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MDAC First Listen (part 00100001)

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stellablues

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I usually run -15 to 0/+3 if i'm trying to crank it. My amp is the Decware Mystery amp. 40w PP kt66 amp with volume control. does not have a preamp but it does have an attenuator knob which i keep cranked to full power. claimed FULL POWER @ 2.0 VOLTS ON RCA INPUT. speakers are ~85db two way hiquphon/seas. I have tried the RCA inputs as well and don't seem to be significantly louder so I have ruled out a transformer "mistake" on the xlr.

Nothing to be done perhaps but would rather not spend 2-5k on a balanced preamp just to get a few db gain. I don't need the extra inputs given MDAC2 analog inputs.

cheers,
 
I was hoping to be able to record and playback from the SDcard, is this still possible if the software is also stored onto the card? or is the SDcard only used to download the software into the modules on-board RAM?

As rear panel space is very limited on the MDAC2 I'm hoping to use a MicroSD card to save space - is there any advantage these days between the full size SDcard and the micro cards? every SDcard I've bought recently is a Micro card fitted within a full size adaptor.
Click to expand...

The only advantage of SD cards versus microSD is the optional write-protection notch.

I would expect the system to be loaded from an image file on the file system of the SD card into a RAM fs. So it should be possible to store recordings there too.
 
JohnW said:
I still not see a route to producing the TDAC chassis here in Europe at an affordable price - so I'd not like to count on the TDAC until I can solve the chassis - the Qtys of the TDAC will be too low to manufacture the chassis in China. I have manage to source 500 tubes, with a percentage left for spares, this equates to only being able to build 200 TDACs.
Click to expand...

Perhaps it is time to keep an old "pending" promise and provide MDAC2 Lx/TDAC upgrade for 8200 CD/CDQ owners.:)
http://www.pinkfishmedia.net/forum/showpost.php?p=1602116&postcount=236
 
stellablues said:
I usually run -15 to 0/+3 if i'm trying to crank it. My amp is the Decware Mystery amp. 40w PP kt66 amp with volume control. does not have a preamp but it does have an attenuator knob which i keep cranked to full power. claimed FULL POWER @ 2.0 VOLTS ON RCA INPUT. speakers are ~85db two way hiquphon/seas. I have tried the RCA inputs as well and don't seem to be significantly louder so I have ruled out a transformer "mistake" on the xlr.

Nothing to be done perhaps but would rather not spend 2-5k on a balanced preamp just to get a few db gain. I don't need the extra inputs given MDAC2 analog inputs.

cheers,
Click to expand...

Have you tried using XLR to RCA interconnects? If you connect your Mdac's balanced output to your amplifier's single ended input you should get a significant gain.
On a sidenote I have the feeling that your wonderful amplifier may not be suited to such low sensitivity speakers.
 
timow said:
Perhaps it is time to keep an old "pending" promise and provide MDAC2 Lx/TDAC upgrade for 8200 CD/CDQ owners.:)
http://www.pinkfishmedia.net/forum/showpost.php?p=1602116&postcount=236
Click to expand...

I don't see a promise there - I don't see a promise in any of the conceptual or outline designs that have been mentioned over the years. It seems apparent that, for anyone, the (only) upgrade is the MDAC2. Apart from a CD drive, the specification list outlined in the post you linked to seems to be contained within the current vision for the MDAC2

I'm not sure where design and manufacture time and affordability would come from for a CD/CDQ upgrade too.
 
...argg, I have been on vacation for 3 weeks and I am trying to keep up with the thread. Did JohnW mention a L4 version? :)
 
I still not see a route to producing the TDAC chassis here in Europe at an affordable price - so I'd not like to count on the TDAC until I can solve the chassis - the Qtys of the TDAC will be too low to manufacture the chassis in China. I have manage to source 500 tubes, with a percentage left for spares, this equates to only being able to build 200 TDACs.

I would also like to build a few Poweramps with the tubes used in the front end.... maybe to preserve TDAC Qtys. I'll use a different higher gain tube for the Poweramps...[/QUOTE]

John have you considered ModuShop in Italy they can make up small batch quantities
Geoff
 
GWM said:
John have you considered ModuShop in Italy they can make up small batch quantities
Click to expand...

Hmm, that looks nice, I esp like the slimline with 10mm front (in black of course) :)

http://www.modushop.biz/ecommerce/cat063_l2.php?n=1

Price appears reasonable, ~50 EUR for one, but I suppose that if you add in the drilling costs +30 EUR for the back panel, +45 EUR for the front panel you're already at 125 EUR. Still ~100 GBP, and I suppose there's some discount if you do 50-100 Qty, but then there's shipping.

Might work.
 
Or find a cheap existing product that is aesthetically pleasing and plan on gutting it...

Or find a manufacturer who is prepared to take this on as a product.. All the development work is complete, they just need to supply a suitable chassis and logistics...
 
JohnW said:
Graham,

Your units been posted - Renata will forward your Tracking number :)
Click to expand...

As promised, a few words to express my findings on my revised MDAC to a "Premium Fusion".

