Review and Measurements of Pioneer VSX-LX504 AVR

[jamescarter1982]

has the pioneer vsa ax10i been tested I can't find it on here . I own this unit using it as a dac in stereo it sounds good ! also have a yamaha dspa3090 which is also particularly good on voices although the amp section isn't as robust as the pioneer .compared to a benchmark dac1 neither is better or worse just different . what does everybody think about using a former flagship pre hdmi reciever like these as a stereo dac Pre or dac integrated ? if the distortion and noise is inaudible can different products still sound different ?

 

[MLaranjeiras]

This is a review and very detailed measurements of the Pioneer VSX-LX504 Home Theater Audio & Video Receiver (AVR). It came about when my trusty Pioneer Elite SC-61 started to produce a UE22 Error. A bit searching showed this is a TI DSP that goes bad causing audio to mute and eventually go dead completely. Despite being acquired by Onkyo, Pioneer made good for a while by sending replacement DSP board to owners. Alas, the replacements are all gone and now Pioneer only offers a trade in. After filling out paperwork and such, they offered me a VSX-LX504 for around US $540 or so. I see it listed on Amazon for US $899 with a list price of US $999. The unit arrived yesterday and I was anxious to put it on the bench and see how it performs.

From the outside, you would think nothing is changed in Pioneer AVRs as it looks almost identical to my SC-61, with the exception of a lot more labels stuck to the front panel:

View attachment 32586​

Same stiff and lousy feeling volume control adorns the unit on the right. Ditto for the source selector knob on the left. Neither imparts feeling of luxury or quality.

The back panel is the usual affair too with more connectors than you ever use:

View attachment 32587​

The speaker terminals feel pretty cheap, wiggling with any movement of my banana jacks.

Who on earth needs analog component video in this day and age is beyond me. They should eliminate those and instead, give us a proper USB input to be used as a DAC.

We have a nice set of pre-out connectors which I used for testing the performance of its internal DAC (and processing). No multi-channel analog input is provided for people who want to feed it SACD and such from days long gone.

I did not mess with much on the unit other than configuring it for 2-channel output and testing Direct and Pure Direct mode:

View attachment 32588​

Strangely, every time I let go of the button to put it in Pure Direct, it would change to Autosurround or some such nonsense. Fortunately seemed to work in Pure Direct regardless.

The user interface is much improved over the primitive one in my SC-61. There is however a 3 to 4 second delay before the menus come up. Why? This should be instant.

Compatibility with my PC's Nvidia was horrific with resolution all over the place on my BenQ 4K monitor with colors washed out and seemingly wrong. I suspect the latter could be fixed with setting the mode to video range rather than "PC" but I wish the Pioneer would maintain that in pass-through mode. I did not reboot however so maybe that fixes things.

The unit itself is surprisingly light for something with 9 channels of amplification, rated at some 135 watts each. The heatsinks are beefier than other lower priced AVRs we have tested but they are very short. A rather large 5 ot 6 inch fan sits on top of them which never came on during my testing. The unit seemed to operated pretty cool despite using traditional amplification. Likely uses class G voltage switching to keep efficiency higher, and heat dissipation low.

There is a lot of data coming your way so buckle up and lets get through it!

S/PDIF DAC Audio Measurements
For ease of testing I stated by using the S/PDIF coax input. Later I will show HDMI performance as well for a couple of tests. Here is the DAC performance in VSX-LX504 using coax input and pre-out with the speaker cables connected to my dummy load:
View attachment 32590

Yuck. What a disaster. We have tons of distortion and noise product. Output level is just 1.6 volt instead of 2 at 0 dB on the volume control. Remembering that the amplifier clips in some of these products and then destroys the fidelity of the power to the DAC, I disconnected the speaker wires and measured again:
View attachment 32591

OK, that is much better. I turned up the volume to 2.5 dB I think and got 2 volts. SINAD (signal relative to noise and distortion) did not improve hardly at all. So 97 dB is it:

View attachment 32592

Above, I have highlighted the VSX-LX504 which landed in third tier in orange and the previously reviewed Pioneer VSX-LX303. I don't recall if the LX303 also could have benefited from not using its speaker terminal. Either way, this is "OK" performance but of course beaten by a number of DACs some of which retail as low as $70. And the Apple dongle at just $9.

Above were in Direct mode. Switching to Pure direct didn't make much difference in SINAD:
View attachment 32594

But does clean up the spectrum of the FFT substantially, leaving us just the harmonic distortion spikes.

Signal to noise ratio is decent:
View attachment 32593

Jitter performance was rather ugly:
View attachment 32596

Clearly there are many sources of interference in the output of the front left and right DACs which I tested in this review. Fortunately not an audible concern.

