Hacking a Dolby Headphone AVR: Adding a digital output?!?!
Jan 25, 2015 at 11:11 PM Thread Starter Post #1 of 7

rc10mike

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So I have Marantz SR6005 home receiver that I use for gaming. It has Dolby Headphone built into the headphone jack.
 
One day, I came across some tutorials on adding a digital audio output on old game consoles like the Gamecube and original Xbox. The process seemed pretty simple, just soldering a few contacts on the board and adding the physical plug to the system.
 
My brain started storming.....what if I could add a digital out to my AVR??? Then I could use a high quality DAC and avoid using the receivers built-in amp, and at the same time I could still enjoy the Dolby Headphone surround!
 
Problem is I dont know where to start. Im not circuit expert, so I have no idea where the the contacts might be.
 
Jan 26, 2015 at 9:34 AM Post #2 of 7
So I have Marantz SR6005 home receiver that I use for gaming. It has Dolby Headphone built into the headphone jack.

One day, I came across some tutorials on adding a digital audio output on old game consoles like the Gamecube and original Xbox. The process seemed pretty simple, just soldering a few contacts on the board and adding the physical plug to the system.

My brain started storming.....what if I could add a digital out to my AVR??? Then I could use a high quality DAC and avoid using the receivers built-in amp, and at the same time I could still enjoy the Dolby Headphone surround!

Problem is I dont know where to start. Im not circuit expert, so I have no idea where the the contacts might be.

You can solder and read schematics and datasheets etc.?
Only the Xbox COAX digital out was simple to do, not the Gamecube (only the 1st vers. with digital connector) is more complex with a circuit: http://www.gamesx.com/wiki/doku.php?id=av:nintendogcda

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Ofcource its possible to get Dolby HP digitally, just tap the digital signal before going into the DAC in the SR6005.
But why bother as the Receiver (my SR5500) already have HQ DAC CS4382= 8 channel 24bit/192kHz.
Do you like DH sound quality? or are there some amplifier hiss in it , if MARANTZ still use simple amp resistor for the headphone output, then its crappy.
You can use the LINE-OUT mod to bypass that to get the "superior" SQ possible.

-Its rather easy to hack the digital DH signal, just find out inside what IC's DAC,ADC ETC. are used and google to get their datasheets for the pin-outs.
Too bad the free SR6005 Service Manual is no more http://elektrotanya.com/marantz_sr6005.pdf/download.html
paidversion:https://www.tradebit.com/filedetail.php/201881590-marantz-sr6005-av-surround-receiver-service-manual
Google:http://www.google.com/search?hl=hp&q=marantz+sr6005+service+manual
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But without SM is possible just find the IC's that are use and their pin-outs, follow the Marantz Optical/Coax Digital Output lines from the inside to find the ICs they are connected to etc.
Maybe they use the same chips as in the SR5500, here is the SR5500 modification description for compare etc:
http://www.head-fi.org/content/type/61/id/1288450/

-DH use FRONT L/R as output so for the analog LINE-OUT mod, just solder a stereo output socket to LINE-OUT D-FL/FR, GND.
-TO redirect the digital DH to the Marantz built-in Digital Outputs: Solder 4 wires pins 6,7,8,9 for IC16 to resistors of IC13.
Depends on the IC's position/location on the board, find/use out the shortest wire/way that 4 DATA lines can connect to ie. use those lines that are closer from IC16 to IC35 or IC19 to IC13 etc. to minimize long wires/interferences etc.

http://www.head-fi.org/content/type/61/id/1288451/

Here the 4 wires is to bypass the Marantz stereo Digital Output.
The 4 datalines are:
MCLK - pin 6
LRCL1 - pin 7
SDIN1 - pin 8
SCLK1 - pin 9
There are the COAX/OPTICAL Digital Outputs.

http://i62.tinypic.com/11iea01.jpg
11iea01.jpg

Here IC13 (LC89057W Digital Audio Interface Transceiver) is connected to IC35 stereo ADC CS5361.

http://www.head-fi.org/content/type/61/id/1288453/

At last to get rid of IC35 ADC occupation of the data lines, a 2-pole switch or more common available double 3-pole toggle switch to switch the IC35 POWER OFF= CUT the VL and VD powerlines to install switch, so the data lines become free for DH data.

