Maverick Audio DAC/Amp - Page 40

@DannyBuoy:

Sorry, I missed your post the first time... so here we go.

I'll try the J.River although I'm a foo2k hardliner. In the meantime I tried the same in foo2k what you did in J.River:
-> DirectSound @Mav @USB
-> forced 24bit
-> forced 96k resampler (pphs@ultra mode)

Works flawlessly! I am surprised, honestly. So now we can get 24/96 records bit perfect to the Mav, that's not bad.
Sadly we still have no solution for bit perfect 16/44.1...

I'll play around with J.River this evening and will try some things with foobar. Hopefully we can work this out. Thanks for your help, DannyBuoy!

best regards.
bearmann

Hi Bear. I don't understand your statement. You say you are getting bit perfect to the Mav, then say you don't have a solution for bit perfect 16/44.1

Excuse my ignorance, I an new to all this.

I can imagine that it's a bit confusing... let me try to explain it with some screenshots.



Here you can see that the output format in foobar2k is fixed to 24bit. So if your record is a normal cd rip (16bit) it'll be converted to 24 bit! But your native 24bit record (some live tape or hi-def DVD rip) won't be touched because it already has the correct/needed bit depth.
Long story short: because of this every 24bit record won't be touched (= bit perfect) and every 16bit record will be converted (NOT bit perfect).



Here you can see the resampler. Every record will be resampled to 96k. So again, if you have a hi-def 24/96 rip nothing will happen (read: bit perfect!).
But if your record has only been sampled with 44.1k it'll be resampled/upsampled to 96k! (NOT bit perfect!)

Hopefully it's a bit clearer now...

Again, long story short: With those two settings you'll ONLY get 24/96 records bit perfect to your Mav, because you force foobar2k to convert/resample every record to 24/96.

best regards.
bearmann

Doesn't matter much, just rather than being resampled twice, it is only resampled once. Doesn't the device itself automatically upsample? so you can never get true bit-perfect 16-bit <96k audio. Unsure of how it works, so feel free to explain if I am deathly wrong.

Though I think he had trouble with Vista sound properties as well, where you set the sample rate of the device itself. Unsure of how it works though, can't really find a description of what "shared mode" is.

It's right that the Mav uses an upsampling DAC. So yeah, as soon as the signal gets to the DAC it'll get upsampled and therefore isn't "bit perfect" anymore. But with every resampling you get errors so you definitely want to avoid every unnecessary resampling before the signal gets to the DAC.

Upsampling and oversampling is not the same fyi. DACs usually do oversampling, but not upsampling.

Setting the D1 at 24/96

Thanks for the compliment. There are quite a few more details in what I have learned in playing around with Microsoft's newest implementation of the DirectX (DirectSound in this case) replacement called "Microsoft Universal Audio Architecture (UAA)" which is designed to simplify connecting the audio file to the device interface.
I believe that setting the USB device in an application such as J.River's Media Center to 24/96 it is helping to bypass the restriction imposed at the hardware level to 16/48 as Direct Sound in Vista or greater (2008 or Win7) the data stream may be able to send at 44.1,48, or 96 as required since we are bypassing the 16/48 limitation set through Control panel/Device Manager.
I have some USB packet analyzer code that I am going to play with next that will help to confirm or reject that assumption and I will have time later this week to do this.
As a concept you should start to think of the hardware layer as being a separate entity altogether from the software (device driver/filter/codec) level as MS has been pushing to separate the two once the divorce from KMixer took place in going from XP to Vista. The new specifications for the UAA design calls for up to 32 Bit resolution (up from 24 Bit) and ability to operate at 32 OR 64 Bit (helps with HD Audio with many streams).
They have moved from the restrictions of having a device driver tied to a PCI or USB bus to an abstraction above this allowing XBox, Win, Maybe Zune, etc. to be utilized with the same code base.
I will let all know what I find going across the USB DeviceID for the D1 with the 24/96 settings with a Redbook 16/44.1 file being played very soon.
I am still thinking that it would help if I were to write an Audio Driver for Windows that a person would install if using Vista or Win7 and the D1 would be assigned to it upon audio stream initialization bypassing the WASAPI/ASIO/Direct Sound choice you would normally make in your media players and instead you would pick the D1 output instead.
Sorry if this is not detailed enough for some. It would take quite a bit of writing to detail this at this time and I need to do the first steps to see if this is even achievable before investing in the detail. Right now this is just wild theories without evidence to back it up. But, I promise to share success or failure along the way, and give details as more is known.

Thanks for the insight, i'll do some research to figure out the differences.

Hmm but if Jriver is using Direct Sound wouldn't that cause it to be governed by the vista sound settings. Obviously your testing will conclude this but this has been my only real confusion with vista. It is not well documented imo(on a the user end at least).

Just tip of the Direct Sound Iceberg...

Direct Sound (the label) is just a legacy word. The technology behind that word has been in a growth mode for several years. Direct Sound has splintered off from DirectX.
While MS continues DirectX focusing it on gaming and graphics more and the branch of Direct Sound re-organized under the "Microsoft Media Foundation " Media Foundation Architecture (Windows) moniker. This new group which has its roots back as far as DirectX 8.0 was focused on HD Audio and Video and how to move the standard forward while making it easier to access filters, transforms, piplines, streams, and the like.

That turned out to be an ambitious project and the team has been undergoing a further division so the SDK's and API's were seperated into smaller elements and in it's newest incarnation that I know of is the "Microsoft Universal Audio Architecture (UAA) initiative" Audio Device Technologies for Windows

So the label "Direct Sound" you see in FooBar and J.River is just an old label for a deprecated technology and it is really just a hand off to the MMF/UAA interface (which you mention accurately by acknowledging that Vista is really the handler of the stream).
Since this interface does not have a handle for us to interact with in our media players yet, it is wise (IMO) to use Direct Sound as the "gateway" to the interface and this is exactly why I thought I should write a device driver that would be user selectible and have it focused on what we as a community want it to do most which I believe is bit perfect, 2 channel, jitter free, 32 and 64 Bit OS compatible, cache and buffer adjustable, am I missing anything?

Wow, is all I have to say about this. Running it through SPDIF straight from my pc and it sounds great.

Does anyone else notice an increase in bass with the NOS tube?

I am really interested in this DAC/Amp, I am just nervous about the noise for my high sensitive denon 2000 headphones. I know you can adjust the gain, but I have never used a soldering iron in my life. Is this noise constant or does it go away once you play music?

Im running these through my AD700s and K702s, and with the 700s I do notice the gain, but are practically non-existent once you're playing music - unless ur playing it very low.

Pretty much hit it all, i'll check out those resources in more detail.

If it does bother you, you can wait as well. From what I can gather of recent discussion there might be a version(or perm tweak) which lowers gain.

Personally I prefer the higher gain as this device allows for speakers which are more finicky. Some require a higher gain, much higher than headphones. This is more from experience than pure fact since the technology is not my strong point atm.

I missed the DHL delivery today so I should have mine tomorrow.

Ryan as far as the volume gain tweaking is this something we can change on our own with some minor DIY or will it be another pot, or can you recommend another pot?

Scott

Ryan helped Bearmann with this:
http://www.head-fi.org/forums/f5/mav...4/index38.html