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Reference DAC Module - Discrete R-2R Sign Magnitude 24 bit 384 KHz

Just to report, I received my DAC today. Easy set up, beautiful board. Have it running with Arduino. Tried only single ended. Great sound, well balanced, detailed and warm. Not a trace of harshness. I am very happy. The best part is that is so easy to set it up. Easy power supply, easy with output. I am running it straight to amps. This is such a pleasure project. Thank you Soekris!

I will be so happy to have it as a crossover when available. I do not know how you will make it in regards to the clock, but it would be great to have as well, an additional clock output to run source in the slave mode.

Looking forward for the development while enjoying great sound!
 
Just to report, I received my DAC today. Easy set up, beautiful board. Have it running with Arduino. Tried only single ended. Great sound, well balanced, detailed and warm. Not a trace of harshness. I am very happy. The best part is that is so easy to set it up. Easy power supply, easy with output. I am running it straight to amps. This is such a pleasure project. Thank you Soekris!

I will be so happy to have it as a crossover when available. I do not know how you will make it in regards to the clock, but it would be great to have as well, an additional clock output to run source in the slave mode.

Looking forward for the development while enjoying great sound!

Hi
Some pictures to show us your project ;)

Thanks
Serge
 

TNT

Member
Joined 2003
Paid Member
Oouch, sorry to hear that. But it could actually happen with any potmeter where you loses gnd.

The R-2R DAC actually have a little failsafe as it will not add gain until set at or below 0db first. But that just at power up, no protection against sudden problems.... But in contrary to an analog potmeter, I have a uC in control and will look into adding additional failsafe, one possibility is if potmeter goes up too fast it should be detected as error.

Your last point is briliant. Please implement and with an error signal somehow (green led flash cadence)

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What is the worst load the unbuffered outputs should see ideally?

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No real limitation, the direct R-2R output is like a voltage source with 625 ohms pure resistor in series, any load will just lower the output voltage as per ohms law....

The RC filters cut off frequency will be higher with heavy load, so I would say don't go below 2 Kohm.
 
Disabled Account
Joined 2005
dam1021 uManager Rev 0.80 20150121 FPGA Rev 0.8 Press ? for help.

No 0.9 after PW cycle...

used ZTERM on OS X

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ZTERM on OS X works fine providing you use the right settings. I've just done the 0.9 update using a MacBook Pro, Z-Term and a USB-Serial adapter marked UC-232A and it worked first time.

If you go to File > Transfer Covert then select "Binary", rather than the default "Smart MacBinary" you shouldn't have any trouble. I'd been tripped up by this setting updating firmware on a Soekris SBC. "Smart MacBinary" seems to mangle the firmware.
 
ZTERM on OS X works fine providing you use the right settings. I've just done the 0.9 update using a MacBook Pro, Z-Term and a USB-Serial adapter marked UC-232A and it worked first time.

Once you've got a de9 serial plug attached, what is the wiring standard to the connector on the board? It looks like with a d9 txd is 3, Rxd is 2, and gnd is 7--so just these three wires would get attached to the DAC board?
 
Last edited:
Disabled Account
Joined 2005
Once you've got a de9 serial plug attached, what is the wiring standard to the connector on the board? It looks like with a d9 txd is 3, Rxd is 2, and gnd is 7--so just these three wires would get attached to the DAC board?

What I have is:

RS232_RXD -> DB9-3 ( Transmit Data)
RS232_TXD -> DB9-2 (Receive Data)
RS232_GND -> DB9-5 (Signal Ground)

I used a 10 pin IDC header and ribbon cable, then isolated the required wires and soldered to DB9 plug. I only have three wires connected at the DB9 end.
 
What I have is:

RS232_RXD -> DB9-3 ( Transmit Data)
RS232_TXD -> DB9-2 (Receive Data)
RS232_GND -> DB9-5 (Signal Ground)

I used a 10 pin IDC header and ribbon cable, then isolated the required wires and soldered to DB9 plug. I only have three wires connected at the DB9 end.

Thanks spzzzzkt! I'll add a db9 plug to my parts list-I have a feeling I must have several old cables in my attic I can repurpose.
 
Hi,

with M2Tech USB-I2S there occurs switching noise when changing track clock too.
Soomtimes it takes the Dac takes up to two seconds to lock on.
IIrc the M2Tech supplies a status bit or a clock dependant signal that could be used to switch a DAC much faster, so that it locks in less a ms.
Maybe other USB-I2S converters provide for a similar feature that may be used here?

jauu
Calvin
 
is there any way to fix i2s as a default connection and disable others to eliminate lock on time. For sure it must be valid even after power off and on.

Or maybe Soren you can release variant firmware for spesific usages/purposes.

Connect INP_SLCT0 and INP_SLCT1 pins to GND, see post #901.

It will always take a little time to switch sample rates with the reclocking FIFO. I will for next release check on the timings and optimize, should cut it down to below a second.

But it's always a compromise, it really need enough time to measure the incoming clock to set the initial oscillator frequency.