Setting an amp up properly:

ENVYMYZ · Post by **ENVYMYZ** » Thu Aug 31, 2006 6:34 am

Is there any specific way this should be done? Im referring to all the gains and crossover settings and whatnot.

swimmerdude · Post by **swimmerdude** » Thu Aug 31, 2006 6:50 am

Yes there is a specific way it should be done. For the gain, you want to use a DMM(volt meter) to set it. What you are measuring is the AC voltage at the outputs of the amp. The formula for this is ohm load X rms, and take the square root of that. And when you are doing this, you want to use a 45hz +0db test tone and play it at 3/4 volume of the cd player.

Is this for a sub or components?? That will determine which crossover you are setting. For a sub, on the low pass filter, you want to set it around 80hz. For components, on the high pass filter, 80hz is also a good place.

For the Bass Boost.... I don't use it. If you have a properly set amp, Bass Boost is not needed.

ENVYMYZ · Post by **ENVYMYZ** » Thu Aug 31, 2006 6:52 am

swimmerdude wrote:Yes there is a specific way it should be done. For the gain, you want to use a DMM(volt meter) to set it. What you are measuring is the AC voltage at the outputs of the amp. The formula for this is ohm load X rms, and take the square root of that. And when you are doing this, you want to use a 45hz +0db test tone and play it at 3/4 volume of the cd player.
Is this for a sub or components?? That will determine which crossover you are setting. For a sub, on the low pass filter, you want to set it around 80hz. For components, on the high pass filter, 80hz is also a good place.
For the Bass Boost.... I don't use it. If you have a properly set amp, Bass Boost is not needed.

Wow. That's a lot of stuff just to set an amp. What do I connect the voltmeter to?

JL Audio 500/1 powering a JL Audio 10w6ea subwoofer

swimmerdude · Post by **swimmerdude** » Thu Aug 31, 2006 6:56 am

DMM's usually run on batteries and will have two wires with metal leads at the end. You will put them in the output terminals of the amp.

two4fifteen · Post by **two4fifteen** » Thu Aug 31, 2006 7:02 am

if you don't have one or are not comfortable using a dmm, you can set the gain by ear by playing a favorite track you know well at 3/4 volume, starting from the lowest setting and slowing turning the gain up until you hear slight distortion, then back down the gain a bit. Whether set by ear, dmm, or oscilloscope, usually its gunna be pretty close.

ENVYMYZ · Post by **ENVYMYZ** » Thu Aug 31, 2006 7:30 am

two4fifteen wrote:if you don't have one or are not comfortable using a dmm, you can set the gain by ear by playing a favorite track you know well at 3/4 volume, starting from the lowest setting and slowing turning the gain up until you hear slight distortion, then back down the gain a bit. Whether set by ear, dmm, or oscilloscope, usually its gunna be pretty close.

That's what I've always done. Ive never heard of setting this stuff up via voltmeters. It's kind of cool actually

two4fifteen · Post by **two4fifteen** » Thu Aug 31, 2006 7:35 am

the dmm is a great tool to have

ENVYMYZ · Post by **ENVYMYZ** » Thu Aug 31, 2006 8:09 am

two4fifteen wrote:the dmm is a great tool to have

Know where I could pick one up cheap?

two4fifteen · Post by **two4fifteen** » Thu Aug 31, 2006 8:12 am

radioshack

solacedagony · Post by **solacedagony** » Thu Aug 31, 2006 8:22 am

To really set your gains, use an oscilloscope so you can see the sine wave and know when you're clipping it :)