I think my amp has some kind of problem

[winkychevelle 10+ year member]

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

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[metalheadjoe 10+ year member]

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 10+ year member]

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 10+ year member]

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

 

[WNP]

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

I've got the exact same amp and problem. If you find out anything let me know please.

 

[1aespinoza 10+ year member]

I've got the exact same amp and problem. If you find out anything let me know please.

Would you post a picture of the amp's wiring?

 

[WNP]

Would you post a picture of the amp's wiring?

Yes as soon as I can. If there's any details I can offer before I can take some pictures when I get back home I should be able to answer them. Ive got 1/0 wiring with 1/0 x 4 gauge reducer lugs at the terminals for the power and it's grounded well if that helps. Ive done a big three upgrade as well and I don't have any dimming issues with my two amp setup I had before. I'll post some pics as soon as possible. Thanks

 

[1aespinoza 10+ year member]

Thanks

I was thinking more along the lines of speaker connections. I saw a picture of it and the 10 connections look a bit confusing.
Also want to look at the "input" setting.

 

[WNP]

I was thinking more along the lines of speaker connections. I saw a picture of it and the 10 connections look a bit confusing.
Also want to look at the "input" setting.

Sure, I will post a picture when I can. It is a bit confusing, but there's a diagram on the amp on how to wire the speakers. I'll check over that again and make sure it's right. It would be easy to miss something.

 

[DRBOOM]

Sounds like your electrical in issue mate, check your wire gauge connections, Make sure you are using the correct size wire gauge, and connections are secure. I had that issue with one of my terminal blocks, as it was loose and the bass was week. Once I checked the connections and secured it, the bass returned! With car audio you should check your wiring every six months as the movements do tend to loosen contact points over time. Also you can check voltage, or amperage with multimetre so that is one way to see amp current draw as well.