Freesound Forums
A/B switch for 1/8" stereo cable?
Started April 28th, 2009 · 9 replies · Latest reply by mr16ga 14 years, 1 month ago
Does anyone know of an affordable A/B switch for 1/8" stereo audio cables? What I'm trying to do is share my PC's speaker system with my Mac. I used to have a KVM switch with audio support that worked for this purpose, but that was so flaky (unrelated to audio) that I had to replace it and the new one doesn't have audio support. So now I mostly use headphones when working on the Mac and once in awhile I go through the trouble of disconnecting the speaker system from the PC and plugging it into the Mac. Would be great to have an A/B switch, like the old one I have for parallel printer cables, for the audio. I'd make one myself but I'm not really that savvy with that sort of thing...
This is pretty much what I had in mind, although the cost (including shipping) is higher than I was hoping for:
http://electronicsusa.com/mk7.html
Since I simply can't keep things simple, I'm now looking at adding another computer to use as an occasional input, so now this looks more appropriate except for the need for adapters which increases cost (and probably reduces quality, although in this case that's less of a concern than convenience):
http://www.onecall.com/ProductDetails.aspx?id=4083
Not quite ready to buy, in case anybody would like to share alternative ideas. 
The Sony switch device you linked to is designed for milliWatt input-level (line level) signals and
may not be able to handle the higher output-level (speaker level) signals, (which could be several Watts).
Ah, thanks for pointing that out -- I hadn't even looked at that switch until today, and then only briefly. I'm leaning toward the one at the first link, I don't really need that third system to be connected. And it's such a low priority anyway that I may never actually get around to buying one at all. It's just something I've wanted since I changed KVMs, so I figured I'd ask and look around a bit to see what I could find.
The Sony switch also uses phono (RCA) type connecters, not the 1/8th" (3.5mm) stereo you requested.
If all your cables terminate in 1/8 th" plugs, as in the diagram you linked to, then this type of female-female adapter may be useful.
Timbre
The Sony switch also uses phono (RCA) type connecters, not the 1/8th" (3.5mm) stereo you requested.
Yeah, I did at least see that much. :lol: Adding the cost of three RCA-to-1/8" adapters was my first hesitation on that switch, as that could be close to half the price of the switch itself (based solely on a quick search on RadioShack.com).
The more I think about this (the more coffee I drink!), the more I realize the new computer that should arrive next week is going to require a lot more thought and work to integrate it than just whether I can run its audio through my computer sound system. As in, office/desk rearranging, etc. {sigh} Anyway, for my audio needs (er, wants), I'm still thinking that switch at electronicsusa.com is probably going to be the best I can do, even if their order process looks really unprofessional (or at least "unmodern"
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If everything is line-level (i.e. the normal output from a sound card feeding amplified speakers) then you can pretty much just combine them with 1/8" stereo headphone splitters. Just hook it up backward. Plug the splitter into the output of one computer. Plug the line to the speakers into one of its sockets, and a male to male cable from the other socket to the output of the other computer. This will form a very simple mixer. If either sound card has a power amp built in so it can drive non-powered speakers directly, then this will not work well.
Alternately you can use the male to male cable to route the output of one compute to the line input on the other, then its output to the speakers. Use the mixer utility on the downstream computer to balance their levels. This requires that computer to be on to get the sound from the other though.
I too searched for one and found one on my favorite purchasing site
I bought this one:
www.meritline.com/showproduct.aspx?ProductID=40342&SEName=salar-sr1000-multi-function-audio-switch
For less than $6 including shipping. I'm using it to switch output from my computer between the computer speaker and my component stereo system. The switch also includes a volume control and a plug/switch for the microphone. No more crawling under my desk to plug and unplug.
You can make your on with one dpdt toggle switch and a four 1/8 inch female connectors. and a plastic box and some connectors. would be easy is you know how to solder.
do a Google search for a DIY A/B switch. or email me and I will draw up schematic and scan it.
Depending on the quality of switch you buy I would guess it would cost less than $20 bucks to build.
Joe