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Hello. This will be one of the first times I start a thread here, but I figure I've gotten so much insight from diyma, and the internet, that it's about time I give some output as well.

Anyways, here we go.

The point of this project is to have a seemingly simple install in a e39 BMW, with excellent SQ from a navigation head unit.

First, the Navigation unit is a Panasonic CN-HX3000D (I live in Japan). It features a flipout 720p screen, with an HDMI input (w/HDMI audio btw).

The problem is that the unit does not feature RCA outputs, so I am stuck with the 50w x 4 max output from the head unit amp. I didn't want to install a second SQ oriented head unit, and def. wanted the navigation and the 720p display.

So this here is the idea for the project. Take apart the navigation unit, find the final dac section, tap the digital audio I2S lines, feed the lines to a external dac, and then to external amps. It seemed difficult at first, but this is what I have so far.

Head unit (Panasonic CN-HX3000D):


DAC located inside navigation unit, and I2S(BCK, LRCK, D-IN1(Front R+L) D-IN2(Rear R+L)) lines tapped and fed outside the unit to a Ethernet cable recepticle


Now that I got the raw digital lines outside the unit, it was time to figure out which dac to use. I ended up using a pair of Twisted Pear's Buffalo III's(Perhaps worlds first?). The buffaloIII uses the Sabre ES9018 DAC, which feature dynamic range of 133db and a THD of -120db. It sounds amazing btw.

Also, I used the Twisted Pear IVYIII's for the output stage.

The problem of course was powering the units. The Buffalo III's include 3 on-board shunt regulators, so I decided to power the units using a adjustable DC-DC converter set for 5.25 volts directly. I'm hoping the shunt units will help eliminate the DC-DC's noise.

The IVYIII output stage requires +/- 15 volts to operate, and need good clean power. I used a adjustable DC-DC converter set for +/-16.8 volts and fed it to a modified twisted pear Placid BP HD with the bridge rectifier circuit removed, so it could work with the DC +/-16.8 volts instead of AC that would usually be fed from transformers.

Power supply board w/ the two DC-DC Converters.


Placid BP HD, and the two Buffalo DAC and IVYIII's powered successfully off of a 12v DC source.


Here is the I2S line coming from a STP Ethernet cable from the head-unit going into the Buffalo DAC's


I am able to get 4 balanced outputs from the two IVYIII units.


Where to connect the balanced outputs? The Mcintosh MC430 of course!



I will have the MC430 feeding the front (HAT Clarus C61-2 and rear fill speakers (HAT Imagine I51-2).

The IVYIII also features single ended outputs that can be used at the same time. I have pulled the L+R pair from the Front DAC to a MCC402 that will be powering a pair of Legatia L8V2's (crossed as subwoofers) on the rear deck as IB.


As for now, the system sounds great. Because the DSP, the Dolby Digital Processor, the ADC, and the Volume control happens before the DAC in the navigation unit, I am able to retain all of the functions on the Navigation, although I am worried about the internal bit rate of the volume control and the DSP system. I have been unsuccessful in finding a data sheet for the TI DSP that is in the head unit.

My next step is to fit the external DAC into a case, and then I should have the unit ready to be installed into the car. I have the L8V2's on the way, and I'm currently negotiating L1 Pro R2's to replace the stock Clarus tweeters.

I also have 2 pairs of balanced cables, and a pair of RCA's coming from Blue Jeans Cable.

Please let me know if you anyone has any input on the project. I apologize for the messy layout of wires. It's only a prototype.

Anyways, I will keep everyone updated in the future. :)
 

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Ummmm wow dude you have mad skills. You are waaaaaayyyyyyyyyyyyyy over my head with what you are doing but I appreciate the engineering. Great work. :D
 

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Ummmm wow dude you have mad skills. You are waaaaaayyyyyyyyyyyyyy over my head with what you are doing but I appreciate the engineering. Great work. :D
Thanks for your feedback. It's not too difficult once all the pieces come together, but I am still in the process of learning. But hey, that's why I love this hobby so much!
 

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Thanks for the link to this thread. Excellent work!

