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Yamaha A-S801 Integrated Amplifier Measurements and Analysis

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

Frequency Response

All measurements of the A-S801 were done in pure-direct mode bypassing the tone and balance controls unless otherwise noted.

A-S801 Freq(192kHz, 24bit).jpg

Yamaha A-S801 Analog Frequency Response Direct Mode

Whether I measured the A-S801 via analog input or with a 192kHz/24bit test signal on the COAX digital input, I found ruler flat frequency response from 10Hz to 80kHz  - .6db.  Via the analog inputs, I measured +-.043dB Ch-Ch Deviation and a vanishingly small +-.008dB when using the digital inputs.  This is excellent.

Bass Management

The A-S801 bass management in pretty primitive but I found it very useful that Yamaha included a filtered subwoofer output. 

A-S801-Sub.jpg

Yamaha A-S801 Frequency Response with Bass Management Engaged

The -3dB point of the HPF seemed to be about 95Hz with a 12dB/oct rolloff.  Yamaha specs this at 100Hz.  Personally I would have preferred it set to 80Hz or not filtered at all since most folks using a sub will simply engage their subwoofer’s internal crossover anyways.  As previously mentioned, I recommend either bypassing your subwoofer crossover filter offsetting it +-20Hz than this filter to mimimize interactions between the two.

Signal to Noise Ratio

A-S801SNR(1 watt).jpg

Yamaha A-S801 Signal to Noise Ratio @ 1watt (CCIR filter engaged)

With a 200mVrms input, I measured > 89dB at 1 watt output and >93dB with A-wt filter engaged.  This is a great result and demonstrates why I felt the noise floor on this product was completely inaudible.

A-S801 SNR 200mVrms (CD Direct).jpg

Yamaha A-S801 Signal to Noise Ratio 200mVrms output (CD Direct, A-wt)

Yamaha specs the A-S801 to deliver 99dB (A-wt) or better SNR via the CD analog direct path driven by 200mVrms.  I was able to verify this claim as you can see in the above graph. The CD Direct engaged did improve the SNR by about .5dB.  It's not much of a difference and likely not audible given how quite the product is in any mode, but hey it's something that is verified with measurements.

The DAC performance isn't quite as pristine as the analog section but it's still good nonetheless.  At full digital scale (0dBFs, 2Vrms out), SNR was >100dB A-wt.  This translates down to 83dB at -20dBFS or 200mVrms output. 

Distortion Performance

A-S801 FFT (0dBFS).jpg

Yamaha A-S801 FFT Distortion Analysis (0dBFs)

I ran the USB-B digital interface at digital full scale (0dBFs) which yielded 2Vrms from the analog outputs to see how the ESS Sabre DAC section performed.  You can see the residuals above the 1kHz fundamental along with quantization noise were in the -103dB or lower range.  While this result isn't SOTA in terms of the best of the best DAC performance, it's still respectable and within the performance limits of the ES9010K2M spec sheet for DNR and THD+N as follows:  DNR=116dB, [email protected], -60dB.

A-S801 Freq-vs-Dist (0dBFS,AES17).jpg

Yamaha A-S801 Distortion vs Frequency (0dBFs, AES17 filter engaged)

Again I verified the distortion limits of the ES9010K2M DAC per their data sheet as being under .005% THD+N for the entire audio band.  Yamaha appeared to implement this DAC to reach within its theoretical limits of performance.

A-S801-FFT-1watt.jpg

Yamaha A-S801 FFT Distortion Analysis (1 watt)

The amplifier section of the A-S801 behaved quite well as you can see in FFT distortion analysis at 1 watt.  The distortion byproducts were > -100dB below the fundamental.  Even when driving the amp section to its 100 watt rating, I measured the distortion byproducts > -90dB below the fundamental.  This is very solid performance.

Channel to Channel Crosstalk Performance

A-S801 Xtalk.jpg

Yamaha A-S801 Crosstalk Tests (One Channel Undriven)

 

The crosstalk sweep tests I ran on the A-S801 produced very good results. At 1kHz the channel-to-channel isolation was about -90dB and –60dB at 20kHz. I consider anything less than -40dB @ 10kHz acceptable and the A-S801 beat that with 25dB to spare.  Incidentally, measured stereo separation of the A-S801 was about 20dB better at 1kHz and 15dB better at 10kHz than specified by Yamaha.

Power Amplifier Measurements

The A-S801 was tested on a dedicated 120V / 20A line.  Unless otherwise stated, all power measurements were done with the default 8-ohm impedance setting.

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
  • 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 number 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 since 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

A-S801-Freq@PWR-4ohm.jpg

Yamaha A-S801 Full Power Bandwidth Continuous Sweep (185wpc, 4 ohms)

The A-S801 produced respectable output on the continuous sweep tests.  For 8 ohms, two channels driven, output was around 105 watts/channel and 185 watts/channel for 4 ohms under 0.01% THD+N (well below clipping).  