Intermodulation distortion follows the lead of THD+N:

View attachment 32597

As noted earlier, Pure Direct doesn't help much here either.

Linearity is good until we get to the limit at -120 dB:
View attachment 32598

S/PDIF doesn't support 192 kHz so I had to settle for my 7-tone test:

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We have about 100 to 110 dB of distortion free range so better than 16 bits but not 20 bits which we can get with music-centric high-performance DACs.

Reconstruction filter is the typical one that balances attenuation with slower than required roll off:
View attachment 32600

This hurts the wideband THD+N versus frequency due to aliasing components sneaking out in ultrasonics:

View attachment 32601

View attachment 32602

The filter needs to have higher attenuation to kill that 47 and 49 kHz spikes in order to improve the previous test. Fortunately these tones are not audible so not a real concern.

HDMI Audio Measurements
I used Roon to play my reference 1 kHz, 24-bit signal in exclusive WASAPI mode to measure the dashboard performance using HDMI input and pre-out:

View attachment 32603

SINAD drops 1 or 2 dB likely due to higher noise floor (harmonics are below 100 dB).

Jitter performance remained more or less the same:

View attachment 32604

Overall, HDMI input seems to impart a small penalty over S/PDIF input.

Amplifier Audio Measurements
This test turned out to be a lot more of a pain than would be otherwise if the unit was well designed and documented. Let me show you how with frequency response test:

View attachment 32605

As you see, in Direct mode, the input is seemingly digitized using a low sample rate of 44.1 kHz or 48 kHz. I suspect this is due to ability then to provide equalization and other digital processing to this analog input.

Switching the unit to Pure Direct mode allowed the full bandwidth of the unit to shine, extending to 100 kHz and beyond. Note that I did not equalize the levels in the above graph so don't mind them being at different reference value to 0 dB.

Switching to S/PDIF input, shows the same discrepancy:
View attachment 32606

So it is pretty clear that internal processing is at just 48 kHz or so. Any dream you had of high-resolution audio is dashed if you use any of the equalization features! That high-res sticker on the front of the unit needs to be removed.

The resampler sure adds a not of noise and spurious tones as this dashboard view in Direct mode shows with digital input:
View attachment 32607

Switching to analog input gives us this:

View attachment 32609

Noise floor is higher but the spectrum is much cleaner showing the issues with the resampler as noted.

The spectrum of 1 kHz shows the difference between direct and pure direct modes:

View attachment 32610

With all effects turned off, there should not be this kind of difference.

We see the same in signal to noise ratio in both modes:
View attachment 32611

Power output versus load at 4 ohm was initially shocking at just 33 watts!

View attachment 32612

Then I remembered the problem with VSX-LX303 where it would severely limit power when warm. So I power cycled the unit and got the much higher 204 watts of power. Same thing happened using 8 ohm load:

View attachment 32613

I measured how long it took for this to happen at different power levels:

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What is odd here is that the amplifier did not feel warm at all, nor did the fan come on. Seems to be some kind of timer that counts how long power is needed above the low power supply rail and clicks into this low output power mode. VW dieselgate anyone?

I forced the same thing to happen with a 50% duty cycle sine wave burst:

View attachment 32618


Burst power was quite high in both impedances:
View attachment 32619

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Conclusions
5+ years have gone by since I had my Pioneer SC-61. Sadly, there doesn't seem to be much progress here. If anything, we seem to have taken a step back with Pioneer AVR line. Even in a "$1000" AVR, there is that power pull back with no documentation whatsoever. Also disappointing is that the internal processing is stuck at 48 kHz. I would have wanted to at least see 96 kHz there. Surely DSP power is that much cheaper than it used to be. I know, they have to spread that out to 9 channels so the budget per channel can't be increased. Sigh. As a minimum, companies need to document such things.

I returned the Pioneer VSX-LX303 to Amazon. No such luck here because these trade-ins are not reversible so I will be putting this unit in my living room.

Needless to say, I can't recommend Pioneer line of AVRs. Hoping other brands don't have such restrictions.

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

I am going to hold a funeral for my older Pioneer SC-61 AVR. Everyone is invited as long as you first donate generously to the forum: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

I recently made a firmware update on my Pioneer VSX LX503 AV Receiver and now native Tidal instaled on it plays full audio resolution, different from the boring 44.1kHz/16bit that it showed before. Once it does not support MQA, it does not unfold to higher resolutions, like 96kHz and 192kHz. But the sound quality gave a great improvment. Amirn commented when reviewd the VSX LX504 (https://www.audiosciencereview.com/...d-measurements-of-pioneer-vsx-lx504-avr.8862/) .... "Also disappointing is that the internal processing is stuck at 48 kHz. I would have wanted to at least see 96 kHz there. Surely DSP power is that much cheaper than it used to be. I know, they have to spread that out to 9 channels so the budget per channel can't be increased. Sigh. As a minimum, companies need to document such things." - I have a doubt about this conclusion: when I send a track with, let´s say, tha is 192kHz 24 bit filed on my smartphone via UPnP to the 503, the receiver displays this resolution. De boubt is: It only displays 192kHz and processes, in fact, at 48kHz or, "de facto", processes 192kHz 24bit as its specification declares?

