Amp Gain Set Up

[Teacher Denis]

Hello. I am setting up the gain on my Autotek M4000 amp. (used for 2 12'' subs in parallel) I ran a 50 hz tone at 80% volume (Pioneer head unit). The highest voltage reading I could get was 15 volts. That is with the gain tuned all the way up (reading 0.2 Volts on the amp). I should set the gain to 44 AC volts. ( V = the square root of (1000 rms x 2 ohms) ) The subs are disconnected. What am I doing wrong? What could be the problem that I can’t get the volts to 44? Thank you.

Click to read more...

 

[Buck 5,000+ posts]

you need to check what your head unit's pre amp voltage is (rca voltage from the head unit). You may have 2v pre-outs

 

[Buck 5,000+ posts]

turn your radio up fairly high and disconnect the rca's from the amp and play music and read the rca voltage. that'll tell you too

 

[dragon.breath 10+ year member]

Also check the settings on your pioneer. Make sure that the balance and fade settings are correct. The subwoofer volume could be turned down.

 

[Teacher Denis]

you need to check what your head unit's pre amp voltage is (rca voltage from the head unit). You may have 2v pre-outs

My pioneer head unit has a 2 volt output that goes into my clarion 7 band pre-amp EQ that has an 8 volt output (to the sum amp)

 

[Teacher Denis]

Also check the settings on your pioneer. Make sure that the balance and fade settings are correct. The subwoofer volume could be turned down.

My pioneer head unit has a 2 volt output that goes into my clarion 7 band pre-amp EQ that has an 8 volt output (to the sub amp) All EQ settings and headunit settings are at zero.

 

[Teacher Denis]

Also check the settings on your pioneer. Make sure that the balance and fade settings are correct. The subwoofer volume could be turned down.

My pioneer head unit has a 2 volt output that goes into my clarion 7 band pre-amp EQ that has an 8 volt output (to the sub amp) All settings on my headunit and EQ are at zero / flat.

 

[Buck 5,000+ posts]

My pioneer head unit has a 2 volt output that goes into my clarion 7 band pre-amp EQ that has an 8 volt output (to the sub amp) All settings on my headunit and EQ are at zero / flat.

just start reading the voltages on your rca's before they reach the eq and after the eq and see if they're within range. just take a dmm and set it to AC, then put one lead on the center of the rcas that pokes out and put one on the outer edge of the rcas. you'll be measuring ac current coming through the rca,s. iirc the center wire on a rca is + and the outer ring is -

 

[Teacher Denis]

just start reading the voltages on your rca's before they reach the eq and after the eq and see if they're within range. just take a dmm and set it to AC, then put one lead on the center of the rcas that pokes out and put one on the outer edge of the rcas. you'll be measuring ac current coming through the rca,s. iirc the center wire on a rca is + and the outer ring is -

HI Buck. I will check the ac voltage on the rca cables coming out of the Clarion Pre-Amp EQ. They should be 8 volts according to the manual. Even if they are less volts, I think I should be able to get more than 15 volts on the speaker output wires to the subs. My calculations say I aim for 44 volts on the speaker wires. ( volts = square root of (1000 watts rms x 2 ohms)

 

[Buck 5,000+ posts]

HI Buck. I will check the ac voltage on the rca cables coming out of the Clarion Pre-Amp EQ. They should be 8 volts according to the manual. Even if they are less volts, I think I should be able to get more than 15 volts on the speaker output wires to the subs. My calculations say I aim for 44 volts on the speaker wires. ( volts = square root of (1000 watts rms x 2 ohms)

you won't need 8v. your amp has a maximum RCA voltage, so make sure you don't exceed that. i think 4.5, 5v may be max input voltage for rca's on a lot of amps. varies though, haven't messed with amps in a while.

 

[Buck 5,000+ posts]

i mean keep your eq, just don't over-volt your amp