[DIY]Stereo I/O AB Selector (image heavy)

[creatip123]

So I got a bit of a spare time, and I thought I'd do this project, because it's simple, cheap, and not too much time consuming.

 

For those of you who don't know what an AB selector is, it's a mechanism that lets you choose between 2 input/output (A or B with a very simple gesture, usually a button, or a switch. One example of application is if you got 1 sound output source, and you want to be able to choose where the signal output to, either to a speaker set, or a headphone. Another example is if you're doing an ABX test between 2 sources (usually 2 amps), you'd flick the switch back and forth to control which source is being send to your headphone. Well, enough theory....

 

 

This is all the 'ingridients' you'll need:

 

- small gauge cables. Of course the gauge is up to you, but smaller gauge is easier to work with and don't take up too much space. Get 3 colors, it'd make the work so much easier with color coded cables. I use red, black, and white.

- project box. Nothing special, just a plastic box with screws. You could use just about anything suitable, actually. Maybe a cookie box, altoids cans, or even a soda can. 

- toggle switch

- 3x 3,5mm stereo jacks. You could also use 1/4" ones, if you want. It's the same thing, only larger

- 2x mini stereo to mini stereo, male to male cables

 

 

The project box is just a cheap plastic box with screws. There were some nice looking aluminium project boxes in the store, but I don't have metal drill bits, so I bought the plastic one instead.

 

Like I said above, this project is cheap, here's the rundown:

 

- cables, 1m each colors = 3m = 40 cents. You won't need the whole 1m long, but the minimum sale is 1m each.

- 3x mini stereo jacks = 80 cents

- toggle switch = $1.20

- project box = $1.20

- 2x male to male cables = $1.20

 

Total = $4.80. Yep, under 5 bucks. Needless to say, price may varies.

 

Equipment you'll need:

 

- Standard soldering stuffs (soldering gun, soldering iron, flux, etc)

- Scissor or wire stripper (either one is usable)

- Electric drill. If you don't have one, you could use an Xacto knife (more sweats and time consuming)

- Digital multimeter/DMM (optional, for a bit of testing only)

 

 

For stereo signals, you must get a toggle switch with 9 pins (3 channels per selection). it's a little harder to find, the regular ones are 6 pins. Radioshack should have them. Also there are 2 types of toggle switch. The on-on type, and the on-off-on type. The on-on type is the 'either' type, you must select 1 between 2 sources. The on-off-on type is the 'either-neither' type, you could select 1 between 2 sources, or you could select neither one (off position). Both types can be used. I bought the on-on type.

 

 

The 3,5mm stereo jack. Again, don't get the wrong one. Stereo jacks got 3 poles, like in the picture. Top pole is the ground, bottom poles are the left and right channels. If it only got 2 poles, then it's a mono jack. Actually, you don't have to know which pole is which channel. I'll tell you why later.

 

 

First, measure and mark the spots on the project box, where you'd want the switch and the jacks to be placed. Drill the spots with the correct diameter drill bit. You could also make holes with an Xacto knife, if you don't have access to an electric drill, but it's a lot harder. After the holes are ready, set aside the box for the moment, we'll prep the switch next.

 

 

Measure and cut the cables. This is why we drilled the holes first, so we can place the switch and jacks in their positions, to measure the correct length of the cables. I gave extra lengths on the cables, so later, if I want, I can disassemble it and install it in a bigger box. Strip the ends, and solder them to the poles in the switch. This is why color coding is important, so you'll recognize easily, which cable corresponds to which pole between the jacks. Like in the picture above, top row is all red, middle row is all black, and bottom row is all white. The columns are the selections. The middle one is the selection that doesn't change (the input or output that doesn't change). Left and right columns correspond to changing selections (input or output that you'd select). Sorry if it's confusing, it'll become clearer below.

 

 

Install all the jacks and the switch to the box via the holes. Bolt them tight to the box. In the picture above, the top jack is the static I/O one, while the left and right jacks are the I/O selection you'd select later via the toggle switch. In the case:

 

- 1 audio source, I wanna select between either the headphone or the speaker (1 input, 2 outputs). Plug the audio source to the top jack, the headphone and speaker to the left and right jacks (either one)

- 2 audio source, 1 audio output (2 inputs, 1 output), I wanna quick select which source I'm gonna listen to (for example, 2 amps). Plug my headphone to the top jack, and the 2 amps to the left and right jacks

 

 

Solder the cables to the poles on the jacks. My switch is a little strange. When I flick it to the left, it will select the right poles, and vice versa. I found out about this with the DMM. That's why in the wiring, I invert the cables. Left column to the right jack, and right column to the left jack.

