That's something I've been wanting too. I remember something about reduction on FIR-filters as well, has there been any progress there?
NOOB question here, having just bought a used Najda board.
Would it be possible to add a filter to a single input ? More specific, would it be possible to add a RIAA filter to the analog input section ?
Would it be possible to add a filter to a single input ? More specific, would it be possible to add a RIAA filter to the analog input section ?
Hey Noob 🙂
Unfortunately not but it is simple to use the preset manager to have a set of filters including and excluding the riaa filter available via remote. I'm pretty interested in whether you like digital riaa filtering as it's been on my todo list a while now.
Sent from my D5833 using Tapatalk
It will be on my long list of projects as well, first there is a speaker project to finish and filter. But it feels logical, if we use the Najda for filtering, to use it as a RIAA filter as well.
+1
Also who has tried to connect several external DIY DACs in // behind Najda ? SPDIF or I2S prefered ? Any clock problem ?
BR
Can anyone knows how to do that when you turn off the display, also turn off the LED display? A little irritate the green LED SPDIF.
@Gijsch (&MellowFellow):
As You call it a NOOB question: are You aware of the necessary amp between turntable and Najda´s analog input? (There is a loss of a lot of digital resolution, if You connect it directly, remind the gain!)
This amp should have the character of a phono-amp without RIAA-stage, please publish Your findings...
Beneath this problem, which maybe is none, this is a logical idea!!
Good luck!
As You call it a NOOB question: are You aware of the necessary amp between turntable and Najda´s analog input? (There is a loss of a lot of digital resolution, if You connect it directly, remind the gain!)
This amp should have the character of a phono-amp without RIAA-stage, please publish Your findings...
Beneath this problem, which maybe is none, this is a logical idea!!
Good luck!
Lots of ranting here
I'm currently working on another project that's going to keep me busy until JAN 2016. As soon as I've put that aside, I'll be working again on the new code. We'll set here together a list of the features to come.
I beg a little more patience, I do as much as I can.
I2S buses are currently clocked by the codec chip.
In order to gain a good understanding of the clocking, you should look at the datasheet of that chip (CS42428).
The basic idea is that the DSP generates a base FS clock (so 48 kHz at 48 kHz sampling rate, 96 kHz at 96 kHz sampling rate etc). This FS clock is fed into the codec PLL, which on its turn derives all required clocks to sample the audio and drive the I2S buses.
As discussed previously with MellowFellow, I don't think there's much benefit in replacing the DSP crystal. On the other hand, the new firmware will activate the external clock input, and this will allow short-cutting the PLL.
That's a good idea. That's not possible now, but could be added to the system.
Also not possible now, but could be easily implemented.
We'll be back on the upgrade topics soon.
Dear Santa Nicolas,
here my wishlist for X-mas (or easter...🙂):
1. Nothing (I dare not mention FIR / IIR - MIXING)
2. Rien (I do not dare to mention DECIMATION)
3. VOLUME CONTROLLING A PROFILE like DieterK wrote, for loudness or cutting off ultra deep frequencies at high volume. This might "only" affect the input section.
.
.
13. Storing a setup including the measured frequency response files.
14. Printing a setup including processed frequency response(s).
15. Showing selected input frd-filename "on mouse over" the file symbol.
With best wishes for christmas holidays...!
here my wishlist for X-mas (or easter...🙂):
1. Nothing (I dare not mention FIR / IIR - MIXING)
2. Rien (I do not dare to mention DECIMATION)
3. VOLUME CONTROLLING A PROFILE like DieterK wrote, for loudness or cutting off ultra deep frequencies at high volume. This might "only" affect the input section.
.
.
13. Storing a setup including the measured frequency response files.
14. Printing a setup including processed frequency response(s).
15. Showing selected input frd-filename "on mouse over" the file symbol.
With best wishes for christmas holidays...!
This is surprise for me that CS42428 also handles I2S in Najda, I not find any information in datasheet it is capable to feed out 3 pairs I2S channels or I misunderstand something?
