Isn´t there a HDMI to Spdif converter?
Edit:HDMI to SPDIF Converter | eBay
Link not working,but do a search on Ebay.
Edit:HDMI to SPDIF Converter | eBay
Link not working,but do a search on Ebay.
Last edited:
It will not convert the hi-res files from copy protected material such as that on bluray. Might as well use a bluray players built in HDMI to spdif, which similarly uses the lower-res soundtrack.
Hi Sean,
Your main issue is that your player is outputting an analogue level which is too high. Indeed, the ADC clip led lighting on warns you that the signal magnitude exceeds the admissible limit. At this stage you cannot do anything in software: you must insert an attenuator between your player and the Najda.
As long as you don't lower the analogue signal, you will always have bad clipping.
Once you have done that, you'll find that 6dB (Bass/Treble) along with 24 dB headroom elsewhere is far too much (well I suppose, I don't know how much boost you need for your setup, but these figures are exceptionally high).
In order to make things easier, disable for now the bass/treble unit (the disable checkbox is on the same dialogue where you have set the headroom).
Your issue is not related to output level.
Analogue input to the DSP is not a problem if the input signal is properly scaled. Of course, if your content is originally digital, then it's always better to skip the DA and AD successive and useless conversions.
Hope this helps, otherwise please shout.
Hi Nick, thanks for looking at this. Your solution sounds like a straightforward fix. I do want to make this Denon player work, not least because well made bluray players cost a fortune, and I got this as last one going cheap).
in-line attenuators
I guess -10db would be appropriate?
My dilemma is low-res without the ADC-DAC step, or hi-res with the ADC-DAC step. I am betting that the hi-res will be worth the effort, even if the multi-channel stuff is down-mixed to stereo.
in-line attenuators
I guess -10db would be appropriate?
My dilemma is low-res without the ADC-DAC step, or hi-res with the ADC-DAC step. I am betting that the hi-res will be worth the effort, even if the multi-channel stuff is down-mixed to stereo.
Hi Sean,
I checked the specs of your Denon player, the user manual states output level is 2 Vrms.
As a consequence the amount of attenuation you need is 6 dB.
The -10 dB attenuators you've shown will do the trick. Alternatively you could put together a few resistors and save some cash if you wanted; depends on how much patience left you have in store
I checked the specs of your Denon player, the user manual states output level is 2 Vrms.
As a consequence the amount of attenuation you need is 6 dB.
The -10 dB attenuators you've shown will do the trick. Alternatively you could put together a few resistors and save some cash if you wanted; depends on how much patience left you have in store
Thanks Nick,
You know it is a long running project for me, but I have a little patience left since I remembered today I have a Google TV box that strips optical from the HDMI input. Am listening to CD from this Denon now over the Najda and my new Nao Note II speakers. Sounding damned good. My old Sony bluray sounded nothing like this Denon, so it's a keeper, and I'm getting closer to the potential of this Najda board now.
I may try to make my own attenuators. Found a few recipes on the internet.
The ADC clip warning still lights up when I am running only the optical input. That cannot be right can it?
You know it is a long running project for me, but I have a little patience left since I remembered today I have a Google TV box that strips optical from the HDMI input. Am listening to CD from this Denon now over the Najda and my new Nao Note II speakers. Sounding damned good. My old Sony bluray sounded nothing like this Denon, so it's a keeper, and I'm getting closer to the potential of this Najda board now.
I may try to make my own attenuators. Found a few recipes on the internet.
The ADC clip warning still lights up when I am running only the optical input. That cannot be right can it?
Ok Nick, please let me know if this is too much off topic, but it seems that this board NeTV Starter Pack ID: 609 - $150.00 : Adafruit Industries, Unique & fun DIY electronics and kits might work to decode HDMI audio.
It was designed to overlay graphics on top of a HDMI stream, and for that purpose it needs the master key to encrypt the overlay. So a board with hdmi in, hdmi out, a CPU powerful enough to handle HDMI video, and all open source, it seems it could work. An 8 channel USB->I2S streamer could be connected perhaps.
They key is included in the software (for their intended use they are not violating any laws it seems). For private persons (in many countries at least), what you do with content you have bought is your own business, so it shouldn´t be a problem to use the device to decrypt audio to be able to use active crossovers without the unnecessary DAC->ADC conversions.
It was designed to overlay graphics on top of a HDMI stream, and for that purpose it needs the master key to encrypt the overlay. So a board with hdmi in, hdmi out, a CPU powerful enough to handle HDMI video, and all open source, it seems it could work. An 8 channel USB->I2S streamer could be connected perhaps.