 

Also, I said above that you don't have test each poles of the jacks to know which one is the left and which one is the right channel. As long as you use colored cables, just solder the same colors to the same poles of the jacks. In the picture above, the blacks to the middle poles, reds to the right poles, and whites to the left poles. The right jack's cabling in the picture was inverted (which I found out after I took the picture). The red cable should have been soldered to the right pole, and the white to the left pole. It's easily fixed later though. Test it first, before closing the box.

 

 

If it works as expected, then close it and install the screws to the box. This is the finished project.

 

 

 

The top plug is my headphone's plug, the left and right cables would run to 2 different sources (2 inputs, 1 output), for example, 2 different amps, for ABX testing. 

 

 

Application example: comparing 2 different amps, the built-in amp of the T1 (left) and Lepai 2020A+. The lepai got its source signal from T1's line out (the blue transparent cable). Don't follow this setup though. I can use the Lepai because the headphone is planar. With dynamic driver headphones, there's a chance your headphone will fry on the spot....

 

Total time I took, as an amateur in electronic projects: ~1,5 hours. Of course it will take less time if you're already good at electronic projects. 

 

Hope this is helpful...

[BoredErica]

 

 

This is all the 'ingridients' you'll need:

 

- small gauge cables. Of course the gauge is up to you, but smaller gauge is easier to work with and don't take up too much space. Get 3 colors, it'd make the work so much easier with color coded cables. I use red, black, and white.

- project box. Nothing special, just a plastic box with screws. You could use just about anything suitable, actually. Maybe a cookie box, altoids cans, or even a soda can. 

- toggle switch

- 3x 3,5mm stereo jacks. You could also use 1/4" ones, if you want. It's the same thing, only larger

- 2x mini stereo to mini stereo, male to male cables

 

 

Can't find those at my local supermarket.

Instructions not clear, dick caught inside a Sata port.

The last time I soldered anything, I melted my house.

 

:wub:  :wub:  :wub:

 

Although, what advantage does this have to a $30 a/b switch from Sescom?

[creatip123]

 

Although, what advantage does this have to a $30 a/b switch from Sescom?

 

The ability to rub 'my switch is 1/6 the price of your switch, and does the same job' in yo face.....

 

Actually, it's just the satisfaction of DIY-ing something that actually works....

[BoredErica]

The ability to rub 'my switch is 1/6 the price of your switch, and does the same job' in yo face.....

 

Actually, it's just the satisfaction of DIY-ing something that actually works....

Sounds delicious.  :wub:

 

I don't haz equipment though. 

[DigitalHermit]

Just what I needed!

 

Thanks a lot!

 

I'm finding unplugging my Component system and plugging in my headphones (and vice versa) to be very tedious and I think it wears down the socket and plugs...

 

I'll try my hand making this next month...

[Lutkeveld]

Very nice post and high quality photo's Creatip! Props to you!

 

You can use a 6 pole switch tho, just use a common ground.

[pas008]

nice diy guide

 

made one similar with 1/4 though, with switch and hp in front, other 2 in rear, and had tech key business card with windows volume programmed on top, until I did my external pcie sound card project

[creatip123]

Just what I needed!

 

Thanks a lot!

 

I'm finding unplugging my Component system and plugging in my headphones (and vice versa) to be very tedious and I think it wears down the socket and plugs...

 

I'll try my hand making this next month...

 

Yeah, it's not that hard to do. Only need a bit of basic soldering skill...

 

 

Very nice post and high quality photo's Creatip! Props to you!

 

You can use a 6 pole switch tho, just use a common ground.

 

Tie the ground wires together, right? Yeah I thought of that earlier, but then I remember I tested the Lepai when I was doing a review of it. Turned out the ground (black) is not zero volt. Tested with a DMM, 1 wire inside the black speaker jack, the other wire was held in my hand. I got some readings. That's why I insist on using a 9 pole, to stay objective. By just tying all the grounds together, the other amp could be affected also.

 

 

nice diy guide

 

made one similar with 1/4 though, with switch and hp in front, other 2 in rear, and had tech key business card with windows volume programmed on top, until I did my external pcie sound card project

 

Nice...

[TheKDub]

(Sorry about the necropost, but I am curious of something on this project)

 

How would one go about switching this so it is one input and two outputs? would it just have the same layout and just change what is plugged in where?

