MDAC First Listen (part 00110011)
- Thread starter adamdea
- Start date
- Status
JohnW
pfm member
This weekend I validated both the MDAC2 analogue stage simulations results verse "reality" and the Tube gain stage.
The MDAC2 simulations where within 0.2dB on a rats nested prototype while the Tube Gain stage (for VFET amp) matched simulated open loop gain results to within 2.4dB - those are both excellent confirmations that our device models can be trusted - this speeds up the MDAC2 as we can avoid an "intermittent" PCB design.
The considering how variable tubes are, a 2.4dB "error" is very reassuring
The MDAC2 simulations where within 0.2dB on a rats nested prototype while the Tube Gain stage (for VFET amp) matched simulated open loop gain results to within 2.4dB - those are both excellent confirmations that our device models can be trusted - this speeds up the MDAC2 as we can avoid an "intermittent" PCB design.
The considering how variable tubes are, a 2.4dB "error" is very reassuring
JohnW
pfm member
John, so there will be two balanced headphone outputs? Does that mean you're going to supply a replacement front panel as well? And where will you find the space for the ADC board?
(Are you sure you don't want to rename MDAC2 to FDAC?
Please note my post above and corrected Spec and not Tims repost of my original spec. with the error - there is ONLY ONE headphone balance output and that's located on the MDAC2 rear panel.
The ADC boards mounts upside down above the analogue stage with the ADC's Mini XLR inputs mounted ABOVE the RCA outputs.
I decided on adding the ADC as a septate PCB to ease production (only one type of mainboard manufactured) - and the ADC can be released after the MDAC2 is put into production (again so no extra delay too MDAC2). Also the ADC can be added to any MDAC2 at a later date.
Mark Dirac
pfm Member
So, if I plug an XLR into the XLR headphone socket, will it disconnect all other equipment (apart from front headphone jack)? What I am trying to get at is, will I still need to unplug my amplifier when using XLR headphones? Thanks.
Hi John et al.,
I have been a bit of from the forum due to travels at work. It is very hard to skim though this long thread.
Can anyone tell me what is the "difference" between MDAC2 and FDAC? Is the MDAC2 retaining the original MDAC footprint?
What is the price? Is it possible to jump from FDAC to MDAC2?
Cheers!
Mark Dirac
pfm Member
That's great. May I therefore swap from the FDAC project to the MDAC2 project please, assuming that the MDAC2 will be delivered first.
JohnW
pfm member
Yes sure, everyone will have that option once the PCB's are ready to go into production
JohnW
pfm member
Same front panel / Chassis as MDAC.
GBP 500 development fee transferable from FDAC.
PCB "at cost" GBP150 to GBP250 + external PSU (say GBP100)
stephengrenfell
pfm Member
Hi John,
Can you give a ballpark cost for the "Optional Vishay Bulk Foil Resistors upgrade in critical audio positions" ?.
timola
pfm Member
I'm having both...mdac2 to eventually star in a second system when the FDAC appears. IMHO everyone who loves the MDAC should go for the MDAC2...those caps are very likely bulging already!
John, I'm interested in the option for Vishay Bulk Foil resistors ... any ballpark costs for these? Also any other component upgrade options in mind?
John
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?
It will be great to meet, and that I will be able to upgrade PFM'ers MDAC to MDAC2's at the Munich show
At the Munich show we will also have a few surprises
I will probably also go to the Munich show. it will be great to meet you again and hopefully a bigger group of PFM'ers than this year.
Mark Dirac
pfm Member
I am setting my sights rather closer, on the Bristol (UK) show end February. Any PFMers interested to meet up there?
adamdea
You are not a sound quality evaluation device
And the $64,000 question is: when will that be?Yes sure, everyone will have that option once the PCB's are ready to go into production
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?
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
s1h1
performing within expectations
Are 'salvaged' MDACs available?
JohnW
pfm member
They will be available closer to the production date.
- Status