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.
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.
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:
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):
Frequency response shows the typical load/speaker dependency of lower cost class D architecture used in these car amplifiers:
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:
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:
Company spec is 128 watts driving one channel into 4 ohm. I drive two channels:
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:
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:
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
-----------
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/
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.
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:
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):
Frequency response shows the typical load/speaker dependency of lower cost class D architecture used in these car amplifiers:
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:
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:
Company spec is 128 watts driving one channel into 4 ohm. I drive two channels:
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:
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:
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
-----------
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/