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Yamaha RX-A860 AVENTAGE Measurements and Analysis

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All measurements were conducted using our Audio Precision APx585 8 Channel HDMI Audio Analyzer.  The Yamaha RX-A860 was defaulted to high impedance mode (8-ohms or more), which is the setting we recommend using regardless of your loudspeakers’ impedance rating if you are concerned about achieving maximum output power and performance from this unit.

See:  Setting the A/V Receiver Impedance Switch

For more information about how we measure power amplifiers, please check out:

Basic Amplifier Measurement Techniques

Yamaha RX-A860 Preamplifier Measurements

In the past some Yamaha AV receivers had weak output drivers in their preamp outputs where they didn't supply enough voltage to hit the magic 2Vrms, which is what most power amplifiers need to achieve full rated power.  Sadly, it looks like Yamaha has taken a step backwards with the RX-A860.  At 1.9Vrms output, the receiver shut down.  When I checked at a slightly lower output (1.6Vrms), I noticed a pretty nasty FFT distortion profile.  There simply is NO excuse for this in a day and age when opamps are cheap and supply voltage is plentiful. 

Yamaha RX-A860 FFT @ 1.6Vrms.jpg 

Yamaha RX-A860 Preamp Out FFT Distortion Analysis @ 1.6Vrms

  Yamaha RX-A860 FFT @ 1Vrms.jpg

Yamaha RX-A860 Preamp Out FFT Distortion Analysis @ 1Vrms

At 1Vrms, the output looks much cleaner.  If you're planning on using external amplification with the RX-A860, look for a power amplifier with a relatively high voltage gain (29dB or greater) so that it can achieve full rated power below where the preamp outputs of the RX-A860 starts clipping.  For example, a 200-watt amplifier with a voltage gain of 29dB will reach its rated power at around 1.4Vrms.

Yamaha RX-A860 Pure Direct.JPG 

Yamaha RX-A860 Frequency Response - Pure Direct 

Frequency Response was ruler flat from 20Hz to 20kHz with about -1dB at 10Hz and 80kHz.

Yamaha RX-A860 Straight mode.JPG 

Yamaha RX-A860 Frequency Response - Straight Mode 

While many AV receivers downsample to 44kHz with the DSP engaged, the RX-A860 actually appears to have 2X that sampling rate as can be seen by the flat frequency response out to 44kHz (1/2 Nyquist frequency).  Kudos to Yamaha for employing some heavy DSP processing to keep the digital signals as unadulterated as possible.  This is unusual for an AV receiver of this price class.

Power Measurements

Using our Audio Precision APx585 8-channel HDMI analyzer, we conducted a full barrage of multi-channel amplifier tests on Yamaha RX-A860 per our Amplifier Measurement Protocol. 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

# of CH Test Type Power Load THD + N
2 CFP-BW 100 watts 8-ohms 0.1%
2 1kHz Psweep 127 watts 8-ohms 0.1%
2 1kHz Psweep 132 watts 8-ohms 1%
1 1kHz Psweep 163 watts 4-ohms 0.1%
1 1kHz Psweep 182 watts 4-ohms 1%
5 1kHz Psweep 35 watts 8-ohms 0.1%
5 1kHz Psweep 37 watts 8-ohms 1%
1 Dynamic PWR 174 watts 8-ohms 1%
5 Dynamic PWR 139 watts 8-ohms 1%
2 Dynamic PWR 255 watts 4-ohms 1%

     Yamaha RX-A860 Power Measurement Table

 

Yamaha RX-A860 Frequency Response _100wpc (pure direct).JPG

Yamaha RX-A860 CFP-BW (2CH) Power Test - 8 ohms

With two channels driven, the RX-A860 delivered its rated 100 watts/ch power for full bandwidth 20Hz to 20kHz.

Yamaha RX-A860 1kHz Psweep-5CH.JPG

Yamaha RX-A860 1kHz ACD (5CH) Power Test - 8 ohms

With just two channels driven, the RX-A860 produced impressive 1kHz power tests that exceeded its 100 watts/ch rating.  However, once five channels were driven, the receiver went into heavy current limiting bringing the power down to a measly 35 watts/ch.  With most program material, it's unlikely under normal listening conditions that the current limiting would kick in, but I'd still expect more robust output at this price point, like some of Yamaha's peers offer.

