I also really need better test equipment, the choice seems to be between real audio analyzers starting at $10K, or inadequate low cost AD/DA boxes like the EMU-0404. Something in between are needed, that might be my next project
Geee... that's why I started my SW project about 20 years ago
, while at that time, it was much more than 10k.. and finally I have no much room for other projects..
Hp
I also really need better test equipment, the choice seems to be between real audio analyzers starting at $10K, or inadequate low cost AD/DA boxes like the EMU-0404. Something in between are needed, that might be my next project
Another one eagerly waiting
Regards
Ok... thanks for explaining.
EMI can be fought in several ways and the micro-ohms advantage of silver... who's gonna notice...
Well, every single resistor got its own parasitic capacity, no matter how the layout is routed. (Even soldering joints are relevant)
Beside this, your switching is done via MOSFETs? Those gates are capacitiv coupled via the bulk, so there are more than a few pF. Clean plots? Easy explanation. At 384kHz the 470pF capacitors have a capacitive resistance of ~880Ohms, so 384kHz wont be possible with full output signal scale. (Would guess, even 20kHz will be damped) Conversation error induced harmonics are just shorted this way.
A 384kHz frequency plot would show this.
Well, every single resistor got its own parasitic capacity, no matter how the layout is routed. (Even soldering joints are relevant)
Beside this, your switching is done via MOSFETs? Those gates are capacitiv coupled via the bulk, so there are more than a few pF. Clean plots? Easy explanation. At 384kHz the 470pF capacitors have a capacitive resistance of ~880Ohms, so 384kHz wont be possible with full output signal scale. (Would guess, even 20kHz will be damped) Conversation error induced harmonics are just shorted this way.
A 384kHz frequency plot would show this.
The switching by the mosfets inside the LVC595's is not an issue driving the resistors, more a power supply decoupling issue.... And of course the resistors have parasitic capacitance, like between any two signals, but those are sub pF. Lets just say I'm not worried about the parasitic capacitances anywhere in my DAC design. Although I'm not a RF designer, I design Ghz computer boards in my day job so I have some experience there....
384 Khz sampling is more for show anyway, afaik there are no 384 Khz music files available, I could as well do 768 Khz sampling.... I have have one more analog bessel low pass filter in the output drivers, have decided on a system -3db at 200 Khz, 12 db per octave passive filter, which in my opinion is perfectly fine, there isn't any music up there.... But feel free to remove those capacitors
Havent gotten that far yet, but I have a couple of xmos boards from diyhk and will get an amanero too.
But almost anything should work as the I2S interface is isolated and reclocked with FIFO.
Micro-ohm? The advantage of Silver is in phonon acoustics, lower resistance is only a side-effect.
See you
No, the R-2R DAC is voltage output, with the "raw" output at 1.4V RMS with a source impedance of 1.25 Kohm. The "raw" output can driver a power amplifier directly, although I recommend buffering.
In the first post: Soekris wanted to see if there was interest (I guess he's not disappointed)
Interest post with everyone re-adding his name will flood the thread and reduce visibility of discussion as it seems there is already be lots of interest... and orders.
A google doc or a separate thead for the group buy would reduce the noise in the discussion thread.
It's probably something that we should let Soekris decide.
Interest post with everyone re-adding his name will flood the thread and reduce visibility of discussion as it seems there is already be lots of interest... and orders.
A google doc or a separate thead for the group buy would reduce the noise in the discussion thread.
It's probably something that we should let Soekris decide.
Hi Soekris,
Count me in for 1 unit at 0.2% . I'm going to sell a Proac D15 Speaker at 60% of its price if any frenchies interrested, please let me know in PM.
Come back to the technical discussion, may you please accept the questions of a noob in technic :
What about EMC with big (no laser trimmed) smd résistors ? Also does some brand new very low regs where a longer wire connection could solve some problems about transformer radiation ? Like Acko fellows just maid (look at its web shop) with compact regs to allow to use farer radiating PS & putting it in a separeted box ?
About the caps and its size & temperature effect like the way they are maid : My underdtanding is the TotalDac use Z foil because non inductive wirewound for "transparency"... Did you check some famous brand like Rohpoint which smd resistor are SOTA ?
An another caps is the IPEDIAs glass : one of the best for temperature drift, better than NPO : size as small as 02xxx or more case size : woerth a try as I understand now than this unit can only be maid in factory !
Sorry if naives questions or inputs, I'm not a technician... my first motivation is a musical DAC... but if a DIP 24 bits deep resolution with a good filtering curves (with DSP...wow ! great !), no glitch can allow that with the possibility to ear the strings of a cello or the teeth of Jimmy Hendrix on him guitar... I'm definitly on the waiting list (hopping wife is not going to buy a discrete gun)
Count me in for 1 unit at 0.2% . I'm going to sell a Proac D15 Speaker at 60% of its price if any frenchies interrested, please let me know in PM.
Come back to the technical discussion, may you please accept the questions of a noob in technic :
What about EMC with big (no laser trimmed) smd résistors ? Also does some brand new very low regs where a longer wire connection could solve some problems about transformer radiation ? Like Acko fellows just maid (look at its web shop) with compact regs to allow to use farer radiating PS & putting it in a separeted box ?
About the caps and its size & temperature effect like the way they are maid : My underdtanding is the TotalDac use Z foil because non inductive wirewound for "transparency"... Did you check some famous brand like Rohpoint which smd resistor are SOTA ?
An another caps is the IPEDIAs glass : one of the best for temperature drift, better than NPO : size as small as 02xxx or more case size : woerth a try as I understand now than this unit can only be maid in factory !
Sorry if naives questions or inputs, I'm not a technician... my first motivation is a musical DAC... but if a DIP 24 bits deep resolution with a good filtering curves (with DSP...wow ! great !), no glitch can allow that with the possibility to ear the strings of a cello or the teeth of Jimmy Hendrix on him guitar... I'm definitly on the waiting list (hopping wife is not going to buy a discrete gun
)
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