC transformer that comes with the Empeg cares about polarity, so it's probably not a big deal.

[Oh, the green is ground, white is +/hot and black is -/ground]

Clear as mud?

Okay, lets see if i have this right....


that look right??

Okay, lets see if i have this right..

Whoa. Instant graphics! Yes, that looks right. I can't be 100% certain about polarity (black/white) but a) it may not matter to the Empeg DC transformer and b) you can check by following polarity with a multimeter/ohmeter.

Just my neurosis, but I put my switch in the + side of the DC side of the equation -- on the Empeg side of he transformer. I'm happier dealing with Empeg DC +/- for some superstitious reason! Ignore my superstitions as needed!

So you cut the power cable between the transformer and the empeg? Hm. I think i'll try it this way... a big part of the design of this box is not altering any of the hardware to the point where it can't be removed. Like the connectors on the sled for instance... everything just screws right off. No goo anywhere. =].

Alrighty, if i hear a second on this setup ... anyone.... i'll go ahead and hook it up tomorrow night and give it a go.

Thanks Jim!

that looks like it is coming across nicely, how exactly did you rig up that ac and ethernet ?>

As a comment on the above.

You have to bear this in mind: I live in a country that uses 240 volts AC, but AFAIK the basis of 110 Volt AC supplies as per the US is similar, baring the voltage [and AC frequency] of course.

It looks like you have wired this up correctly, but I cannot confirm if the switch is breaking/switching the correct wire.

If you got it wrong, then the brick will still power up/down like it supposed to when you use the switch.
The DC will still have the right polarity as the AC is still AC whether hot/+ and ground (called Neutral over here) are swapped.

The only 'bad' side effect would be if the power brick has a internal thermal cut out to protect against fires due to overheating (most powerr bricks do I believe to get certified), and then an electrical short develops in the power brick due to over heating, then maybe the thermal cut out might not stop the power brick from conducting voltage to places where it shouldn't go.

However thats a big if.

To be 100% certain, get a AC rated double pole switch - i.e. a switch that can switch both hot/+ and Ground leads off or on at once, that way you're covered.
But that means 4 wires to solder (i.e. twice as much soldering of wires to switches than you've done already).
You have to make sure that you connect these wires up correctly otherwise you will cause a short circuit or something worse when you plug it in!
[or the Empeg won't go].

Oh and you ARE going to put lots of insulation tape around all those bare live wires right?

Especially as the Empeg sled is all Metal and we all know how much Metal loves to conduct electricity and any shorts against the empeg sled could send your empeg to MP3 heaven [and any owner touching it at the time along with it too possibly].

I know that 110 Volts is not supposed to be fatal, but try it with wet feet on a damp floor and see if it feels non-fatal to you at the time.
And in any case, the old heater in the bath/spa-pool sure looks fatal in movies at least.

BTW: You could consider doing what I did on my docking station - I installed a 240 volts rated micro-switch into the rear of the sled, which acts like your switch does - except the docking/sliding in to the sled of the Empeg switches the AC to the power brick on automatically, to power down, undock the empeg sled slightly [or remove the empeg altogether].

This feature saves inefficiency in running the power brick when no empeg is attached [doing my bit to reduce CO2 emissions by a tiny fraction].
Of course I insulated the wires going to and from the micro-switch really, really well - that metal chassis is not that far away from the 240 volts!

BTW: I don't have a digital camera [yep, must be just about the only person left on the planet without one], so I can't post any pictures or close ups.

[Oh, the green is ground, white is +/hot and black is -/ground]

ack! green is ground, but the white wire is the neutral, and the black wire is hot. you always want to match these up, and you want to switch the black (hot) wire.

on the socket you're wiring inside, the hot (black) wire should connect to the narrower of the two slots.

see, i have learned a couple of things while rebuilding a 90-year old house.

--dan.

Just my neurosis, but I put my switch in the + side of the DC side of the equation -- on the Empeg side of he transformer.

