USB vs Optical

[El Hefe]

Hello, I have just purchased the iMac 27" and has since set up the following: 1. MF X-A1 amp 2. ARCAM rDAC 3. EPOS M12.2 speakers 4. Airport Express Based on tehcnical specs on iMac, Airport Express and ARCAM rDAC (not based on what you hear), which one provides the highest SQ/ least signal and data loss?: 1. iMac to ARCAM rDAC via USB 2. iMac to ARCAM rDAC via optical 3. iMac wireless to Airport Express and then via optical from Airport Express to ARCAM rDAC I rip my CDs into either Apple Lossless or 320kbps MP3.

 

[garyw77]

Personally i wouldn't use any, i would consider using a coaxial input to the rDac enabling the 192Khz input (all the other inputs are 96Khz max), maybe using something like the M2Tech HiFace from USB to coaxial from your imac. I use one on my imac 27 and one on my mac mini with excellent results.

Just a suggestion, horses for courses on what sound you prefer

 

[El Hefe]

garyw77,

Thanks for the feedback. Yes, you have answered my question. Without basing it on how good each set up sounds, I wanted to know which set up 'streams' or 'allows' the highest bitstream.

But, did you actually mean the coaxial enabling the 192KHz input (meaning the source needs to produce 192 KHz in the first place) or you mean to allow rDAC to upsample the digital source?

I will google M2Tech HiFace.

 

[garyw77]

With the rDac the coaxial input will allow up to 192khz input where as the other inputs are limited to their maximum of 96khz. The source of course would have to produce 192khz in the first place for the dac to take advantage of this.

The M2Tech Hiface does support up to 192khz, so this enables you to use something like Pure Music which you can use to upsample to 64bit 192khz on your Mac and pass this to the rDac fully.

This is the system i use and find very good.

I'm sure other people will prefer other methods, but this is the one that works for me as i wanted to use the full input capabilities of the rDac. For some, the addition of around another £100 for the M2Tech HiFace is expensive, but in my opinion it produces a great sound from the Mac enabling a coaxial out. There are many threads on here regarding this little device of which i think most are pretty favourable.

Hope that helps. Good luck

 

[El Hefe]

You are right. rDAC only accepts but does not upsample as oppose to MF M1 DAC.

More questions if you dont mind:

1. Without Pure Music, the iMac does not transmit 192 kHz music to rDAC via M2Tech?
2. When I look at my music files info, it shows that my 320 kbps MP3 and apple lossles files are all at 44.1 kHz sampling rate. Hence, technically I dont need the M2Tech as the source is not 192 kHz anyway right?

 

[iMark]

El Hefe: 1. iMac to ARCAM rDAC via USB2. iMac to ARCAM rDAC via optical3. iMac wireless to Airport Express and then via optical from Airport Express to ARCAM rDACI rip my CDs into either Apple Lossless or 320kbps MP3.

Since your files are Apple Lossless or 320kbps mp3 I don't think there will be any difference in sound.

If you use an Airport Express you will get best results with Apple Lossless files because that's the file protocol that Apple uses. I use an Airport Express to a DACMagic and both Apple Lossless and other files sound excellent.

 

[noogle]

Not sure why everyone is so hung up on 192/24 - there's virtually no music available at this data rate. Even 96/24 albums are as rare as hen's teeth...

 

[Anonymous]

I'm new in computer-based music, and I'm pretty confused and happened to have the similar question. I would very appreciate if someone can offer the guidance:

1) If my lostless music is only converted from audio CD (16 bits/44.1Khz), would that make any difference among USB, TosLink or coaxial output to my DAC? If my DAC has upsampling, like MF M1 DAC, would that make any difference for the question?

2) If even there is no difference among the differenct output interfaces, considering the max sampling limitation for 16/44.1 source, is there still some possible sound quality difference? I was told that USB communication may be easily affected by unstable computer power supply, and that may affect the sound quality. Does that mean the digital data will not be "lostless" over the USB communication between computer and DAC? How is the situation if we use coaxial or "Mac->AirportExpress->Toslink->DAC"?

3) The other question is about the Software for the music source. I saw some people posted that Foobar may have better sound quality than iTune as the music source. Is it true? If I got the same lostless music file, shouldn't that be the same no matter I use Foobar or iTune to play and send the music bit streams to DAC via USB or coaxial?

Any comments will be very appreciated. Thanks.

 

[noogle]

1) I don't think you'll find much difference between the three interfaces. Toslink has a slight advantage in that, because it's optical, it isolates the electrically noisy laptop from the sensitive DAC.

2) You won't lose any data down any link - the problem is in the timing of the data. PCs and Macs have cheap/noisy clock circuits that have high jitter, which results in loss of sound quality. A USB to Toslink adapter like the MF V-Link will re-clock the signal using a much better quality clock circuit and fix this problem. Airport Express will also generate jitter.

3) I think iTunes is capable of "bit perfect" playback (i.e. you get out what you put in) but I'm not an expert on this. Some players and OSs transcode the input files and are not bit perfect. A general rule is to always leave the player volume control at 100%.