In theory, I2S should have the edge over SPDIF because it skips the SPDIF encoding and decoding stages.
On the other hand, if you route your PC player to the I2S port, then you keep the SPDIF available for another application.
On a related topic, has anyone thought about testing this?
http://www.diyaudio.com/forums/pc-b...aspberry-pi-into-audiophile-audio-player.html
That would be a Raspberry Pi with a hard disk running Volumio, connected to Najda via I2S on the Expansion Port ...
For now I used this v1.0.3 beta and not find any more problem of settings update.
Problem with mute and distortion
Hi,
I experience problems with the mute function and have high distortion.
Here is the story: Because of other topics my Najda build was delayed. But now I found the time to assemble it. First I connected the LCD, the LEDs, the buttons and the IR receiver. I use an external power supply. A picture of my prototype is attached. I double checked every connection and powered it on. Everything worked fine, I was able to scroll to the LCD menues. Then I downloaded Najda SW 1.04 with Firmware 1.1, connected Najda and did a FW upgrade. All without problems. I played a bit with filter settings and checked the LEDs for overload, SPDIF Lock-in etc. All worked as expected.
Then I decided to listen to it. I configured Najda as coax 96 pass thru and did not define any filters. I connected the coaxial ouput of a CD player to the corresponding coax input of Najda. Two Najda analog outputs I connected to the input of an amplifier with two cheap loudspeakers for first test. I set the Najda volume to -50dB. Then I played a CD and was surprised by the heavy distortion I noticed. I pressed the mute button of Najda, but the output did not mute. I further reduced the volume of Najda. According to the LCD even to -96dB. But the distorted sound did not get reduced. So obviously mute and Volume control do not work as expected.
I then put Najda back to the PC and did some tests with Arta. All test have been done with 96kHz project setting and without any filters defined.
1. I first tested the mute functionality. According to the documenation muting only works for analog outputs. I used the optical Najda input with Pink Noise at -5dB FS and measured the analog output with full volume and muted. You see the result in the picture. The mute function of my Najda does not really mute, but reduces the volume by about -40dB. With the volume setting I could adjust the output, but not less than the "mute level". This means the volume control works only from the 0dB to -40dB setting. From -40dB to -96dB the level stayed constant at the mute level. Strange!
2. Then I measured the distortion. I put a 1kHz sine through the optical input and later through the analog input. Output was coax or analog. I carefully watched to not clip the input signal. I used -1dB FS for digital input and 0.97mV rms for analog input (ADC LED never lighted). You see the results in the attachment.
You notice for optical input and analog input a very high THD of about 2%. And this is with almost full level input. When using a smaller input signal the distortion relative to the signal gets even worse.
It is definitely not a measurement setup issue because I noticed the distortion already with my "conventional setup" mentioned above.
Anyone having an explanation?
Best regards,
Uwe
Hi,
I experience problems with the mute function and have high distortion.
Here is the story: Because of other topics my Najda build was delayed. But now I found the time to assemble it. First I connected the LCD, the LEDs, the buttons and the IR receiver. I use an external power supply. A picture of my prototype is attached. I double checked every connection and powered it on. Everything worked fine, I was able to scroll to the LCD menues. Then I downloaded Najda SW 1.04 with Firmware 1.1, connected Najda and did a FW upgrade. All without problems. I played a bit with filter settings and checked the LEDs for overload, SPDIF Lock-in etc. All worked as expected.
Then I decided to listen to it. I configured Najda as coax 96 pass thru and did not define any filters. I connected the coaxial ouput of a CD player to the corresponding coax input of Najda. Two Najda analog outputs I connected to the input of an amplifier with two cheap loudspeakers for first test. I set the Najda volume to -50dB. Then I played a CD and was surprised by the heavy distortion I noticed. I pressed the mute button of Najda, but the output did not mute. I further reduced the volume of Najda. According to the LCD even to -96dB. But the distorted sound did not get reduced. So obviously mute and Volume control do not work as expected.
I then put Najda back to the PC and did some tests with Arta. All test have been done with 96kHz project setting and without any filters defined.
1. I first tested the mute functionality. According to the documenation muting only works for analog outputs. I used the optical Najda input with Pink Noise at -5dB FS and measured the analog output with full volume and muted. You see the result in the picture. The mute function of my Najda does not really mute, but reduces the volume by about -40dB. With the volume setting I could adjust the output, but not less than the "mute level". This means the volume control works only from the 0dB to -40dB setting. From -40dB to -96dB the level stayed constant at the mute level. Strange!
2. Then I measured the distortion. I put a 1kHz sine through the optical input and later through the analog input. Output was coax or analog. I carefully watched to not clip the input signal. I used -1dB FS for digital input and 0.97mV rms for analog input (ADC LED never lighted). You see the results in the attachment.
