I have some questions about the Mark Levinson system in the LS 460. I understand that there is an optical interconnect between the head unit/nav up front and the ML amp in the back.

- Is the optical connection to the amp a standard toslink connector?
- Is there only one optical line between amp and HU?
- Are there any analog audio signal lines between amp and HU?
- Are there any control lines between amp and HU?
- What is the format of the digital signal on the optical cable? Is it standard stereo 2-channel SPDIF, and if so what is the bit resolution/frequency (e.g. 16bit/44.1kHz, etc)? Or is it something else?
- Is the optical signal preprocessed at the HU, or does the amp do all the processing (EQ, surround, etc)?

Reason I'm asking all this is, I'd like to remove the ML amp and replace it with a standard stereo DAC (toslink SPDIF input and analog stereo output), which I can then feed to my own DSPs and amps. I want to know if it is possible to get an unprocessed flat SPDIF signal from the optical output.

 

OK, I think I found the answer to my question, in this thread:

https://www.clublexus.com/forums/gs-...ctory-amp.html

To summarize: the best way to add an aftermarket sound system to an ML-equipped Lexus is to take the speaker outputs from the ML amp and input them into a Signal Summation/De-EQ device that has 8 channels of summed input (and also has individual per-channel input time alignment). The 8 channels would be tweeter, midrange, woofer, and subwoofer; one left and one right for each. One such summing device would be JBL's upcoming MS8 processor.

This allows seamless operation of the stock nav/HU, including all audio sources, bluetooth, nav voice, and volume controls.

Furthermore:

- There are both analog and digital audio lines between amp and HU
- There are several control lines between amp and HU
- A DAC placed at the output of the digital audio line would not work seamlessly for several reasons: missing audio sources, lack of stock volume **** operation, etc.

 

There are NO stock systems using optical outputs or toslink or even the high grade st gen. Just way too much for them to add in the 2 dollar TOSLINK module. The ML system is pretty low on the chain when it comes to actual parts quality.