I like Loren's way better, with the switch on the AC side. That way he can easily remove the power supply and replace it if it goes bad or whatever.

but the white wire is the neutral

Ack! thanks for catching me! I actually knew that (once!), but I think I have boat-DC-black-is-ground on the brain. Of course, for numbskulls like me, they're now making red/yellow 2-conductor cable for DC on boats just so that you don't go confusing it with the hot AC black...I'm getting confused!

I'm going to post a full series of photos on how i did it all once it's done. It's all undoable... except for the holes in the sled of course. =]

AH! Good thing i waited for a second opinion. =]

Okay, i'll solder all this up tonight. I've gotta go pick up some heat shrink tubing on the way home, lest i use electrical tape.

Thanks a ton for the help fellas!

hey thanks a lot, i am interested in doing this too.. looks good.

None of the three different 2-prong Empeg transformers is polarized, so they probably won't care, but it seems like it would be a nice idea to switch the "hot" lead on AC, eh?!?! (Hmmmm, or does it matter? In DC you can switch the ground with the same effect...and you can certainly have both switched in AC. Anybody?)

To number6's microswitch (which I'd seen a long time ago and which certianly seems like a cool idea), I have a question for electrical types: If the transformer is constantly plugged in, but there is no draw on it, how much power does it consume? I had the notion that it would only draw significantly if it was serving a load (the Empeg). If I had a shunt of some sort I guess I could measure that, but I don't.

ummm.... am I looking at that wrong or does he have the ground running off the wrong connector there? the 2 side by side are your AC alternating current the third below is your ground.

nevermind... just saw where it said green was ground! sorry!

> I'm going to post a full series of photos on how i did it all once it's done.

I would very much appreciate it if you would. This is on my list of projects as well.

None of the three different 2-prong Empeg transformers is polarized, so they probably won't care, but it seems like it would be a nice idea to switch the "hot" lead on AC, eh?!?! (Hmmmm, or does it matter? In DC you can switch the ground with the same effect...and you can certainly have both switched in AC. Anybody?)

it's more of a safety issue than anything else. when you're wiring your car amp to your battery, you put the fuse as close as possible to the battery, right? that way, if a short should occur in the system, the fuse will prevent the car from igniting.

the same thing is going on here. if you were to switch the neutral wire instead of the hot, you have the possibility that a short will develop somewhere between the hot wire and ground. of course, you have circuit breakers in your house to prevent fires, but it could still cause a nasty shock.

If the transformer is constantly plugged in, but there is no draw on it, how much power does it consume? I had the notion that it would only draw significantly if it was serving a load (the Empeg). If I had a shunt of some sort I guess I could measure that, but I don't.

it draws the same amount of current whether a load is present or not.

--dan.

Cool, i figured people would want a basic how to, so i've been snapping shots along the way. It's actually very easy, it just takes a little time to plan it all out. I think the hardest part is going to be cutting all the holes in the project box with my dremmel =].

That way he can easily remove the power supply and replace it if it goes bad or whatever.

I can't tell for sure, but with Loren's (much snazzier -- if they're working well he should fab a bunch and sell them!) brackets for ethernet/power, you may be able to remove the power plug. With my La-Z-Boy, approach, it wasn't an option. For one, the hole was a bit tapered, so I had to cut the wire to pass it through. For another. my candidate replacements (two of the Qualcomms) don't have the same plug style, so I'd wind up splicing anyway. And then there's the Shoe Goo! . I'll keep the DC front panel switch so that I can cycle power to the player while docked (an AC switch would also work), but I just may have to think about adding number6's microswitch.

t's more of a safety issue than anything else. when you're wiring your car amp to your battery, you put the fuse as close as possible to the battery, right? that way, if a short should occur in the system, the fuse will prevent the car from igniting.

This puzzlement visited me in part because I've made some minor changes to my new car and it has a number of "switched ground" systems, mostly lights. All other truths about + fusing still apply. First time I'd ever encountered such a thing.

it draws the same amount of current whether a load is present or not.

Look for me next week on America's Most Wanted. I can see about 12-15 of those darned spud transformers (plugged in) from where I sit -- many of them serving stuff that is switched off!

