Amp not putting out what it should? plz help

[FML 10+ year member]

Did you add a larger ground to the body from the battery? The stock ones are only a braided wire with spring clips. I would also try undoing the ground block from the body so that it only goes through the frame ground. I had an older suburban that worked fine till I upped the amp then I started to have problems like what you are having, it just didnt seem like there was any more output.

Also I will mention that trying to check poor connections with an ohms meter may not always show a problem. There could be 0 (zero) ohms but when you try to run a few hundred amps through it, it just can not carry the power.

Forgot to mention that why I ask is that the body is isolated from the frame with rubber bushings.

Yeah I have big 4 done under the hood.

And using the floor pan as a ground was working fine, i just added the leads to the frame just to be safe. Also, only way for me to go directly to the frame ground and bypassing that ground block would be drilling huge holes in my floor. Want to avoid doing that.

I have plans after work to get this amp in another vehicle. If it does indeed perform, then it will be clear that theres a hidden variable somewhere in my truck. And at that point, i will switch everything up and track down the problem.

Just a slight hint is all im after here. Just an idea of where to start changing things. As of now, iv done everything besides change boxes and re do my power wiring. Ill know more this evening.

I actually pray it IS as simple as a power/ground issue. Have No problem routing more cable and adding a few more batteries if so....

 

[Jeffdachef 5,000+ posts]

yes pray this is a cheap problem.

 

[FML 10+ year member]

yes pray this is a cheap problem.

Honestly i don't care if its an expensive problem. I just want to know what it is!

And as long as its not my brand new amp, i don't care. Thats the only piece that i would be seriously bummed about having to replace (again) .

 

[FML 10+ year member]

Ok, heres todays update.

Nothing to really announce. Hooked up the M3b in my buddies car, put out identical numbers.

So that rules out any electrical or signal issue. Keep in mind, the amp was still outputting to MY woofers and box thru a length of speaker cable. He only has 750 RMS woofers and was scared id blow them out with my amp if it turned out to be working properly, so i didn't get as much conclusive info as i would've liked.

So, in my eyes that leaves 3 things:

The box (not likely)

How the woofers are wired (most likely)

The amp (highly unlikely, god i pray not)

With most DD woofers having direct leads and all, i didn't want to twist + tape. So each voice coil cable has a ring terminal crimped onto it, then nut and washered onto a square piece of wood about 2 inches square. Same with the other woofer, with jumpers from positive to pos, negative to neg to the respective woofers. Then finally one more positive and negative lead coming off those 2 junctions to the binding posts on the side of the box.

Iv heard and seen this done a lot. Cant see it causing my issue. Anybody have any info on it? Ill be wrestling the beasts out of their box tomorrow and giving it a try regardless, but some input would be cool.

Also, i do realize with parallel wiring, all the positive and negative terminals are essentially 1 in themselves. Would twist and taping together all 4 negative and all 4 positive, then the final speaker wire (making a total of 5 positive/ 5 negative) cause any adverse operation? I seem to remember trying wiring this way with some older AQ woofers and it didn't work at all (meaning they wouldn't take any power) .

Just trying to get as much info i can, minimize wasted time and most importantly, the mere 10 to 12 inches of direct voice coil lead that DD supplies...

 

[negolien]

I don't think it would matter as long as you're getting a 1 ohm reading on a DMM when checking them their going to be running 1 ohm.

 

[FML 10+ year member]

Well i rewired the woofers into the box. Took out all the wiring junctions and posts and just ran direct cable. Hard to tell if it made any difference. Im guessing it didn't because 4000 watts vs 1000 is pretty obvious.

Only things left now are box and amp.

 

[negolien]

Well you said you DMM'd the box so if it's reading 1 ohm at the terminals I don't see how it could be the box.

 

[garychoffmann 10+ year member]

Did your rise calculate out the same?

 

[adulbrich 5,000+ posts]

Lol at @los33;

Hate to call DD a reputable company??

Haters gonna hate :fro:

 

[FML 10+ year member]

I haven't re clamped yet today. Im honestly so over it all im about to just say F it and either tear it all out and sell it or just settle at a lame 900 watts.

 

[FML 10+ year member]

Well you said you DMM'd the box so if it's reading 1 ohm at the terminals I don't see how it could be the box.

Not sure what you mean by metering the box. Yes, final impedance has always been 1 ohm. Was with all the crazy ring terminals, wire junctions and binding posts, and was today after running direct wiring and twist and taping.

I honestly dont see any other possibilities. Iv ruled everything else out, but SOMETHING is still holding everything back. I have flawless operation for every part of this build. I have lots of different things running, multiple amps, volt meter displays, HO alt, fusing, Everything is right. Iv checked and checked again.

Still not pulling any current either. Which is whats odd, before this setup i was pulling tons of current with only 1500 rms between 2 amps. Now i have wired in a ballpark range of 4500 watts and i don't even flinch at 14.1v.

If these woofers weren't practically brand new i might suspect something funny with them, but they've been in literally a few weeks, fresh out of their boxes.

 

[WhiteYota]

Maybe try clamping the power lead going in the amp and figure what it is drawing on the 12v side. See if it is even drawing power from the truck.

 

[FML 10+ year member]

Maybe try clamping the power lead going in the amp and figure what it is drawing on the 12v side. See if it is even drawing power from the truck.

That requires a DC clamp, don't have one.

And we thru it in my buddies car Friday and ran a patch speaker cable to my truck with same results.

 

[Jeffdachef 5,000+ posts]

That requires a DC clamp, don't have one.
And we thru it in my buddies car Friday and ran a patch speaker cable to my truck with same results.

So i just clamped my system with the dc 3.5k in. Highest number i got was with a 34hz test tone at 2.3 rise 1627 watts dropping to 13.7V (wasnt reving) at the amps. However with 40hz and above test tones, I got rise up to 4.1 ohms around 800 watts. Basically 400 watts per 18 on my music library's freq range. lmfaooo fking box rise. Still loud beyond belief on such low power draw. Different test tones, you'll get different rise. I went from 28 to 50hz in two hz increments.

 

[adulbrich 5,000+ posts]

So i just clamped my system with the dc 3.5k in. Highest number i got was with a 34hz test tone at 2.3 rise 1627 watts dropping to 13.7V (wasnt reving) at the amps. However with 40hz and above test tones, I got rise up to 4.1 ohms around 800 watts. Basically 400 watts per 18 on my music library's freq range. lmfaooo fking box rise. Still loud beyond belief on such low power draw. Different test tones, you'll get different rise. I went from 28 to 50hz in two hz increments.

Yea, I get a lot more voltage drop at lower frequencies. Makes sense because there's less rise and your amp is making more power.