Need advice DMM testing resistance.

[i2ain2thunder 10+ year member]

Hello. I've had some electrical issues with my setup forever. The voltage does drop slightly below 12.6v which seems to cause my amp to clip. Obviously due to this I keep gain low and don't clip. However with a HO alt, 1/0 recleaned and sealed connections, optima yellow top, I don't think my 1200watt amp should be clipping at around 750watts on that kind of power.

One thing I've never done is test my resistance. I know the resistance of coils isn't ever exactly as stated I.E. dual 4 ohm vcs are probally around 3.6 or so per coil from my experience. However I'm kinda new to actually testing my resistance levels with a DMM.

What setting do I use on the DMM? Can I measure the resistance from the wires or at the amp, or do I need to check them at the coils? I want to make sure that everything I have wired is legit. I wired my 2x dual 4ohm subs in parallel, but they are not wired directly to eachother. I have 1 sub wired + to + / - to - and the other wired the same way. Then on each sub I have a lead going from + to + on the amp and - to - on the amp. It is a mono amp, but has those 4 terminals, kind of like a 2 channel, but obviously that is a combined 1 channel, so I should be good to wire each sub to a respective + and - and the ohm load should be 1ohm at the amp in theory right?

The speakers are all 4ohm components wired to a 4channel amp, no series or parallel, just wired to 4ohms at the amp on each channel.

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[LosIsATool 5,000+ posts]

What amp?

 

[i2ain2thunder 10+ year member]

sub amp AT1200.1 D

Speaker amp MA Audio 489i

 

[LosIsATool 5,000+ posts]

sub amp AT1200.1 DSpeaker amp MA Audio 489i

Amp should be fine no matter what the coils read, sounds like a bad ground which is 98% the problem

 

[i2ain2thunder 10+ year member]

Amp should be fine no matter what the coils read, sounds like a bad ground which is 98% the problem

I've redone all the grounds nothing but shiny metal. well there were a couple I skipped, because they looked good and are a bich to get at....guess I'll have to spend some time though and actually get to them.

 

[LosIsATool 5,000+ posts]

I've redone all the grounds nothing but shiny metal. well there were a couple I skipped, because they looked good and are a bich to get at....guess I'll have to spend some time though and actually get to them.

Shiny good, location? One bad ground can kill it

 

[CrossoverOre 10+ year member]

big 3?

 

[™Caveman 10+ year member]

Are yellow tops really that great? I almost bought one but opted for a dh platinum. Have you ever charged your battery?

 

[LosIsATool 5,000+ posts]

Are yellow tops really that great? I almost bought one but opted for a dh platinum. Have you ever charged your battery?

Old tech that cant hang anymore

 

[i2ain2thunder 10+ year member]

Well ok guys did some work on it, all grounds are spiffy now. Voltage at amp input on DC with DMM shows never less than 14 volts even with amp clipping if I turn it up that high. Soooooo, why is AT D clipping at anything over 500 watts? I got this because the DMM output voltage (ac) at the gain level that starts to clip shows 20volts, @ 1 1200.1hm 20 squared is 400 watts (its a little more than that so we'll say at 500 watts shes clipping with 14 volts

WTF?

 

---------- Post added at 05:04 PM ---------- Previous post was at 05:03 PM ----------

 

big 3?

of coarse.

 

---------- Post added at 05:04 PM ---------- Previous post was at 05:04 PM ----------

 

Shiny good, location? One bad ground can kill it

well i'm sitting purdy at 14 or above volts even on the hardest bass now. Isn't that an indication the ground is fine?

 

[clickclickw00t 10+ year member]

What is your head unit set to? Subwoofer level at neutral? Eq at neutral? Loudness off? Are you using high quality mp3s or CDs?

 

[i2ain2thunder 10+ year member]

What is your head unit set to? Subwoofer level at neutral? Eq at neutral? Loudness off? Are you using high quality mp3s or CDs?

CDs only bro, EQ is cut at a couple mid frequencies 2-3 DB narrow bands. SubW level(non fader)=0 bass boost= 0 loudness off, HU is max volume for my gains set at 58/80 HU total max.

HU is high quality SQ, Eclipse CD7100. 8v Preouts

 

[i2ain2thunder 10+ year member]

Am I stumping you guys yet??? I know I'm stumped.

I just don't get it, how can a 1200watt amp thats getting 14 volts solidly clip after only 500 watts? I'm about to run to an audio shop and see if I can test one of their comparable amps, to determine if it's just the amp. Coarse the only way I know it's clipping is the clipping indicator light on my remote switch, not a lot of amps have that.

 

[LosIsATool 5,000+ posts]

Stumped. Could be a bad amp.

 

[clickclickw00t 10+ year member]

Give us some more info:

What gauge/brand wire are you running front to back?

What gauge/brand are you running for grounds?

What kind of box are you running your subs in?

Have you tested the TOTAL resistance (ohm load) for the entire load for the subs?

Have you tested the voltage for the RCAs coming out of your head unit?

What test tone are you running to set your gains? 30hz40hz50hz60hz? 0dB or -3dB?

What subs are they? Model #s ?

My thoughts, and I'm sure someone could chime in on this, is the 8V pre-out on that head unit too high? to the point that its clipping the input?