I've gotta go pick up some heat shrink tubing on the way home

(Side rant...) I try not to beat up on Radio Shack. They fill a useful place, IMO, in our society. BUT, out of sheer laziness, I made the mistake (for the 2nd and last time in my life) of buying a little package of heat-shrink at RS. Bad, bad, bad. It went in the trash and I went and got some of the real thing.

Damnit! I went and got some at Rat Shack because i happened to be near one at the mall during lunch...i saw it for $1.99 and figured why not. So what's wrong with it?

I've only ever bought the ratshack shrink tubing because I have no other easy way of getting shrink tubing. It's always worked for me. Ignorance is bliss, I don't know what I'm missing I suppose.

For instance, I used to work at a jewelry store, and they used a special kind of solder flux that was amazingly good. I got used to using it, and really liked it. Then I stopped working at the jewelry store and had to go back to the Radio Shack brown-sticky-paste stuff. Yuck! I've gotten used to using the paste again, and I can now use it as effectively as I could use the jeweler's stuff, but I still dream of the old days.

So I can understand how it's possible to find something that's better quality than rat shack. But if one has no choice, one goes to rat shack.

Dang, I should have thought to mention it sooner. Oh, well, just $2.00!

What I've experienced: Their adhesive stinks for one (if there even is any!) and, the black at least, doesn't shrink very evenly. The end of the tubing tends to curl *up* away from the wire/whatever you are trying to cover, making it look ratty and defeating the purpose. I tried some from Home Depot once and it wasn't much better. My conclusion? Avoid the heat-shrink products that are the glossy kind. Find the stuff that has a duller surface, maybe from a local electronics house. It *will* be more expensive. I've gotten used to using over-priced "marine-grade" heat shrink like Ancor with lots more glue, but even adjusting for that I think the RS tubing stinks.

Wow, you can get shrink tubing that doesn't curl on the ends? And there's a such thing as adhesive shrink tubing?

(Actually, I knew this, my point is that I usually manage to make do with what I've got on hand...)

So I can understand how it's possible to find something that's better quality than rat shack. But if one has no choice, one goes to rat shack.

There are lots of sources, but it's true that places like Graybar aren't usually around the corner the way Radio Shack is. There are lots of outlets on-line like Jensen Tools , but it's nice to get a look at the stuff. Marine supply outlets carry it but pricing varies from OK to ridiculous. Some hobby shops carry some, too.

In Loren's shoes I'd give the Radio Shack stuff a whirl. I think if you have a real heat gun and go gently, you may have a better chance of success. One of my observations is that I think the RS stuff denatures (or something like that!) if overheated and thus the deforming at the ends. I was too lazy to go get my heat gun when I used the RS stuff last and tried gently using a flame from wooden matches, but no-go.

Anyhow, Loren is going to do what I did, box-wise, but do it right! (so I figured my tubing rant might help)

Whoa, they make heat guns for this stuff? You mean you don't have to use matches?

LoL... i'll be using a blowdryer. =]

and of course, i got the shiny black tubing instead of the multicolored matte stuff. Ah well, i'll give it a shot, and if it absolutely sucks, i'll go pick some incredibly overpriced tubes up at Electronics Plus tomorrow. That is if i don't get impatient and use electrical tape... which is probably what will happen.

Ugh, i need a new soldering iron too. The cheap POS i got from Rat Shack suuuuucks. Anyone have any recommendations for one? I dig the snazzy butane powered instant on ones.

LoL... i'll be using a blowdryer.

A good, pointy "1200W" blowdryer may be hot enough to do the trick.

You're putting the most thought into this that I've seen so far and you'll have that nice CH-2 box (I may not be able to resist redoing mine with one of those!), so I'm betting you'll wind up with the best box yet if you don't watch out.

Resist the (electrical tape) Force, Luke! Granted, this won't be in an exposed environment, but good heat-shrink does a much better job of sealing connections against air/oxygen (and thus oxidation). Electrical tape, especially when warm, has a habit of loosening up. I did use some electrical tape on my AC inlet 'cos I ran out of 1 1/2" heat-shrink...

As if I know anything about electrical!

