Touch I2S-out and Clock-in mods

[omainik]

I don't use SPDIF, so I can't say whether you will run into problems with the receiver chip at the different frequencies.

I also use a TDA 1541. I can switch between OS (for redbook) or NOS.

Jack

You feed 24 bit data direct to the tda1541 or is there any logic to convert data to 16 bit?

I used the spdif route just to be compatible with other sources. Reclocking with no clock injection. Works good too. There are missing or repeating samples, but the subjective sound quality is rather good.

Actually i use only the squeezebox as a source, so no need for spdif.

[JIJ3]

You should try slaving the Touch to the master clock of your DAC. This makes a huge difference. No missing data and minimal jitter.

I feed the TDA 1541 24 bits. It ignores the least significant 8. I haven't tried using Squeezebox server and SOX to dither the 24 bits down to 16. No need to do anything special in hardware.

Jack

[breizheau]

Hi JIJ3 and the others.

I translated the first post of this thread in French on a famous french board (took me long time...).

if there is ANY problem with the translation, the attached photos, please tell me, i'll modify...

Thanks for what you did.

Best regards,
Olivier

[breizheau]

The link to the French board : http://www.homecinema-fr.com/forum/v...331#p175652331

[breizheau]

I have a trouble...

you wrote : I traced out a spot that was directly connected to pin 16 of the 74LVC04U
But there is only a 74LVC04A and on this chip there are only 14 pins, not 16...
What about this ?

Olivier

[JIJ3]

Thank you very much for this translation. My French is too poor to really judge its accuracy, but from what I can tell it is right-on.

You are correct of course. I actually meant pin 14, which is the Vcc pin on the 04 chip, not pin 16.

I hope your efforts result in more people trying this mod, which I still delight in every day.

Jack

[breizheau]

Thx Jack.

I have created a thread about the other mods i have found and translated them on my own board.
http://www.passiondiy.fr/forum/viewtopic.php?f=7&t=201

Slimdevices board is a treasure for me

Could you tell me why there are 2 clocks on the board ?

[JIJ3]

Sure, the Touch requires the 22.5792 MHz clock to generate data streams at 44.4 and 88.8 KHz sample rates, and the 24.576 MHz clock for 48 and 96 Khz sample rates. My music library contains music at all of these sample rates, so I needed to supply both master clocks.

[breizheau]

Thanks for all the replies.

[breizheau]

Another question Jack.... (i try to work very hard to mod my SBT )

You say "First you need to remove the existing 22.5792 and 24.576 MHz crystals and their associated 4 capacitors".

OK, i can see the 2 oscillators, not so difficult. About the 2 caps associated, do you mean : C61, C79, C84 and C85 ?

What i want to to :

- change the 2 oscillators by another SMD clock (my DAC doesn't have these clock signals...)
- extract the I2S signal and put a board with a LVDS31 as you did and a RJ45 socket.

My DAC is at less than 1m from the SBT. A very good CAT6 FFTP network cable could be good i think.