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Soundstream RN4.1400D Rubicon Nano Review (Car Amp)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 35 37.6%
  • 2. Not terrible (postman panther)

    Votes: 41 44.1%
  • 3. Fine (happy panther

    Votes: 15 16.1%
  • 4. Great (golfing panther)

    Votes: 2 2.2%

  • Total voters
    93

amirm

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This is a review and detailed measurements of the Soundstream RN4.1400D Rubicon Nano four channel car power amplifier. It is on kind loan from a member and costs US $150.
Soundstream RN4.1400D  Rubicon Nanon Review  four channel car audio amplifier.jpg

I could not believe the price of this unit given the exceptionally nice fit and finish of this amplifier. It is also extremely heavy and dense for its size. The terminals while using Philips screws were actually much nicer and easier to tighten than typical hex drivers.

Soundstream RN4.1400D  Rubicon Nanon Review Wiring Terminal auto four channel car audio amplif...jpg


You have the usual controls. I tested the unit in flat EQ setting and focused on only left and right channels.

Idle current draw as about 0.8 amps. During the testing the unit remained almost at room temperature, backing companies claims of high efficiency.

Soundstream RN4.1400D Rubicon Nano Measurements
This amp gave me a lot of difficulty in measuring it due to mains intrusion:
Soundstream RN4.1400D Measurements four channel car audio amplifier.png


Power was provided by 300 amp/hr Lithium battery cell so that was not the source of noise. But the analyzer is mains powered so caused mains leakage which I could reduce by tiny amount but no more. Whether this is a design issue with it picking up noise or an artifact of my test setup, I can't say. Going along with it, here is the SNR (which most likely is impacted by above noise):
Soundstream RN4.1400D Measurements SNR four channel car audio amplifier.png


Frequency response shows the typical load/speaker dependency of lower cost class D architecture used in these car amplifiers:
Soundstream RN4.1400D Measurements frequency response four channel car audio amplifier.png


At 20 Hz, the 8 ohm load causes 2 dB of peaking at 20 kHz. If the amp sounds bright, you may want to dial down the treble a bit.

Crosstalk was extremely poor:
Soundstream RN4.1400D Measurements Crosstalk four channel car audio amplifier.png


I spent a lot of time messing with the unit but I could not get any better results. Worse yet, the amp would keep going into unstable operation, not putting out a valid output. Again, whether this is caused in testing, I can't be sure.

Multitone shows the problem with mains noise and rising distortion at high frequencies:
Soundstream RN4.1400D Measurements Multitone four channel car audio amplifier.png


Company spec is 128 watts driving one channel into 4 ohm. I drive two channels:
Soundstream RN4.1400D Measurements Power into 4 ohm  four channel car audio amplifier.png


Soundstream RN4.1400D Measurements Peak and Burst Power into 4 ohm  four channel car audio amp...png


So looks like we are spec compliant (if you add both channels). That is not a lot of power.

Switching to 8 ohm we get far less power:
Soundstream RN4.1400D Measurements Power into 8 ohm  four channel car audio amplifier.png


DC input started at 14 volts or so and dropped to 13.6 volt during the top two tests (I fully charged the cell before running these power sweeps).

Changing frequencies shows the issue we already know as far as more distortion at higher frequencies:

Soundstream RN4.1400D Measurements Power into 4 ohm vs frequency distortion four channel car a...png


Conclusions
I am most impressed with the mechanical design of this amplifier and its efficiency. But it doesn't have a lot of power. And if the instrumentation to be trusted, it has very poor crosstalk, frequency dependency and noise. I hope there is an amp with same outside design but much better guts.

I can't recommend the Soundstream RN4.1400D Rubicon Nano

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

DSJR

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...But we're getting CAR AMPS today which equal out out perform many hairshirt domestic amps from the 80's which budget conscious audiophiles raved over.
 

anphex

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If you think about the speakers that follow after this amp I wouldn't worry much about needing a very transparent ASR-certified amp. For this price and purpose it's alright!
 

DSJR

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This amp is garbage compared to typical 80s amp in good working condition. All D-class issues without any benefits.
Which 80's amps do you refer to? Not challenging, but the popular lower cost UK amps had SINAD in the estimated 70's to 80's, not always wide bandwidths and IMD (19+20khz) figures were judged good at around 75dB or so back then. Even early Krells were estimated in the mid 80's SINAD (using that as a very crude benchmark here).

