Amp voltage output...

[xromarx]

Hey guys, I decided to become a member of the this site to hopefully get some advice. I’ll list my setup first.

Head Unit: Sony XAV-AX100

Subwoofer: MTX Terminator Dual 12” - 2Ohms 400 Watt RMS

Speakers: 4x JBL GX602 60Watt RMS @ 2.3 Ohms each

Amp: Kenwood x801 5 channel 75Watt RMS x 4 @ 2Ohms and 500Watt RMS x 1 @ 2Ohms

6 Gauge Wiring Kit - I read somewhere this is enough for 1600 watts.

Anyways I’m trying to set my gain/input sensitivity based on what I’ve read all over the place using a digital multimeter Square root (Amp RMS/Channel x Ohms of speaker). For midrange I play 1kHz sine and able to adjust the gain accordingly.

I’m having trouble with the sub channel. If I did my calculation right, I should set my gain to 31volts. However when I play a 50Hertz sine at 3/4 of the volume, the max I get is around 22.8volts and that’s with the gain maxed. I can reach the desire voltage by adjusting the bass boost but I know that setting the gain all the way up is bad. it also causes my amp to heat up a lot. I’m afraid of burning out my amp as that is what happened to my last amp which only lasted 3 days. Am i doing something wrong? Please help!!

thank you

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[THATpurpleKUSH 5,000+ posts]

Are you using a 40 or 50hz tone to set the sub amp gain?

What is the subwoofer level on the headunit set at?

Are you measuring AC volts at the speaker terminals on the amp with them disconnected and headunit volume at 75-80% of max?

 

[Boomin_tahoe 5,000+ posts]

Hey guys, I decided to become a member of the this site to hopefully get some advice. I’ll list my setup first.
Head Unit: Sony XAV-AX100

Subwoofer: MTX Terminator Dual 12” - 2Ohms 400 Watt RMS

Speakers: 4x JBL GX602 60Watt RMS @ 2.3 Ohms each

Amp: Kenwood x801 5 channel 75Watt RMS x 4 @ 2Ohms and 500Watt RMS x 1 @ 2Ohms

6 Gauge Wiring Kit - I read somewhere this is enough for 1600 watts.

Anyways I’m trying to set my gain/input sensitivity based on what I’ve read all over the place using a digital multimeter Square root (Amp RMS/Channel x Ohms of speaker). For midrange I play 1kHz sine and able to adjust the gain accordingly.

I’m having trouble with the sub channel. If I did my calculation right, I should set my gain to 31volts. However when I play a 50Hertz sine at 3/4 of the volume, the max I get is around 22.8volts and that’s with the gain maxed. I can reach the desire voltage by adjusting the bass boost but I know that setting the gain all the way up is bad. it also causes my amp to heat up a lot. I’m afraid of burning out my amp as that is what happened to my last amp which only lasted 3 days. Am i doing something wrong? Please help!!

thank you

Where did you see/read that at?! Can tell ya right now....it's not true.

 

[xromarx]

Are you using a 40 or 50hz tone to set the sub amp gain? What is the subwoofer level on the headunit set at?

Are you measuring AC volts at the speaker terminals on the amp with them disconnected and headunit volume at 75-80% of max?

Hi Kush and thanks for your reply. The tone im using is 50Hz. The subwoofer level on the headunit is set at 0. However, when I set it to max on the HU I can most definitely achieve the 31v needed. Yes I am measuring using AC Volts on the terminals with no speakers attached. My max volume is 50 so I set it to about 36-37

 

[xromarx]

Where did you see/read that at?! Can tell ya right now....it's not true.

I forgot the website I found it at but unless this has an effect on achieving desired results then I can definitely change it to a thicker power wire.

 

[Boomin_tahoe 5,000+ posts]

I forgot the website I found it at but unless this has an effect on achieving desired results then I can definitely change it to a thicker power wire.

Absolutely....or that wire will melt.

 

[xromarx]

Absolutely....or that wire will melt.

I know about wires melting due to thin wire and could possibly cause a fire hazard. Howver would this be the sole reason why I’m not able to get 31volts by adjusting the gain? Hypotethically speaking, If I were to change the wire to a thicker wire lets say a 4 or 2 gauge and does not change the outcome. What else would cause it?

 

[Boomin_tahoe 5,000+ posts]

I know about wires melting due to thin wire and could possibly cause a fire hazard. Howver would this be the sole reason why I’m not able to get 31volts by adjusting the gain? Hypotethically speaking, If I were to change the wire to a thicker wire lets say a 4 or 2 gauge and does not change the outcome. What else would cause it?

Could very well be because that thin wire is being "limited" by current flow.

 

[xromarx]

Could very well be because that thin wire is being "limited" by current flow.

Okay, I will upgrade to a thicker wire then. Hopefully it fixes the problem

 

[THATpurpleKUSH 5,000+ posts]

Hi Kush and thanks for your reply. The tone im using is 50Hz. The subwoofer level on the headunit is set at 0. However, when I set it to max on the HU I can most definitely achieve the 31v needed. Yes I am measuring using AC Volts on the terminals with no speakers attached. My max volume is 50 so I set it to about 36-37

There's your problem. The amp isn't getting a strong enough signal. Sub level should be up all the way and then like you said, you will get the 31v you need. And get rid of that 6a and get some 4ga oxygen free copper wire.

 

[Boomin_tahoe 5,000+ posts]

Okay, I will upgrade to a thicker wire then. Hopefully it fixes the problem

Any idea your HU pre out RCA voltage?

 

[THATpurpleKUSH 5,000+ posts]

Any idea your HU pre out RCA voltage?

https://www.crutchfield.com/p_158XAV100/Sony-XAV-AX100.html?tp=78184&awkw=265923137692&awat=pla&awnw=g&awcr=147314861724&awdv=c&awug=9016888&gclid=CjwKCAjwopTYBRAzEiwAnU4kb9mPJfzfY8UHa_0WVnwwAJiETUDrbreNCDNg8LakNXCcvPgpOy3R_RoCjBwQAvD_BwE

2v

 

[Boomin_tahoe 5,000+ posts]

https://www.crutchfield.com/p_158XAV100/Sony-XAV-AX100.html?tp=78184&awkw=265923137692&awat=pla&awnw=g&awcr=147314861724&awdv=c&awug=9016888&gclid=CjwKCAjwopTYBRAzEiwAnU4kb9mPJfzfY8UHa_0WVnwwAJiETUDrbreNCDNg8LakNXCcvPgpOy3R_RoCjBwQAvD_BwE
2v

Oh snap...was afraid of that....he's gonna have to turn the gain up slightly higher then than normal.

 

[THATpurpleKUSH 5,000+ posts]

You can always add a line driver.

I'm using a line driver to run my phone directly to my xtr1500 for spl. It boosts Samsung's crappy .609v to around 4-5v.

 

[Boomin_tahoe 5,000+ posts]

Wouldn't that dirty the signal even more?