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In Reply to: RE: NOS USB DACs: Valab, Gigalab, & Fathom posted by Gevo on June 30, 2009 at 12:46:42
No as far as USB use because they are realtek devices and hence directsound.
You must have ASIO support. That is why so many USB dac just miss the point.
I don't care how many people are selling USB dac without ASIO support. It is a disservice to hifi. I don't sell any gear; this is just the honest truth.
By all means, use one of the Gigalab, Valab, Pacific Valve... but lead into them with a proper ASIO transport via USB or PCI or firewire.
You don't *need* ASIO for bitperfect playback.
WASAPI / exclusive mode in Vista works.
Kernel Streaming is also bitperfect and low latency.
Directsound in XP can also be bitperfect, but it's not exclusive. (If additional streams are played to the default device, kmixer will mix them).
Kmixer sits idle when only a single stream is present. It always has.
DTS passthrough tests can show when kmixer engages / disengages. Kmixer actually comes on automatically and goes OFF automatically as follows:
1 Stream: kmixer off (bitperfect)
2 Streams: Kmixer on (mixed and resampled to 48khz)
back to 1 stream: kmixer off (bitperfect again).
If you don't have a source of a second audio stream enabled or running, then directsound can be as bitperfect as ASIO, albeit at a slightly higher latency.
The more I compare directsound to kernel streaming to ASIO the more I find that "bit perfectness" is really critical, but beyond that these different methods are starting to sound more and more similar to me as I test. Not more different from one another.
Much psychological influence is at play when comparing output plugins and streaming methods.
Cheers,
Presto
I just replugged the Gigalab to the PC. It is not realtek as I remembered wrong, it is a c-media.
As with other consumer products, the c-media hardware and drivers need to be examined closely if they can indeed provide bit perfect.
Only once the hardware is capable, then we can worry about ASIO or WASPI for those on newer Windoze.
Suffice to say, be cautious around c-media.
Another bromide I would like to see tested is whether sound cards really have audibly more noise than external DACS.
Good one DBB!
Me too.
I have not bought my "be all end all" DAC yet.
I will need 8 channels - so I will probably get into a MOTU, RME, Lynx Aurora or other solution. Might run a digital out slaved back to the DAC box with proper 75ohm terminations.
But I just bought a house (!!) and audio budget will be zippo for a year or two.
Quite frankly, from the way my modded DCX2496 box sounds, or even the analog outputs of my M-Audio Revo 7.1 card... I bet I would be happy as a clam with a Lynx / Aurora, Motu or RME solution.
I don't think using (3) USB dacs for tri-amping is going to work! ;)
The tinfoil hat wearing guys around here (who have nightmares about becoming mutants from their audio PC's RFI) would probably never even give a PCI solution a fair shot. There are some solutions that use a PCI card to send digital to an outboard box. These are custom designed solutions just for that box. (Creamware was a good example, they used a RJ45 network cable to send their data to their converter box).
Everyone here is so stuck on USB and now Amarra...
I probably won't get a MAC. Thus I don't have to worry about Amarra. And my love for multi-amping will most likely rule out USB...
I'm just a different kind of cat when it comes to PC audio.
By the by. I tested the phase correction on the Thuneau Allocator with all different orders of Butterworth, Linkwitz-Riley and even Deulund crossovers. The LR4 variation corrects to a bloody square wave. Perfect step response with no phase distortion. All you need is time aligned drivers and a transfer function that yields a true LR4 response and you speakers that are transient perfect. And getting a LR4 acoustic response is one of the easier ones to obtain using conventional drivers.
I managed to get (4) Vifa MG10MD09 4" fiberglass mids (!) and am going to build a time-aligned and phase-corrected WMTMW using the Allocator as a crossover. Can't wait for that to get finished!
I wonder how many guys here worry about speaker performance as much as they do jitter and USB cable "quality"??
Cheers,
Presto
Hey Presto,
I think for the most part we are on the same page on a great many things.
Your post is appreciated and timely.
I found myself stressing over the thunea allocator with my cmp2 setup. They seem at odds with one another. CMP2 is all about low latency, and well Thuneau isn't requiring big buffers.
I was thinking about passive line level crossovers but I have to remember that any solution will have some compromises and perhaps a bit of latency is a lessor evil vs extra connections, insertion losses, and transient imperfect crossovers.
YOu might want to look at some of the firewire products like the Aurora and the RME fireface as that could be the best of all worlds.
But I have to tell you that I really like my Lynx 2b. Not saying it is the best, but I certainly cant think of a product that has 6 channels of DtoA of that quality for the price.
And yeah, I cant tell you that the crossover in my system is probably the biggest weak link. True I modded it heavily, but active I think will take things to the next level. Speakers still do make a huge difference.
"I wonder how many guys here worry about speaker performance as much as they do jitter and USB cable "quality"??"
Good point Presto!
Yours truly, the USB manic with his cables and Amarra couldn't agree more with your statement. I just replaced my Wilson WP8s with Wilson Sasha W/P speakers. A truly amazing speaker; a little Maxx3. A revelation in audio reproduction here at Lucy's Lab.
Hi Presto,
Just wanted to say thanks for the experimenting, testing, and sharing of information you've done regarding the different output plugins.
Alan
... I do this stuff for fun! ;)
I must say some of the kmixer and volume control generalizations have been a hoot to investigate.
And most humbling of all is helping to bust myths that one I once partially or strongly believed in - or even helped to perpetrate...
Oh well, everything has a learning curve I guess.
Cheers,
Presto
What bit rates and sampling rates do these DACs handle? Is it just 16/44.1?
Thanks, but ASIO is important only if you're using Windows XP. With Vista and Windows 7, there is a new WASAPI exclusive mode that works similarly to ASIO in XP, but is more flexible in configuration.
I was told the Gigalab unit is to be dropped as the Fathom is better sounding, more reliable and of higher quality.
What makes Fathom better than Gigalab? Was it compared to the mk2 Gigalab?
All these DACs are made by TeraDak. The only difference is in the choice of capacitors, and resistors used...
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