07-13-2018, 03:04 PM
Le nouveau DAC progresse. Voici quelques informations:
"It is a S/PDIF Toslink DAC based on the DIR9001. It comes in 17 or 24 bit version and it is battery powered (3V7 Lithium Polymer battery).
The battery can be charged with a standard 5V adapter through the USB charger socket on the top right.
It has a standard rectangular Toslink optical socket (next to the USB charger socket).
Mechanical switch connects the battery to either the charger or the circuit (both plus and minus are switched). So the DAC circuit is never connected to the charger when switched on.
The 10Ah battery (on the picture at the right) can power this DAC for 285 hours.
The DIR9001 has a modified PLL for low very low jitter.
Hardware decoder extracts sample rate from the DIR9001 and drives a dual white seven segments display (-- not locked, 44, 48, 88, or 96). There is a photodiode that automatically controls the brightness.
Second hardware decoder converts 24 bit left justified from the DIR9001 to either 17 bit or 24 bit data & clock burst signals the drive the Mosaic converters.
So there is no micro controller and no master clock in this DAC, therefore noise levels and EMI are extremely low and power consumption is only 130 milli watts during streaming so the battery lasts very long.
These are new D/A converters (routing was quite a challenge). These are based on the mirror bridge concept that offers superb low level performance, even with 1% resistors (I use 0.1%) and is rather insensitive to jitter as all interface (clock and data) signals are completely shut shut down well before latching the outputs.
There is no CPU nor crystal oscillator running that could cause interference. The DIR9001 consumes only 26 milli watts and produces very little interference. I put it as far away from the converters as possible to ensure noise levels stay low.
Huge decoupling caps (I plan to use 3 x 10000uF ensure that the battery power supply approaches a perfect power supply
This way the digital interface noise level is almost zero (no jitter is transferred) when the latch pulse occurs.
This requires very fast logic (CPU is not fast enough) as all data has to be clocked into the converters in the fraction of the time that it would take to clock in I2S for example.
The output (4Vpp, 750 Ohm) are directly connected to two RCA sockets on the top left.
And that's about it, a very simple, straight-forward DAC that outperforms all USB versions we designed and tested."
"It is a S/PDIF Toslink DAC based on the DIR9001. It comes in 17 or 24 bit version and it is battery powered (3V7 Lithium Polymer battery).
The battery can be charged with a standard 5V adapter through the USB charger socket on the top right.
It has a standard rectangular Toslink optical socket (next to the USB charger socket).
Mechanical switch connects the battery to either the charger or the circuit (both plus and minus are switched). So the DAC circuit is never connected to the charger when switched on.
The 10Ah battery (on the picture at the right) can power this DAC for 285 hours.
The DIR9001 has a modified PLL for low very low jitter.
Hardware decoder extracts sample rate from the DIR9001 and drives a dual white seven segments display (-- not locked, 44, 48, 88, or 96). There is a photodiode that automatically controls the brightness.
Second hardware decoder converts 24 bit left justified from the DIR9001 to either 17 bit or 24 bit data & clock burst signals the drive the Mosaic converters.
So there is no micro controller and no master clock in this DAC, therefore noise levels and EMI are extremely low and power consumption is only 130 milli watts during streaming so the battery lasts very long.
These are new D/A converters (routing was quite a challenge). These are based on the mirror bridge concept that offers superb low level performance, even with 1% resistors (I use 0.1%) and is rather insensitive to jitter as all interface (clock and data) signals are completely shut shut down well before latching the outputs.
There is no CPU nor crystal oscillator running that could cause interference. The DIR9001 consumes only 26 milli watts and produces very little interference. I put it as far away from the converters as possible to ensure noise levels stay low.
Huge decoupling caps (I plan to use 3 x 10000uF ensure that the battery power supply approaches a perfect power supply
This way the digital interface noise level is almost zero (no jitter is transferred) when the latch pulse occurs.
This requires very fast logic (CPU is not fast enough) as all data has to be clocked into the converters in the fraction of the time that it would take to clock in I2S for example.
The output (4Vpp, 750 Ohm) are directly connected to two RCA sockets on the top left.
And that's about it, a very simple, straight-forward DAC that outperforms all USB versions we designed and tested."