 

[MLaranjeiras]

If they just documented the deficiencies I would have been in much better mood. A footnote that says you can't run more than 33 watts for 30 seconds would do. And the fact that all internal processing is at 48 kHz. That way, I would have searched for another unit without these deficiencies. Or buy it fully aware of the restrictions. They seem to just "know" that no one measures these things anymore.

About 48kHz maximum rate, what do you think that happens on the receiver for it to show rates like this on the picture?

 

[jamescarter1982]

what equipment do I need to test the sonar of an avr or dac ? a laptop an audio interface with adc is that it ? and I can measure up to the performance of the interface is that right? what would I need to see if it's clipping a speaker dummy load and an scope ? thanks

 

[restorer-john]

what equipment do I need to test the sonar of an avr or dac ? a laptop an audio interface with adc is that it ? and I can measure up to the performance of the interface is that right? what would I need to see if it's clipping a speaker dummy load and an scope ? thanks

Sonar. Right, OK.

Maybe tow the AVR behind a boat and see if you can find a school of fish, or maybe, if you're lucky, a submarine.

 

[jamescarter1982]

Sonar. Right, OK.

Maybe tow the AVR behind a boat and see if you can find a school of fish, or maybe, if you're lucky, a submarine.

auto corrected sonar from sinad but thanks

 

[Vintage. Dude]

Some of the Pioneer high end gear from the 80's was remarkable in terms of build quality and design and they were often the "go to" supplier if you wanted a down to earth affordable good performing system along with Rotel, or I thought so.

Yeah i read somewhere this nonsense "Pioneer couldnt make good amplifiers".

I have pioneer elite c90 /m90a separates. There are opinions that this Elite set is better than sony es like 707 es, sony ta n 80es, ta n 77es. Better than technics se a 3000 separates, which were labeled hi end 20 years ago. Also better than sansui 907i mos limited and its not inferior when compared to accuphase e405

Pioneer Elite m90 in japanese Stereo sound magazine back in 1980s got better reviews than sansui b2201l, sansui b2301l, accuphase p300l, luxman mq 360 tube AMP etc.
In stereo sound got Best product distinction, along with luxman l550, l530, l570, mq 360 tube AMP etc

Pioneer Elite c90a /m90a is appreciated by those who dont like it. On polish forum tube AMPs fan said that QUOTE "Pioneer c90a/m90a isnt that bad, it has warm plush sound"

I had conversation with a guy who is servicing hifi amps and he said that pioneer Elite m90 "is far from being bad sounding amplifiers"

So on

 

[Vintage. Dude]

That may be one of the most ignorant things I've read in a long time.

SX-1980 anyone?

Yup its bs.

 

[Robesini]

If they just documented the deficiencies I would have been in much better mood. A footnote that says you can't run more than 33 watts for 30 seconds would do. And the fact that all internal processing is at 48 kHz. That way, I would have searched for another unit without these deficiencies. Or buy it fully aware of the restrictions. They seem to just "know" that no one measures these things anymore.

I use a Pioneer SC-LX86. I am pretty sure that it will deliver more than 33 watts for 30 seconds. I did run these with a Rotel 6ch poweramplifier. But at the moment i am running with the internal class D setup. It still doesn't feel to replace it. I hear a lot of critisism about class D amplifiers. Most AB amplifiers have to be recalibrated for bios every 2 years to sound good. This Pioneer always sounds the same from day one. Big question to me is always if the measeruments made will be heard trought the speakers. Most amplifiers do outspec the speaker distortion. Most important in the amplifier is the ability to deliver a stable signal when load fluctiates due to impedance variations. But ok that said the receiver is pretty old and mabye should be replaces to use more recent audio formats. If is see the red display i will skip the Pioneer even if it was good receiver. Blue or Green for me not red. It hurts my eyes.

 

[Sal1950]

Most AB amplifiers have to be recalibrated for bios every 2 years to sound good.

You mean bias? I run 5 near 30 year old Adcom amps in my rig, I've checked bias on
them all and none had drifted more than slightly, requiring only the slightest tweak.
As to sounding different, bias would have to go substantially out of spec to make an audible
difference and normally would be related to some components pending failure.
As to power spec's, AVR builders are specially bad for fudging the amps true capability.
A/B or D, it's too easy to make inflated claims unless someone like Amir puts it on the bench.