Yamaha RX-A860 1kHz Psweep  4 ohms.JPG

Yamaha RX-A860 1kHz (2CH) Power Test - 4 ohms

I observed some bizarre behavior on the test bench when driving 4 ohm loads with the RX-A860.  As you can see with the Nike swoosh looking part of the graph at 160 watts under hard clipping, it also begins current limiting too.  It didn't matter if I drove one or two channels, the result was the same. Yamaha didn't design this receiver to deliver lots of output into low impedance loads and I would advise against using 4 ohm speakers with this model, regardless of how you set the impedance switch.

Yamaha RX-A860 CEA 2006 Dynamic Power 4 ohms.JPG

Yamaha RX-A860 Dynamic Power Test (1kHz) 2CH Driven, 4-ohms

The RX-A860 performed well for CEA 2006 short dynamic burst tests that didn't trip the internal current limiting circuits.  It was able to muster 174 watts/ch into 8-ohm loads and 255 watts/ch into 4-ohm loads.  These results exceed the JEITA dynamic power specs Yamaha gives for this unit (130 watts/ch into 8 ohms, and 190 watts/ch into 4 ohms).  The amp section is capable of producing dynamics but unfortunately the overzealous current limiting really hampers its ability to produce continuously sustained power.

 

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Recent Forum Posts:

Zildjianmeister posts on July 13, 2019 18:58
I agree with all the above comments. If I was to go with just an AVR I would pick one of the higher Yamaha models.

I wanted to share that 860 review for those that haven't seen it. At least they did test with some respectable speakers.as opposed to sounding like a marketing ad.

Z
PENG posts on July 13, 2019 16:38
Andrein, post: 1326212, member: 80761
It might be not fine if you listen at high levels or use 7ch stereo. But then it will be an issue even for more expensive yamaha avrs, maybe just the issue starts manifesting itself sooner with 8xx series.

True, though I suspect not too many people who would enjoy the 7 Ch Stereo at near reference or higher level. THX standard's is for each speaker to be able to produce 105 dB peak at the main listening position, but 105 dB is very loud to most people, period, whether it is from 1 speaker, or 7 speakers.

The popular calculator below shows only 30 watts per channel is required to produce 105 dB at the listening position 12 ft from the speakers, when 7 channel stereo mode is engaged.

https://myhometheater.homestead.com/splcalculator.html
Andrein posts on July 13, 2019 16:12
snakeeyes, post: 1326217, member: 85468
The F36 is 91dB sensenitivity so RXA2070 won’t be having any issues even at max volume but that’s loud enough to really damage your hearing.
https://forums.audioholics.com/forums/threads/revel-concerta2-f36-tower-speaker-review.105070/
Still depends on the distance from LP, listening level, content being played (multich stereo likely to create more problems sooner). Was speaking in general. A8xx in this respect is going to suffer sooner and more. Though if gear is adequate for the task it should work just fine.
snakeeyes posts on July 13, 2019 11:50
Andrein, post: 1326212, member: 80761
It might be not fine if you listen at high levels or use 7ch stereo. But then it will be an issue even for more expensive yamaha avrs, maybe just the issue starts manifesting itself sooner with 8xx series.

The F36 is 91dB sensenitivity so RXA2070 won’t be having any issues even at max volume but that’s loud enough to really damage your hearing.


https://forums.audioholics.com/forums/threads/revel-concerta2-f36-tower-speaker-review.105070/
Andrein posts on July 13, 2019 11:29
PENG, post: 1326208, member: 6097
That was just a subjective review with no measurements taken on the amp's preamp and/or power amp output so you can't assume Yamaha had “fixed” the pre out related issues Gene commented on in the AH review. I do agree with ADTG, that for real world use, it should be fine, but it you intend to use it with external power amp, then the higher series are highly recommended, or at least aim for a power amp that offers higher gain than the typical 28-29 dB.
It might be not fine if you listen at high levels or use 7ch stereo. But then it will be an issue even for more expensive yamaha avrs, maybe just the issue starts manifesting itself sooner with 8xx series.
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