[Scrith]

After acquiring a Benchmark DAC1 USB I was able to conduct some direct blind comparisons between it and my Empirical Audio Off-Ramp Turbo 2 w/ SuperClock 4. To both my ears and my wife's (whose ears are more sensitive than mine) the Benchmark DAC1 USB sounded SLIGHTLY better when being driven directly by a USB connection. I sold the expensive S/PDIF converter a few days later.

 

[mrfloopy]

Quote:

Originally Posted by athenaesword /img/forum/go_quote.gif you received a more jittery signal on the USB->dac than through a usb-> spdif converter? i thought USB is supposed to have minimal jitter?

Quote:

Originally Posted by Fidelity /img/forum/go_quote.gif USB does not provide a smooth constant stream of data it sends bursts (chunks) of data at a time, unlike SPDIF.

Quote:

Originally Posted by Andrew_WOT /img/forum/go_quote.gif Except that most USB DACs work in Isochronous transfer mode, which is a continuous stream.

Quote:

Originally Posted by Fidelity /img/forum/go_quote.gif Yes but the packet sizes are not 100% consistent, no guarantee that each packet will arrive 100% on time, IIRC some buffer mechanism is used.

USB audio is apparently quite jittery as I understand it, so the system that's receiving the USB data relies on the quality of the USB receiver chip and the system's clock to pass good-timing-quality data to the actual DAC chip – in my case, the USB receiver and clock in my USB-to-SPDIF adapter apparently does this better than the built-in USB-receiver-plus-internal-clock in my NOS DAC! (Which is not a bad thing, because the DAC's designer deliberately designed a simple clock system in the DAC!)

 

[theeviljesus]

Quote:

Originally Posted by Scrith /img/forum/go_quote.gif After acquiring a Benchmark DAC1 USB I was able to conduct some direct blind comparisons between it and my Empirical Audio Off-Ramp Turbo 2 w/ SuperClock 4. To both my ears and my wife's (whose ears are more sensitive than mine) the Benchmark DAC1 USB sounded SLIGHTLY better when being driven directly by a USB connection. I sold the expensive S/PDIF converter a few days later.

The Off-Ramp is 990$ right?...I mean expensive mustn't mean good, but this is really disillusioning. Well it's just (not meant disrespectful) two opinions and I already read the opposite, but even the possibility that it's just as good or even worse than a direct USB input makes me worry about a pc -> USBtoSPDIF -> DAC solution. Nonetheless I'll buy a USBtoSPDIF unit (a cheaper one though

) because my Yamaha receiver has an integrated 192 kHz/24-Bit DAC - that's why I try this first before I buy a separate DAC (no HP amp yet anyways).

I found some options like: ESI U24 XL, M-Audio Transit, HagUSB or more expensive: Trends Audio UD-10.1 and emu 0404 (I think 0202 has no digital out, right?)

Any opinions on these? (searched the forums and found some comments but would appreciate some more input - especially direct comparisons)

I hope the question is also in the OP's interest - actually don't wan't to hijack his thread

Thanks!

 

[Andrew_WOT]

Quote:

Originally Posted by Scrith /img/forum/go_quote.gif After acquiring a Benchmark DAC1 USB I was able to conduct some direct blind comparisons between it and my Empirical Audio Off-Ramp Turbo 2 w/ SuperClock 4. To both my ears and my wife's (whose ears are more sensitive than mine) the Benchmark DAC1 USB sounded SLIGHTLY better when being driven directly by a USB connection. I sold the expensive S/PDIF converter a few days later.

Wow, thanks for sharing that, I was sooo curios about these converters.
Read this
http://www.head-fi.org/forums/4981107-post1.html
Quote:

Originally Posted by bdh When Steve sent back the DAC, he wrote: "BTW, I demoed the S/PDIF input on your modded DAC-1 with my Off-Ramp Turbo 2 USB converter.* It completely buried the Benchmark USB input, even going through S/PDIF.* I didn't realize the stock USB input was that bad.* You cannot believe everything you read, especially from Benchmark." So I ordered one of those, well actually it will be a Off-Ramp Turbo 3, as he said there are some improvements he's making over version 2. His products currently have a three month waiting list, but I'm excited to try it given how much I've liked the Benchmark mods.

 

[b17m4p]

Yeah I would be very interested in some opinions about the empirical audio converters from non-biased users (a.k.a. not the desiner and not people who have just spent ~$1k on one of these).

 

[athenaesword]

Quote:

Originally Posted by Andrew_WOT /img/forum/go_quote.gif Wow, thanks for sharing that, I was sooo curios about these converters. Read this http://www.head-fi.org/forums/4981107-post1.html

wow. completely polarized opinions.

 

[banause]

how about using a emu 0202 usb or 0404 usb with software upsampling to 24/192 - than grab the i2s signal from the dac and use a better dac instead (like opus dac)...

seems like the only possibilty to get 24/192 via usb 2.0 right now...
any thoughts?

banause

 

[athenaesword]

Quote:

Originally Posted by banause /img/forum/go_quote.gif how about using a emu 0202 usb or 0404 usb with software upsampling to 24/192 - than grab the i2s signal from the dac and use a better dac instead (like opus dac)... seems like the only possibilty to get 24/192 via usb 2.0 right now... any thoughts? banause

some have mentioned that certain dacs like the Benchmark DAC1 can handle 24bit/192khz straight out from USB.