Better jpg here zipped:
http://www.sendspace.com/file/kvk7i9
===
EDIT: nevermind the switch, just cut off the VL and VD lines to shut down permanently as this mod will disable the normal Digital Outs anyway.
See last post for the correct mod!

Note I haven't done the mod because I don't like DH, but above should work (in theory).
 
Jan 27, 2015 at 12:17 AM Post #4 of 7
Wow, I wasnt expecting such a helpful first reply! Thank you so much!
 
The SR6005 headphone output doesnt sound bad at all. In fact it sounds great. I love DH for gaming. It "opens" up the soundstage so much that I cant imagine playing without it.
 
Im not going to lie, I had to re-read your reply probably 10 times.
 
So with this method, I would send the digital DH signal over to one of the existing "Digital Out" of the SR6005, and then install a switch to bypass all other digital signals from interfering. Is that correct?
 
Jan 27, 2015 at 7:42 AM Post #5 of 7
Wow, I wasnt expecting such a helpful first reply! Thank you so much!

The SR6005 headphone output doesnt sound bad at all. In fact it sounds great. I love DH for gaming. It "opens" up the soundstage so much that I cant imagine playing without it.

Im not going to lie, I had to re-read your reply probably 10 times.

So with this method, I would send the digital DH signal over to one of the existing "Digital Out" of the SR6005, and then install a switch to bypass all other digital signals from interfering. Is that correct?

Are you Serial? :xf_eek: don't pretend if you're actually going to do the mod, its just a wishful thinking, as you never'd opened an amp, holding a solder iron and let alone soldering on micro-electronics SMD level.
Thanks for bringing up the idea, so I going to this mods someday as the SR5500 HP output hiss.
http://www.hifivision.com/surround-amplifiers-receivers/27095-help-me-choose-between-these-mega-monsters-15.html

If you're happy with the sound now, than its totally useless to use an external DAC via Digital Outputs Cables that can degrade sounds further cause by transmission conversions/ jitter etc.
As the $999 SR6005 has 8 ch- 24bit/19kHz DAC beats any $100ish eternal DAC on digital quality.
Whats matters is the quality of the Analog Audio Circuit and Powersupply which the SR6005 is in the top range.
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The former mod is flawed, it makes the normal Digital Out (Tape Out/monitoring) invalid!
Yes, its using the existent Digital Output Connectors, when SR6005 detects the HP is connected it switch off the speakers and using the Front L/R channels to output the DH Audio.
The correct way is just switching the 4 DATA LINES between the normal Digital Out and Digital DH signals using 1 multipoles switch:
http://www.ultimate-guitar.com/forum/showthread.php?t=1288038
=http://i61.tinypic.com/mj61at.jpg=
Description is about 1 switch, multiple view is for the clear view of the solder points!


The 4 DATA Lines are standards of the I2S bus: only manufacturer using different notations:
MCLK - pin 6 = XI = SCKO = main clk , Master clock
LRCL1 - pin 7 = LRCK = LRCK = LR clock , Word clock line
SDIN1 - pin 8 = SDA = DOUT = Serial digital data, Serial Data Line (SDA)
SCLK1 - pin 9 = BCK = BCK = Bit Clock line, Serial Clock Line (SCL)

http://en.wikipedia.org/wiki/I%C2%B2S
http://www.edn.com/design/consumer/4390981/Common-inter-IC-digital-interfaces-for-audio-data-transfer-
 
Jan 27, 2015 at 10:56 AM Post #6 of 7
I'm very comfortable soldering which is why I even want to attempt the mod in the first place.

You're probably right though, it likely won't sound a whole lot better. Perhaps I should just practice this mod on my TB DSS before I try the SR6005.

Thanks for the help and detailed replies! Its helping me better understand ICs
 
Jan 27, 2015 at 11:47 AM Post #7 of 7
Yes, good idea, as long as you can tap the digital lines going into DSS DAC and MCK=Masterclock line is not even needed, when using above Gamecube Digital Audio Circuit (XI is his own MCK).
SDA - DATA
SCL - BCK
LRCK - LRCK
Just find the datasheet with pin-layout of the used DDS DAC IC will do.
 

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