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Genesis 1 Audio Distortion Fix

Started by Talasonic, January 20, 2004, 05:27:59 pm

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Talasonic

January 20, 2004, 05:27:59 pm Last Edit: January 21, 2004, 02:34:03 am by Talasonic
Genesis 1 has no stereo audio output in the DIN plug, so to get stereo, you must use the headphone jack.  

When you use the headphone jack, the higher you turn up the volume, the more distorted the sound becomes.  But, the lower you put the volume, the poorer the signal to noise ratio.  So, I was always stuck with an unhappy medium between crappy sound and crappy s/n ratio.  Not any more!

I opened it up and looked at the traces.  The sound actually comes out of a chip, goes to that volume control pot, and then goes back into that same chip.  From there, it goes through some other circuitry that I haven't bothered to trace, eventually leading to the headphone jack.  

It's REALLY weird, but it appears that when that chip is used to amplify for headphone output, it distorts the sound that is coming out of it in the first place.  So, what I did was this, cut the headphone wires inside, and connect them to the always-on side of the volume control pot.  

What you then have is a fixed volume line-out on the headphone jack, and a distortion control with the volume control pot.  (Of course, before it controlled volume and distortion, but now it only controls distortion.)  BUT, now you can turn it down to zero and still have perfect s/n ratio, and it's ALMOST as good as the CDX or NOMAD.  

If you wanted the volume control to remain functional, you would just cut the trace going back to the chip, and tap into the attenuated side of the volume control instead of the always-on side.  Of course, it won't be amplified for headphones very well if you do that.  Might cause damage, too, from the greater load, I don't know.

NFG

That's very interesting, thanks for the post.

(Pics are good too).