I'd rather spend the money that on a single better DAC than a 2 DAC solution.

 

[audioengr]

Quote:

Originally Posted by theeviljesus /img/forum/go_quote.gif The Off-Ramp is 990$ right?...I mean expensive mustn't mean good, but this is really disillusioning. Well it's just (not meant disrespectful) two opinions and I already read the opposite, but even the possibility that it's just as good or even worse than a direct USB input makes me worry about a pc -> USBtoSPDIF -> DAC solution. Nonetheless I'll buy a USBtoSPDIF unit (a cheaper one though ) because my Yamaha receiver has an integrated 192 kHz/24-Bit DAC - that's why I try this first before I buy a separate DAC (no HP amp yet anyways). I found some options like: ESI U24 XL, M-Audio Transit, HagUSB or more expensive: Trends Audio UD-10.1 and emu 0404 (I think 0202 has no digital out, right?) Any opinions on these? (searched the forums and found some comments but would appreciate some more input - especially direct comparisons) I hope the question is also in the OP's interest - actually don't wan't to hijack his thread Thanks!

Here is a reviewer shootout of various USB converters:
ramblings computer based audio

Scriths Off-Ramp Turbo 2 was an earlier version that was never updated. I since received it from the new owner and updated it.

The third generation Off-Ramp 3 has now replaced it and is $999. It has I2S, S/PDIF and AES/EBU outputs and can accomodate Superclock or Ultraclock.

If someone wants to do a comparison of the USB input on the DAC-1 to the S/PDIF input driven from an Off-Ramp 3, I will provide money-back less shipping if it is not significantly better.

BTW, the S/PDIF input on the DAC-1 needs modding to be decent IMO.

Steve N.
Empirical Audio

 

[audioengr]

Quote:

Originally Posted by athenaesword /img/forum/go_quote.gif some have mentioned that certain dacs like the Benchmark DAC1 can handle 24bit/192khz straight out from USB.

Not true. The USB interface is limited to 24/96. Off-Ramp uses the same USB firmware as the Benchmark DAC-1.

Steve N.
Empirical Audio

 

[Scrith]

I think it comes down to the implementation, rather than just some blanket statement of one approach always being better than the other.

And, yes, I was running an Off-Ramp that hadn't been updated to the latest firmware (although it was only a few months old at the time). As I understand it, the Off-Ramp now uses the same firmware that is built into the Benchmark DAC1 USB, so it no longer requires that awful M-Audio driver that it used to ship with.

I'm happy for now with the Benchmark DAC1 USB, but my next big test will probably be the new soon-to-be-released Ayre DAC that is receiving a lot of attention. The Ayre DAC has the same USB implementation as the Wavelength DACs, which use some type of asynchronous approach for data transfer that leaves all timing-related control in the DAC itself. There is no possibility for "jitter" from the computer end because it is merely transferring data using asynchronous packets...which is probably how external USB audio devices should have been implemented in the first place.

 

[audioengr]

Quote:

Originally Posted by Scrith /img/forum/go_quote.gif I think it comes down to the implementation, rather than just some blanket statement of one approach always being better than the other. And, yes, I was running an Off-Ramp that hadn't been updated to the latest firmware (although it was only a few months old at the time). As I understand it, the Off-Ramp now uses the same firmware that is built into the Benchmark DAC1 USB, so it no longer requires that awful M-Audio driver that it used to ship with. I'm happy for now with the Benchmark DAC1 USB, but my next big test will probably be the new soon-to-be-released Ayre DAC that is receiving a lot of attention. The Ayre DAC has the same USB implementation as the Wavelength DACs, which use some type of asynchronous approach for data transfer that leaves all timing-related control in the DAC itself. There is no possibility for "jitter" from the computer end because it is merely transferring data using asynchronous packets...which is probably how external USB audio devices should have been implemented in the first place.

Actually, there were additional improvements to the Off-Ramp Turbo 2 besides the new firmware, which makes a huge difference.

Async is certainly nice, and I'm in the process of doing one with 24/192 support myself, but I dont expect it to be a lot better than my current Off-Ramp 3 with a good USB cable. It will however save the customer money because they can use any USB cable, in theory.

The reality is usually a bit different than theory though, if you read the posts on computer asylum about the Synergistic USB cable used with Async interfaces.....

Steve N.

 

[theeviljesus]

Quote:

Originally Posted by audioengr /img/forum/go_quote.gif Here is a reviewer shootout of various USB converters: ramblings computer based audio Scriths Off-Ramp Turbo 2 was an earlier version that was never updated. I since received it from the new owner and updated it. The third generation Off-Ramp 3 has now replaced it and is $999. It has I2S, S/PDIF and AES/EBU outputs and can accomodate Superclock or Ultraclock. If someone wants to do a comparison of the USB input on the DAC-1 to the S/PDIF input driven from an Off-Ramp 3, I will provide money-back less shipping if it is not significantly better. BTW, the S/PDIF input on the DAC-1 needs modding to be decent IMO. Steve N. Empirical Audio

Thanks for the link. Thumbs up for your testing offer! I haven't decided on a DAC yet, but the DAC1 is on my list