New amp distorts when both channels are connected. What gives?

[tobey 10+ year member]

I just bought a Massive NX4 to replace an old Precision Power PPI-3050. Very nice looking amp, slight problem though, the NX4 is heavily distorting when trying to produce any kind of bass. I discovered that with any one of the rear RCAs removed, it'll put out some decent bass, but as soon as I reconnect the other cable it goes to crap. The amp is just powering two Infinity Kappa 6x9s in the rear and two Polk 5 1/4s in the front, so I'm not asking miracles from it or anything.

Is this a defective amp, or am I missing something? The PPI would pump out enough bass to rattle the trunk lid, not so much with the twice-as-powerful NX4...

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[LosIsATool 5,000+ posts]

Did you set the gain properly?

 

[tobey 10+ year member]

Well, I'm an idiot. While I was fiddling with the gains, I noticed I had the polarity of one of the rear speakers reversed. //content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif In my defense, I installed it at midnight when I got home from work and lighting wasn't the best. That's what I tell myself anyway...

I love this thing now! Wayy more power than the PPI. My stupid Kappas are producing lows I didn't even know they were capable of.

Thanks!

 

[Wingman0121 10+ year member]

I was just gonna say you might have the polarity on one of the speakers wired backwards so when you have both speakers running they cancel each other out especially in the bass region.

Enjoy the new amp.

 

[olds97_lss 10+ year member]

Well, I'm an idiot. While I was fiddling with the gains, I noticed I had the polarity of one of the rear speakers reversed. //content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif In my defense, I installed it at midnight when I got home from work and lighting wasn't the best. That's what I tell myself anyway...
I love this thing now! Wayy more power than the PPI. My stupid Kappas are producing lows I didn't even know they were capable of.

Thanks!

I know this is an older thread, but I thought I'd ask if you still have the NX4 and if so, how is it holding up?

Hopefully it's doing well... Just bought one off ebay to power some polk 6x9's and 5x8's.