The far eastern amps with much better paper performance were mostly criticised for a thin and spacially 'flat' kind of sound. No idea how 'sighted' or not these tests were though (HiFi Choice supposedly had panels of listeners and the author often acted as a 'consultant' to the UK-tweaked versions of some amps too I gather). So yeah, the better amps DID all 'sound' much the same :D

This thing is $150 for four channels. I'm still amazed it's as good as it is, even if not for indoor domestic use.
 

Triliza

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Great, more gears for those few attention-seekers out there to spread their love of music (usually of bad taste) to the rest of us, sometimes during the night too. Someone should talk to those people about the dangers to their hearing of having the music too loud in their cars. This amp not having alot of power may be a good thing after all. I voted Fine for that.
 

tomtoo

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That +2db at 20 khz is for me the same distourbing as one pubic hair from a good looking woman in 20 gallon of the best hot goulash soup i ever have eaten.
 

tomtoo

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Yes, i mean come on
:oops:
I suspect that will be the weirdest thing I read today.

Thats ok. Hey you ever tried a EQ curve from 5khz to 20khz +2db? And how much it changes? At 30khz we are 5db up, who the hell can hear this?
Its just as importend as i said, and some may even find it thrilling?

We have to watch not to go to much into measurement fetish. +2db from 5 to 20khz is very different than +2db from 2 to 5 khz.
 
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KxDx

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Great, more gears for those few attention-seekers out there to spread their love of music (usually of bad taste) to the rest of us, sometimes during the night too. Someone should talk to those people about the dangers to their hearing of having the music too loud in their cars. This amp not having alot of power may be a good thing after all. I voted Fine for that.
"Don't park on my lawn!" :D
 

ROOSKIE

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I have the 5 channel version of this amp. It has an extra 200watt subwoofer channel.
It is the Hifonics brand but surely the exact same performance. (Same company sells several brands all with the same specs)
I use it to drive a small dash mounted 2way passive mid/tweeter, 2 6.5" midbass in the doors and an 8"sub that is between the front seats.
It gets plenty loud in that small environment.
Old school car audio type of install in a paint fading 2007 crv.

This amp is garbage compared to typical 80s amp in good working condition. All D-class issues without any benefits.
The larger 5 channel version still fits under the front seat in my car along with a DSP unit. I drive around with it hidden away powering a decent sound system. So yup that is huge benefit you seem to have overlooked.

This is great for what it is.
 
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solderdude

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Yes, i mean come on

Thats ok. Hey you ever tried a EQ curve from 5khz to 20khz +2db? And how much it changes? At 30khz we are 5db up, who the hell can hear this?
Its just as importend as i said, and some may even find it thrilling?

We have to watch not to go to much into measurement fetish. +2db from 5 to 20khz is very different than +2db from 2 to 5 khz.

Consider that most car speakers are 4ohm or lower.
 

ROOSKIE

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Why so many Poor ratings?

This is okay for the price. Now if it cost a small fortune, THEN poor.....!
I don't understand them either. I feel they are completely unwarranted, but I guess most of these folks have absolutely zero knowledge or experience with car audio, yet they vote. Oh well. They have no idea how useful a tiny amp with good power is - and one so inexpensive. The whole line is inexpensive (Soundstream, Hifonic, Precision Power - all the same).
The rest is good enough it doesn't matter in a typical car. This is easy to hide away and fit into various places.
Car audio speakers are 4ohm or 2ohm or even 1ohm. Even if one is using an 8ohm DIY system it will be just fine with a little PEQ.

Perfectly serviceable car audio unit.
 

tomtoo

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Consider that most car speakers are 4ohm or lower.

Yes the measurments are at 4 ohm. And i talked about 4 ohm. Maybe they should say, dont go under 4 ohm at ONE channel, exept for the bass? Couse there are +5 db at 30khz as importend as that prominent rise bag in china?
 
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tomtoo

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Usually i would not care. But that sentence from @amirm must be some kind of joke?

".. If the amp sounds bright, you may want to dial down the treble a bit..."

It should be " If you feel a littel to much air in the sound, your ears are exeptional, or your windows are open" ;)
 
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