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Re: headphone socket
7/10/2006 4:00 PM
Tom Jackson (837) wrote:
You must have an older amp to not have a headphone jack. What ever the case may be, it would be possible, and safe to add a headphone jack. The problem is, it might be difficult. The wiring for an amp is quite complicated. It would be difficult to add a headphone jack that would defeat the speaker, which is what I'm assuming you're trying to do.
As has been said, your line out jack might be a better solution. Here's some solutions: If you have a 1/4" line out jack, you might want to pop over to an electronics store (Best Buy, Circut City, Radio Shack, are good ones) and pick up a 1/8" to 1/4" adapter. It will only be a couple of bucks, and, depending on your amp, you might be able to turn the speaker volume all the way down, and then adjust the line out volume to power the headphones. If your line out is a 3-prong microphone cable, while you're at the electronics store, you'll need to get a 3-prong to 1/4" (I say 1/4" because they are the most common, if you can find it, get a 1/8") and the 1/4" to 1/8" adapter, and try that. It might stick out 6" from the amp, but if it works, it's a cheap fix.
If you don't have a seperate volume from your line out, this might require some actual wiring. It can be done without actually having to install a speaker defeating headphone jack. What you can do is use the line out jack, and whatever adapters are necessary to hook it to your headphones, and manually bypass the speaker. What you're going to have to do is open up the amp, and find the wire loop that goes from the imput, then probably into the EQ, and then into the amp, and then, if you have one, the effects loop. When you've found this loop (it should be wired in series) you are going to want to find where it goes into the actual speaker, and between the speaker and whatever came before it (amp, EQ, or FX loop) install an A/B switch.
To install the A/B switch, you're going to have to use a wire gauging tool (sometimes included on wire stippers) to figure out what gauge wire your amp uses. Once you do that, you are going to need some extra wire of that guage. You can get this and the switch at Radio Shack, but I'm not sure about other retailers. You can decide if you want to mount the switch (whidh I would recommend, but may require cutting your amp), if you do, you will want to cut the wire in a place that you're not going to have to add more wire to reach you're mounting spot. Without seeing your amp, I can't help you out with this. Once you've got it cut, the A/B switch should come with some kind of wire already soldered to the switch, and you can just use a wire nut (also sold at Radio Shack) to attach the two wires. Then, from one side of the switch, which I'll call side A, you will want to attach the wire to the speaker, which will complete you're origional circut. At this point, you may want to test your wiring, and make sure that your circut is complete before moving on. Make sure that the switch is set to which ever side you put the wire on. After you've tested it, install a length of wire to the other side of the switch, and then you're going to have to splice it to the wire on the other side of the speaker (going back to the imput). You can get a "T" to do this with at Radio Shack (which will soon become your favorite store). So that you're wiring won't overheat and become a fire hazard, you're going to want to put in a resister. You can use a digital multimeter to find out how many ohms the speakers use, and then buy some resisters at...you guessed it, Radio Shack. If you don't have a multimeter, you can probably bring your amp down to Radio Shack, and, depending on how friendly the people working there are, you might talk them into testing the ohms for you, and then help you out with finding the right resisters.
Basically, what you're doing with this wiring is installing the option to short the speaker, or bypass it, so that your line out will work without the speaker, rather than trying to add and completley different jack.
I really hope I haven't made this too complicated, but I tried to make it as simple as I could. If they're any good, the folks at Radio Shack should be more than willing to talk to you and make reccomendations, after actually seeing your amp. If you have a really good repair shop that you know of, they would be able to do this for you, if you can explain what you want, but it might cost you more than the $15 or so you will spend for parts if you do it yourself.
Please remember that when doing any wiring, always unplug whatever you're working on, you do NOT want to be electrocuted.
P.S. Welcome to AB. You'll find a bunch of bass players of all ages here, I first picked up a bass last year at the salty old age of 15.