Something just isn't right...

[redngreedy 10+ year member]

For starters, I have 2 brand new Fi q 12's (dual 1 ohm voice coils) with the BP option. I'm running a JBL BP 1200.1. Stock electrical, except battery. Running the q's in a sealed box with about 2.5 cubs total. Power and grounds are all 4 gauge. Wire for subs is 12 gauge.

I'm having a problem with the amp clipping. I have set the gains with a DMM, and still come up with horrible clipping. It's worse when I have the sub control on the hu high (which was set with a DMM as well.) It doesn't matter if I set it at 1, or 8, I still encounter clipping. I'm not losing voltage, as I can't get the volume up enough to draw the power. Even if I back the bass down a couple of notches on the hu, it still clips. Even when setting up with a DMM, if I back it off a little, still same thing. Ideas?

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[.... 10+ year member]

I'd check my rca's

 

[Blinkrazy 10+ year member]

wiring?

 

[Blinkrazy 10+ year member]

probably lower impedence than your amp can handle so go to rockford fosgate and check the diagrams for sub wiring, if the amp is bridged, check your series/parallel options.. gl

 

[redngreedy 10+ year member]

Wiring is fine. I think I have an extra set of rca's laying around I may try out.

 

[redngreedy 10+ year member]

Amp is not bridgeable. It uses one channel, and is stable at 1 ohm.

 

[Pl8er 5,000+ posts]

How do you have the speakers wired?

What did you set the amp to using the DMM? Do you keep the HU at a constant or does it clip even when at low volumes?

 

[redngreedy 10+ year member]

How do you have the speakers wired?
What did you set the amp to using the DMM? Do you keep the HU at a constant or does it clip even when at low volumes?

Subs are wired like so.

When I set it up with the DMM, I set it right at 34 volts, which it called for 34.64, so I backed it down a tad. No, it's not clipping at low volumes, just when I get to about 85% of the hu volume.

 

[Pl8er 5,000+ posts]

Could be that your HU is clipping, not the amp. Especially with you saying that it doesn't matter if your bass boost is on or not.

Everything else looks right.

 

[redngreedy 10+ year member]

Well if all else fails, I do have 2 extra hu's at the house. I shall try that as well I guess.

 

[dman4486 5,000+ posts]

Could be that your HU is clipping, not the amp. Especially with you saying that it doesn't matter if your bass boost is on or not.
Everything else looks right.

^^^agreed

Well if all else fails, I do have 2 extra hu's at the house. I shall try that as well I guess.

What hu? brand/model?

 

[Pl8er 5,000+ posts]

Well if all else fails, I do have 2 extra hu's at the house. I shall try that as well I guess.

That would be my suggestion. You may just be reaching the limit of the HU. I'm hoping they are different HU models etc and also remember to reset the amp as a different HU could have a different pre-out voltage.

Edit: What test tones did you use?

 

[Blove1991 10+ year member]

Try setting your gains at 75% of the HU volume not 85%

 

[Rashaddd 5,000+ posts]

yea, different HU's have different limits but most will clip well before 100% volume, just like most amps will clip before 100% gain, there's no reason to expect to be able to have the HU on max and not have clipping, unless its a really nice one, and even then...

 

[redngreedy 10+ year member]

That would be my suggestion. You may just be reaching the limit of the HU. I'm hoping they are different HU models etc and also remember to reset the amp as a different HU could have a different pre-out voltage.
Edit: What test tones did you use?

I used 50 at 0db.