I caught a shop master of a new yintenet official shop. At first he denied. Then he said the rate is manual set instead of following original document. He said has not re-sample it. No loss in audio quality. Raise the sample rate for compatible with DAC filter. Asked the calculation method of raising sample rate, no answer give.
Is raising sample rate matter, or no harm as the shop master said? I am not electronic professional.
EDIT:
He suggest you using internal DAC, the sound quality is very good. No frequency change in internal I2S.
Should you confirm the internal frequency?
Is raising sample rate matter, or no harm as the shop master said? I am not electronic professional.
EDIT:
He suggest you using internal DAC, the sound quality is very good. No frequency change in internal I2S.
Should you confirm the internal frequency?
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Its definitely resampled or it could not come out at the same pitch when played back at 48kHz. Its not a major problem no, but it is strange that one of the selectable sample rates is 48kHz. Nobody uses that any more. I'd prefer that the internal clock oscillator gave rates at multiples of 44k1 though.
I will take a look inside in the next day or so to confirm what the original vendor said. It is very hard to believe that he'd run the I2S at 44k1 and the SPDIF at 48kHz - that would require having two independent clock oscillators. But its possible that internal to the DSP there are two PLLs to generate the required frequencies. Possible, but unlikely. I disagree with him about the sound of the internal DAC - but as Jean-Paul says, its early days yet for the SQ. Over time, it might become less tizzy.
I will take a look inside in the next day or so to confirm what the original vendor said. It is very hard to believe that he'd run the I2S at 44k1 and the SPDIF at 48kHz - that would require having two independent clock oscillators. But its possible that internal to the DSP there are two PLLs to generate the required frequencies. Possible, but unlikely. I disagree with him about the sound of the internal DAC - but as Jean-Paul says, its early days yet for the SQ. Over time, it might become less tizzy.
May be the DSP resampled the data. The volume control can control SPDIF and RCA out.
The website has not state what DSP used. Look for the part no. of DSP may have some hints.
The website has not state what DSP used. Look for the part no. of DSP may have some hints.
I opened it up - there's one crystal oscillator at 24.576MHz and the data pins of the SPDIF transmitter (CS8406) and the DAC (CS4398) are connected together. So its impossible that the DAC could run at a different clock rate from the SPDIF out.
There are two 48pin QFPs, neither of which have identifiable markings. On one they've been scratched off.
The internal opamps are NE5532 and socketed - I'll try substituting them for LM6172 and see if the tizziness in the sound mellows out. Build quality looks above average for the price - nice job.
There are two 48pin QFPs, neither of which have identifiable markings. On one they've been scratched off.
The internal opamps are NE5532 and socketed - I'll try substituting them for LM6172 and see if the tizziness in the sound mellows out. Build quality looks above average for the price - nice job.
May be he said the I2S run at different clock rate. Resample may occurred at the DSPs. Its overdone for DIY but nice to mid-low end market.
The last choice may by Maya.
bbp hifi²¥·ÅÆ÷ Êý×ÖתÅÌ 192k 24bit wav²¥·ÅÆ÷ bbp-101plus-ÌÔ±¦Íø
This has nice looking. Expensive and sound in theory.
The last choice may by Maya.
bbp hifi²¥·ÅÆ÷ Êý×ÖתÅÌ 192k 24bit wav²¥·ÅÆ÷ bbp-101plus-ÌÔ±¦Íø
This has nice looking. Expensive and sound in theory.
Swapped over the opamps - seems quite a significant step up, though its early days and I have mislaid the original SD card I was listening to with my Mozart on it. So I'll hold off giving the unequivocal thumbs up to changing the opamps to LM6172 until I've listened to the same music. But early impressions very promising, especially as 6172s aren't particularly expensive.
It would be wise to first let it run in and then do any changes IMO as things will interact with eachother. It would not surprise me that putting the original opamps back in after a few days will give different results. The factory offers an upgrade in the form of OPA2604's. I decided to order it with OPA2604 as NE5532 are not my cup of tea (although they measure best of all).
Anyway, the LM6172 are bipolar opamps with AFAIK much higher input bias and offset current than NE5532 which can/will result in a higher offset voltage at the output. Can't check both data sheets right now but I think changing them for JFET input opamps would be a better choice. As soon as I have full docs I will check the schematics.
Edit: just checked and statements regarding opamps are right. Sorry for sounding patronizing but intentions are positive.
BTW is the oscillator a 3.3 V version or are they doing the same trick many companies seem to do by using 5 V oscillators combined with 3.3 V logic ? Hate that !
Anyway, the LM6172 are bipolar opamps with AFAIK much higher input bias and offset current than NE5532 which can/will result in a higher offset voltage at the output. Can't check both data sheets right now but I think changing them for JFET input opamps would be a better choice. As soon as I have full docs I will check the schematics.
Edit: just checked and statements regarding opamps are right. Sorry for sounding patronizing but intentions are positive.
BTW is the oscillator a 3.3 V version or are they doing the same trick many companies seem to do by using 5 V oscillators combined with 3.3 V logic ? Hate that !
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You don't sound patronizing to me - I'm unconcerned about output offsets as there are those big red caps between the opamps and the RCA connectors. The bias currents are indeed high but not bad enough to impact headroom as the supplies are +/-12V.
