Gain Setting Tutorial

[bikejunkie223 10+ year member]

okay, My situation is a bit weird. My amp has 2 stages of amplification- it can boost the input signal (like a post-line line driver) and then the usual output gain. The front channels are rated at 75w/ x 2 into 4 ohms, and the sub channel is at 250wrms into 2 ohms (single sub- dual 4ohm VC's) Help!

 

[twoloudforyou 10+ year member]

What happened to the link on the first page.

It dont work.

 

[bikejunkie223 10+ year member]

Just go to JL's website and it's still there under support.

 

[HellyHans 10+ year member]

My amp will be bridged on a 2ohm DVC sub wired down to 1ohm load

If I understand, my calculation should be..

1*400 sqrt=20V ?

I use my DMM to set my gain to 20V?

running off an alpine HU with 4v outs

 

[Jacobman 10+ year member]

I have the old school phoenix gold M25 and i dont know how to set the bass or gain. It will be bridged at 2ohms putting out about 140watts i think. This is on my 12" Type-R. There are 2 knobs on the amp, 1 for bass and the other for gain. The gain one says .2-2 for it, where should it be? Also what do i do with my bass knob?

If your sub is clipping can you hear it?

 

[Nukedsodapop 5,000+ posts]

1400w at 1Ohm?

Sorry I dont have a calculator on hand....

And I listen to it on 90/100 most of the time

how is this supposed to determine if It's clipping or not?

-Blake

 

[danteBirosel 5,000+ posts]

setting your DMM to reach 37.4v but make it around 35-36ish volts to be on the safe side.

 

[Nukedsodapop 5,000+ posts]

and the JL Website doesnt work anymore

I see some peoples amps have about 50-50V, Why are their's more than mine?

Lol sorry for the Newb questions

-Blake

 

[danteBirosel 5,000+ posts]

My amp will be bridged on a 2ohm DVC sub wired down to 1ohm loadIf I understand, my calculation should be..

1*400 sqrt=20V ?

I use my DMM to set my gain to 20V?

running off an alpine HU with 4v outs

yes you are correct on your calculations. make sure everything on your H/U is flat line and LOUD is off. use the correct test tones and make sure your amp has bass boost off.

 

[danteBirosel 5,000+ posts]

and the JL Website doesnt work anymore
I see some peoples amps have about 50-50V, Why are their's more than mine?

Lol sorry for the Newb questions

-Blake

It still does work here:

http://mobile.jlaudio.com/products_amps_pages.php?page_id=30

What amps have u seen go 50-50V? i dont get it?

 

[Nukedsodapop 5,000+ posts]

I meant 50-60V

Like some guy in the early pages of this thread had like 56.7 volts

-Blake

 

[danteBirosel 5,000+ posts]

I have the old school phoenix gold M25 and i dont know how to set the bass or gain. It will be bridged at 2ohms putting out about 140watts i think. This is on my 12" Type-R. There are 2 knobs on the amp, 1 for bass and the other for gain. The gain one says .2-2 for it, where should it be? Also what do i do with my bass knob?
If your sub is clipping can you hear it?

First, you should consider buying yourself a Digital Multi Meter (DMM).

Next, follow this tutorial:

http://mobile.jlaudio.com/products_amps_pages.php?page_id=30

Re-read many times before attempting so you can learn.

Now, for your amp, the bass i would suggest to set down to zero. Because setting the gains will do the job. You will learn about the gains on that tutorial.

For the bass knob, i have no clue. Never really messed around with one, nor owned one.

 

[danteBirosel 5,000+ posts]

I meant 50-60V
Like some guy in the early pages of this thread had like 56.7 volts

-Blake

Basically, your just going with the formula that is provided.

Here's the formula you'll need ...

Sqrt(Power*Resistance) = Voltage

(i.e. If you bridge a 4 ohm subwoofer to your amplifier that is rated to produce 100 RMS @ 4 ohms in bridged mode, you would want Sqrt(4*100) = 20 volts)

Square Root ( RMS of SUB * Ohms You will be using) = The Volts you will need to set gains.

Try and remember where u saw that post about "50v" i will check it out.

Love,

Dante

 

[caliece 10+ year member]

hi just wondering will it hurt my amp if i run it 250 watts over rms is that a little too much over, i have a power acoustik ov2-1600 and 760 watts rms at 2 ohm 1600 watt max power

 

[Lakota 5,000+ posts]

hi just wondering will it hurt my amp if i run it 250 watts over rms is that a little too much over, i have a power acoustik ov2-1600 and 760 watts rms at 2 ohm 1600 watt max power

It will probably cause it to clip. I wouldn't do it.