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Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project

Looks like a winner!

I've been looking at an active crossover/ DSP for my system for a long time. I've considered various ones like the DCX2496 through to the DEQX (way too expensive but probably the best).

I need to learn a lot more about the various programs used to create filters and DSP in general.

I don't know if it's still beneficial but is it possible to use multiple power supplies to each stage?

What are you considering for the analogue output stage/s and their power supplies?

Sorry if I'm asking stupid questions but I've been away from electronics DIY for quite a few years and need to catch up. Last thing I built was an Audio synthesis DAC (PCM63K) which uses over 12 power supplies.

There are multiple power supplies on the board itself as well as an externally regulated +/-15V supply. Extensive LC filtering is used to filter the analog supplies to further reduce noise. Digital supplies are generated from an onboard switching regulator which generates 5V, 3.3V and 1.1V for the DSP.

The analog output stages operate from a well filtered +/- 12V onboard regulated supply. They are based on the IV converter from the ESSTech app notes http://www.esstech.com/PDF/Sabre_8_2Channel_64PIN_V3_SCH.pdf
 
I still have not heard back from HDMI, not that should be of any surprise to anyone. They are heavily licensed and into the big $$$$$, I was way out of my league even contacting them.

So I am going to eat some crow here, and apologize if I have mislead anyone with my excitement on post #59.

As I more then likely will never hear anything from HDMI, I have dug a little deeper myself on various HDMI Receivers and Transmitters...

First of all, if HDMI signal is encrypted with HDCP, then the HDMI receiver and transmitter will need to be HDCP compliant. There are a lot of stand alone HDCP compliant boards that are designed for the AVR market. Many of these offer extracted, unencrypted I2S lines that can be plugged into this pre-amp. But, I am not sure if these big corporations would be willing to deal with this. Yet, the potential demand in the market for a pre-amp like this is large enough that there is $$$$$ to be had for any of these board manufacturers willing to take a leap of faith.

Some examples:

http://www.grandbeing.com/product/HDMI%20Audio%20Extractor.htm

2nd Generation HDMI Repeater/Switchers with Audio Extract - Momentum Data Systems


As it stands, if the HDMI input Tranquility has designed in this pre-amp is not HDCP compliant, there is no guarantee it will work for decoded Movie based 7.1 audio. It might work with the OPPO Blu-ray players, as they have two HDMI outputs were the audio can be split off, but I am not sure if the HDCP encryption is removed. I will need to do some more research to see. I am sure Oppo will communicate with me, they are good folks.

Now there is another option for PC based users. One can use a USB interface to transmit decoded 7.1 audio to an 8 channel USB interface. Tranquility has designed this pre-amp with the Amanero Combo 384 which is only two channel, but it works up to 384 kHz sampling rate. Most USB 8 channel interfaces only go up to 192 kHz, so that is the trade off.

One can use the MiniDSP USBstreamer and run at least one of the I2S (stereo) lines into PSAudio interface. I am not sure if Traniquility has designed this board to run the various inputs simultaneously. For example with a LPCM 7.1 signal: inputting the front channels into the PSAudio interface, running the side channels via USB, back surrounds via SPDIF and Center and Sub via SPDIF. I would not do this my self, but wondering if the possibility is there.

So I hope this helps clarify things a little better. I may still have some of this wrong, but I think there is some hope for multi-channel Dolby and DTS applications.

Allen

Everything looked good in the data sheet until I got to the end of it. Seems to be a closed shop type of standard.

Licensing

These products use licensed technologies and are only available
for sale to authorized audio / video companies. Please
contact MDS for more information.
 
HDMI deadend

Yes, I saw the deal with Licensing.

And to add more salt on an already open wound, I called OPPO digital today to find out if the LPCM audio from their dual HDMI outputs is still Encrypted. Even though these players can be configured to split the audio and video into two separate HDMI outputs, the audio IS still encrypted HDCP. So in regards to HDMI, it is not even worth considering without HDCP compliant receiver boards. And we are finding, You need a license to have assess to one. The only option there is, is to tear apart an existing HDCP product, which is outside the scope of this project.

The other option in terms of using an OPPO player is this - Vanity 103 High resolution digital audio SPDIF output module:

JVB Digital, Vanity103 HD SPDIF version

That is only $1015! :eek: so needless to say, it looks like I am going the PC route myself, where I can access the decoded I2S lines via USB. Thank God we still have some freedom with our PCs despite the amount of work keeping one running smoothly.

With HDMI, I think we are spinning our wheels here. I do not think it would even be worth having HDMI on this pre-amp. The space would be better served with a second USB input that could accept an 8 channel signal even if at 192 kHz.

Allen
 
Other options for 8 channel SPDIF outputs on BD players

I looked a little deeper on the JVB Digital site. As is turns out, there is a more affordable upgrade for 8 channel SPDIF outputs on not just OPPO players, but several other brands also. Prices range from about $400 to $600 depending on the player. The downside is You have to send the player to JVB for the upgrade.

JVB Digital for all your MultiZone MultiRegion Codefree Blu-ray and DVD players. Including 3G-SDI, HD-SDI, SPDIF and Darbee

I know this is not a practical option for most of You outside the United States, but I am bringing this up as more of an idea then a JVB promotion. I am sure the more tech savvy of You out there can find a way to modify your existing player. I do not think You are limited to SPDIF either, Twisted Pair has a Cat5/6 teleporter transceiver if you wanted higher sampled I2S signals instead. Of course this can be a whole new thread, so I will leave it at that...

