That's not as silly as it sounds, but not as elegant as everything all in one chip on the motherboard. Still if the end result is stereo then by all means!!!
A couple of points from the above posts:
1. There is no difference between the ASIC chips on a USA or UK motherboard as I have swapped chips on a board that although was not 100% working and it wasn't the ASIC at fault like I thought. I have brand new ASIC chips that were destined for UK TiVo's on hand. I'll repeat the procedure soon on a totally working USA board just to rule it out soon*
2. I was tracing the I2S (yes that's right it is I2S which is the sound version of the data I2C bus just in case other's were wondering if we have all been doing typos). From what I have gathered the main players involved here are the Micronas, the TiVo ASIC and the Analogue Devices audio encoder which is a microcontroller in itself and is quite possibly where our master/slave culprit is. I'll do a full trace on both a UK and USA board soon that are essentially bare so I do not miss any diversions on the bus to other weird places*
*both points have the asterisk (*) as time at present is a little limited. For anyone wondering why you are quite welcome to visit my website (link in signature) and see why! :)
Cheers