My main system comprises of Macbook pro font end, Perreaux DP32 dac pre amp.....which up till now I have been and still impresses with a superb sonic performance into a pair of ATC active 50 towers and a ATC 15" sub.

I had on loan for some weeks just prior to the return of the MDAC 'PF' a Resonessence Mirus DAC which surpasses the Perreaux by some margin apart from the lower registers, where the Mirus seemed to be 'to soft' in my room.

Against the DP32 the Mirus was good but to 'polite' IMO or not to my liking in the end. I couldn't make it work within my room.

So, out of the box, connect and power up the MDAC PF. I gave it an hour to warm up (Im old fashioned like that) The first track played..... Bonnie Raitt, Luck of the Draw.

This was a revelation with an analogue presentation and with superb low level excavation (retrieval). Everything 'weighted' just right, even the lower registers which the Mirus struggled with. Imaging is very good indeed along with great spacial ambience (atmosphere).

As a headphone amp its stunning, driving HD700 effortlessly. A sonic delight IMO.

So, I'm well chuffed and now the MDAC PF is the 'one to beat' in my house....

Thanks John....
 
JohnW said:
Adrian,

Thank you for your valued input - its truly appreciated as while I can design the hardware - it will be up to others like yourself to support the software.

I was hoping to be able to record and playback from the SDcard, is this still possible if the software is also stored onto the card? or is the SDcard only used to download the software into the modules on-board RAM?

As rear panel space is very limited on the MDAC2 I'm hoping to use a MicroSD card to save space - is there any advantage these days between the full size SDcard and the micro cards? every SDcard I've bought recently is a Micro card fitted within a full size adaptor.

Also, if we use the Micro-SOM i2 module will a standard build of LMS run smoothly - or would it need a custom build? (I know little about Linux).

For appreciation of your support of the MDAC and hopefully MDAC2 I'll insure you get one of the first MDAC2 L4's.
Click to expand...

I think micro sd is preferred - the new PI B+ has moved to this from a full SD and most other small arm boards are using micro SD. Speed of SD card really matters for performance and fast micro SD cards are cheap these days. The SoM you are planning looks like is shows us of a UHS-1 micro sd card on the Hummingboard carrier.

As for software it all depends how much time you are putting into creating it and how much development and test + some on the commercials of how much it is a product. If you want to leverage the standard distributions used by these small arm devices and the wider community (i.e. do least work) then I think you should plan to use the approach used by the main distributions - i.e. the card acts as the file system. Linux will boot from it and assume it is always there so that it can store any files it wants to. This can include saving data to the card, but you can't take the card out while linux is running. The reason why it is useful (in my view) to have the card externally exposed is that it means if something goes wrong then it is easy to take the card out and reprogram it. This is why the PI and other devices work - if you screw it up, you just reflash the card with the original image from a PC and it all works again. If however you are making a more formal product with a locked down software image and lots of QA, then you can assume you won't need this [assuming you have the software development team and QA department...]. In this case you could have software stored on internal flash. You would still need a specific approach if you wanted to only use this flash for booting rather than as a general filesystem though.

Re LMS. If you want to run an LMS client then the SoM you have should be fine. It will also run the LMS server on the dual core (I'm going by the wandboard which is the same cpu) but will be slightly slow - I use a wandboard quad for this. I suspect people only want to integrate with existing LMS rather than run LMS on the device though?

The software development needed is a linux kernel driver for whatever output device you want. Beyond this it depends on what you want to use from the existing distos and what you want to do custom yourself.

Remember - anything is possible - its only software... but it depends how long it takes to do it (and whether you have the resources to do it.)
 
tunkejazz said:
...argg, I have been on vacation for 3 weeks and I am trying to keep up with the thread. Did JohnW mention a L4 version? :)
Click to expand...

3 week vacation??? :p Please don't mention that to Renata!

L4 - a future version after the L1-L3 units are released. The L4 will integrate a Linux based "Computer" (based on a Micro-SOM module). This allows an integrated streamer etc.

As not to delay the L1 to L3 units it will be released as an upgrade (replacement rear panel + Digital PCB).
 
GWM said:
John have you considered ModuShop in Italy they can make up small batch quantities
Geoff
Click to expand...

Geoff,

Thank you for the link - the problem with ModuShop is that its looks so Micky Mouse home made DIY.... After the amount of design effort afforded to the design of the MDAC2 / TDAC I'd like it to be more professional even if its manufactured in a "Rabbits hutch" of a lab in Czech Rep :p
 
peterzz said:
Price appears reasonable, ~50 EUR for one, but I suppose that if you add in the drilling costs +30 EUR for the back panel, +45 EUR for the front panel you're already at 125 EUR. Still ~100 GBP, and I suppose there's some discount if you do 50-100 Qty, but then there's shipping.
Click to expand...

At these prices we could open tooling and manufacture larger Qtys. in China even if we end up manufacturing only 200 pcs.

We already own tooling, so its really a question of insuring quality and importing into Europe.

The biggest issue is quality - as once the chassis items have been loaded onto a pallet for shipping then we have no method to reclaim on any quality / fit / finish issues, it could turn into a nightmare.
 
laverda said:
As promised, a few words to express my findings on my revised MDAC to a "Premium Fusion".

