Outlaw Audio RR2150 Measurements & Analysis

All measurements were conducted using our Audio Precision APx585 8 Channel HDMI Audio Analyzer following our rigid Amplifier Measurement Test Protocol.

Signal to Noise Ratio

Outlaw RR2150 SNR @ 1 watt (A-weighted)

The RR2150 exhibited a low noise floor.  At 1 watt I measured 83dB (A-weighted) and 76dB with no filter engaged.  The relatively small difference between A-wt and un-weighed measurements indicates that out of band residual noise residuals are low.  At rated power, I measured 103dB (A-wt).

Frequency Response

Outlaw RR2150 Frequency Response @ 1 watt

The RR2150 exhibited ruler flat frequency response at all power levels within the audio band.  I measured a -3dB point of 60kHz from the speaker outputs. 

Power Measurements

Using our Audio Precision APx585 8-channel HDMI analyzer, I conducted a full barrage of multi-channel amplifier tests on the RR2150. We tested power using three methods all of which were taken at < 0.1% THD + N:

• Continuous Full Power Bandwidth (CFP-BW) from 20Hz to 20Khz into 8 and 4-ohm loads (up to two-channels)
• 1kHz Power Sweep vs Distortion (1kHz PSweep) - popularized by the print magazines, this is an instantaneous power vs distortion test at 1kHz. The problem with this test is it often masks slew related and or frequency response problems some amplifiers exhibit at the frequency extremes, and thus inflates the measured power results. It does provide an instant gratification # for consumers to argue over on the forums so we are now incorporating this test to please the masses.
• Dynamic PWR - 1kHz CEA-2006 Burst Method testing. This is a dynamic power measurement adopted from the car industry similar to IHF method only a bit more difficult for an amplifier and more representative of real musical content.

Keep in mind most review publications don't do continuous power measurements and they usually publish power measurements into clipping at 1% THD + N. Our measurements are very conservative as we use a dedicated 20A line with no Variac to regulate line voltage.  We constantly monitor the line to ensure it never drops more than 2Vrms from nominal which in our case was 120Vrms. 

For more info on amplifier measurements, see:  The All Channels Driven (ACD) Test

Outlaw RR2150 Frequency Response @ Full Rated Power (100wpc x 2, 8 ohms)

Outlaw RR2150 1kHz Power Test

Top Pic: 2CH driven, 8 ohms;  Bottom Pic: 2CH driven, 4 ohms

Outlaw RR2150 Dynamic Power Test (1kHz) 2CH Driven, 8 ohms

Outlaw RR2150 Power Measurement Table

Outlaw rates the RR2150 as follows:

• 100 watts x 2 continuous @ 8-ohm  from 20Hz to 20kHz < 0.03% THD + N
• 160 watts x 2 continuous @ 4-ohm from 20Hz to 20kHz < 0.03% THD +N

Most amplifier companies never give such detailed continuous full bandwidth power ratings like this, let alone receiver companies.  This type of honesty is refreshing.

The RR2150 not only met the specified manufacturer power figures, it beat them.  For continuous power, I measured 110wpc x 2, 8 ohms and 165 wpc x 2, 4 ohms at below 0.1% THD+N.  Using the typical 1kHz Psweep tests, you can see the RR2150 produced above its continuous ratings for 8 ohm and 4 ohm loads, both channels driven.  Dynamic power was an impressive 168 watts into 8 ohms and almost 300 watts into 4 ohms with one channel driven.  I did measure one channel to be slightly more powerful than the other by a few watts, so my figures always reflect the lower power ratings. 

That being said, the RR2150 exhibited 2.3dB of dynamic headroom based on the comparison of the continuous power ratings to what I measured dynamically.  It’s clear that the power supply in this amp section, coupled with high current output devices provides plenty of real world power to drive a wide variety of speakers, even those rated down to 4 ohms.  Not once in any of my power torture tests was I able to cause the power protection circuits to kick in.  This is one ballsy amp section for a receiver!

Distortion Analysis

FFT Distortion

Outlaw RR2150 FFT Distortion Analysis @ 1 watt

I ran FFT distortion plots at 1 watt and full rated power to determine how clean this amplifier really is.  At 1 watt, the spectral distortion pretty clean with the 2^nd order harmonic down 90dB from the fundamental.  At rated power, things got a bit less sterile as expected with the 3^rd order products dominating but still -85dB below the fundamental. 

Intermodulation Distortion

We just started including SMPTE IMD distortion tests to see how amplifiers react to non-harmonically related signals.  The test signal consists of a 60Hz and 7kHz test signal summed together at a 4:1 amplitude ratio.

Outlaw RR2150 SMPTE IMD Distortion Test

This test was conducted at 25 watts with both channels driven.  The RR2150 exhibited good results in this test.  No residuals were present for 60Hz (which is important for power supply noise rejection) and the harmonics at 7kHz were -80dB or lower than the fundamental. 

Crosstalk

Low channel to channel crosstalk ensures good stereo separation.  I consider anything less than -40dB @ 10kHz acceptable and anything less than -80dB to be superb.  The Outlaw RR2150 exhibited good, though not stellar crosstalk performance with about -50dB at 10kHz of isolation between the channels.

Outlaw RR2150 Crosstalk Measurement at Rated Power