# NVX 4 channel micro amplifier.



## qwertydude (Dec 22, 2008)

Just got my NVX 4 channel micro amps. I gotta say they are impressive. The one thing I will fault them on is internal construction. When I took them apart I noticed immediately the telltale signs of cheap Chinese construction. They use handmade solder bridges for some components instead of using traces and surface mount soldering. In the long run in high vibration environments this can lead to the solder joints breaking due to vibration, especially more true if lead free solder was used. Maybe since it's Chinese built they used lead solder by "accident".









For size reference. It's small, very small. As you can see there's no visible fuse, it's because it's actually an external component consisting of a simple inline blade fuse holder. Kinda cheesy but it does keep the amp small.









The backside of the board I was disappointed to see handmade solder bridges on components like the input caps.









For those wondering it does seem well thought out in terms of heatsinking. Pretty much all of the large and power consuming components have a contact on the heatsink which is cast into a purposeful shape in order to make good contact with all the heat producing components including the inductors which on most amps are only cooled by ambient air or at most cooling air.

Now for the performance. I tested it on my benchtop power supply which can provide 14.4 volts as needed. This is what blew me away. On two ohms I got 90 watts per channel, on 4 ohms it was smack dab 50 watts. Amazing pretty much as rated, good considering it's CEA compliant. Now testing for power consumption this did draw right around 30 amps when producing 90 WPC which is the fuse rating for the amp so I do think it does need a bigger fuse technically.

I thought I might be able to use it in a portable battery powered rig but it simply consumes too much idle current .670 amps idle. Most chip amps will consume .1 amps which is better for battery powered gear so slight downside for some DIY projects.

All told this gives an overall efficiency at 2 ohms of 83%. Pretty good for a class D amplifier Since this is at it's most stressed you can surmise it's likely higher than 83% most of the time especially when run at 4 ohms per channel.

But when putting out 360 watts the total consumed power is 432 watts which means you've got 72 watts of heat needing dissipation. Normally not too big a deal but even with the well designed heatsinking you're still dealing with 72 watts of heat in essentially tiny block of metal. If you're gonna run this amp full tilt definitely give it some breathing room.


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## rton20s (Feb 14, 2011)

Hey, thanks for being the guinea pig! One thing seems to be apparent, this doesn't look to have any relation to the Soundigital amplifiers. I know that was a question that someone had asked.


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## foreman (Apr 18, 2007)

I want one of these so bad. All i'd run is a pair of Silver fulte 6.5's and an id 8 IB in my deck. Think it will do that ok?


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## SkizeR (Apr 19, 2011)

foreman said:


> I want one of these so bad. All i'd run is a pair of Silver fulte 6.5's and an id 8 IB in my deck. Think it will do that ok?


no tweeters?


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## AAAAAAA (Oct 5, 2007)

Very nice thanks for that. Amp looks great..output is impressive.


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## foreman (Apr 18, 2007)

Yes, a pair of PE tweets in the dash, going to run off the pioneer deck i'm putting in.




SkizeR said:


> no tweeters?


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## thebigjimsho (Jan 11, 2009)

Amazing the advancement...


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## PPI_GUY (Dec 20, 2007)

Absolutely amazing. I've got an old school amp that probably doesn't make much more power than that and it is 6-8 times the size. Reliability might be another story all together but, talk about your ultimate stealth install! 
I was hoping someone would buy one of these and open it up. Saw them on the NVX website a few weeks ago and was very intrigued. Thanks for posting this OP!


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## theoldguy (Nov 17, 2009)

sorry for resurrecting this thread, but this is the first time Im seeing it. Cant believe I havent known of this amp until now. qwerty, do you happen to have an update on this thing? still running strong? Did you ever swap out the fuses? Did it make a difference? Also, do you still ahve the manual for the amp? Im trying to figure out from the pictures how to connect the RCAs if you are running the amp in bridged mode but not having any luck. Any chance you could assist?


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## qwertydude (Dec 22, 2008)

I didn't just swap out the fuse I swapped out the entire thing. It only came with a short 12 gauge lead with an inline automotive blade type fuse holder. I switched it out to an 8 gauge lead with a 40 amp glass fuse. As for making a difference no it really won't make any difference at all. The 30 amp fuse worked but considering how close in draw the amplifier was at maximum to the 30 amp fuse it's definitely the wrong fuse size for it.

You connect both the left and right RCA's to the inputs to bridge and you simply bridge the output as indicated on the output.

If you're running both front and rear outputs bridged off one stereo source then make sure to switch the RCA source switch to 2 channel. If you're using the rear channels as a subwoofer amp with only the two channel input on the fronts being used then switch it to 3 channel the rears will automatically sum and you run it bridged. If you're separately running rear stereo channels and front stereo channels when you bridge the output the amp will automatically sum whichever set of RCA's you bridged in which case you then set the switch to 4 channel.

If it's still confusing tell me your exact setup inputs, outputs and how many RCA's you're connecting.


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## chuyler1 (Apr 10, 2006)

Have you done a side-by-side with this amp and a class A/B (ie normal sized) amp? I can't find any professional reviews. I'm tempted to buy one and do my own review. I want to know if there is any down side to installing an amp 1/4 the size and weight of what I currently have.


