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MDAC first listen (part XX)

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Akasha said:
makes perfect sense, I'll take one for a start anytime, untill then I will enjoy the MDAC/nc400 minor magic combination
Click to expand...

Akasha please post your impressions once you get John's amp. I consider the DIY Ncore N400s to be the biggest bargain in hi fi that I've ever come across. If John's amp betters them it will represent a truly staggering price / performance ratio.
 
JohnW said:
The problem appears to be related to USB 3.0 ports - for some reason USB3.0 host controllers can split the audio frames at the 16Bit boundary (each complete audio frame is 24Bits). The solution is to configure the the USB port in the PC's Bios to USB 2.0 Mode only.

Sorry, but we do not support Windows 8 - some have reported here that Windows 8 works without issue, others have experienced problems.
Click to expand...

Thank you. Problem turns out to be more a USB 3 issue than Windows 8. Switched to a USB 2.0 configuration and all seems to be well.
 
brab,

Great news, I've been feeling rather down thinking you had been left out in the cold...

Thank you for the very useful feedback.
 
JohnW said:
brab,

Great news, I've been feeling rather down thinking you had been left out in the cold...

Thank you for the very useful feedback.
Click to expand...

I have both USB3 and USB2 ports.. Will try and replicate the problem and then try forcing it through a USB2 hub and see if that helps.

As an aside, a new laptop I have just encountered has ONLY USB3 ports... so a workaround may become needed!
 
JohnW said:
brab,

Great news, I've been feeling rather down thinking you had been left out in the cold...

Thank you for the very useful feedback.
Click to expand...

By the way, I just checked what firmware generation I have. The display reads something like v99/97. Is it safe to upgrade to the latest, or should I leave well enough alone, given that I'm using Windows 8 and it works.

Thanks again.
 
sam_cat said:
I have both USB3 and USB2 ports.. Will try and replicate the problem and then try forcing it through a USB2 hub and see if that helps.

As an aside, a new laptop I have just encountered has ONLY USB3 ports... so a workaround may become needed!
Click to expand...

A USB2 hub could be worth a try, although I suspect it might not help - the USB Host controlled is splitting the packets - this is in violation of guaranteed bandwidth... It might just be confined to a family of USB Host controllers rather then a general issue with USB3.
 
brab said:
By the way, I just checked what firmware generation I have. The display reads something like v99/97. Is it safe to upgrade to the latest, or should I leave well enough alone, given that I'm using Windows 8 and it works.

Thanks again.
Click to expand...

No problem to upgraded the MDAC software, you can always roll back to an ealier version if you encounter an issue.
 
JohnW said:
How many chassis do you need? They are our own custom design - using our tooling.

We could manufacture a batch of chassis for you - our just supply a single unit if its for your own build.

The Chassis are not cheap as they are all aluminium - but are very solid and match the MDAC.

John
Click to expand...

Although I'm not active in the current phase of Community Squeezebox, I'm very keen to get one up and running when the design settles down. A MDAC matching Squeezebox device would be hugely appealing to me, and I suspect many others too. Although I'm not trying to make work for John, maybe a Lakewest badged and boxed streamer based on this project would be a nice little earner, or possibly something for Lakewest to sub-contract?

I could also do with a MIMP or two, and an MPAX - oh, and a TDAC too (though would dearly love that in a MDAC width box, to save me building a new rack!).
 
sam_cat said:
I have both USB3 and USB2 ports.. Will try and replicate the problem and then try forcing it through a USB2 hub and see if that helps.

As an aside, a new laptop I have just encountered has ONLY USB3 ports... so a workaround may become needed!
Click to expand...
JohnW said:
A USB2 hub could be worth a try, although I suspect it might not help - the USB Host controlled is splitting the packets - this is in violation of guaranteed bandwidth... It might just be confined to a family of USB Host controllers rather then a general issue with USB3.
Click to expand...
It *might* be a driver problem as well, my MDAC works fine on USB3 on linux (kernel 3.7), the xhci_hcd driver (usb3) creates 480M ("usb2") buses by default as well:
Code: 
$ lsusb -t
/:  Bus 06.Port 1: Dev 1, Class=root_hub, Driver=ehci_hcd/2p, 480M
    |__ Port 1: Dev 2, If 0, Class=hub, Driver=hub/8p, 480M
/:  Bus 05.Port 1: Dev 1, Class=root_hub, Driver=ehci_hcd/2p, 480M
    |__ Port 1: Dev 2, If 0, Class=hub, Driver=hub/6p, 480M
        |__ Port 1: Dev 3, If 0, Class=HID, Driver=usbhid, 1.5M
        |__ Port 1: Dev 3, If 1, Class=HID, Driver=usbhid, 1.5M
        |__ Port 2: Dev 4, If 0, Class=HID, Driver=usbhid, 1.5M
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 5000M
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 5000M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M
    |__ Port 2: Dev 2, If 0, Class=HID, Driver=usbhid, 12M
    |__ Port 2: Dev 2, If 1, Class=audio, Driver=snd-usb-audio, 12M
    |__ Port 2: Dev 2, If 2, Class=audio, Driver=snd-usb-audio, 12M

