How do I set the gains with a DMM?

[Jer510 10+ year member]

Do you recommend setting the sub amp gains by ear or by DMM? And how do I set the gain with a DMM?

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[n2audio 5,000+ posts]

It's not that hard to set it by ear to some degree of accuracy, but if you have doubts JL's tutorial is pretty easy to follow. The only problem is you have to have a good idea of how much power your amp is TRULY capable of. The qsa1000d, being class a/b, rated at 1000w, but only having 2x30A fuses...I can't tell you what it's actually capable of, but I know it isn't 1000w.

http://mobile.jlaudio.com/support_pages.php?page_id=143

 

[jeepintn 10+ year member]

to set the gain, first figure up how many ac volts it should read out. take your ohm load and multiply it by your rms watts. for example, a 1 ohm load trying to achieve 900 watts would be 1x900 = 900. when u get the answer, get the sq root of it, as in the example, the sq rt of 900 is 30. now tight the leads of your multimeter to your speaker terminals, turn your HU up to about 3/4 volume and run a test tone to it(if its for subs, 50hz and for comps 1000hz). now adjust your gain until it reads as close as possible on your multimeter to the sq rt of your number.

 

[hornedfrog1985 5,000+ posts]

Isn't there a chart somwhere around here that is more conclusive? I know I've seen it.

 

[inkfx 10+ year member]

Yeah there is a chart or you can just use the formula and figure out the voltage quick and easy. As jeepintn was saying, V = Square root of (rms x ohms)

 

[hornedfrog1985 5,000+ posts]

http://i76.photobucket.com/albums/j23/steveo200077/RMSchart.jpg

I dug it up.

 

[hornedfrog1985 5,000+ posts]

I assume it would be better to underestimate your amps TRUE power capability, then overestimate it?

 

[n2audio 5,000+ posts]

I assume it would be better to underestimate your amps TRUE power capability, then overestimate it?

yes

Isn't there a chart somwhere around here that is more conclusive? I know I've seen it.

what is more conclusive than v=sqrt(p*r)?

 

[hornedfrog1985 5,000+ posts]

I don't know what I was thinking that is as exact as it gets.

 

[Unfortunate 10+ year member]

http://i76.photobucket.com/albums/j23/steveo200077/RMSchart.jpg
I dug it up.

props.

makes things very simple

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