Still haven't turned up the original material but I'm noticing the tonality of solo violin corrupted - this is something I've noticed on other S-D type DACs. The violin is made to sound more like a viola, losing its bite - as if the rosin on the bow got changed to treacle somehow. But the upside is the tizziness is lower and the soundstage has deepened. But come to think of it I think I had the treble control in a random position (above zero) without realizing it before, so that early listening is nullified 🙂 Anyway the jump factor just isn't there when compared to my multibit DAC. I'll swap NE5532 back in to see how much of the improvement is the opamps and how much the treble control 😀
Still haven't turned up the original material but I'm noticing the tonality of solo violin corrupted - this is something I've noticed on other S-D type DACs. The violin is made to sound more like a viola, losing its bite - as if the rosin on the bow got changed to treacle somehow. But the upside is the tizziness is lower and the soundstage has deepened. But come to think of it I think I had the treble control in a random position (above zero) without realizing it before, so that early listening is nullified 🙂 Anyway the jump factor just isn't there when compared to my multibit DAC. I'll swap NE5532 back in to see how much of the improvement is the opamps and how much the treble control 😀
The new official shop in Kwangchow has a Mod version at RMB1280. The shop master said all op amps upgraded.
The QFPs may be the dual DSPs. Raising frequency may no harm, as some DACs has raising option.
The QFPs may be the dual DSPs. Raising frequency may no harm, as some DACs has raising option.
Some hint from the web site leaflet:
Audio document decoded by dual DSPs hardware decoder....
Its possible that the SD stream send to the DSPs and then decode to I2S. The output sample rate is always resampled by the DSP.
Audio document decoded by dual DSPs hardware decoder....
Its possible that the SD stream send to the DSPs and then decode to I2S. The output sample rate is always resampled by the DSP.
It may use vs1053 of VSLI. This chip read the pcm stream and convert the sample rate. Other solutions use FPGA or mcu, need to code it. The vs1053 has other benefit such as tone control, volume control and fade in fade out between songs.
I think the impact on audio quality is important.
I think the impact on audio quality is important.
A good guess at the VS1053 - it agrees with one of the Taobao photographs. But this part's datasheet does not say anything about it being able to do sample rate conversion so I'm even more puzzled now than I was...😕
Hi, maybe this is of some assistance deciphering whether it is the VS1053 chip (and for other possible future owners of this device):
http://www.vlsi.fi/fileadmin/datasheets/vlsi/vs1053.pdf
Edit: I noticed VLSi made some patches just 2 days ago for this chip. It seems we have to regularly check on firmware updates. I was promised those will be emailed to me since a support page does not exist...
http://www.vlsi.fi/fileadmin/datasheets/vlsi/vs1053.pdf
Edit: I noticed VLSi made some patches just 2 days ago for this chip. It seems we have to regularly check on firmware updates. I was promised those will be emailed to me since a support page does not exist...
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I haven't seen this machine. I am not electronic trained. I have a strength that connect irrelevant information to assemble a whole picture.
I had taught to the shop master of yintenet and Maya. And look at what QA550 and bb101 plus said. So I guess Maya and Yintenet use Wince or Linux embedded system and a MP4 decode chip.
BB101 plus use FPGA to decode pcm document and FPGA to convert I2S to spdif. QA550 use pic to decode pcm and may be an transmitter chip to convert I2S to spdif.
BB101 plus and QA550 is easy to understand, but not necessary make it better. VLSI(may be TI has equivalent) is technically and financially sound. Its better to judge the audio quality.
I found vs1053 evaluation board around RMB60. Should you buy one to make your own SD player?
µ¥Æ¬»ú¿ª·¢°åµ¥Æ¬»úѧϰ°åÅä¼þ-VS1053Ä£¿é MP3Ä£¿é(°åÔؼÒô¹¦ÄÜ-ÌÔ±¦Íø
I had taught to the shop master of yintenet and Maya. And look at what QA550 and bb101 plus said. So I guess Maya and Yintenet use Wince or Linux embedded system and a MP4 decode chip.
BB101 plus use FPGA to decode pcm document and FPGA to convert I2S to spdif. QA550 use pic to decode pcm and may be an transmitter chip to convert I2S to spdif.
BB101 plus and QA550 is easy to understand, but not necessary make it better. VLSI(may be TI has equivalent) is technically and financially sound. Its better to judge the audio quality.
I found vs1053 evaluation board around RMB60. Should you buy one to make your own SD player?
µ¥Æ¬»ú¿ª·¢°åµ¥Æ¬»úѧϰ°åÅä¼þ-VS1053Ä£¿é MP3Ä£¿é(°åÔؼÒô¹¦ÄÜ-ÌÔ±¦Íø
Note: The sample rate of the audio file and the I2S rate are independent. All audio will be
automatically converted to 6.144 MHz for VS1053 DAC and to the configured I2S rate using a
high-quality sample-rate converter.
p. 77 of the datasheet.
Very well spotted Sherlock 🙂 I'd made the lazy man's assumption that if they'd put an SRC inside they'd want to trumpet that on the first page or the block diagram. But they squirreled it away inside, the sneaky b*ggers 😀
That explains the three choices of output sample rate as the config register on that page has precisely those three options. As to how high quality the SRC is, I plan to make some measurements at some point.
<edit> As for the eval board, the fact that the SRC isn't bypassable is something of a show-stopper for me. If and when I build an SD card player, I definitely want bit perfect.
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