They key is included in the software (for their intended use they are not violating any laws it seems). For private persons (in many countries at least), what you do with content you have bought is your own business, so it shouldn´t be a problem to use the device to decrypt audio to be able to use active crossovers without the unnecessary DAC->ADC conversions.
I get again the "double section" problem on NUC 1.0.3 and send you nsf file by e-mail.
It seems not related to usage of maximum 15 sections but to section bypass. Now I had nowhere 15 sections and notice that problem occurred after I bypassed some sections when I was connected online to Najda.
Hi Stephen, input impedance is 8 kOhms.
I'm ready to pay when boards ready too!
Been borrowing a DBX PA to get me by for past couple of weeks. I have hopes that the Najda will bring some sonic improvements
I've tested yesterday the first sample of the new batch, it's all good so I'll have a full stock early next week.
That's an interesting board, but I couldn't find anything explicit about audio. The main question is: Are there I2S lines conveying the decrypted audio here?
Thanks Meelis, I've received your email, I'll be back in touch on that matter.
chaparK said:
This is all beyond my competence level, but it seems to me that the "stock version" needs to go between a "real" hdmi receiver and a "real" transmitter - this way they can argue that they don´t break any laws. For audio only, I suppose one could reprogram the device to act as a "receiver unit" (pretend to be a TV or similar), and reprogram the FGPA to send 8 I2S channels over the HDMI bus.
Another option, which could retain the ability to show the video somewhere (which is useful...
) would be to connect a USB to I2S-converter such as the exaU2I (which seems to be discontinued...).Personally I welcome suggestions such as Cookiemonster's. Potential components that go with this Najda board I think are best mentioned here.
In my set-up, as mentioned before, the compromise is using downsampled bluray material in stereo through Najda's analogue input. Because of the gain problem I made some attenuators using values suggested as good for 10db.
10K in series - 4K7 shunt
Knowing Najda's input impedance is 8kOhms, and the bluray outputs 2V (10KOhm), I am trying to work out if these values are optimal. At least it works, and I now use -4db input gain, and +4db output gain.
The following calculator is all I could find but it is for an II attenuator I believe.
Pi Attenuator Calculator
Attenuation: 10dB
Input Impedance: 8000 Ohm
output Impedance: 10000 Ohm
Giving;
Ideal Values
R1 Ohm
R2 Ohm
R3 Ohm
In my set-up, as mentioned before, the compromise is using downsampled bluray material in stereo through Najda's analogue input. Because of the gain problem I made some attenuators using values suggested as good for 10db.
10K in series - 4K7 shunt
Knowing Najda's input impedance is 8kOhms, and the bluray outputs 2V (10KOhm), I am trying to work out if these values are optimal. At least it works, and I now use -4db input gain, and +4db output gain.
The following calculator is all I could find but it is for an II attenuator I believe.
Pi Attenuator Calculator
Attenuation: 10dB
Input Impedance: 8000 Ohm
output Impedance: 10000 Ohm
Giving;
Ideal Values
R1 Ohm
R2 Ohm
R3 Ohm
Here is another option, seems much easier to implement:
Cypress CLUX-11SA
The Cypress box is HDPC-compliant, and outputs per default 8 channels of analog audio. The link shows how somebody installs a transceiver to output 4xSPDIF. However, I suppose it could be possible to connect this board directly to the Najda. HDMI passthrough + extraction of PCM.
All these possibilities make me regret getting a 1U chassis...
Cypress CLUX-11SA
The Cypress box is HDPC-compliant, and outputs per default 8 channels of analog audio. The link shows how somebody installs a transceiver to output 4xSPDIF. However, I suppose it could be possible to connect this board directly to the Najda. HDMI passthrough + extraction of PCM.
All these possibilities make me regret getting a 1U chassis...
SAC - your blu ray output impedance sounds high. Ideally it should be one tenth of the input impedance of the Najda. It may not matter if the output stage in your blu ray player can cope, although it will cause a high frequency drop (but again maybe a non-issue - there are on-line formulae to use to work out the drop), but use short low capacitance cables and you may be OK. I'm going from a tube phono stage (output impedance of 4kohms) and will try just a series 8kohms resistor to bring down the input to the Najda by 6 dB. You don't always need a shunt resistor, and I doubt a pi attenuator is needed either. You can always try a Rothwell attenuator too for ease.
Stephen
Stephen
Stephen, thanks for your input. The bluray impedance is typical of CD players I understand, 2V being common. If it needs to be one tenth of the Najda 8Kohms, and therefore 800ohms, how many db would that be? If you have half the output impedance at 4kohms on your phono stage and are using a 8kohms resistor, could I double that value and use a 16kohms resistor? Then again, the Najda instructions are advising to get the input to just barely clip, which would not be one tenth would it?
