Am I correct in which component/function goes where below?
Digital board: Various digital inputs/receivers eg USB, S/PDIF ...
Analog board: DAC's, Clocks, ADC, FPGA, Analog out
MDAC First Listen (Part 00101010)
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Am I correct in which component/function goes where below?
Digital board: Various digital inputs/receivers eg USB, S/PDIF ...
Analog board: DAC's, Clocks, ADC, FPGA, Analog out
JohnW
pfm member
The FPGA's are on the digital PCB, but otherwise correct - the digital board is "Simple" but will take about 2 months... We can be building and testing the FDAC in the meantime - and fit the digital PCB at the last stage.
Thats a real big question - without the Clocklocking, the Detox's prime purpose is to "equalize" the quality of the USB data stream. However your "USB Card" which is hung of the optical PCIexprsss isolation link should do a very good job, certainly magnitudes better then your typical PC USB port. But whos to say how good really the USB output is - I still suspect the Detox's output will be significantly cleaner
As you already have a good "USB port" and cannot clock-lock the Detox to your DAC you will benefit less then others from the Detox... but lets see (hear)
No none, its a very clean supply rail so no harm can be done.
Understood. Thanks.
travelfotografe
pfm Member
John, given there is now space on the FDAC, for the balanced headphone out, would you use the (somewhat industry standard) 4-way female XLR balanced connection: 1 left positive, 2 left negative, 3 right positive, 4 right negative
iansr
pfm Member
One day Dominik swapped the naming of the filters behind my back without telling me - and I was so So very upset and confused with myself because all of a sudden I preferred the other filter. After about half a day!!!! he just smiled and said he was just testing me - so that's a double blind test if there ever was one!
My expertise lies elsewhere. I was once handed a G&T by an air stewardess and upon tasting it promptly identified it as Tankerey.
Ciunas Audio
Trade: Ciunas Audio
Sorry for the follow-up question but are you saying that your audio clocks 22.5796MHz & 24.576MHz (fed to your DAC) are derived by fractional division of the 84MHz master clock?
JohnW
pfm member
The MDAC's ASync USB mode the audio rate clocks are derived by fractional division of the 84MHz master clock, but its not 512fs related (I guess your thinking typical XMOS based designs) - FDAC has a very different clocking structure but again everything by design is fully synchronous.
With the ESS the modulator can operate at any rate it does not need to be audio related - whats important is to insure that the DPLL operates with a fixed number without modulation over time.
With non synchronous data the DPLL would be constantly changing which results in unwanted modulation and related artifacts. With the Synchronous clock structure used in the MDAC, the DPLL values are fixed. The input data verses modulator rate is locked / fixed.
Its important to understand that a modulator can operate at any rate independent of the audio data, the fact that a typical DAC operates the modulator at an audio related rate is just due to the local clocks available.
JohnW
pfm member
John, do you still have slots for the modified 8200MB? Given that I have finally decided to go all in for the FDAC, I will have to sell my current Naim system (for good!)
Will you finally install the tube?
I have a couple of pallets of the amps so plenty to go around!
If the modifications where only to remove the design defects and convert to fully balanced operation then it would be a relativity easy job - but as we all know I tend to make my life difficult and push the boundary's, so adding the tube requires an extra 6V heater supply = small transformer + PCB, which complicates the picture.
I guess in my heart I know I have to add the tube but don't see when I will have the time - that said I need to convert these units back into cash so I can pay for the new custom VFET chassis - so I will need to work on these amps this side of Christmas!!!
Now that I have my small lab - I really need to find someone who could work with me to help ease my workload.... anyone want a job in the Czech Rep?
When I first started out in HiFi I would have loved such a job opportunity - not to mention living in a country surrounded by beautiful ladies and cheap beer!
misterdog
Not the canine kind
JohnW
pfm member
Might Dominik have done this to other Mdac's also
Not by design!! but IIRC I once caught an error in filter naming while testing a "Lakewest" software build (before it was publicly released).
misterdog
Not the canine kind
I would if the Fdac chassis were made of plywood.
