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MDAC First Listen (part 00110010)

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...

Ideally, it be better to merge our "XMOS development board", Superior PCB & Clock PCB onto one board and this becomes a direct MDAC PCB replacement PCB - reusing the rear panel & Chassis. ...

Déjà vu from 2012 .... ;-) Need to buy a MDAC again.
 
No, we would use the new dual Hyperstream2 ESS devices.

You can see the dual DAC's above the headphone Jack on our XMOS test PCB:-

https://dl.dropboxusercontent.com/u/86116171/Dual ESS Mini DAC.jpg
So what is missing from the fdac design apart from the discrete output stage fpga and dsp?

I have to admit to having some difficulty keeping up with whether this is the same as the f-dac lite or different. Sorry for all the questions but am very interested.
 
The FPGA (XMOS) is not missing.

What will be missing:
DSP, optional ADC, optional phono stage, av bypass, discrete gain stage in the analogue output stage, shunt based internal psu, arm based computing unit (streaming client, internal storage support), touchscreen, master-slave design to support with more channels and/or the VFET digital input boards, digital interface card slot, more inputs/outputs, trigger out, HDCD filter option, isolated analog/digital sections, optional extra screening, slot loader, balanced headphone out (besides main balanced out), ..

Think of it as a new approach to the FDAC lite.
 
I have to agree that is not easy to keep up with the remaining activities and where we are for each product.
JohnW, if possible and without appointing dates to it, a list of sequential remaining activities would be brilliant for each product. Everyone could then see for each product where we are, what's left to do and even interlink dependencies of each product.
Without assigning a date to the task you don't run the risk of being late :)

Just a suggestion.
Again, can't wait for the day both vfets and fdac arrive here!

Keep up the good work
 
Adam,


The trouble with the superior PCB's is the cost - and that we are "so close" to a complete replacement DAC PCB.

Ideally, it be better to merge our "XMOS development board", Superior PCB & Clock PCB onto one board and this becomes a direct MDAC PCB replacement PCB - reusing the rear panel & Chassis

The final decision comes down to the listening tests of the merged Superior + XMOS PCB and the just issued Clock circuit and what to do for a PSU - as the MDAC's current PSU solution is a limiting factor - which will become even more limiting with the mew PCB.

If we de go ahead, then we can have the first PCB's within a month as basically all the hard work has already been done.

John
If this single combined board does come together do you envision that it would be a DIY drop-in for someone with a bit of soldering experience?

Re the PS, how about an external box to provide DC, a la the 5 rail Calex ? I'm sure you could knock out a discrete PS design pretty readily :)
 
Its a section of the FDAC's "Advanced Clock" added to the MDAC:-

1. A "Test PCB" to gain "Working experience" of a important section of the FDAC design as the Superior PCB was for the Analogue stage.

2. Offer a future replacement / upgrade for the failed MDAC Crystals (clocks).

3. Will Morph onto the FDACLite later

The few Superior upgraded MDAC's will also be fitted with the new Clock circuit to gain "field experience"....

Hi John

Is now a good time to send in my MDAC for repair and capacitor replacement? I'm also interested in having the upgraded clock circuit fitted since my crystal is suspect.

Many thanks

mrflibble
 
Hi John

Is now a good time to send in my MDAC for repair and capacitor replacement? I'm also interested in having the upgraded clock circuit fitted since my crystal is suspect.

Many thanks

mrflibble

Yes, if you ship over the weekend, then next week will be a good time to look at your DAC - once I have the Clock PCB's.
 
John
If this single combined board does come together do you envision that it would be a DIY drop-in for someone with a bit of soldering experience?

Ian,

No soldering would be required, just swap over the Rear panel & Power Switch and then slide-in the new PCB's.
 
So what is missing from the fdac design apart from the discrete output stage fpga and dsp?

I have to admit to having some difficulty keeping up with whether this is the same as the f-dac lite or different. Sorry for all the questions but am very interested.

The would be the FDACLite = MDAC2 I guess - basically a new MDAC Mainboard + PSU.

The problem being the "new" external PSU - I don't see a practical cost effective solution ATM but I we have some options open, but currently I'm working on the FDAC ADC section (I need to get the PCB design to Jarek) so it will happen in due course....
 
Adam,

I have 4 Superior PCB's - two are spoken for.

The trouble with the superior PCB's is the cost - and that we are "so close" to a complete replacement DAC PCB.

Ideally, it be better to merge our "XMOS development board", Superior PCB & Clock PCB onto one board and this becomes a direct MDAC PCB replacement PCB - reusing the rear panel & Chassis.

On the XMOS development board I was able to design critical sections such as the Clock circuit in my CAD system and then Jarek "imported" the design into his CAD system so that I only need to design the critical sections then Jarek is rapidly able to spin a design.

The beauty of this approach is that we can have the PCB manufactured here in Europe with a vendor I've been in recent contact with.

The final decision comes down to the listening tests of the merged Superior + XMOS PCB and the just issued Clock circuit and what to do for a PSU - as the MDAC's current PSU solution is a limiting factor - which will become even more limiting with the mew PCB.

If we de go ahead, then we can have the first PCB's within a month as basically all the hard work has already been done.

Hi John,

Would the Superior + XMOS PCB's MDAC upgrade also require a new firmware version? The listening tests you made already seem to be very positive although limited by available amp & speakers. However this was with the Detox IIRC. Would we also need a Detox even with the XMOS PCB?

All the best
 
Well, you have there already a box with my 2 MDACs ... Any look at those?

I'll take a look at your DAC's later towards the end of next week, we are just completing the XMOS DAC PCB testing and software - then we need to build and listen to the MDAC Clock PCB... If it works well then we can fit to your units if your interested...
 
Well i received the vega dac today. I wasnt sure what to expect as the mdac did so very well. It was hard to imagine how well a dac could go from that point.
Well i'd remembered how much a dac can make a difference after the vega.
Instant noticeablilty was in texture, channel separation and soft sounds creeping through.
Im still holding back the full potential of the vega as its hot 4v output requires me to attenuate quite heavily and the rca output is not as good as the xlr output due to its seperatley driven stage design. But its still better than the mdac regardless.

A XLR to RCA with pin 3 floated will allow a 2v output for better matched systems and higher quality output stage.

Id eyed the vega for a while but never thought it would be in my reach, id considered it about the best dac you could get prior to the most expensive dacs you could buy with even smaller returns for money.

Fdac vs Vega battle is on the horizon, prepare to fight.

Danny
 
I know what you mean. The MDAC is a great unit for it's pricepoint. I wasn't sure what to expect from FDAC until I heard the Superior MDAC. Exciting times ahead!
 
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