You guys are a laugh. I feel like I'm watching a voting process on how to install a light bulb.

I'll second Jim's opinion of Radio Shack heat shrink. It stinks. NEVER buy the glssy stuff if you can avoid it. Never buy pre-cut tubing if you can avoid it. I've used 3M brand and a few other similar varieties that are excellent. They're all matte in appearance and are available in every colour you can think of. I buy from local electronic stores (each piece is at least a metre long) and it's cheaper than the cut packaged stuff at Radio Shack.

I've used a hair drier which worked fine - it's busted and gets un-naturally hot. But my favoourite thing to use is a small torch (normally used to light cigars).

But would I bother with heat shrink for this project? Maybe. But maybe not. When working with thick gauge AC wiring, I use Marrettes. The plastic caps (copper on the inside) that you twist onto your wires. Very secure.

Let us know when you've got pictures up somewhere Loren. Even if you're not done with writing up any description.

I'll be making my own enclosure from scratch using satin-finish aluminum (really excited about this because I've nearly finalized the design in my mind ) and I'll be powering the empeg with a power supply from an old drive chassis. I'll use a small adapter to fool it into home mode. I'm also going to throw in a pair of speakers and a small amplifier (courtesy of a set of decent PC speakers - this is cheaper in the end than building my own amplifier, which I also looked into). This way it will double as a component for my large system as well as a portable player - and most importantly, it's going to be my alarm clock. Haven't decided on the dimensions yet, but it will probably be 3" tall, 17-19" wide and 8-10" deep.

Bruno

Guys, shouldn't the green (ground) also be tied to the sled?

You guys are a laugh. I feel like I'm watching a voting process on how to install a light bulb.

Heh. Obsessed Anodized Aluminum Extrusion Man calls Kettle Black!

I've used 3M brand...

I Googled for "3M heat shrink" and lots of places selling on-line -- in the long lengths, too.

But my favoourite thing to use is a small torch (normally used to light cigars).

I used a butane mini-torch for a while. The good thing about a real heat gun like a Weller is that you can surround the work with heat and the tubing contracts evenly. I was using some fairly big diameters and lengths for a while (and the marine stuiff is loaded with glue), so it's possible to get trapped air pockets if the heating is spotty.

But would I bother with heat shrink for this project? Maybe. But maybe not. When working with thick gauge AC wiring, I use Marrettes. The plastic caps (copper on the inside) that you twist onto your wires. Very secure.

For stuff like the boat, it's not negotiable, but I like for car and whatnot because it protects and reinforces things if you are using terminals or lugs. Also, if you want the wire to lay a certain way, you can bend it, heat-shrink it, then hold it till it cools to help hold the shape.

Marrettes? Is that what i'd call wire nuts? Will those hold with stranded wire? Is this something different?

... and I'll be powering the empeg with a power supply from an old drive chassis.

I'll be interested to see that. I felt like using the OE brick with an extension cord stub was pretty cheesy. I went looking for a 12-13V power supply/transformer with terminal connectors, but didn't find any.

Back to fixing the black wire on that light bulb!

Marrettes? Is that what i'd call wire nuts?

http://www.faqs.org/faqs/electrical-wiring/part1/section-23.html

I'd never heard them called that before, either.

Alrighty, i wired it up loosely last night to test it and it worked perfectly. I cut the holes for the AC socket and the rocker switch. Tonight i'll mount the ethernet plug and serial port. The one i'm sorta stuck on are the RCA's. I Think i'm gonna buy some bare female terminals from good ol' rat shack since i believe i saw them in strips of 2x3. I'm gonna do this without shoe goo if it kills me! I've got a tube of it in the closet calling my name... but i've resisted thus far.

Ideally you'd wire connections directly from the docking unit to the RCA terminals on the back of your case. If you don't have an extra harness you don't mind modifying, then the best thing you can do is to use some adapters for the connection.

Since I don't plan on using a tuner module, I think I'm going to end up using some of its pins on the harness. I'll fit them with new wire (a delicate matter) and transplant them into the correct sockets for the audio (that part's easy).

