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Setting gain with line driver

Posted: Sat May 10, 2008 10:50 pm
by kevinberry1
There have been a lot of threads on gain setting in recent months, but I was wondering if a line driver has any affect on the process of setting your amplifier's gain?

I have an Arc 1000.2t that only accepts 2.5v and I'm using an AC3xs with an output up to 9.5 volts. When I used my DMM to set the gain I noticed that I could not reach above 22 volts output when I needed 47. I played around with the output level on the 3xs but couldn't get the voltage I desired.

So then I decided to set my gains by ear using a 60hz tone I downloaded to my Ipod. When listening to the sub I didn't notice any distortion but smelled a burning smell from my new sub (Oz Matrix 15). I hoped that this was just do to being a new sub, but I decided to set the gain very conservatively. So is there a more accurate way to set the gain when using a line driver?

Posted: Sun May 11, 2008 6:54 am
by smoker
the 3xs is a crossover with output level controls so i think the output of the crossover is going to be affected by the amount of input it recieves. its not a true line driver. you probably smelled the burning because test tones are pretty hard on a speaker when compared to music. the gain setting process is the same except you now have a level control for your sub. are you using the high pass output of the crossover as well? if not yo9ur probably just as well off running it straight from the head unit.

Posted: Sun May 11, 2008 5:49 pm
by kevinberry1
Thanks Terry, I didn't know it wasn't a true line driver. I am using the high pass part for my components and I'm kind of stuck using the crossover because it has balanced inputs and I'm using the factory stereo. I soldered on RCA plugs on the front and rear speaker outputs.

I played around last night for about an hour and was able to set the ouput of the x over at a point where I could set the amplifier's output to the right voltage. The sub sounds pretty quiet to me so I probably need to double check.

Funny thing...I opened the case and found that the PFM filter was set to 80hz when the factory setting is 33... so that would explain the lack of low response lol.

Posted: Sun May 11, 2008 7:53 pm
by kevinberry1
delete