You notice for optical input and analog input a very high THD of about 2%. And this is with almost full level input. When using a smaller input signal the distortion relative to the signal gets even worse.
It is definitely not a measurement setup issue because I noticed the distortion already with my "conventional setup" mentioned above.
Anyone having an explanation?
Best regards,
Uwe
Attachments
Thanks Meelis for reporting. There was indeed some pairing rework that must have solved the issues you found with the previous version.
Hi Uwe,
Sorry to hear about your problems.
Can you please check the following:
- The voltages delivered by your power supply
- If the same problems happen on every output.
- If you have a DAC lying around, can you check how it sounds? (for example through the SPDIF)
It could be that the CS3318 is fried. I'm thinking of this because mute and volume are both handled by this chip.
If you find out that your voltages are OK - which is what I expect - and that all outputs exhibit the same fault, then I suggest you send the board back to me.
Best,
Nick
Hi Nick,
thanks for the fast reply!
1.)
I measured the following voltages.
+5.1 V
-12.1 V
+12.2 V
I guess that is close enough.
2.) On every analog output there is similar high distortion.
3.) I included a measurement of the 1kHz sine using Najda optical in and coax out.
Looks better.
Best regards,
Uwe
thanks for the fast reply!
1.)
I measured the following voltages.
+5.1 V
-12.1 V
+12.2 V
I guess that is close enough.
2.) On every analog output there is similar high distortion.
3.) I included a measurement of the 1kHz sine using Najda optical in and coax out.
Looks better.
Best regards,
Uwe
Attachments
Hi Uwe,
Thanks for these additional details.
Please send the board back to me. Even the digital out looks bad actually: the noise level shouldn't be that high (or is that related to your measurement setup?). In any case, I'll check the board at the lab and I'll keep you informed.
Best,
Nck
Thanks for these additional details.
Please send the board back to me. Even the digital out looks bad actually: the noise level shouldn't be that high (or is that related to your measurement setup?). In any case, I'll check the board at the lab and I'll keep you informed.
Best,
Nck
Hi Nick,
thank you very much for your support!
I will send back the board to the address of the invoice.
I did some further measurements. There are some strange things going on which I do not fully understand.
1. Setup:
Najda
- project set to 96kHz and classical free routing
- Optical-in Coax Out (pure digital processing), no filters set.
Arta
- sampling set to 96kHz
- used soundcard is an RME Fireface UC
First measurement: no signal (Najda SPDIF locked)
Second measurement: 1kHz sine (-3dB FS)
In the attachment (both measurements shown as overlay) you see for no signal the line at -233dB noise (which I believe is related to the digital resolution of the soundcard).
Strange is the signal for 1kHz (upper line). I guess there are some interactions going on with Najda and Arta both set to 96kHz
2. Setup
Same as 1) except Arta set to 88kHz (but Najda still to 96kHz)
Result see attachment: No signal: -233dB noise as before. The 1kHz signal looks better but for pure digital processing there is high noise.
3. Setup
Same as 2) but second measurement is soundcard analog loopback (lower line, no Najda connected). The analog soundcard loopback is much better than the pure digital signal via Najda.
4. Setup
No Najda involved.
Analog soundcard loopback (same as in 3.) and digital soundcard loopback (using soundcard SPDIF in and out ). Looks good.
It seems that the digital part of Najda is also not working correctly.
Uwe
thank you very much for your support!
I will send back the board to the address of the invoice.
I did some further measurements. There are some strange things going on which I do not fully understand.
1. Setup:
Najda
- project set to 96kHz and classical free routing
- Optical-in Coax Out (pure digital processing), no filters set.
Arta
- sampling set to 96kHz
- used soundcard is an RME Fireface UC
First measurement: no signal (Najda SPDIF locked)
Second measurement: 1kHz sine (-3dB FS)
In the attachment (both measurements shown as overlay) you see for no signal the line at -233dB noise (which I believe is related to the digital resolution of the soundcard).
Strange is the signal for 1kHz (upper line). I guess there are some interactions going on with Najda and Arta both set to 96kHz
2. Setup
Same as 1) except Arta set to 88kHz (but Najda still to 96kHz)
Result see attachment: No signal: -233dB noise as before. The 1kHz signal looks better but for pure digital processing there is high noise.
3. Setup
Same as 2) but second measurement is soundcard analog loopback (lower line, no Najda connected). The analog soundcard loopback is much better than the pure digital signal via Najda.
4. Setup
No Najda involved.
Analog soundcard loopback (same as in 3.) and digital soundcard loopback (using soundcard SPDIF in and out ). Looks good.
It seems that the digital part of Najda is also not working correctly.