$ lspci | grep -i usb
00:1a.0 USB Controller: Intel Corporation Cougar Point USB Enhanced Host Controller #2 (rev 05)
00:1d.0 USB Controller: Intel Corporation Cougar Point USB Enhanced Host Controller #1 (rev 05)
03:00.0 USB Controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 04)
04:00.0 USB Controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 04)

USB2 hub could help - it could force the driver to negotiate usb2 speeds.

JohnW said:
The MIMP's communicate via the MDAC's rear panel IR Out connector (we can supply a small splitter / isolator PCB to allow two units to connect at the MDAC, rather then a simple Daisy chain type connection.

Connection is via 3.5mm "stereo" type Jacks.

10 Meters is a long distance - (this also means you also have 10m audio connections!) - that's a large room indeed, however with the Splitter / Buffer board 10m should be no problem.

New firmware is require for the system communication's - the current software has no idea about the pending MTRN, MIMP's & MPAX designs. Once I have the Mimps I'll spend time to insure we maintain V0.90 SQ with the enhanced software build.

John
Click to expand...
John, thanks for the info. I plan to have MIMPs close to speakers, but I also want to have MDAC on my desk, so I can easily use/switch headphones, with the speakers being on the other side of the room. Those 10m will be over XLR/balanced, so there should be no problem.
If 10m (twisted?) of MDAC<->MIMP data bus is okay, I can probably daisy chain the two MIMPs, I just wanted to avoid adding cabling via a doorway (and keep the bus cables together with the balanced audio ones). If it's not easily possible, I don't mind. Your TODO list is long enough already :)
 
Usb 2 hub made no difference
Plugging the usb 3 cable (and it's associated usb 3 hub) into usb 2 works as you would imagine
Just updating the usb 3 drivers with manufacturer supplied ones to see if that helps.
 
Hi John

Just wondering if you have any working theories yet as to why the SQ changes in firmware? I read how you said even after the proposed modifications that you had hoped would eliminate the changes you can’t seem to lock it down.

I am still finding it hard to believe how code that isn't modified in terms of its sound processing properties is changing the SQ? and I have heard it. I am mainly interested as I find it intriguing due to my background in software development and if I could I would spend an inordinate amount of time finding out why just to satisfy my curiosity, no doubt a luxury of time you can’t afford and maybe a mystery best left unsolved ! :)
 
JohnW, with the capability to assemble and disassemble a pc(no soldering), do you think I can get the mdac mainboard out and sending only it to you for upgrading? It weights much much lighter and convenient I think. :)
 
lapkwan said:
JohnW, with the capability to assemble and disassemble a pc(no soldering), do you think I can get the mdac mainboard out and sending only it to you for upgrading? It weights much much lighter and convenient I think. :)
Click to expand...

I don't think its a good idea, the PSU board, is hard to secure, the front panel will cause much stress on the pcb, maybe the flat cable from back panel will be easy? but I don't remember how much to desolder if to liberate the main board itself
 
iansr said:
Akasha please post your impressions once you get John's amp. I consider the DIY Ncore N400s to be the biggest bargain in hi fi that I've ever come across. If John's amp betters them it will represent a truly staggering price / performance ratio.
Click to expand...


will do, when I get the chance

lately I've heard a mosfet amp that came pretty close, but the ncores certainly delivers, some people have even called Bruno Putzeys a genius, and I won't be arguing with them :)

i'm confident in John will raise the bar for amp performance/price ratio as well as he did for DACs, 50 +50 Watt is less than the nc400, but plenty for most well designed speakers ( I only need around 2 x 10 of the best watts myself )
 
I personally like the idea of including a cd drive in the mtrn. It would be nice being able to play cd:s direcly instead of having to rip them first, If it hits the market i won't have any excuse for not buying the mdac when upgrading to a new system :)
 
Hi John,

I changed my preamp for a LAMM LL2, and now I have a problem. It seems that my DAC sends too much "power" to the preamp, and there is saturation, even if I use the volume control of the preamp at low level. Is there a way to fall the level from the MDAC ?

Thanks a lot for your excellent work !

Olivman
 
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