Help Please - DAC with USB - only 48khz sampling?

[Sally73]

Hi

I wonder if you could give a newbie some advice please. I have today ordered a Musical Fidelity X-DAC v8, it has a USB input so I plan to use it with a laptop this way. However, I've read on the Musical Fidelity website tonight that via USB the X-Dac samples up to 48khz - will I still be receiving 24 bit sound this way? (the unit is capable of upsampling to 24 bit, but I'm not sure if it will upsample to 24 bit by USB). If not, is there a way I can get it to upsample to 24 bit by USB?

Thanks in advance,
Sally

 

[pedxing]

I never heard of this product before and I was interested in it after reading your question, so I downloaded the manual from their web site. I suggest you download the manual too.

The digital output is apparently a simple pass through with the digital inputs, so the signals are not modified.

Otherwise, it seems like everything else is oversampled to 192 kHz and processed by the 24 bit DAC. So all of this is internal inside of a black box. Why is it so important to get 24 bits?

The USB input is USB 1.1. The computer is suppose to detect the DAC and install "generic" driver itself. I am not sure if this is 24 bit or 16 bit stream.

 

[Sally73]

Hi Pedxing

Thanks for your reply. I did not see the manual on the website on my first visit (the website's text is not displaying correctly on my computer for some reason which is probably why I missed it), so I will download that, thanks.

What I am going to do is use a laptop computer as my source, with uncompressed files from my CDs, then plug a USB lead from the laptop directly into the DAC. As the files will be 16 bit that signal should be sent to the DAC intact, and like you say the DAC will then upsample to 24 bit. I believe 24 bits will give my music files greater clarity - I had a demo of the DAC hooked up to a MF X-Can v3 and hard-drive music system yesterday, the sound quality was excellent. I would certainly recommend this DAC - it has just been released here in the UK.

Best wishes,
Sally

 

[nkoulban]

USB gives you 16 bit up to 48K... thats it. If you want to go further, you need to use coax or optical. If you have a mac it has an optical out, if you have a Windows PC you may need to buy a PCMICA sound card with coax and or optical out to get SACD levels of sound quality.

 

[psyllium]

Quote:

Originally Posted by nkoulban /img/forum/go_quote.gif USB gives you 16 bit up to 48K... thats it.

Explain how the M-Audio Transit and Audiophile USB devices do 24-bit/96khz then?

 

[Dept_of_Alchemy]

Quote:

Originally Posted by nkoulban /img/forum/go_quote.gif USB gives you 16 bit up to 48K... thats it. If you want to go further, you need to use coax or optical. If you have a mac it has an optical out, if you have a Windows PC you may need to buy a PCMICA sound card with coax and or optical out to get SACD levels of sound quality.

That's not quite true as far as I know. The m-audio Transit (USB -> toslink converter) for example is capable of handling 24bit/96khz data streams.

 

[cage85]

the dac in question uses USB 1.1 according to pedxing, which is only capable of 16-bit 48Khz. the M-Audio devices mentioned use USB 2.0 IIRC.

 

[Herandu]

Quote:

Originally Posted by psyllium /img/forum/go_quote.gif Explain how the M-Audio Transit and Audiophile USB devices do 24-bit/96khz then?

The most common USB chip mentions only 32/44.1/48KHz as their datasheet.
If the 24bit/96KHz is indeed true then they are using a chip I would like to know about.

 

[psyllium]

Quote:

Originally Posted by cage85 /img/forum/go_quote.gif the dac in question uses USB 1.1 according to pedxing, which is only capable of 16-bit 48Khz. the M-Audio devices mentioned use USB 2.0 IIRC.

I'm preeettyyy sure the M-Audio ones I mentioned use USB 1.1. The 96KHz/24-bit raw data would take around 4.6mbit/sec. The USB 1.1 standard can handle 12mbit/set. Even if the 96/24 stream was padded out to 32 bits, it'd be 6.1mbit/sec, so it looks like there is enough bandwidth for the stream and any additional protocol gear.

I would agree though that a lot of USB DACs only support 16-bit 48KHz. Not sure on what this particular model posted at the top of the thread does.