Uwe
Attachments
It seems that I have encountered a problem. I installed win7 on
the laptop I have been using to control "Najda" and now i cant
connect to the hardware.
I'm using 1.04 and I have installed the drivers as well.
The computer just doesn't find the hardware. Any clues to what is missing ?
It worked like a charm with XP.
the laptop I have been using to control "Najda" and now i cant
connect to the hardware.
I'm using 1.04 and I have installed the drivers as well.
The computer just doesn't find the hardware. Any clues to what is missing ?
It worked like a charm with XP.
Hello and thank you for this great project.
About to get this board and was wondering if the following would work to obtain balanced signal:
It's a simple crossover for subwoofer and main speakers so only 4 channels are required.
Both monitor speakers and subwoofer amplifiers have balanced input and what I was wondering is:
Could I duplicate the low passed outputs and put one out of phase then use the unbalanced in phase and out of phase outputs to combine and feed the balanced inputs of the subwoofer (and do the same for the mains)?
Would this produce true balanced operation without any circuit modifications?
Thank You
About to get this board and was wondering if the following would work to obtain balanced signal:
It's a simple crossover for subwoofer and main speakers so only 4 channels are required.
Both monitor speakers and subwoofer amplifiers have balanced input and what I was wondering is:
Could I duplicate the low passed outputs and put one out of phase then use the unbalanced in phase and out of phase outputs to combine and feed the balanced inputs of the subwoofer (and do the same for the mains)?
Would this produce true balanced operation without any circuit modifications?
Thank You
Has anyone looked at connecting the Nadja to a Buffalo III DAC and running all 8 channels available in the Buffalo? During my planning I overlooked the fact that only 6ch of I2S are available from the Nadja while the Buffalo can accept 8ch on I2S input.
I'm not afraid to hack at the Nadja if the extra 2ch of I2S is running around somewhere - I assume I might be able to locate it near the SPDIF outputs.
Alternatively, does anyone know whether I can convert 2ch of SPDIF back to I2S?
I'm not afraid to hack at the Nadja if the extra 2ch of I2S is running around somewhere - I assume I might be able to locate it near the SPDIF outputs.
Alternatively, does anyone know whether I can convert 2ch of SPDIF back to I2S?
Most of the benefit of a balanced connection comes from a proper, truly differential balanced input - a balanced driver stage doesn't add that much (apart from a little bit of extra gain). Do you really need a "truly balanced" output stage?
Hi,
just in case, I have designed a two symmetrical input pcb ( 5 x 5 cm) and a four symmetrical output pcb (5 x 10 cm) that could fit your bill
. these boards could be seen somewhere in this threadJean Claude
Actually I should be able to provide 2 or 4 more channels over I2S by hijacking a pair of lines from the other expansion port. I would need to check the documentation though before I can confirm. That would be far easier than hacking the board.
I'd appreciate that very much - there's also the 2 "factory use only" pins on port0 which look suspiciously like they're doing something that's not needed in the 'release' version of the firmware... Put "factory use" stuff in your internal builds
I actually can't believe how much junk the Nadja has inspired me to attempt to connect to it. Currently purchased/assembled and going into the box:
* Nadja
* Buffalo III + 4x IVY
* Beis ADC
* USB->I2S board
* Remote motorised pot for volume control
* VU meters + controller
* 2x 5-rail linear PSUs (JLM audio Kraftwerk's)
and connections on the rear for everything...
* 6x unbal-in
* 8x unbal-out
* 8x bal-out
* optical-in
* coax-in
* USB-in (data to USB->I2S)
* USB-in (config to Nadja)
...All going into a custom case I'm getting built by modu in Italy.
PS: Looking forward to the planned expansion board to give me the additional unbal-in's.
I'd appreciate that very much - there's also the 2 "factory use only" pins on port0 which look suspiciously like they're doing something that's not needed in the 'release' version of the firmware... Put "factory use" stuff in your internal builds
I actually can't believe how much junk the Nadja has inspired me to attempt to connect to it. Currently purchased/assembled and going into the box:
* Nadja
* Buffalo III + 4x IVY
* Beis ADC
* USB->I2S board
* Remote motorised pot for volume control
* VU meters + controller
* 2x 5-rail linear PSUs (JLM audio Kraftwerk's)
and connections on the rear for everything...
* 6x unbal-in
* 8x unbal-out
* 8x bal-out
* optical-in
* coax-in
* USB-in (data to USB->I2S)
* USB-in (config to Nadja)
...All going into a custom case I'm getting built by modu in Italy.
PS: Looking forward to the planned expansion board to give me the additional unbal-in's.
Hello.
Are you connecting the Buffalo dacs over I2S, and if so over what cable lengths ?