Not needing a shunt was advised against in my internet search, and is what the Rothwell uses. Can you please point me to any further reading on this perhaps?
The Rothwell is a one size fits all - expensive - solution, and apparently assumes infinite impedance. I want to experiment with suggestions such as yours and so am using two conductor cat5 cable interconnects (is that low capacitance?) into a breadboard to do this currently.
Not needing a shunt was advised against in my internet search, and is what the Rothwell uses. Can you please point me to any further reading on this perhaps?
The Rothwell is a one size fits all - expensive - solution, and apparently assumes infinite impedance. I want to experiment with suggestions such as yours and so am using two conductor cat5 cable interconnects (is that low capacitance?) into a breadboard to do this currently.
Sean,
The manual of your BD player indeed mentions something like:
'Output Level: 2Vrms (10kOhms)'
I think you should understand this as the output level being 2Vrms if the input impedance of the connected device is roughly 10 kOhms or more. The 10 kOhms value should not be immediately associated to the output impedance of the player, although it gives a clue of what it could be - see below.
The Najda input impedance being indeed roughly 10 kOhms, you can expect the Denon BD player to drive the output level to 2 Vrms as stated.
In a typical audio connection, the line level signal is conveyed as a voltage information. The output impedance of the upstream device should be low, typically 50 Ohms or less; and the input impedance of the downstream device should be high, typically 10 kOhms or more. This guarantees that the voltage swing is fully conveyed along the line.
Take the following standard example: the upstream device has 50 Ohms output impedance and the downstream device has 10 kOhms input impedance. The voltage swing at the output of the upstream device is 2 Vrms when left unconnected. How much is it going to be when you connect the downstream device?
Well when you connect the downstream device, you form a simple resistive voltage divider, and you can easily compute the voltage swing as being 2 Vrms x 10000/(10000+50) = 1.99 Vrms.
What you can see is that connecting the downstream device doesn't really affect the voltage swing. Take 8 kOhms and you would still have roughly 1.99 Vrms.
Now imagine that the input impedance of the downstream device is 50 Ohms. This is a completely different situation because the voltage swing falls down to 1 Vrms.
Alright, so what do we know so far in the context of your current application?
- That the Najda input impedance being roughly 10 kOhms, you will have roughly 2 Vrms when the BD player outputs the maximum level.
- That the Najda wants 1 Vrms Max. So we can compute the required gain in dB:
20 x log10 (V_Najda/V_BD) = -6 dB.
That's a 6 dB attenuation.
- Do we know what the BD player output impedance is? Well not really. But we know it's small compared to 10 kOhms, roughly 100x smaller.
Hope this helps and best of luck
Nick
The manual of your BD player indeed mentions something like:
'Output Level: 2Vrms (10kOhms)'
I think you should understand this as the output level being 2Vrms if the input impedance of the connected device is roughly 10 kOhms or more. The 10 kOhms value should not be immediately associated to the output impedance of the player, although it gives a clue of what it could be - see below.
The Najda input impedance being indeed roughly 10 kOhms, you can expect the Denon BD player to drive the output level to 2 Vrms as stated.
In a typical audio connection, the line level signal is conveyed as a voltage information. The output impedance of the upstream device should be low, typically 50 Ohms or less; and the input impedance of the downstream device should be high, typically 10 kOhms or more. This guarantees that the voltage swing is fully conveyed along the line.
Take the following standard example: the upstream device has 50 Ohms output impedance and the downstream device has 10 kOhms input impedance. The voltage swing at the output of the upstream device is 2 Vrms when left unconnected. How much is it going to be when you connect the downstream device?
Well when you connect the downstream device, you form a simple resistive voltage divider, and you can easily compute the voltage swing as being 2 Vrms x 10000/(10000+50) = 1.99 Vrms.
What you can see is that connecting the downstream device doesn't really affect the voltage swing. Take 8 kOhms and you would still have roughly 1.99 Vrms.
Now imagine that the input impedance of the downstream device is 50 Ohms. This is a completely different situation because the voltage swing falls down to 1 Vrms.
Alright, so what do we know so far in the context of your current application?
- That the Najda input impedance being roughly 10 kOhms, you will have roughly 2 Vrms when the BD player outputs the maximum level.
- That the Najda wants 1 Vrms Max. So we can compute the required gain in dB:
20 x log10 (V_Najda/V_BD) = -6 dB.
That's a 6 dB attenuation.
- Do we know what the BD player output impedance is? Well not really. But we know it's small compared to 10 kOhms, roughly 100x smaller.
Hope this helps and best of luck
Nick