[fordgtlover]

Hi

I have been running a USB DAC for a while now, but I am looking to explore an option that only uses SPDIF.

Do people use USB to SPDIF convertors? ARe they reasonable for decent audio?
Is a sound card with SPDIF out a better, quieter, more cost effective option?

I am really more focussed on quality rather than a cheap solution.

Any views on this would be appreciated.

Cheers

 

[nick_charles]

Quote:

Originally Posted by fordgtlover /img/forum/go_quote.gif Hi I have been running a USB DAC for a while now, but I am looking to explore an option that only uses SPDIF. Do people use USB to SPDIF convertors? ARe they reasonable for decent audio? Cheers

I use an Edirol UA-1EX USB sound card, but I only use it as a USB to SPDIF converter and feed the SPDIF to my Entech. It works very well and is very quiet with a born digital signal.

 

[1UP]

Variability of implementation of the devices involved makes it impossible to generalise, really.

But have a read of this: Audial :: S/PDIF or USB? (page 1)

 

[nick_charles]

Quote:

Originally Posted by 1UP /img/forum/go_quote.gif Variability of implementation of the devices involved makes it impossible to generalise, really. But have a read of this: Audial :: S/PDIF or USB? (page 1)

Interesting. The jitter graph for the Philips UDA1321 suggests that this receiver has really really high jitter. The author mentions ~ 1ms this is something like 250,000 x worse than the Oppo (which is bad enough) if jitter is such an issue how on earth could something like this be even remotely listenable ?

 

[FallenAngel]

Bottom line for me - if you're going for CD content, USB-S/PDIF is OK, if you're going for higher definition, go with a soundcard that offers S/PDIF output.

 

[Andrew_WOT]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Bottom line for me - if you're going for CD content, USB-S/PDIF is OK, if you're going for higher definition, go with a soundcard that offers S/PDIF output.

The linked article shows the same amount of jitter for USB and card with S/PDIF output.

 

[1UP]

Wavelength's USB DACs support up to 96khz; they also (uniquely at this time, I believe) implement ASYNC mode USB which takes jitter pretty much out of the equation.

So again, it's not quite enough to just decide between USB vs soundcard; rather than evaluating the performance of a given unit's implementation and how that interacts with the rest of your gear. within a given budget ofc. Those Wavelength units aren't cheap.

Here's another interesting precis: http://www.computeraudiophile.com/node/460#comment-2367

 

[LnxPrgr3]

My Audigy 2 NX does 96kHz/24-bit over USB, and from what I've read also does async transfers. It was $100 new, and a refurb can be had now for around $50. I can tell you that some experimentation here has found the USB to be far cleaner than the optical input, for odd test signals (43kHz is properly inaudible over USB, and produces a mess over optical).

I've read people swear up and down though on here that, given a choice between USB and optical to get out of the computer, optical is the best option. I'm sure that's true in some cases, but implementation does matter.

 

[nick_charles]

Quote:

Originally Posted by LnxPrgr3 /img/forum/go_quote.gif My Audigy 2 NX does 96kHz/24-bit over USB, and from what I've read also does async transfers... I can tell you that some experimentation here has found the USB to be far cleaner than the optical input, for odd test signals (43kHz is properly inaudible over USB, and produces a mess over optical).

I would wager that 43Khz is still inaudible over optical, do you mean that it folded noise into the audible range ?, if all the noise was hypersonic it probably isnt worth worrying about

Quote:

I've read people swear up and down though on here that, given a choice between USB and optical to get out of the computer, optical is the best option. I'm sure that's true in some cases, but implementation does matter.

I use a USB to SPDIF gizmo and I can do (near) instant switching between it and the optical feed from a CD transport and instant switching between the analog outs from my CD player and the analog out from the external DAC fed by either CD transport or PC.

If there is any degradation going by this circuitious route it is pretty small and I cannot detect it.

 

[LnxPrgr3]

Quote:

Originally Posted by nick_charles /img/forum/go_quote.gif I would wager that 43Khz is still inaudible over optical, do you mean that it folded noise into the audible range ?, if all the noise was hypersonic it probably isnt worth worrying about

It folded over into the audible range, so the result was very audible when it shouldn't have been -- it sounded like a loud buzzing.

 

[nick_charles]

Quote:

Originally Posted by LnxPrgr3 /img/forum/go_quote.gif It folded over into the audible range, so the result was very audible when it shouldn't have been -- it sounded like a loud buzzing.

Interesting, how loud was the test signal and how much gain did you need to make the buzzing audible ?

