Amp question.

[Jmw703]

Ok, so first off i have a hifonics brutus brz 1200d.

I was trying to use a DMM to set the gains on my amp. I roughly estimated 800 watts at 2 ohms for desired output so 800x2= 1600 sqrt = 40. So i need 40V on the meter.

I used a 50 hz test tone on a cd and set the HU to 29/35,

In order to get 40v the gain on the amp needs to be maxed basically (.2) I dont think this is right, however the sub seems to be playing fine(i dont think its clipping) and it also seems to crave more power. The Hu is a kenwood ddx318 that supposedly has 4v preouts so max gain seems a little off.

Is there something wrong here?

[Wicks]

You have the DMM and a test tone.

Unplug the RCA's and check the HU output voltage.

EQ settings flat?

Sub output level on HU?

[Jmw703]

EQ settings are flat except for treble but that doesnt affect bass..

How do i check voltage on rca's?

Sub output level on HU is set to 0, it ranges from either -40 or -35 to +10. I assume 0 is full tilt or full gain and anything up from there is basically bass boost. Or is +10 full gain? i can get 40v with the HU on +10 sw output setting and at about 3ish V on the amp which makes way more sense than 0 sw setting and .2 v on the amp, i just dont know if thats how it should be. This is my first sub on a kenwood HU, i switched from alpine. I Just dont want to clip my new sub.

Also im meeting someone locally to look at an AQ1200 amp, im going to try to hook it up and see if theres a difference.

[Wicks]

Disconnect RCA's from amp.

Play test tone on HU at same level you did before.

Use DMM and probe the RCA cable (black probe on shield, red probe on center conductor).

Set DMM at AC volts.

You should see a voltage around what the HU is rated at (2V, 4V, etc...).

That verifies that you're getting full output from the HU.

As you mentioned, you don't want anything clipping.

Investing in a DD-1 would be great insurance for that. Or if you have access to an O-scope.

Yeah, I think you want the full +10 on the sub output although you want to be careful of clipping whenever you're "maxing out" any setting.

Again the DD-1 is a great tool to look for clipping/distortion.

With all those settings, you could easily introduce distortion without knowing it before its too late.

[stipek]

any amp gain setting tutorials i have seen say to set the sub level at max. what model kenwood is it?

[Rebel4055]

Obviously it won't be correct. Your trying a method that has been known not to work. As you can see your running into more issues than just either setting it by ear or getting a scope or similar product.

[lazie420]

your deck may have lower volt outputs at that volume ,you should have the volume on the deck at 3/4 and all eqs set to flat and the sub gain full and the amp settings ,the bass boost off ,crossover turned to 250hz lpf,and unhook the bass knob .if you did this than check for loss in the rca cables they could be bad and not sending a good signal from the head unit

[Guest]

eq flat. Sub level on +15. Kenwoods don't clip til you get into the 30s. My mp238 could be turned up to like 33.

Dmm is a terrible way to test gains