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Discussion Starter #1
I have a 4ch amp with 4 gain knobs. After level matching by output voltage, I looked at all 4 gain controls and noticed that 1 was turned appx 20* further than the rest, yet all read the same output voltage.

Should I be concerned about this?
 

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Maybe or maybe not.

Am currently working on my line driver/equalizer and notice the same thing but I found out a relay that was in the signal path was either worn out or rusty and one side was stable and the opposite side was moving up and down (on a sinewave) and at some points it would go crazy high like 8v while the other channel was steady at 4.5v.

But aslong as you have a steady&equal output from all four channels on a sinewave you should be good to go. If you notice that one channel in question move up and down from the rest than get it checked out.

There could be something inside thats worn out or worse rusty from humidity and one channel got the worse of it.
 

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Discussion Starter #3
Maybe or maybe not.

Am currently working on my line driver/equalizer and notice the same thing but I found out a relay that was in the signal path was either worn out or rusty and one side was stable and the opposite side was moving up and down (on a sinewave) and at some points it would go crazy high like 8v while the other channel was steady at 4.5v.

But aslong as you have a steady&equal output from all four channels on a sinewave you should be good to go. If you notice that one channel in question move up and down from the rest than get it checked out.

There could be something inside thats worn out or worse rusty from humidity and one channel got the worse of it.
Hmm, its a VERY new amp. Guess Ill have to do another gain match and this time do some more digging..
 

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Did you use a sine wave when trying to match them?
 

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Discussion Starter #5
Did you use a sine wave when trying to match them?
Of course, but Im beginning to think it could be any number of things.

The culprit gain pot was for ch2, I use ch 1 and 2 for my tweets. Lets say one tweeter has slightly higher resistance in its vc, could this be why I needed a higher gain setting to match the voltage? Or maybe theres a bad connection somewhere causing higher resistance in the speaker wire? Is this a possibility?
 

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you should have the speaker wires off the amp when setting your gains so you get a proper voltage reading.
True, thats how JL recommends it to be done- without speakers hooked up and you have to achive a certain voltage for a certain load.
 

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Discussion Starter #8
Well, I'm not doing this to set the gain. I'm only level matching. Simply making sure left and right are even...

Sent from my DROID RAZR using Tapatalk
 

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Well, I'm not doing this to set the gain. I'm only level matching. Simply making sure left and right are even...

Sent from my DROID RAZR using Tapatalk
What fhz did you use? Did you use different sinewaves and notice any difference (if left or right now is louder than the other?)
 

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Discussion Starter #10
Just went out and tried it again, all I can say is Im baffled now...ALL the channels are not matching anymore, granted they are only off by a few tenths of a volt or two. I dont think this should matter too much. I did turn off all audio processing to get equal signal to each channel.

I used 25hz for subs, 100hz for mids and 10khz for tweets (since they are crossed at 8k).

Again, Im not trying to set gain, just match level.

My question now though is how much voltage difference is audible? My best guess is a few tenths isnt...
 

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It has been my experience that the outputs will measure differently based on how warm the amp is when you are checking it. It is my opinion that you will not hear much difference in about .25 Volt, and I think that you will find that even if you set them so they are consistant after 10 minutes of amp idle warmth, you find it probably drifts as much if you check it after being run at moderate volume or as much dead cold.

One thing you might try is switch the wires around between the tweeters and see if the 20* gain position switches with them.
 

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Discussion Starter #12
It has been my experience that the outputs will measure differently based on how warm the amp is when you are checking it. It is my opinion that you will not hear much difference in about .25 Volt, and I think that you will find that even if you set them so they are consistant after 10 minutes of amp idle warmth, you find it probably drifts as much if you check it after being run at moderate volume or as much dead cold.

One thing you might try is switch the wires around between the tweeters and see if the 20* gain position switches with them.
I almost tried switching wires, but first I disconnected both tweets from the amp and read resistance from the trunk, both read 3.2, so I guess wiring is ok.

At this point Im not really worried about it.
 
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