Setting gains

[DylanH]

Is there any way to set the gains on an amp with a DMM. I really dont want to buy an O-scope

[kl0wn]

There are tons of topics on here already on how to set your gain with a DMM. Sadly I never saved any of them. Here is a simple way.

Set all the gains on the H/U on zero, or off. Turn the gain on the amp all the way down. Unhook the sub(s) from the amp, and plug the DMM into the amp. Play a 40-50hz tone, you decide which one, all in that range will work (I personally used a 50hz). Now the formula with an example.

Let's say you want 500 RMS. You will find the square root of 500 which is 22.36. So if you are running the amp at 1 ohm, you will want the DMM to read out 22.36. If you are running at 2 ohm, you will want the amp to read out 44.72 (which is 22.36 x 2). So on and so on.

[DylanH]

There are tons of topics on here already on how to set your gain with a DMM. Sadly I never saved any of them. Here is a simple way.

Set all the gains on the H/U on zero, or off. Turn the gain on the amp all the way down. Unhook the sub(s) from the amp, and plug the DMM into the amp. Play a 40-50hz tone, you decide which one, all in that range will work (I personally used a 50hz). Now the formula with an example.

Let's say you want 500 RMS. You will find the square root of 500 which is 22.36. So if you are running the amp at 1 ohm, you will want the DMM to read out 22.36. If you are running at 2 ohm, you will want the amp to read out 44.72 (which is 22.36 x 2). So on and so on.

SWEET!!! Thank you very very much!!

[alan412]

the way i go about it is first starting with the dmm leads hooked up in the amps + - terminals. i set the dmm to read ac voltage. i than play decaf's -5.6dB @ 45Hz test tone. I make sure to have the headunit volume set to 3/4. also i turn the sub setting all the way up when i set my gains, this way i will never send my subwoofer a clipped signal. all other settings i keep at 0. such as low,mid,high

when trying to figure out the voltage to set the gains at i first start by looking at the amps fuse rating. for example my amps fuse rating is 150. i take 150 x 14.4(voltage) = 2,160. 2,160 x .707(rms value) = 1,527 watts rms. now say i want to run my amp at 1 ohm. i take 1,527 wrms x 1 ohm = 1,527. take the square root of 1,527 and you get 39.07volts. 39.07 is what i would set my gains to.

hope this doesn't confuse you too much.

[Boon]

when trying to figure out the voltage to set the gains at i first start by looking at the amps fuse rating. for example my amps fuse rating is 150. i take 150 x 14.4(voltage) = 2,160. 2,160 x .707(rms value) = 1,527 watts rms. now say i want to run my amp at 1 ohm. i take 1,527 wrms x 1 ohm = 1,527. take the square root of 1,527 and you get 39.07volts. 39.07 is what i would set my gains to.

You forgot to allow for the amp's efficiency loss... probably in the region of 25%...

EDIT: No point doing the RMS conversion either, although you just get lucky enough that it equates to the same as calling the amp 70.7% efficient.

So I call this 'right-ish answer, wrong working'

[tumminellon]

So if i have a audiopipe 3000d bridged at 2ohms , The multimeter should say 109.54... since the square root of 3000 is 54.77...

Is this correct?

[Team_DC-Derrick]

dont forget thats with a -3 or -5 db 50hz tone as well...

[tumminellon]

Is what i asked right?

[Decaf]

the way i go about it is first starting with the dmm leads hooked up in the amps + - terminals. i set the dmm to read ac voltage. i than play decaf's -5.6dB @ 45Hz test tone. I make sure to have the headunit volume set to 3/4. also i turn the sub setting all the way up when i set my gains, this way i will never send my subwoofer a clipped signal. all other settings i keep at 0. such as low,mid,high

when trying to figure out the voltage to set the gains at i first start by looking at the amps fuse rating. for example my amps fuse rating is 150. i take 150 x 14.4(voltage) = 2,160. 2,160 x .707(rms value) = 1,527 watts rms. now say i want to run my amp at 1 ohm. i take 1,527 wrms x 1 ohm = 1,527. take the square root of 1,527 and you get 39.07volts. 39.07 is what i would set my gains to.

hope this doesn't confuse you too much.

hrmm i thought i posted the link to -4.6@45hz, hmm well it was suppose to be -4.6, but i just called it -5

i replaced the tone link i thought, because when i first started the music thread it was -5.6

:censored: , lol

and ur voltage is practically never 14.4v, using 13.8v is a bit more realistic

[tumminellon]

butp

Hey decaf can u tell me the proper voltage that the meter should read for a audiopipe 3000d at 2 ohms bridged.