My main system comprises of Macbook pro font end, Perreaux DP32 dac pre amp.....which up till now I have been and still impresses with a superb sonic performance into a pair of ATC active 50 towers and a ATC 15" sub.

I had on loan for some weeks just prior to the return of the MDAC 'PF' a Resonessence Mirus DAC which surpasses the Perreaux by some margin apart from the lower registers, where the Mirus seemed to be 'to soft' in my room.

Against the DP32 the Mirus was good but to 'polite' IMO or not to my liking in the end. I couldn't make it work within my room.

So, out of the box, connect and power up the MDAC PF. I gave it an hour to warm up (Im old fashioned like that) The first track played..... Bonnie Raitt, Luck of the Draw.

This was a revelation with an analogue presentation and with superb low level excavation (retrieval). Everything 'weighted' just right, even the lower registers which the Mirus struggled with. Imaging is very good indeed along with great spacial ambience (atmosphere).

As a headphone amp its stunning, driving HD700 effortlessly. A sonic delight IMO.

So, I'm well chuffed and now the MDAC PF is the 'one to beat' in my house....

Thanks John....
Click to expand...

Graham,

Thank you so much for your feedback - comments like this helps to keep me going here in Czech Rep. :)
 
Adrian said:
I think micro sd is preferred - the new PI B+ has moved to this from a full SD and most other small arm boards are using micro SD. Speed of SD card really matters for performance and fast micro SD cards are cheap these days. The SoM you are planning looks like is shows us of a UHS-1 micro sd card on the Hummingboard carrier.

As for software it all depends how much time you are putting into creating it and how much development and test + some on the commercials of how much it is a product. If you want to leverage the standard distributions used by these small arm devices and the wider community (i.e. do least work) then I think you should plan to use the approach used by the main distributions - i.e. the card acts as the file system. Linux will boot from it and assume it is always there so that it can store any files it wants to. This can include saving data to the card, but you can't take the card out while linux is running. The reason why it is useful (in my view) to have the card externally exposed is that it means if something goes wrong then it is easy to take the card out and reprogram it. This is why the PI and other devices work - if you screw it up, you just reflash the card with the original image from a PC and it all works again. If however you are making a more formal product with a locked down software image and lots of QA, then you can assume you won't need this [assuming you have the software development team and QA department...]. In this case you could have software stored on internal flash. You would still need a specific approach if you wanted to only use this flash for booting rather than as a general filesystem though.

Re LMS. If you want to run an LMS client then the SoM you have should be fine. It will also run the LMS server on the dual core (I'm going by the wandboard which is the same cpu) but will be slightly slow - I use a wandboard quad for this. I suspect people only want to integrate with existing LMS rather than run LMS on the device though?

The software development needed is a linux kernel driver for whatever output device you want. Beyond this it depends on what you want to use from the existing distos and what you want to do custom yourself.

Remember - anything is possible - its only software... but it depends how long it takes to do it (and whether you have the resources to do it.)
Click to expand...

Adrian,

Once again, thank you for the in-depth feedback, If I can reserve the rear panel space then maybe 2 Micro SDcard slots would be the solution, the first for the "system" and the second for storage.
 
sam_cat said:
Or find a cheap existing product that is aesthetically pleasing and plan on gutting it...
Click to expand...

Cheap, but well made & aesthetically pleasing :p

sam_cat said:
Or find a manufacturer who is prepared to take this on as a product.. All the development work is complete, they just need to supply a suitable chassis and logistics...
Click to expand...

I'm really disillusioned with "others" making significant profit from my design work - while I'm fed "crumbs"... I'm not interested in giving others the Golden jewels in exchange for bird food...

I'm happy to manufacturer "bespoke" small batches of "state of the art designs", each individually built and tested by myself :)
 
adamdea said:
I have a feeling that if we knew the bandwidth its was measuring when it showed the 6.2 fs noise floor, someone could probably work it out. As a matter of interest does your system give phase noise at particular frequencies? Also would the standard M-dac clock look like?

Still it seems comforting that the new clock apparently exceeds the resolution of the measuring system.
Click to expand...

I run-up my PLL analyser system to plot the control voltage curves the system also has a phase noise feature - but once again the MDAC2's clock phase noise is below the systems noise floor.

The quoted "typical" Phase noise levels of the system:-

100Hz 90dBc/Hz
1KHz 117dBc/Hz
10KHz 137dBc/Hz
100KHz 147dBc/Hz

The MDAC2 result almost exactly fit HP's quoted "typical" system noise floor measurements:-

https://dl.dropboxusercontent.com/u/86116171/MDAC2 Phase noise plot 56M448.jpg

The Mains related spurs are due to the LO generator output.

https://dl.dropboxusercontent.com/u/86116171/PLL System.JPG

As you can see rather limited lab bench space! - and the Pups where not happy that I had to move their baskets!

Looks like I'll have to invest in the advance clock analysis software for the Wavecrest ScopeMax system... US$15K :(
 
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