Benchmark DAC1 now available with USB

[Wavelength]

Originally Posted by gregeas

What about using XP with a program like J River Media Center, which permits ASIO output? This would still be bit perfect to the USB DAC1, correct?

I actually like Media Center much better than iTunes, so I'm using it in any case.

I have taken to using my laptop and DAC1 in my surround system, and the sound quality is outstanding with Media Center. If there are any bits being altered, I certainly can't hear the problem.

Greg,

Yes that would be bit perfect if the ASIO does not corrupt the data. We have actually found some versions and setups of the generic ASIO drivers to not be bit perfect. But at this time I cannot recall all the situations with which ones or how and why.

But in general I found that Vista worked better because of the lack of the KMIXER and also because of the updated USB drivers (Good Job DJ!).

Thanks
Gordon

[sangel]

Hello Elias,

Back again.....reinforced, offcourse..

I have just recieved my new DAC1 usb and I am ready to set it up.
But before doing so, I would be very grateful if you let me know the MAX usb cable length, for best results, between the PC's usb and the DAC1 usb input.
Note, my PC to DAC1 usb distance is about 5 meters.
Alternatively, do you suggest any of the market's usb - bridge type extension cables or usb - electroptical fiber type cables!!

Your input would be very much appreciated.

Best

sangel

[poo]

Originally Posted by sangel

But before doing so, I would be very grateful if you let me know the MAX usb cable length, for best results, between the PC's usb and the DAC1 usb input.
Note, my PC to DAC1 usb distance is about 5 meters.

The first few points here will answer your question, and there is plenty more info too...

USB.org - FAQ: Cables, Connectors, and Networking

In short, you should be fine.

[tuffgong]

This is the best thread i've ever read ever, bar none. I just wanted to thank Benchmark for participating. My question to Elias is:
Some of the reviews mention you are always upgrading your pcb board layout. It appears from this thread that anything after may '04 has the same parts, but from what I understand the pcb layout is always being perfected, this being one of the places you engineers shine the most. Audiogon.com has an extremely strong presence in the second hand market for the dac-1, it is a steal at $750 used, and very telling that most of the dac-1's are being sold on audiogon, not ebay, probably because ebay is too inexperienced for your product. I just purchased one that is being delivered next week, the previous owner said it was made two years ago. If at all possible, could you list serial number ranges for models made before the '04 change? Also, could you detail your changes made to the pcb layout, if they were significant, and what serial number ranges have which pcb layout? I bet a lot of audiogoners would love to know what they are getting into with a used model, knowledge is power. Perhaps this is what people refer to when they say some dac-1's sound different. The parts could be the same, perhaps the specs so close to be negligible, but I believe you folks are always improving on the layout of the board, the one place to improve upon. Perhaps if you did indulge us with this info, you might sell alot of new units and see a rash of listings on audiogon, laf j/k. This thread seems to get all the facts straight, my apologies if this was adressed earlier but after page 65 I just had to fast forward... it took me two days to get to 65. Most enjoyable though. Besides the pcb info, i'd love to hear Elias' thoughts on upgrading everything outside the dac-1, does a power conditioner help? Silver Signiature blahblah IEC cord help? Putting a weight with sorbathane feet on top of the unit help? Is this all mental masturbation? I plan on buying some PMC AML-1's (active monitors) for the benchmark to run into for the purest, more revealing sound possible. If that's what they used to master it with (probably a benchmark as well), why try to improve it. I noticed Rick Rubin uses the benchmark and Stevie Wonder likes the aml's, so i'm going that direction and retiring from the upgrade game. Anyone want some platinum audio duo's and solo's for sale? Selling my amp next...
Thank you Benchmark.
I love the review on audioreview of the benchmark that says you should have made this unit twice as big and twice as heavy and called it the merlot signiature dac and charged 3 times as much, so funny.

[Telynau]

Per Elias's suggestion, I downloaded VLC. Bottom line, if you want to play your albums off a hard drive (which is all I ever do), it works.

On one of my systems I use a Mac PowerBook Pismo (500MHz, 512MB). It won't run Leopard, so Gordon Rankin's upgrade suggestion doesn't help (I will try the Leopard upgrade on my MacBook after Leopard settles down some more).

VLC is noticeably more clear to my ears than iTunes 7.5.

Two quirks of VLC really stumped me, so I will repeat the resolutions here for those who might want to try it on their Mac's.

First, in the Benchmark Wiki Elias says to keep the VLC volume control at 100%. OK, that is the consistent advice we hear (e.g, from Gordon, too). The quirk is that in VLC, under "VLC -- Preferences -- Audio" you will see that the volume can be set anywhere from zero to 1024. This volume control should be set at 256 because 256 = 100% or "0 db". If you set it higher you will probably add distortion because you are amplifying the signal. I made the mistake of setting it at 1024 (thinking that was 100%) and spent several hours figuring out why at that level the music was clearly distorted on my system.

