Amplifier Setting Tutorial

[bigbud747 10+ year member]

I would also like to know why the first post is gone, because I need that info again to set my amp.

 

[Torr 10+ year member]

I would also like to know why the first post is gone, because I need that info again to set my amp.

I don't have a copy of the original post, but the process is rather simple and I have memorized it. Here is how I did it:

1. Multiply the maximums watts you want going to your speakers by the ohms of the speakers. The square root of that result is the voltage you want going to your speakers. So, the formula is: SQRT (watts x ohms).

2. Lower the gain on your amp to the minimum. Play some music and keep cranking the volume up until you start hearing distortion. Turn it back down a little. This is your max volume.

3. With power off, disconnect your speakers from the amp (at the point where it goes from your amp to the speakers, not at the head side). Hook up a multimeter to your amp where you would normally connect the speaker cables for one of the speakers. Set the multimeter to measure AC voltage.

4. Put in a 1khz test tone cd and crank it up to the volume you got from step 2. You shouldn't be hearing anything right now because your speakers are disconnected, but you should be seeing the voltage reading on the multimeter.

5. While watching the multimeter readings, start turning up the gain until you reach the voltage you got from step 1.

6. Lower your stereo volume, turn off the car, disconnect the multimeter and reconnect your speakers.

7. Don't ever go over the max volume from step 2. That's your max volume.

 

[zeuolaxxx 10+ year member]

Hey guys can I used a clamp meter for setting my gains?

I have this one:

 

[aeon 10+ year member]

that should be fine.

 

[keith89 10+ year member]

Hey guys. Great info here. I'm a bit of a noob and have read on other "less technical" audio forums that I should never go past 1 or 2 o clock on the amp gains. I have an alpine 4.100 amp and am setting for 20VAC per channel. I have a Pioneer AVIC-n3 source with volume set to 45 out of 62 for max. The amp has normal voltage set at the 12 o clock position and i do not reach the 20VAC. Since the headunit isn't clipping at 45/62, is it ok to increase the gains until i reach the 20VAC, even if it is close to the max gain setting?

Thanks!

 

[helotaxi 5,000+ posts]

Yes, it's fine.

 

[keith89 10+ year member]

thanks helotaxi!

 

[brady-lamb-ctfb 10+ year member]

So does ne one notice that the guide isnt visible ne more? its like the first page is missin????

 

[IgnoreMe 5,000+ posts]

So does ne one notice that the guide isnt visible ne more? its like the first page is missin????

because i think someone went crazy on Jmac (the guy who made the tutorial) and deleted his posts and thats why the thread is all ****ed up.

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

then click on the amplifer sensitivity "gain" tutorial

 

[keith89 10+ year member]

because i think someone went crazy on Jmac (the guy who made the tutorial) and deleted his posts and thats why the thread is all ****ed up.
http://mobile.jlaudio.com/products_amps_pages.php?page_id=30

then click on the amplifer sensitivity "gain" tutorial

That's weak...I bookmarked this page because it was a good tutorial.

 

[thch 10+ year member]

Hey guys can I used a clamp meter for setting my gains?

The model you show has an AC-Volts option listed, and should function as a DMM in that regard. as such, you can set gains using this setting and the normal probes.

using the clamp function for setting gains is not practical. you would need to have a speaker or test load hooked up. the impedance of the speaker likely won't be exactly 4ohm, or 1ohm, or whatever. the amplifier trys to control the output voltage and provide whatever current is required for that. this is why going from 4ohm to 2ohm provides 2x power, and not the other way around.

the clamp is more often used with the DMM to measure the impedance (magnitude) of the speaker. Also it can be used to better estimate actual power. A few other technicalities prevent it from being perfectly accurate. (no measure of distortion, no measure of phase differences between voltage and current)

 

[ramone]

where is the orig wite up???

 

[beyap 10+ year member]

http://caraudio.com/forum/showpost.php?p=4104530&postcount=623 - orig write up...

where are the -10db and -6db test tones?

 

[SkyLegend 10+ year member]

Theres a quide in this topic?