[creatip123]

(Sorry about the necropost, but I am curious of something on this project)

 

How would one go about switching this so it is one input and two outputs? would it just have the same layout and just change what is plugged in where?

 

Assuming you're not talking about splitting the signal, it's the exact same principle

 

 

Plug the input (i.e. PC audio out) on top jack, and for example, the bottom left goes to headphone, right goes to speaker. It's the same.

[TheKDub]

Assuming you're not talking about splitting the signal, it's the exact same principle

 

 

 

Plug the input (i.e. PC audio out) on top jack, and for example, the bottom left goes to headphone, right goes to speaker. It's the same.

 

Alright, thanks!

[SSL]

Radioshack should have them.

 

That's not necessarily going to make them easier to get.

 

[creatip123]

That's not necessarily going to make them easier to get.

 

 

That's the only electronic shop selling DIY stuffs in the states that I know of, from many mentions in the net. Remember, I'm not in the states and never been to the states, so I don't really know where's where. 

[SSL]

That's the only electronic shop selling DIY stuffs in the states that I know of, from many mentions in the net. Remember, I'm not in the states and never been to the states, so I don't really know where's where. 

 

They're pretty much bankrupt at this point and likey to go byebye.

[KaminKevCrew]

That's the only electronic shop selling DIY stuffs in the states that I know of, from many mentions in the net. Remember, I'm not in the states and never been to the states, so I don't really know where's where. 

For anyone else reading this thread, and wondering where to get gear in the states, the easiest place at this point would probably be a fry's electronics. If you don't have one near you/don't know of another electronics shop, the internet is your friend. Amazon should have everything you could need, for a pretty reasonable price.

 

/edit: If any mods are listing, I think that this would be a great thread to pin on the audio section, because I feel like a lot of people (Including myself, several years ago) would ask about a project like this, and having it pinned would make it much easier to find.

[Dingus]

I'm glad I found this before my local Radio Shack closes its doors.  This is exactly what I need so my wife can switch over to speakers and I can use my new headphones (once they come).

[TheKDub]

Quick question, I am planning on building two of these this weekend, and got slightly different parts, my audio jacks have 3 poles total, and my switch has 6 poles total, would I still be able to build this and have it work correctly? or do I have to get a switch with 9 poles?

[ShearMe]

Quick question, I am planning on building two of these this weekend, and got slightly different parts, my audio jacks have 3 poles total, and my switch has 6 poles total, would I still be able to build this and have it work correctly? or do I have to get a switch with 9 poles?

 

No, you need 9 poles, one group of three for each channel and another for ground. 

 

If you bought a big bag of them, you could use two switches per unit...

[TheKDub]

No, you need 9 poles, one group of three for each channel and another for ground. 

 

If you bought a big bag of them, you could use two switches per unit...

ugh... What if I just tied all the grounds together?

[ShearMe]

ugh... What if I just tied all the grounds together?

 

Only if the connected devices will be off when not in use, but even then you might introduce a ground loop. Probably wont break anything by trying.

[TheKDub]

Only if the connected devices will be off when not in use, but even then you might introduce a ground loop. Probably wont break anything by trying.

 

Alright, that's pretty frustrating because I just spent $10 at radioshack for two on-on switches that have 6 poles because that's all they had...

 

I wonder if they would let me return them so I can just order some 9 pole switches online.

[ShearMe]

Alright, that's pretty frustrating because I just spent $10 at radioshack for two on-on switches that have 6 poles because that's all they had...

 

I wonder if they would let me return them so I can just order some 9 pole switches online.

 

:-/

 

Even the Fry's by me have been liquidating their stock.

[TheKDub]

:-/

 

Even the Fry's by me have been liquidating their stock.

 

Well radioshack is going bankrupt so I doubt they will be restocking much..

 

I wonder if microcenter would have little switches like that, if not, ebay/amazon here I come! lol

[creatip123]

Quick question, I am planning on building two of these this weekend, and got slightly different parts, my audio jacks have 3 poles total, and my switch has 6 poles total, would I still be able to build this and have it work correctly? or do I have to get a switch with 9 poles?

 

Well, if all of the devices that use AC main power line is properly grounded, and plugged into the same power line branch, you might be able to get away with common ground.

 

Otherwise, you could try wiring them in a 'balanced' connection. 1 switch = 1 channel. So to switch properly, you gotta flick the 2 switches at once.

[Lutkeveld]

Ive used common ground in a setup like this and it worked just fine