 

[fordgtlover]

Quote:

Originally Posted by 1UP /img/forum/go_quote.gif Wavelength's USB DACs support up to 96khz; they also (uniquely at this time, I believe) implement ASYNC mode USB which takes jitter pretty much out of the equation. So again, it's not quite enough to just decide between USB vs soundcard; rather than evaluating the performance of a given unit's implementation and how that interacts with the rest of your gear. within a given budget ofc. Those Wavelength units aren't cheap. Here's another interesting precis: http://www.computeraudiophile.com/node/460#comment-2367

This is an excellent point. While I am looking for decent quality, the DAC option I am looking at is somewhat speculative. So, I am looking to balance two objectives. The first is to buy something that will allow the DAC to work properly without being impeded (too much) by the quality of the connection between my PC and the DAC. Secondly, too not spend too much money at this stage on a speculative option.

I have no idea whether the wavelength gear is really any better than other options, but it is well beyond my reach for this. I'd have to get some 'very' solid references to consider spending that sort of money.

I am looking at perhaps the Edirol unit or a M-Audio Transit. Although I would prefer Coax rather than Toslink.

There are a few soundcards that might be reasonable short term options. If I can get them for the right price. I am struggling to find a decent card for reasonable money that outputs SPDIF through coax. There seem to be a few available in the US, but I can't find them here in Australia.

The other one I am looking at is the Blue Circle Thingee. Although in a recent review in UHF magazine, the reviewer commented that its onboard DAC sounded better than when he used the Thingee to output SPDIF to his external Counterpoint DAC[?] Article Link

The comment in that review confused me greatly. I could understand the difference in quality if the connection types were different. But assuming that the Thingee was connected via USB in both cases, it suggests that the Thingee is better as a DAC than for converting USB to SPDIF. I am assuming that its DAC would be using SPDIF anyway - although we don't know what DAC chip they are using in the Thingee. So why should there be a difference?

 

[1UP]

Alright then; according to Gordon Rankin's distinctions you want, "1) Standard Adaptive products based on the PCM27xx series parts from TI/BB"

This is what the HagUSB, Trends UD10.1 and Thingee all do (USB-S/PDIF with same DAC). All have been recommended on this board.

I can't read that review but it's not a huge surprise if the external DAC gives better sound with the Thingee used as a pure S/PDIF transport. The PCM270X's direct analogue out is a mid-fi solution designed originally for low-z headphones, as provided on the HagUSB and Trends.

I would guess what the Blue Circle guy's done is just change the cap values on the analogue out to adjust the RC filter for line out. They should all offer comparable performance as a pure transport, though.

The HagUSB and Trends look better value to me if used for this purpose; both simple solutions, circuits are public, both transformer coupled S/PDIF - the Trends with BNC and SMD parts, which are good. Despite the Thingee being oh-so-secret in its "enclosure", I seriously question how much better it could be to justify the extra cost. Better PLL, better power regulation? Would these make a quantifiable difference/improvement? Ditto the Trends' battery power option.

As long as you're happy with 44.1, 48 khz sample rates, any of these USB devices looks fine for you.

 

[fordgtlover]

Quote:

Originally Posted by 1UP /img/forum/go_quote.gif snip I can't read that review but it's not a huge surprise if the external DAC gives better sound with the Thingee used as a pure S/PDIF transport. The PCM270X's direct analogue out is a mid-fi solution designed originally for low-z headphones, as provided on the HagUSB and Trends. snip

Thanks for the response.

The section I have highlighted above is the part in question. The reviewer found the exact opposite. He found that the Thingee sounded better as a standalone DAC compared to when he used it as a USB -> S/PDIF convetor fed to an expensive external DAC. That's the part that doesn't make sense to me.

In another review I found, the reviewer comments that he has used the HAGUSB for a while and the Thingee sounds better to him than the HAGUSB.

 

[1UP]

Well for the first review, I don't know that DAC or his system - maybe they just suck.

For the second review, honestly I've never read such appalling drivel.

[size=x-small]"Whether it was newer-technology chips (IT'S THE SAME CHIP), the circuit design (THEY BOTH TAP THE ANALOGUE OUT DIRECT FROM THE CHIP AND APPLY A HIGH-PASS FILTER, OTHER THAN THAT, THERE IS NO "CIRCUIT"), the integral filter (NO IDEA WHAT HE'S TALKING ABOUT), or maybe even the pipe (!) (YEAH RIGHT, MATE), the Thingee is the new standard bearer among USB-to-S/PDIF converters."[/size]

He's comparing the HagUSB's headphone out to the Thingee's lineout - the bass cutoff of the HagUSB in this application makes the comparison completely invalid.

Both these reviews/reviewers look like tosh to me.