A-S801-Psweep-2CH-8ohm.jpg

A-S801-Psweep-2CH-4ohm.jpg

Yamaha A-S801 1kHz Power Sweep Test
Top Pic: 8 ohm load, 2CH;  Bottom Pic:  4 ohm load, 2CH

The Yamaha A-S801 belted out some great power numbers with 125wpc at 1% THD+N and 118wpc at  0.1% THD+N with both channels driven into 8 ohms.  Into 4 ohm load, the A-S801 mustered 188wpc at 0.1% THD+N and about 200wpc at 1% THD+N with both channels driven.

There is a dreaded impedance switch on the back of the A-S801 that reduces the output power of this unit for certification purposes only. We recommend leaving it at the default 8 ohm setting and NEVER changing it. 

For more information see:  A/V Receiver Impedance Selector Switch

A-S801-CEA2006-4ohm-1CH.jpg

Yamaha A-S801 Dynamic Power Test (1kHz, 4 ohm load, 1CH driven)

The CEA-2006 burst tests simulate musical program material to illustrate dynamic capabilities of the amplifier.  The A-S801 produced 260wpc into 4 ohms with both channels driven and almost 300 watts with one channel drive.  At 8 ohms, I measured 165 watts which would give this amp > 2dB of headroom based on its 100 watt rating!  There's something to be said about good 'ol fashion Class AB amp design with plenty of heatsinking.

# of CH Test Type Power Load THD + N
2 CFP-BW 105 watts 8 ohms .01%
2 CFP-BW 185 watts 4 ohms .1%
1 1kHz Psweep 139 watts 8 ohms 0.1%
1 1kHz Psweep 148 watts 8 ohms 1%
2 1kHz Psweep 118 watts 8 ohms 0.1%
2 1kHz Psweep 125 watts 8 ohms 1%
1 1kHz Psweep 228 watts 4 ohms 0.1%
1 1kHz Psweep 241 watts 4 ohms 1%
2 1kHz Psweep 188 watts 4 ohms 0.1%
2 1kHz Psweep 199 watts 4 ohms 1%
2 Dynamic PWR 156 watts 8 ohms 1%
2 Dynamic PWR 260 watts 4 ohms 1%
1 Dynamic PWR 165 watts 8 ohms 1%
1 Dynamic PWR 295 watts 4 ohms 1%

    Yamaha A-S801 Power Measurement Table

Our test results validate Yamaha’s power specification for both channels driven and proved that it had plenty of reserves for dynamic power demands.  It also demonstrated excellent stability with 4 ohm loads so don't be afraid to pair it with lower impedance speakers.

 

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Recent Forum Posts:

kenwstr posts on June 08, 2020 05:37
lovinthehd, post: 1396490, member: 61636
Am familiar with the AH articles on the subject. Gene does use mostly regular old 10g speaker cables, but does have his fancy Kimber twisted cables, too.

Maybe if the 90% were heavily weighted towards speakers rather than cables instead of 90% of the time being speakers and cables….as my comment was more about the cable side; cables are generally not an issue at all let alone 90% of the time. I also didn't say cables didn't matter, you need them or no audio! . If they are of sufficient gauge/construction generally that's all you need worry about for speaker cables. Your anecdote about 1m of 18g vs 14g is not very believable, tho I have no idea what an EBT is nor do you describe any meaningful comparison. Whether you cancel some interference with twisted cable, that's a pretty rare instance….but using doubled up pairs of cables to increase effective gauge may be useful. My grandfather was an EE/pro sound guy and set me on the speaker wire path long ago, like 45 years ago. YMMV.

Yes. I know Gene has used 10 AWG pretty extensively though in a recent video he said he prefers 14 x 4 now.

From what I have read, twisted speaker cable reduces one of the 3 cable properties pertinent to low pass frequency to below that obtained with parallel conductors. This allows for longer cable runs without attenuating the top end, it is not essentially about interference. Maybe that’s more relevant to auditorium systems.

EBT is ProAc Extended Bass Tablet. It's oldish but well regarded for the small size and I wanted to keep the price down for the spare room system. They are a slightly taller cabinet than the normal tablets, so lower bass frequency cut-off. Similar performance otherwise. I don't have a spec sheet for them but they measure 6 ohm DC. These are powered with a Pioneer A-400 int-amp, about 60W from memory.

In my experience, apart from enthusiasts, most other people are using woefully inadequate cable gauges in Australia. It makes no sense to me nobbling a system over a few buck’s worth of copper.
Pogre posts on June 07, 2020 23:58
onyx cat, post: 1396456, member: 91931
36935
lovinthehd posts on June 07, 2020 20:35
kenwstr, post: 1396488, member: 80215
Well if you look at the videos Audioholics have produced on this, you will see that the context of their comments is comparing good pro audio cables like Blue Jeans with say boutique cables like Van Den Hul for example. In that context I'd agree it's nonsense.

