RF PBR300x2's vs. BT4180
Extreme HDF Member
Joined: Nov 2007
Posts: 14,670
Likes: 139
From: East of the Sun, West of the Moon
this is the only review worth reposting that I've seen on this amp...
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 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.
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 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.
Outstanding HDF Member
Joined: Mar 2009
Posts: 2,930
Likes: 4
From: OHIO......UGH !!
Not another one of those 'chase your tail' all summer waiting for a release...
Cruiser
Joined: Apr 2008
Posts: 183
Likes: 0
From: West Virginia
has anybody tried the PPI 900.4? I've been looking at the specs. Better signal to noise ratio than the KS125.4, and better power output in a smaller amp at about half the price. I'm seeing an experiment in the near future.
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Outstanding HDF Member
Joined: Mar 2012
Posts: 2,843
Likes: 0
From: Michigan
I believe that is the same amp UltraNutz uses, but with a different name. Soundstream 4.900. He loves his, just keep in mind that he says it won't fit in the fairing and will kill your FM.
Extreme HDF Member
Joined: Nov 2007
Posts: 14,670
Likes: 139
From: East of the Sun, West of the Moon
yes sir that is correct. PPI and SoundStream are manufactured/owned by the same mother company, Epsilon.
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