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MDAC First Listen (part 00110011)

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Achim said:
Styrenes would probably not live long in the very hot class A environment of MDAC/FDAC.
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The PCB does not get hot enough to cause problems with Styrenes - they dont dry up - in fact they work better with any internal moisture dried out...

Achim said:
Maybe the heat is also the problem with those bulging caps.
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The problem is not heat related I have "New" old boards that have never been powered and the caps have failed - theres some internal chemical reaction going on.

Its mos often the 470/6.3V parts that fail - 80% of the time the other values near the hot heatsinks are OK.

There is no heat on the PSU PCB yet these caps pop.
Achim said:
It's just not "normal" to see so many bulging caps inside hifi devices, or is it?
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No its not normal, my best guess is that the problem is the capacitor vendor has messed up the Chemical formulation of the Electrolyte...
 
adamdea said:
And the $64,000 question is: when will that be?

Could you give us a quick timeline of what needs to be done to get the Mdac2 into production, and delivered into our hands, with an estimate as it currently looks of when each stage will be completed. Obviously leaving the SoC streamer and ADC for later makes complete sense. Is the design now complete?
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I'll have the PCBs for Munich - the production takes time - we currently have two products going into production (Detox one of them) - so as we now have an established relationship with the vendor each new project becomes easier and faster (especially when they share common components). About 50% of my time is now spent with vendor Emails, confirming component samples and working on BOM costings etc.

The MDAC2 shares many of the same component with the current two designs going into production so there will be less critical components to approve - the past few months I must have spent over US$3K paying for TNT / DHL express parcels from China with components for approval.

Each critical circuit section of the MDAC2 apart from the ADC and SOC has been tested (on separate PCB's) - now I need to combine these onto one PCB, I hope by the new years I'll be very close to issuing A02 MDAC2 PCB.
 
JohnW said:
I'll have the PCBs for Munich - the production takes time - we currently have two products going into production (Detox one of them) - so as we now have an established relationship with the vendor each new project becomes easier and faster (especially when they share common components). About 50% of my time is now spent with vendor Emails, confirming component samples and working on BOM costings etc.

The MDAC2 shares many of the same component with the current two designs going into production so there will be less critical components to approve - the past few months I must have spent over US$3K paying for TNT / DHL express parcels from China with components for approval.

Each critical circuit section of the MDAC2 apart from the ADC and SOC has been tested (on separate PCB's) - now I need to combine these onto one PCB, I hope by the new years I'll be very close to issuing A02 MDAC2 PCB.
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Thanks John
Am I right that the two products going into production are the Detox and the MDac2, or is there something else going into production?

So once the Mdac2 PCB is issued is it just a question of getting a pre-production sample tested and then booking the full production?
 
JohnW said:
The problem is not heat related I have "New" old boards that have never been powered and the caps have failed - theres some internal chemical reaction going on.
Click to expand...

Thank you for the explanation - this seems to be clearly caused by the cap vendor, then.
 
If anyone would like to take my place for the FDAC please let me know I'm afraid that I must drop out.
 
adamdea said:
Thanks John
Am I right that the two products going into production are the Detox and the MDac2, or is there something else going into production?
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Detox and an undisclosed project - which will be revealed at Munich.

adamdea said:
So once the Mdac2 PCB is issued is it just a question of getting a pre-production sample tested and then booking the full production?
Click to expand...

Building the first sample board, update any (hopefully small errors) then releases files to production... they will manufacture the first 10pcs as PP1 (Pre-Production one) boards - once these are approved then its 30 days to full shipping.

With Detox and other projects in production I'll be out in China more often next year so hopefully I can speed-up MDAC2 PCB's (I'll be able to approve in China rather then shipping back to Europe etc).

What takes time is dealing with the component vendors on pricing and then testing and approving samples - as the first two design that are currently going into production share a lot in common with MDAC2 then this will be a faster and simpler process for MDAC2...
 
JohnW said:
The problem is not heat related I have "New" old boards that have never been powered and the caps have failed - theres some internal chemical reaction going on.

, my best guess is that the problem is the capacitor vendor has messed up the Chemical formulation of the Electrolyte...
Click to expand...
I checked about 9 months ago and saw a hint of leakage from two small caps.I had a look a few days ago and was taken aback by the amount of leakage and bulging caps throughout. . .severe deterioration.
Luckily,my system still sounds fab. though.
 
JohnW said:
Detox and an undisclosed project - which will be revealed at Munich.



Building the first sample board, update any (hopefully small errors) then releases files to production... they will manufacture the first 10pcs as PP1 (Pre-Production one) boards - once these are approved then its 30 days to full shipping.

With Detox and other projects in production I'll be out in China more often next year so hopefully I can speed-up MDAC2 PCB's (I'll be able to approve in China rather then shipping back to Europe etc).
Click to expand...
So by the Munich show which is in mid May, what stage are you hoping to have reached with the Mdac2: having the pcbh design complete, having the pre-production boards produced (or approved), or having the Mdac2 boards in production?
 
Yes, in the worst case the PCB I have for Munich upgrade will be PP1 PCB's but lets not go there ATM.
 
JohnW said:
Same front panel / Chassis as MDAC.

GBP 500 development fee transferable from FDAC.

PCB "at cost" GBP150 to GBP250 + external PSU (say GBP100)
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John

You may have missed my post yesterday.

I would like to switch to the MFAC2 option. I believe I have made six FDAC payments - L3 with phono stage - so presumably £600. How will that map into MDAC2 costs?
 
Clerenlas,

GBP500 of the FDAC development fee transferred to the MDAC2 Development fee & I'll credit you the GBP100 balance to the MDAC2 PCB "At cost".

As a FDAC to MDAC2 Xfer you quality for FDAC at 50% development fee (+PCB at cost) if your still interested in FDAC once it available.
 
Achim said:
Styrenes would probably not live long in the very hot class A environment of MDAC/FDAC.

Maybe the heat is also the problem with those bulging caps.

It's just not "normal" to see so many bulging caps inside hifi devices, or is it?

Cheers,
Achim
Click to expand...

I guess I have the oldest mdac, its one of johns hand built proto versions, it uses different caps, its been on 24-7 for years and doesn't have a single bulging cap.

Its not the heat. I use styrene in the paradise, it runs a class A shunt in each channel, no issues there.
 
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