However, that isn't the context of my comments. Audioholics has also produced documentation on recommended cable gauges and length which suggest 14 to 10 AWG to be appropriate depending on length. They freely state that they prefer Blue Jeans 14 x 4 twisted cable for everything. This is about equivalent to 11 AWG I believe. There are a lot of people not going anywhere near that thick, which is the context of my comments.

I have been in PA and HiFi for over 30 years, heard and read copious amounts on this topic. There are tables that relate cable gauge and length to impedance and suggest this is all that matters. I thought that was true for a long time. However, I had some issues with certain systems and in desperation tried some different cables. The differences were immediately very obvious and no, it wasn’t poor connections either. So, I decided to try this in some other cases like 1m of 18 AWG for my EBTs which according to the tables should be fine but no it isn't. So, I swapped that out for 1m 14 AWG and it is noticeably more pleasant. With the PA system, upgrading gauge vastly improved clarity and tonality. Not talking a small difference here. I have also had experiences where it didn't seem to matter at all.

So, I have found that reality does not in all cases match with simple theories on this issue. I gave a reason above that seems he most consistent with my experience so far but of course it's another theory and may not be correct in all cases either. It's just that the cables don't matter view is not supportable as a blanket statement in my decades of experience, though there are cases that seem to support it with a certain range. There are also practical cases that do not support it. I am most definitely not defending the overprices boutique market here though. Rather I am defending the sensible use of reasonably priced industry accepted cable as Audoholics do as well.

Ken

Am familiar with the AH articles on the subject. Gene does use mostly regular old 10g speaker cables, but does have his fancy Kimber twisted cables, too.

Maybe if the 90% were heavily weighted towards speakers rather than cables instead of 90% of the time being speakers and cables….as my comment was more about the cable side; cables are generally not an issue at all let alone 90% of the time. I also didn't say cables didn't matter, you need them or no audio! . If they are of sufficient gauge/construction generally that's all you need worry about for speaker cables. Your anecdote about 1m of 18g vs 14g is not very believable, tho I have no idea what an EBT is nor do you describe any meaningful comparison. Whether you cancel some interference with twisted cable, that's a pretty rare instance….but using doubled up pairs of cables to increase effective gauge may be useful. My grandfather was an EE/pro sound guy and set me on the speaker wire path long ago, like 45 years ago. YMMV.
kenwstr posts on June 07, 2020 19:53
onyx cat, post: 1396461, member: 91931
Seriously on the cables? Such nonsense.

Well if you look at the videos Audioholics have produced on this, you will see that the context of their comments is comparing good pro audio cables like Blue Jeans with say boutique cables like Van Den Hul for example. In that context I'd agree it's nonsense.

However, that isn't the context of my comments. Audioholics has also produced documentation on recommended cable gauges and length which suggest 14 to 10 AWG to be appropriate depending on length. They freely state that they prefer Blue Jeans 14 x 4 twisted cable for everything. This is about equivalent to 11 AWG I believe. There are a lot of people not going anywhere near that thick, which is the context of my comments.

I have been in PA and HiFi for over 30 years, heard and read copious amounts on this topic. There are tables that relate cable gauge and length to impedance and suggest this is all that matters. I thought that was true for a long time. However, I had some issues with certain systems and in desperation tried some different cables. The differences were immediately very obvious and no, it wasn’t poor connections either. So, I decided to try this in some other cases like 1m of 18 AWG for my EBTs which according to the tables should be fine but no it isn't. So, I swapped that out for 1m 14 AWG and it is noticeably more pleasant. With the PA system, upgrading gauge vastly improved clarity and tonality. Not talking a small difference here. I have also had experiences where it didn't seem to matter at all.

So, I have found that reality does not in all cases match with simple theories on this issue. I gave a reason above that seems he most consistent with my experience so far but of course it's another theory and may not be correct in all cases either. It's just that the cables don't matter view is not supportable as a blanket statement in my decades of experience, though there are cases that seem to support it with a certain range. There are also practical cases that do not support it. I am most definitely not defending the overprices boutique market here though. Rather I am defending the sensible use of reasonably priced industry accepted cable as Audoholics do as well.

Ken
PENG posts on June 07, 2020 19:43
onyx cat, post: 1396466, member: 91931
I am using 14 g speaker wire that I got with banna plugs on both ends , on the streamer I am using a optical cabal that I got from WalMart , could be I could use a better Op cabal , the CD is also a little distorted on the hi's and I also have a reg. RCA cabals hooked into the amp as well from the TV for the audio , so I can select between Op. and RCA , not much of a difference , so I may have speaker problems as well as streaming problems as well , thanks for your input on this , I will also try a coax cabal as well when I get one .. Bob

Did you check the banana plugs? I know of some cheap gold plated ones that are prone to loose connections that are not obvious to the eyes. They were worse than the red/white ones that are typically packed with BR/DVD players.

If all connections are good then it would have to the source but then you said it was same with CD??
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