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## qwertydude (Dec 22, 2008)

What's to compare? As far as amplification is concerned it will make the least difference in sound quality and most of that would be in the precessing section anyways. The big sticking point with the amp is it idles hot, hot enough that touching the side of the amplifier is downright uncomfortable to painful, but as a class D it doesn't get any hotter when running full tilt as opposed to low power unlike an A/B which gets hotter the more power it outputs.

It's a solid amplifier that sounds as good as any other budget Class D amplifier out there. In other words you won't hear a difference. And if you can hear a difference between a Class D and A/B amplifier in a true ABX level matched blind test, well you should pretty much hire out your fantastic ears to professional audio testing companies.

If you mean professional as in the hifi world, well no these will not make your cymbals more rambunctious, your strings more peppery, your soundstage more brobdingnagian, and other such pretentious nonsense.

These sound like an amplifier, a modern solid state amplifier, that's it.


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## chuyler1 (Apr 10, 2006)

qwertydude said:


> It's a solid amplifier that sounds as good as any other budget Class D amplifier out there. In other words you won't hear a difference.


Maybe I'm just picking through your comment but you said "as good as any other budget Class D amplifier"...but my real question is would it sound as good as my DLS A8 which has a footprint 4 times as large and weighs probably 4 times as much but has similar ratings into 4 ohms? Would I be crazy to sell such a nice amp to buy one of these?

I'm just mainly concerned about weight and real estate in my new vehicle. My days of exotic installs are over and if I can throw a few of these in the space that would normally consume just a single amp, it would be nice...but not if I'm taking a step backward in sound quality.


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## qwertydude (Dec 22, 2008)

Sound would be indistinguishable. But long term if you put this amplifier in a high vibration area, like I said I would be worried about the hand made solder bridges.

The DLS A8 uses discrete components and surface mount components so it would be safer to assume it would survive harsher environments.

Considering how hot it idles if you put this amp in a confined area the small size and heat output may cause the capacitors to dry out long term.

But in terms of sound you won't be able to tell the difference. If you want this amplifier you're obviously buying it for its compact dimensions. If you don't need compact dimensions you're better off sticking with a larger amplifier as it'll run cooler so long term it will probably fare better and not dry out capacitors or in the case of a quality made amplifier not break solder bridges.

If you want a better made amplifier Kenwood has some ultra small footprint amplifiers but they won't sound any better.

Put it this way buy a Boss amplifier connect it with no filters or crossovers, level match it, and put it up against your DLS A8. Have someone else control an AB switch and conduct a true blind ABX test. Surely if the sound quality of the DLS A8 was so superior you'd be able to distinguish it from the lowly Boss. I guarantee you, you wouldn't be able to.


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## Hdale85 (Jan 21, 2012)

So, in terms of other small amplifiers is there anything close in size that you think would stand up in a car better? You said you'd worry about vibrations and enclosed areas. I'm looking for some small amps for my build.


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## qwertydude (Dec 22, 2008)

By vibrations I mean mounting it to your subwoofer box and constantly bumping the system. That's a bad idea for any amplifier you want to really last for the long term but this one would be a bit more vulnerable. Maybe if it had lead based solder it might be safer but lead free solder used to make solder bridges may be at risk of breaking due to high vibrations. The odds that it will break, extremely unlikely, but this nonetheless has an increased chance. Not that I'd be able to quantify since I haven't had mine mounted to a subwoofer box for 10 years. Just there's more chance of it breaking.


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## rton20s (Feb 14, 2011)

Sonic benched these NVX Micro amps on their in-house AD-1. They did better than rated power, but were also being fed more than 14.4 volts. Here is a link to the videos for anyone interested. 

https://www.youtube.com/watch?v=ed9Ii87g7WI&list=UUl76vrtVLcPPnOSIHVs8HMg

https://www.youtube.com/watch?v=y3fFwKtmWHY&list=UUl76vrtVLcPPnOSIHVs8HMg


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## Beckerson1 (Jul 3, 2012)

rton20s said:


> Sonic benched these NVX Micro amps on their in-house AD-1. They did better than rated power, but were also being fed more than 14.4 volts. Here is a link to the videos for anyone interested.
> 
> https://www.youtube.com/watch?v=ed9Ii87g7WI&list=UUl76vrtVLcPPnOSIHVs8HMg
> 
> https://www.youtube.com/watch?v=y3fFwKtmWHY&list=UUl76vrtVLcPPnOSIHVs8HMg


ya 14.7v

Taking that into consideration I can safely say these will do rated OR even slightly more then rated at 14.4v


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## Beckerson1 (Jul 3, 2012)

Well thought I'd give it a try in my garage setup. Small size, heck why not. Well received it today and lo and behold the plexi is scratched quite well. Came double wrapped in plastic and is scratched? That should not be the case. Either I got a installed/repackaged (sold as new) or a return and they placed it back on the shelf. I'm sorry but for the price I'd expect a unit that doesn't look like it's face was hit with a couple screw drivers. I will test it out on my test bench and see if its functional as Plexi can be resurfaced 

I will post pics later as its late here but one is fairly deep.


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