Is there not someone on an electronics/engineering course at Renata's university, who would want some real life experience ?
JohnW
pfm member
They don't have an Electronics Dept at Renata's university,... only in Prague and Brno
Yes I need a second "Dominik" here in Czech.
Ciunas Audio
Trade: Ciunas Audio
Thanks for that explanation - I have to think about it some more but an immediate issue pops into my head - doesn't a local hardware clock (situated as close to the DAC as possible) usually represent the lowest jitter option available?
Are you saying that a fractional division of a clock is a better option when it can be fed upstream & used to synchronise all processes which require clocking?
In other words multiple clock domains derived from low jitter local clocks is audibly worse than synchronised clocks derived by fractional division ( a known source of jitter) from a single master clock?
JohnW
pfm member
The modulator is operated from the clean 84MHz clock located besides the DAC, the fractional derived clock is only for inputting the data but plays no direct part in the actual conversion - its what makes the ESS design so special. This only holds true when the DPLL values are fixed, otherwise you face concerns about the use of ASRC with non synchronous data (changing DPLL values) - we don't need to reject jitter due to the synchronous clock structure in ASync USB mode.
The ESS ASRC is not your typical ASRC, but its still best to avoid - it just feels "cleaner" more direct if nothing else...
The ESS ASRC is not your typical ASRC, but its still best to avoid - it just feels "cleaner" more direct if nothing else...
Ciunas Audio
Trade: Ciunas Audio
Ah, right, the penny has dropped - thanks!
I had always assumed that synchronous meant the same clock signal was used at the ESS DAC & upstream - I hadn't envisaged a fixed rate derived clock being used upstream.
Agreed with ESS asynch Vs synch clocking - it sounds better synched but from what you say it's the drifting of DPLL that causes these audible issues, not the DPLL itself?
JohnW
pfm member
ti33er
pfm Member
Hi John
Just a thought, but most of us are based in the UK?
I have no idea if he would lend himself to this opportunity, or if it suited you either but Kevin is very talented at this kind of thing. He has a very good reputation repairing AUDIOLAB and TAGMcLaren amplifiers and Processors, at very reasonable fees all considered.
He is a genuine guy; I'm sure there are ex TMA people on here that could/would attest.
Anyway just an idea, if it made sense and parties are willing.
Ps. I have no financial affiliation here whatsoever. Also his other passion is the Nurburghring and races there often enough...not sure how far your place and this exactly are apart, if collection were feasible.
Just a thought, but most of us are based in the UK?
I have no idea if he would lend himself to this opportunity, or if it suited you either but Kevin is very talented at this kind of thing. He has a very good reputation repairing AUDIOLAB and TAGMcLaren amplifiers and Processors, at very reasonable fees all considered.
He is a genuine guy; I'm sure there are ex TMA people on here that could/would attest.
Anyway just an idea, if it made sense and parties are willing.
Ps. I have no financial affiliation here whatsoever. Also his other passion is the Nurburghring and races there often enough...not sure how far your place and this exactly are apart, if collection were feasible.
I have a couple of pallets of the amps so plenty to go around!
If the modifications where only to remove the design defects and convert to fully balanced operation then it would be a relativity easy job - but as we all know I tend to make my life difficult and push the boundary's, so adding the tube requires an extra 6V heater supply = small transformer + PCB, which complicates the picture.
I guess in my heart I know I have to add the tube but don't see when I will have the time - that said I need to convert these units back into cash so I can pay for the new custom VFET chassis - so I will need to work on these amps this side of Christmas!!!
Now that I have my small lab - I really need to find someone who could work with me to help ease my workload.... anyone want a job in the Czech Rep?
When I first started out in HiFi I would have loved such a job opportunity - not to mention living in a country surrounded by beautiful ladies and cheap beer!
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