 

[Sally73]

Thanks for all your replies, but I am a newbie and I'm getting rather confused here.

>USB gives you 16 bit up to 48K... thats it. If you want to go further, you >need to use coax or optical.

I really don't understand this. My files on the laptop I will be using will be 16 bit (which is 48k as I understand it) files - this 16 bit/48k stream will be sent via USB to the X-DAC v8. As the X-DAC upsamples to 24 bit, won't this 16 bit stream be upsampled to 24 bit as well? As far as I can see on the Musical Fidelity website, it only says it can send up to a 16 bit/48k stream via USB, not that this 48K stream will not be upsampled to 24 bit/96k?

Sally

 

[slwiser]

Quote:

Originally Posted by Sally73 /img/forum/go_quote.gif Hi I wonder if you could give a newbie some advice please. I have today ordered a Musical Fidelity X-DAC v8, it has a USB input so I plan to use it with a laptop this way. However, I've read on the Musical Fidelity website tonight that via USB the X-Dac samples up to 48khz - will I still be receiving 24 bit sound this way? (the unit is capable of upsampling to 24 bit, but I'm not sure if it will upsample to 24 bit by USB). If not, is there a way I can get it to upsample to 24 bit by USB? Thanks in advance, Sally

The USB interface is a function of the particular designers choice of chips that convert the USB signal to SPDIF. Apparently they are thinking much like Jim Hagerman of www.hagtech.com in that he uses the same chip set for that conversion. Other chips will handled 96 kHz but may not do the job as well as the chip that is being used in the device you are getting, at least from these designers viewpoints. Note that this does not mean that the device is limited to 48 kHz on all digital inputs but only at the USB port. What I do is use eight my HagUSB or my M-Audio USB Audiophile. The M-Audio device can supply 96/24 info to my Lavry while the Hag device will only do what your device does at the USB port.

To answer you last question at upsampling to 24 bits I think that this is done if I am reading the specification right already. It is taking the 44.1 or 48 kHz and upsampling it 8x.

 

[Sally73]

Thanks for your reply slwiser. Just got a couple more questions though regarding USB input on this DAC:

>Other chips will handled 96 kHz but may not do the job as well as the chip >that is being used in the device you are getting, at least from these >designers viewpoints. Note that this does not mean that the device is >limited to 48 kHz on all digital inputs but only at the USB port.

A 96 khz stream would be a much higher audio file though - something like DVD-Audio - wouldn't it? I only have 48 khz (16 bit CD files) to send, so I don't think I need to send a 96 khz stream.

I just want to send a 48 khz/16 bit stream via USB, and for the DAC to upsample it to 24 bit (which like you say is x8 upsampling) - do you think that this will be the case with this DAC?

Thanks in advance,
Sally

 

[slwiser]

Quote:

Originally Posted by Sally73 /img/forum/go_quote.gif Thanks for your reply slwiser. Just got a couple more questions though regarding USB input on this DAC: >Other chips will handled 96 kHz but may not do the job as well as the chip >that is being used in the device you are getting, at least from these >designers viewpoints. Note that this does not mean that the device is >limited to 48 kHz on all digital inputs but only at the USB port. A 96 khz stream would be a much higher audio file though - something like DVD-Audio - wouldn't it? I only have 48 khz (16 bit CD files) to send, so I don't think I need to send a 96 khz stream. I just want to send a 48 khz/16 bit stream via USB, and for the DAC to upsample it to 24 bit (which like you say is x8 upsampling) - do you think that this will be the case with this DAC? Thanks in advance, Sally

A 96 kHz stream would be DVD-A type yes.

Normal CDs are 44.1/16 not 48/16. So if you are streaming 48/16 this suggests that you are recording your own music and wanting to play it out. Yes?

The 8x upsampling is a function of the device your are getting and is done internally. This suggests to me that you can not turn it off unless it has a defeat switch readily available. Some high end stuff provides this type of defeat. All upsampling DACs do upsampling for one reason and that is to get rid of high frequency energy using filters. There are many web sites that discuss these issues which I do not have much depth in.