Bruno

I want to straight mount the RCA Line outs to the back of the box, but i can't think of a clean way to mount them, so i figured i could just take some RCA patch cords, cut em in half, plug one end into the RCA outs from the sled, and solder the other to a female terminal on the back of the box.

Why would you want to rewire the harness when you've got RCA's coming out already?

I'd rewire the harness to avoid doing the connections you just mentioned. The less RCA-plug connections, the better. By rewiring, I'd have only one: the external used to connect the final piece of interconnect to the rest of your stereo system.

If we're speaking completely ideal situations, then I'd love to grab an extra harness connector and pins and make my own soldered connections. Then I wouldn't have to touch the current one at all, and I would be left with far fewer wires inside my case.

I'll be using RCA connectors that thread to the chassis as well. I didn't see these at Radio Shack on the weekend, but I know some of the electronics places around here have them.

Bruno

I have to go with Loren on this one. That's the way I'd do it. I'd leave the sled "pristine" and do a patch to a female panel on the back of the box.

If done carefully, you won't lose any audio quality in the patch, and the result is a sled that hasn't been altered and can eventually be re-sold or repurposed for a car installation.

rather than cut up a patch cord for this, i was planning a slightly different approach to the RCA connections. i'm sure you've seen the type of structured cabling wall plates from several vendors (hubbell, belkin, etc) that allow you to snap in small connector modules for cat 5, rca connectors, et al. there are also plates designed to screw into a standard electrical box and fit a "decora" style trim plate.

my plan was to use either the small snap-in modules, or perhaps the larger decora-style plates, mounted on the rear of the cabinet to provide both RCA and ethernet connections. no muss, no fuss, no shoe goo.

--dan.

Yeah... good idea. I went looking for those plates but decided it wasn't worth the trouble tracking them down, and i'm impatient. But that would definitely provide a super clean install. I just went to Rat Shack and picked up an Octal Phono Jack Board as they call it. Basically, it's got 8 female RCA connectors mounted on a black sheet of plastic with holes in the corners for bolting it down, and ready to solder. Cheap and perfect.

cool, that sounds just as good. i pick up those component jacks at home depot -- not exactly the cheapest place to get them, but since i seem to find myself in the store every 2-3 days, it certainly is handy.

--dan.

f done carefully, you won't lose any audio quality in the patch, and the result is a sled that hasn't been altered and can eventually be re-sold or repurposed for a car installation.


That was the main driver for doing mine the way that I did (just RCAs). I had an RCA panel for soldering and then decided it wouldn't look any cleaner. Rewire the harness?? Well, it's pretty delicate and I need to keep my modest soldering skills in mind. When it comes to hums and buzzes, better a few RCAs than a butchered rewiring and solder job.

I think you missed the part where I said that I can extract and reinsert pins from/into the sled connector without difficulty. What I'd like to get are some extra pins so I wouldn't have to use the ones I'm "temporarily" removing. I'm not planning to hack anything up, so everything will be able to go back to pristine stock.

Anyone interested in seeing about a group buy of connectors? I'd feel fine about making my box without using the car dock, but I'd love another connector.

Bruno

I was woundering if anyone knew what psu I could use that would convert AC to DC so that I can use the power from my docking sled without have to make something so that the empeg will slide into the wall plug. I looked around but the only thing I found locally was an AC to DC that had a car lighter slot to plug in dc stuff like that, It was also very expensive.

Thanks
-Greg

Small power supply used in computer or drive cases. A locall store has them for $10 Canadian (you'd still have to provide all the wiring and switch). I'm sure you should be able to find these online. Surplus and electronics stores are also good for this stuff. The added benefit is that you'll have both 12 and 5v output (for using some LEDs, etc..)

Bruno

Thats what I was thinking but the only ones I have around here are too big for my box. I'll look around.
Thanks

-Greg

Alrighty, it's done! I'm putting up the pictures at RioCar.org right now with a tiny write up. I think i'm gonna have to modify the AC plug holder i came up with, as it's not working solidly every time... but otherwise it came out sweet! I'll post a link as soon as the pics are done!