I think my amp has some kind of problem


winkychevelle

CarAudio.com Veteran
10+ year member
Jun 21, 2009
3,741
45
Ponchatoula, La
Long story short I have a dd d5.1000 5 channel amp.

It outputs sound on all channels but the sub channel is noticeably weak.

I have 2 subs wired to 1ohm, they are brand new and the ohm load was verified by 2 different dmm.

What's weird is as soon as the amp is powered the sub ohm drops to 0 at the amps terminals, But the amp doesn't protect. It still plays fine. Reactively it stays around 60ish ohm while music is playing.

Looking at the amp draw I can only get it to draw about 32amps of current. It should easily be drawing 100amps.

Any idea why it would be acting up or what could be wrong. The grounds are good, powering is 1/0 up to about 2 foot away.

The signal leads work fine.

I'll be replacing the amp when sundown releases the 1800.5 but I don't want to sell a busted amp and this one does still put out some power
 

metalheadjoe

Registered User
10+ year member
Oct 21, 2007
212
85
ND
You can't measure resistance on an energized circuit. An ohmmeter works by putting out a small voltage and seeing what it gets back, so when your amp is on, you are messing up the meter's reading.
 

dragon.breath

Senior VIP Member
10+ year member
Nov 22, 2007
671
77
Al
1. Like the other poster said, you can’t measure resistance on a powered circuit.
2. impedance rise (google it) on the subwoofer can be enough cause the problem you are describing. How did you set your gain?
 

winkychevelle

CarAudio.com Veteran
10+ year member
Jun 21, 2009
3,741
45
Ponchatoula, La
  • Thread Starter Thread Starter
  • #4
1. Like the other poster said, you can’t measure resistance on a powered circuit.
2. impedance rise (google it) on the subwoofer can be enough cause the problem you are describing. How did you set your gain?
It doesn't matter how I set my gain. Whether straight clipping or clean.

I can't get the amp to make anything over 300watt at 1ohm clean and at full clip it still doesn't draw excessive amperage.

The amp is rated at 1000w at 1ohm and ddaudio usually make rated power. If it was putting out 1000w it would be drawing over 100amp especially since the other channels are loaded at 90w×2 at 4ohm for the tweeters, and 120×2 at 2ohm for the mids. Which dynamically I don't expect much draw out of the high side of the amp but adding it all up it should at least come close to the 130amp fuse rating.

When I get time I'm going to rewire the subs up to 4ohm and see if that helps but the amp doesn't have a published rating at 4ohm but I'd expect 250-300w.

And yea I get impedance rise but if I'm rising to 60-70ohm something is very wrong.

It's not like I'm new to this I'm just trying to troubleshoot a new issue. I'm 99% sure the amp is bad. I bought it second hand for fairly cheap so I won't complain but it would be nice if It was an easy fix
 

Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.


Users Who Are Viewing This Thread (Users: 0, Guests: 1)



Newest threads

Most posts - Past 30 days

Latest classifieds