At least there are ways to get our decoded Dobly and DTS signals into this pre-amp.

Allen
 
Yes, I saw the deal with Licensing.

And to add more salt on an already open wound, I called OPPO digital today to find out if the LPCM audio from their dual HDMI outputs is still Encrypted. Even though these players can be configured to split the audio and video into two separate HDMI outputs, the audio IS still encrypted HDCP. So in regards to HDMI, it is not even worth considering without HDCP compliant receiver boards. And we are finding, You need a license to have assess to one. The only option there is, is to tear apart an existing HDCP product, which is outside the scope of this project.

The other option in terms of using an OPPO player is this - Vanity 103 High resolution digital audio SPDIF output module:

JVB Digital, Vanity103 HD SPDIF version

That is only $1015! :eek: so needless to say, it looks like I am going the PC route myself, where I can access the decoded I2S lines via USB. Thank God we still have some freedom with our PCs despite the amount of work keeping one running smoothly.

With HDMI, I think we are spinning our wheels here. I do not think it would even be worth having HDMI on this pre-amp. The space would be better served with a second USB input that could accept an 8 channel signal even if at 192 kHz.

Allen

It looks like you have to be a licensee for HDCP to be able to use it. I wonder how much that costs ?

cheers
 
$15K in 2006

It looks like you have to be a licensee for HDCP to be able to use it. I wonder how much that costs ?

cheers

I am not sure if this is the most creditable source, but according to the Inquirer in 2006, the HDCP licensing fee was $15,000. I have seen that number quoted in other forums also.

HDMI and HDCP licences cost $15K each- The Inquirer

I am not sure how your tax structure is set up in New Zealand, but here, that would be quite the tax write off if You wanted to pursue this...

Allen
 
I am not sure if this is the most creditable source, but according to the Inquirer in 2006, the HDCP licensing fee was $15,000. I have seen that number quoted in other forums also.

HDMI and HDCP licences cost $15K each- The Inquirer

I am not sure how your tax structure is set up in New Zealand, but here, that would be quite the tax write off if You wanted to pursue this...

Allen

That sounds about right which explains why you don't see its use on diy forums ;)

On another note I have split the user controls into two parts including the Navimec control option.

An externally hosted image should be here but it was not working when we last tested it.


cheers
 
I wpuld rather just like to see some connectors on the controller PCB to hook up buttons ,roterary encoders etc via wires.

IM(very)HO:
Putting the buttons, encoders etc on a PCB will still limit the layout/design of the frontpanel, even when split up as you have done now. It will also result in design/mechanical limitations like frontpanel thickness as buttons may be too flat so they do not protrude. Just my 2ct.
 
I wpuld rather just like to see some connectors on the controller PCB to hook up buttons ,roterary encoders etc via wires.

IM(very)HO:
Putting the buttons, encoders etc on a PCB will still limit the layout/design of the frontpanel, even when split up as you have done now. It will also result in design/mechanical limitations like frontpanel thickness as buttons may be too flat so they do not protrude. Just my 2ct.

That's a fair point although the standard Panasonic rotary controller should not be a problem with thick materials. Here is an example of an earlier board mounted on 3mm thick aluminium plate.

An externally hosted image should be here but it was not working when we last tested it.
 
I found some more info on the chip inside the hdmi switch.
http://www.epmi.com.tw/pro_d.php?pk=60
I've got one of the boxes off ebay. It seems to work getting audio out but when I play a SACD doesn't put anything out from the spdif or the analogue ports. But the info above seems to say the ic it will put out dsd.
Shame you are halfway round the world, I could have sent it to you.
 
Last edited:
I found some more info on the chip inside the hdmi switch.
http://www.epmi.com.tw/pro_d.php?pk=60
I've got one of the boxes off ebay. It seems to work getting audio out but when I play a SACD doesn't put anything out from the spdif or the analogue ports. But the info above seems to say the ic it will put out dsd.
Shame you are halfway round the world, I could have sent it to you.

Thanks for that info. What I find interesting is the following spec

•On-chip HDCP Keys

I wonder if this makes it any easier to deal with the HDCP.

cheers
 
After re-reading this thread with excitement, I think you have all my needs covered :)
If this could replace the miniDSP + better DACs + lower noise + FIR with useful amount of taps @96kHz (>8192) + no speaker killin power on/off POPs, then count me in!
Better DACs: check (eventhough I'm kinda fine with the 4x10 DACs)
Lower Noise: i'll just have faith
FIR with lots of taps: check

Please make sure the unit doesn't make any power on/off POP noises. Lot's of other gear (including my 4x10) is horrible in this regard. The 4x10 has already killed one of my tweeters.

So count me in!
 
After re-reading this thread with excitement, I think you have all my needs covered :)

Better DACs: check (eventhough I'm kinda fine with the 4x10 DACs)
Lower Noise: i'll just have faith
FIR with lots of taps: check

Please make sure the unit doesn't make any power on/off POP noises. Lot's of other gear (including my 4x10) is horrible in this regard. The 4x10 has already killed one of my tweeters.

So count me in!

Should be no clicks or pops even from a cold start ;)

cheers
 
Awesome project.
Will this be a kit or fully assembled product?
What is the target price, will it be in the same range as the hypex solution?

Will be available as assembled boards so you just buy the boards you need.

It will most likely be a higher priced solution than the hypex but the end price will depend on what additional boards you need, because not everyone needs analog input, or some may only need USB input only etc.

cheers