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MDAC First Listen (part 00110001)

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fusion5 said:
Yes, I've been playing in the shop for the last 15 minutes :)

Shipment via FEDEX Int. Priority Courier -Trackable & Secure, 1 day
Click to expand...

Wow - the first "Fusion" Superior Board :) we are really keen to hear it against a "Standard" Superior :)

Depending on results of the second spin of our "XMOS Development board" this might make a better DAC with the Superior PCB, then MDAC & Superior as its has Dual ESS and ASRC free USB and other refinements, not to mention DSD 256 and PCM to 768KHz!

Interesting times ahead over the next couple of weeks :)
 
John...This is getting very exciting, the hificollective package is in place and boards almost ready to roll...I can't wait to get my hands on a new Westlake DAC... as soon as possible...Sign me up please, I can have my MDAC shipped on a day's notice...Cheers!;):D:D
 
He did, but only with 8 resistors, not the full 52.

Edit: Might not even have been the pcb, but a rats nest setup.
 
fusion5 said:
Is your first Superior board up and running? How does it sound?
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The first Superior has been Bench tested but I've not had time to listen to it yet for a few reasons. ATM its been powered up and burning in the new Caps - they always sound poor when fresh:-

https://dl.dropboxusercontent.com/u/86116171/MDAC S.JPG

I really like to listen with Jarek, but we have been too busy on other projects, re-spinning the XMOS DAC board and I've also been working on data for the Detox production China requires.

https://dl.dropboxusercontent.com/u/86116171/XMOS DAC S A02.jpg

More importantly, I fitted the Superior PCB into a salvaged MDAC and discovered a very troubling issue with the MDAC's clock circuit that resulted in very High Jitter spurie - at first I thought I had a stability issue with the Superior design, only later to track it down to the MDAC's Clock circuit.

Its the first time I've encountered this issue with the MDAC, and it makes me wonder how many other MDAC's in customers hand have this issue which subsequently results in degraded sound quality. I'm in the process of designing a derivative of the FDAC's advanced clock circuit to upgrade the MDAC's internal Clock - this should be included with the Superior package - much like the Superior Analogue stage it gives us "working experience" of the FDAC's Clock design before we "Mass produce" the 200pcs or so of FDAC!

Maybe early next week we will listen to the Superior - but first I'd like to get the Clock PCB issued and Detox etc. - but at least the new Capacitors are enjoying the benefit of the "extra" run-in time.
 
fusion5 said:
He did, but only with 8 resistors, not the full 52.

Edit: Might not even have been the pcb, but a rats nest setup.
Click to expand...

Yes correct, and the difference from changing just 8 resistors in the Rats nest to Z-Foils was so impressive I'm really wondering about the effect of the "Whole package" of 52 Z-Foils :)

Also, the Superior PCB includes the FDAC's ClassA Mosfet output stage which we are very keen to hear for the first time :)
 
JohnW said:
Its the first time I've encountered this issue with the MDAC, and it makes me wonder how many other MDAC's in customers hand have this issue which subsequently results in degraded sound quality. I'm in the process of designing a derivative of the FDAC's advanced clock circuit to upgrade the MDAC's internal Clock - this should be included with the Superior package - much like the Superior Analogue stage it gives us "working experience" of the FDAC's Clock design before we "Mass produce" the 200pcs or so of FDAC!

Maybe early next week we will listen to the Superior - but first I'd like to get the Clock PCB issued and Detox etc. - but at least the new Capacitors are enjoying the benefit of the "extra" run-in time.
Click to expand...

Yes, it seems like a good idea to test the clock circuit with the superior package.

Exciting times ahead! :)
 
JohnW said:
ATM its been powered up and burning in the new Caps - they always sound poor when fresh:-

https://dl.dropboxusercontent.com/u/86116171/MDAC S.JPG
Click to expand...

Seeing the MDAC burning in reminded me of an issue with my 5 rail power supply:
I want to rewire the PSU with a single cable for later use with the Superior unit, but I'm unsure on how to proceed. I can think of two possible solutions:

a) Drill a hole above the USB port for a new 8 pin connector. Wire the unit with a short unshielded 8x0.34mm² cable. If the second digital ground is a must have, I could go for a 9 pin connector + unshielded 10x0.25mm² cable. I don't think I can fit shielded cables in the GX16-8/9 connectors.

b) Have the MDAC psu board modified for DC input???

Edit: Total cable length for a) might end up 5 to 10cm longer than the internal MDAC power cable.
 
Sometimes i wonder if this can go on forever and does it break a guinness record. Even the bits are running out in couple years or so.
 
fusion5 said:
Seeing the MDAC burning in reminded me of an issue with my 5 rail power supply:
I want to rewire the PSU with a single cable for later use with the Superior unit, but I'm unsure on how to proceed. I can think of two possible solutions:

a) Drill a hole above the USB port for a new 8 pin connector. Wire the unit with a short unshielded 8x0.34mm² cable. If the second digital ground is a must have, I could go for a 9 pin connector + unshielded 10x0.25mm² cable. I don't think I can fit shielded cables in the GX16-8/9 connectors.

b) Have the MDAC psu board modified for DC input???

Edit: Total cable length for a) might end up 5 to 10cm longer than the internal MDAC power cable.
Click to expand...

You could possibly remove the connector on the rear of the MDAC itself and just wire a captive lead with clamping Grommet on the MDAC's rear panel with a suitable plug at the PSU end of the lead.

I can rewire your unit for DC input - do you have a suitable cable?
 
JohnW said:
You could possibly remove the connector on the rear of the MDAC itself and just wire a captive lead with clamping Grommet on the MDAC's rear panel with a suitable plug at the PSU end of the lead.
Click to expand...

That's basically what I did before. I removed the PSU board and wired the MDAC through the power connector hole. Total cable length was about 70cm. If that's fine then I don't have a problem.

How important is the second digital ground connection?
 
WRT Grounding, the more the merrier :) - Hey how come your all awake at this crazy hour its 4.30am :)
 
Pop over to Czech and visit us if you have no plans :), you can listen to the superior boards etc. we can accommodate you above the lab and your only expense would be getting here and back :)
 
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