The slide volume controller on the little VLC menu that pops up when you start VLC is a different matter entirely. It varies the volume level you have set in VLC Preferences. So after you set the Preferences -- Audio level to 256, you want to set the slider on the little menu all the way to the right, which gives you the full 256.

With these settings in place you will then use your preamp or other volume control to actually control the volume of the music.

Second, I suspect the computer guys would have gotten this in about 10 seconds, but if you select "mute" from the Audio pull down menu (or otherwise find that you have muted the sound somehow -- which I did several times) in order to unmute you just right click on the "mute" selection. Left click puts mute on; right click unmutes.

The big downside to VLC is that the documentation is very, very sparse. But I got it up and running -- and it is a solution to play Apple lossless files clearly, with low or no distortion, on a Mac that can't be upgraded to Leopard. If all you want to do is play your albums (and probably a lot more if you can figure out how to use the more advanced functions), it will do the job.

Thanks for the tip, Elias! Regards, James

[thomaspf]

Originally Posted by xp9433

gjwaudio

I was of the belief and clear interpretation that the ball was very much in Thomas's court! Elias answered politely (in the extreme) as always. Elias had a very firm conclusion!

It is/was very much up to Thomas to support/prove his assertions - not the other way around.

I am sure if Thomas comes up with valid (tested/proven) technical support for his arguments we will all listen. Until then, I will trust Elias's tests and explanations thanks very much.

Frank

What more can I do? I have tested the firmware that Benchmark is using and it does not trick the Windows driver into transparency for 16/44.1 data since that is just not possible. The firmware registers the USB device as only supporting 24 bit streams but kmixer is still slightly changing the bits due the way volume processing is implemented.

You can easily get around this by using kernel streaming but that solution does of course work for every USB dac that uses the Windows supplied USB audio driver. So there is nothing special about the Benchmark USB code. Vista does not have kmixer but its pipeline is also not bit transparent not for the Benchmark or any other USB device. Again using kernel streaming for devices using the standard Microsoft USB driver solves this problem.

Besides all this, the Benchmark is still a nice DAC. I thought we had closed this the last time round.


Cheers

Thomas

P.S.: I am not sure I posted this on this thread but if you send a 16bit stream in the upper bits of a 24bit PCM stream and set the format in the Vista sound control panel to 24/44.1 then a 16bit stream survives in there unmodified.

[fradoca]

thanks thomaspf for the info!
I live in italy and i want to buy a dac1 usb in the next few days.
But i'd like to know if benchmark will release soon a new
version of the dac1 ( a dac 2).The price here is 1100 euro
and for me is a money effort.I've tried to ask to Elias
but got no reply about a new dac.I would not buy something
that becomes obsolete in the next 6-8 months due to the
release of a new product
thanks

cheers

Francesco

[Wavelength]

Thomas,

Maybe a better way to say this is that there is not a way for any USB DAC to fool the KMIXER into bit perfect accuracy.

Hey guys this is no big deal. Bypass the KMIXER as it is told everywhere or go to Vista for better results.

I do agree with others though and heck I would not have bought the DAC1 if they would not have said it was bit perfect out of the box in all os's. I think they should change the marketing on that one.

Thanks
Gordon

[Scrith]

Originally Posted by thomaspf

P.S.: I am not sure I posted this on this thread but if you send a 16bit stream in the upper bits of a 24bit PCM stream and set the format in the Vista sound control panel to 24/44.1 then a 16bit stream survives in there unmodified.

This seems like an important caveat to your argument that bit-perfect playback in Vista is not possible with USB devices. If I am reading it correctly, a USB DAC owner using Vista simply needs to set their device to 24/44.1 in the Vista Sound Control Panel (and use 24-bit output in a program such as Foobar2000) to get bit-perfect 16/44.1 sound (which is what most users care about, since CDs are 16/44.1).

I don't think this is new information (I seem to remember doing this on the day I installed Vista for use with my DAC1 USB), but it's interesting to be reminded of how important it is to set this up properly in Vista.

[Scrith]

On another note, Gordon's efforts with USB Audio at Wavelength Audio have apparently yielded important results: he has asynchronous USB support working in one of his DACs.

I am somewhat skeptical that any difference in sound quality can actually be heard between async and standard USB audio, but I haven't tested it myself so this is just speculation.

But it is an important milestone, because in theory this feature finally makes an external DAC completely independent of the computer it is attached to for the timing of the data for playback (assuming the computer can keep up with a perfect 44.1 playback speed).

The downside of this breakthrough is that it is only available on ridiculously expensive hardware (sorry Gordon). Maybe a company like Benchmark could license this technology and make it available at a more appropriate cost so a much greater number of people could one day appreciate it (assuming it actually sounds better)?