Good idea looking further into what is happening to those bits before they hit the head unit DAC. I hope they aren't being mangled to the point where it compromises those excellent component's performance further down the signal chain. If so then I'm sure an external master volume control of some type would fix that.

I see you have an external hard drive as your source (primary SQ source?). Have you check to see if that sources digital signal stay in the digital domain or at least is not compromised some how on the way to the DSP. We are finding that some head units does always behave as they should.

http://www.diymobileaudio.com/forum/1466239-post8.html
 

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Thanks for the link to this thread. Excellent work!

Good idea looking further into what is happening to those bits before they hit the head unit DAC. I hope they aren't being mangled to the point where it compromises those excellent component's performance further down the signal chain. If so then I'm sure an external master volume control of some type would fix that.

I see you have an external hard drive as your source (primary SQ source?). Have you check to see if that sources digital signal stay in the digital domain or at least is not compromised some how on the way to the DSP. We are finding that some head units does always behave as they should.

http://www.diymobileaudio.com/forum/1466239-post8.html
t3sn4f2, Thank you for your feedback! Great thread on the SD card vs. the CD player + iPod. I wish I had the expertise to quantify sound like you do... :)

The screen shot at the top shows the source being a hard drive. Unfortunately, the hard drive only rips songs from CD's to a lossy codec, so I don't think I will be using that. I would probably use CD's, HDMI, and ALAC's on the ipod. The unit should be routing the iPod digital to the dac, but I would have to test that later.

Also, as I stated above, I am worried about what bit depth all the DSP and volume controls are done with on the head unit. To somewhat alleviate this problem, I have the amp sensitivity all the way down, so I would need to turn up the volume very high on the head unit, as to utilize more bits. It definitely sounds better than the sensitivity being high on the amp, so I don't think the digital volume control on the head unit is very good (low bits).

I am also currently planning on using a hiface m2tech plugged into the DAC without the head unit (switchable using relays) which will rely on the buffalo dac's internal volume controller (which is somewhere around 40-48bits). I should be able to play up to 192khz/24bits in the car through a carputer in the future.
 

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t3sn4f2, Thank you for your feedback! Great thread on the SD card vs. the CD player + iPod. I wish I had the expertise to quantify sound like you do... :)

The screen shot at the top shows the source being a hard drive. Unfortunately, the hard drive only rips songs from CD's to a lossy codec, so I don't think I will be using that. I would probably use CD's, HDMI, and ALAC's on the ipod. The unit should be routing the iPod digital to the dac, but I would have to test that later.

Also, as I stated above, I am worried about what bit depth all the DSP and volume controls are done with on the head unit. To somewhat alleviate this problem, I have the amp sensitivity all the way down, so I would need to turn up the volume very high on the head unit, as to utilize more bits. It definitely sounds better than the sensitivity being high on the amp, so I don't think the digital volume control on the head unit is very good (low bits).

I am also currently planning on using a hiface m2tech plugged into the DAC without the head unit (switchable using relays) which will rely on the buffalo dac's internal volume controller (which is somewhere around 40-48bits). I should be able to play up to 192khz/24bits in the car through a carputer in the future.
Thanks. The hiface PC source sounds like a great option. Completely separating the SQ source from the basic head unit sources is the way to go IMO.
 

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Sorry to revive this old thread ...but WOW Kotani!!! You were way ahead of the pack here with this Buffalo III DAC install!

Hoping you are still around, there has been a lot more talk recently about using these sabre dac's in various installs, ie neil_j and his frankendac

http://www.diymobileaudio.com/forum/car-pc-forum/138206-2011-mini-cooper-carpc-build.html

and some more discussion here in chad1376's build thread..

http://www.diymobileaudio.com/forum/car-pc-forum/141734-all-digital-amp-using-nanodigi.html

I'm thinking of combining a minisharc for dsp purposes and a buffalo III for a dac.

Just wondering, are you still running with this setup? Have you upgraded or changed anything? Just wanted to pick your brain a little bit :)

I'm planning to start a new thread regarding using these dacs and was hoping to awaken you :)
 
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