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Bits are NOT bits ….. or ?

Tangband

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I have done a listening shootout with Yamaha wxc50 with Flac from NAS, vs an Ipad pro with Apple Music lossless and an USB bridge to spdif called ” sky song” . Both players digital out to digital in in my Genelecs . The acoustical output from the loudspeakers were within 0.2 dB with both players.

The ipad with USB bridge wins handsdown, there is a rather big difference in better soundstage and dynamics . The USB bridge clocks are driven by a nine volt battery. With a switch you can easy compare the sound with the ipad powering the USB bridge, or using a battery for the clocks.
The difference is clear, with a better, more natural soundstage with batteries.
I was rather suprised that I could hear the difference so clearly.
Comments on this ?
D06B29F1-848F-4809-8BBB-3E13240271D3.jpeg
 
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solderdude

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Tested without knowing what was connected and at least 15 separate attempts with someone changing the cables without you knowing what is connected or...

You connect the stuff and then listen.
 
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Tangband

Tangband

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Tested without knowing what was connected and at least 15 separate attempts with someone changing the cables without you knowing what is connected or...

You connect the stuff and then listen.

Yes, thats true.
I did not test it without knowing which of the sources that was playing. The thing is, when I listen to music I always, after doing this test, listen to the iPad and the Yamaha wxc50 is quiet. Its much more fun to listen to the music with the iPad player. It sounds more natural.

The Yamaha wxc50 in pre amp mode ( wich also changes the volume-control in digital out ) always resample everything to 48 kHz, while the ipad+sky song is native and changes sampling frequency depending on the source material.
The xu208 chip in sky song does volume control by taking the original 16 bit material, making it 32 bit floating point , then dithering to 24 bits and you can then regulate the digital volume from the iPad .
If I understand this correctly.

Maybe the Yamaha wxc50:s resampling is less good ?
 

SIY

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Tested without knowing what was connected and at least 15 separate attempts with someone changing the cables without you knowing what is connected or...

You connect the stuff and then listen.
Also, an accurate level match. Using a mic to measure speaker output is poor practice.
 

DVDdoug

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The ipad with USB bridge wins handsdown, there is a rather big difference in better soundstage and dynamics .
How in the heck can either of those devices affect soundstage or dynamics? (Assuming no intentional processing.)

There is ONLY noise, distortion, and frequency response.

Of course, soundstage is an illusion experienced differently by different listeners and apparently it can be affected by frequency response, but it's more related to speakers, and room acoustics, etc. (and the recording). It's unlikely you'd get enough variation to affect soundstage (if there's any audible difference at all), and you didn't mention anything related to frequency response.

Noise reduces the dynamic range, but nobody explains noise as a loss of dynamics... They just say noise.

Clipping (distortion) is also a bad kind of dynamic compression, but again listeners complain of distortion, not compression.
 
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solderdude

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Maybe the Yamaha wxc50:s resampling is less good ?

Resamplers can be terrible. No idea what is used in the Yamaha.
Would have to be tested to know for certain.
 
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Tangband

Tangband

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solderdude

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Unfortunately the datasheet says nothing about how their conversion from different samplerates are converted to 48kHz and how good it is at this.
Measurements could clear this up.
 
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Tangband

Tangband

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Unfortunately the datasheet says nothing about how their conversion from different samplerates are converted to 48kHz and how good it is at this.
Measurements could clear this up.

Yes.
Is there someone who owns a yamaha wxc50 that has the opportunity to do some measurements , comparing ”pre amp digital out ” ( SRC by YSS 952, everything to 48 KHz ) with ”player” mode digital out ( no SRC , YSS 952 bypassed in direct mode, native sampling frequency ) ?
 

b4nt

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The USB bridge clocks are driven by a nine volt battery. With a switch you can easy compare the sound with the ipad powering the USB bridge, or using a battery for the clocks. The difference is clear

Instead of adding a switch, they shall have better designed the power supply section?
LT1763.PNG
 

b4nt

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I have done a listening shootout with Yamaha wxc50 with Flac from NAS, vs an Ipad pro with Apple Music lossless and an USB bridge to spdif called ” sky song” .

So wether the switch of this reclocker is on battery or USB, the sound is bad?

According to Qobuz, inside the WXC-50, "all audio" (including USB) is processed by a Toshiba TMPM462F15FG, which feeds a Sabre 9006AS:
https://www.qobuz.com/fr-fr/info/hi-res-guide/bancs-d-essai/yamaha-wxc-50-un-streamer178709

Are you sure your USB XMOS reclocker adds something here? I'd suspect the TMPM462F15FG reclocks everything afterwards.
 

voodooless

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The chip that does sample rate conversion AND volume control in Yamaha wxc50 is a yamaha chip.YSS952.

Resampler THD+N is “only” -108 dB. Pass/Stopband is undefined, could be anything.. as far as resamplers go, that is quite poor performance.
 
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Tangband

Tangband

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Instead of adding a switch, they shall have better designed the power supply section?View attachment 142698
Well, the DC from the 9 volt battery goes to a LT1963 in ”sky song” that feeds the clocks and the digital output.
The spec for the external power supply ( in my case a 9 volt battery ) is from 6 volt DC up to 12 volt DC.
60AFC13B-BFAE-4C5B-B064-69D18780BD26.jpeg
 
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b4nt

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Not sure TMPM462 does more than management. All should be reclocked inside the WXC. The ESS dejittering...
 

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Tangband

Tangband

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Resampler THD+N is “only” -108 dB. Pass/Stopband is undefined, could be anything.. as far as resamplers go, that is quite poor performance.
Yes, thats pretty bad by todays standard.
It should be at least -130 dB .
 
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Tangband

Tangband

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Not sure TMPM462 does more than management. All should be reclocked inside the WXC. The ESS dejittering...

I have checked the sampling frequency from digital out on the Yamaha wxc50, and if the streamer is in ” player mode ” ( a switch at the back ) with no Volume Control avaliable, the digital output sampling frequency follows the source material .
If you put the streamer in ” pre amp mode ” then ALL material from spdif digital out is 48 KHz . And the volume can be changed from the spdif output . There is some kind of SRC in YSS952 going on in that case.
 

BluesDaddy

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Confirmation bias plus mismatched level so the iPad is slightly louder. May be other reasons, but until you level match and do some double blind listening tests it's not validated they you're actually hearing a difference. If you ARE really hearing a difference, measurements will show it.
 

b4nt

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The regulator for external supply is upgraded from the first made board of sky song to LT 1963 . The first ones had LT 1763.

An improvement? LT 1763, 20uV noise, LT 1963 40uV noise...

Isn't the external supply option there to use this interface with a phone?

I would use such an interface with old PCM DACs having not so clean clocks, recovering them from SPDIF.
 

Wes

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Confirmation bias plus mismatched level so the iPad is slightly louder. May be other reasons, but until you level match and do some double blind listening tests it's not validated they you're actually hearing a difference. If you ARE really hearing a difference, measurements will show it.

Yes.

Wake me up when a controlled listening test shows something.
 
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