Did I Kill My Audio Technica A900 Headphones???
Jul 28, 2008 at 6:30 PM Thread Starter Post #1 of 26

Zorlac

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So I finally gave in to the pressure and decided to do my first headphone recable.

Canare star quad
Canare 3.5mm jack
Cardas quad solder
Techflex

I was up until 1AM working on this damn thing and now I think I am regretting it....because the right speaker works, but not the left. My continuity test shows that the ground, sleeve (right) and tip (left) are all wired correctly, so it has to be where the live and ground connects to the left speaker.

If I have the live and ground backwards, then would the symptoms just be no sound???

I am so afraid that I ruined the speaker solder pads when I desoldered the old wiring, or something.....

Anyone have any further info on the A900s? There are no markings on the solder pads except for a #1 on the right speaker next to the solder pad and a #2 on the left speaker next to a solder pad.

Please help!
 
Jul 28, 2008 at 6:46 PM Post #2 of 26

n_maher

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What do you get when you measure resistance between L and G? If you get 0ohm's than it's shorted and you did something wrong, you should be able to measure the impedance of the driver. Be careful though, I've heard it isn't a great idea to measure drivers like this since it's unknown how much voltage the meter is putting across the driver to find the resistance. So I wouldn't do it for very long, it shouldn't take more than a second or two to get the reading your after.

And if you had L and G switched at the driver it could yield weird results, not sure it'd result in no sound though.
 
Jul 28, 2008 at 7:14 PM Post #3 of 26

Pars

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I would think having L and G reversed would just put L and R out of phase. You would most notice this in lack of bass response I think.

There really should be a sticky warning to peeps regarding recabling headphones and the dangers therein... the voicecoil wires are very small and unsolder easily
eek.gif


The other possible result when doing what Nate told you to do is an open, which would indicate lack of connection between the L and G, possible one of the voice coil leads or an open (burnt up) voice coil.
 
Jul 28, 2008 at 8:25 PM Post #4 of 26

Zorlac

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Would the voice coil poke up through the round metal housing (back of speaker) and attach between the Left and Ground solder pads? There was a bunch of solder there that was covered in some sort of gray stuff and of course I decided to clean that all off. Sounds like I am a dumb ass with no headphones now...argh!
 
Jul 28, 2008 at 9:05 PM Post #6 of 26

Zorlac

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Should I measure on the speaker where the wires connect or on the 3.5mm connector?

I will take a look after work
smily_headphones1.gif


Thanks for your help!
 
Jul 29, 2008 at 1:43 AM Post #9 of 26

Zorlac

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Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif
Post photos, don't worry yet, might be easily fixable.

What are the resistance readings between Left-Ground and Right-Ground and Left-Right (important as well).




Left-Ground = 0

Right-Ground = All over the place

Left-Right = 0
 
Jul 29, 2008 at 3:09 AM Post #12 of 26

Zorlac

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nothing registers at all on my DMM. Just says 0.L

Not sure was L stands for.

Im using a cheap Extech DMM.
 
Jul 29, 2008 at 3:27 AM Post #13 of 26

Pars

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So L-G AND L-R both measure OL? That is open (no connection). Your meter (Extech) isn't bad. You're going to have to connect the voicecoil back to the pads as noted.
 
Jul 29, 2008 at 5:05 AM Post #14 of 26

Zorlac

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So how do I re-connect the voice coil? I am pretty sure it is sealed and I have no clue how to open up the speaker.
 
Jul 29, 2008 at 3:40 PM Post #15 of 26

diredesire

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I think you need to show us a close up picture if we are to help you more. It's really hard to diagnose exactly what happened to your driver without a visual reference. The voice coil is typically connected to the solder pads via a VERY VERY thin wire. If you disconnected (or even worse... broke) this, you're going to have a fun time getting it working again.

(Note: If you haven't taken a macro picture before, it is the "flower" mode on your camera)
 

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