But how with SPDIF outputs, what is clocking them, DSP or something else?
What kind of clock can be used in new firmware, this can be feed directly to CS42428?
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Forgot to answer this one.
Currently the DSP indeed doesn't get the volume information, but that's not a big deal.
So your idea would be to select a new set of filters when the volume changes. Fine.
Now imagine you approach each loudness level profile with 4 biquads, and you have 100 volume steps. That's 400 biquad coefficient sets we need to store for each sampling frequency -> 400 x 5 x 3 = 6000 coefficients.
That's a lot of resources for this kind of feature. We need to parameterize the loudness curves, and that's where most of the work is lying.
Good note taken! Have a great holiday too! 😉The I2S bus consists in audio lines and in clock lines.
The device generating the clocks is the bus master.
In the Najda, the CS42428 is generating those clocks - i.e. "I2S buses are clocked by the codec chip" - all buses except the I2S input (which is clocked by the master I2S source). So for the SPDIF outputs, the audio samples are coming from the DSP of course, but the clocks are still the ones from the codec.
As for your other question, it's still early to give specs for the external clock. We'll talk about that soon again.
Najda jitter
I tried Najda jitter test with J-test signal.
Results are similar to what Alterfalter get. But I am not sure that this is actual jitter, seems noises are covering actual jitter induced signal as no peaks at 11025-n*229 Hz and 11025+n*229 Hz higher than noise visible.
Signal to Najda was feed over SPDIF.
Najda noise floor (all cables connected just input to Najda was zero) image is also attached. Both have peak hold less than 1 minute. For comparison is 3dr file with Oppo 103 jitter measurements, from same file what was feed to Najda over SPDIF.
Did anyone know what is causing this specific noise distribution in Najda output, is it ASRC on input or dither?
Or this is still jitter but not data-induced jitter what can be measured with J-test signal?
I tried Najda jitter test with J-test signal.
Results are similar to what Alterfalter get. But I am not sure that this is actual jitter, seems noises are covering actual jitter induced signal as no peaks at 11025-n*229 Hz and 11025+n*229 Hz higher than noise visible.
Signal to Najda was feed over SPDIF.
Najda noise floor (all cables connected just input to Najda was zero) image is also attached. Both have peak hold less than 1 minute. For comparison is 3dr file with Oppo 103 jitter measurements, from same file what was feed to Najda over SPDIF.
Did anyone know what is causing this specific noise distribution in Najda output, is it ASRC on input or dither?
Or this is still jitter but not data-induced jitter what can be measured with J-test signal?
Attachments
Lots of ranting here
I'm currently working on another project that's going to keep me busy until JAN 2016. As soon as I've put that aside, I'll be working again on the new code. We'll set here together a list of the features to come.
I beg a little more patience, I do as much as I can.
Don't forget it's a holiday coming up so take some time of as well, I'm sure you have earned it.
Happy Holidays. Bengt
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Just bought a Najda from Jean Claude, a really professional build and would pass for a commercial build easily and I mean that in a good way. Now, even after reading around 200 pages of this thread I am not sure I know how to switch it on, no please don't laugh, and to think I was considering building one myself. Looking at the three buttons on the right of the up, down, left, right and centre buttons I am guessing from seeing another members front panel they are set on the left with standby top right and mute bottom right. If this is correct, with the power on at the back, pressing standby lights the display but is this now on or just in standby.
Paul,
I got your email and answered you (one hour ago or so) how to make it work with a picture to show you what the buttons are for
Enjoy
JC
I got your email and answered you (one hour ago or so) how to make it work with a picture to show you what the buttons are for
Enjoy
JC
Ok that's clear now. I had the USB cable connected and Najda under control said not connected. Not sure I needed to but I did a restart on the PC and under file I saw connect. Don't remember seeing connect as an option before the restart but that doesn't mean it wasn't there. Going to have a play tomorrow