Touch I2S-out and Clock-in mods

[TheOctavist]

are there any hardware modifications that would be useful to a person that is using an external DAC with the SBT??? I have both of mine on external DACs, but I am curious...


if mods would be beneficial to this setup, which ones, and how??

[Aronier]

"TheOctavist" look here: http://forums.slimdevices.com/showth...t=92558&page=3

Anybody knows the right I2S output on the Touch?

regards

[galouche]

Hello and thanks a lot for this good topic.

I have a question, I want to put the SBT pcb inb a new case with just behind a new pcb where to new clocks and a pcm1794 dac will be implemented. so the distance between the 2 pcb will be short enough not to disturb the clock signals.

I think and that's my question to take the Mclk of the AKM4420 sbt dac for mastering the pcm1794 dac. ( the aim of this is to receive the correct clock directly to the pcm1794 dac and not to use d-flip flop ... )

I'm not an expert at all in clocks so please, tell me if I'm wrong lol

Thanks

[prinzinio]

Hi Guys

I bought two crystek oscilators to switch them instead of original ones in SBT.
What PSU r regulator would you recommend to power them up?
I would like to use 5v from main rail and then use a good shunt regulator to get a proper voltage.

Can I switch these clocks one to one or any other modiication is necessary to make them work?

Any help would be appriciated.

Piotr

[prinzinio]

Guys

I need your support..
I removed U14 and all capacitors / resistors around them [please look at attached image where I have shown which elements was removed from pcb].
I've connected OUT pad from crystek 22.57 to pad 8 and 24.57 to pad 6. I took 3.3 voltage from pad 14.

Issue is that its not working.
Whats strange to me is that even if I disconnect 3.3 voltage from crystek and leave on GND and OUT attached to PCB - there is a 1.5v on OUT pin of both oscillators.

What have I done wrong?

Regards
Piotr

[cft]

Hi Jack,

With the EDO loaded on the SBT, and say provided with a very good USB DAC in the market, how close you think it will fare with your i2s modded one?

Thanks!

[JIJ3]

Hi Jack,

With the EDO loaded on the SBT, and say provided with a very good USB DAC in the market, how close you think it will fare with your i2s modded one?

Thanks!

It all depends on the DAC. The idea behind my mod was to transfer the critical timing components out of the Touch and into the DAC. The amount of jitter depends entirely on the clock signal at the DAC chip input. There is no theoretical difference in using I2S or asynchronous USB (EDO) to convey the data, since in both systems the clock is generated by the DAC and the Touch timing is slaved to the master clock in the DAC. In either system, the Touch is simply presenting the data to the DAC, and the DAC itself is clocking it in at its own rate. I used I2S because that is the format my DAC chip prefers.

In fact, one could use a cheap device like the raspberry pi running Squeezeslave, and if it is clocked externally by the DAC, it should sound the same as a Touch.
Jack

[cft]

It all depends on the DAC. The idea behind my mod was to transfer the critical timing components out of the Touch and into the DAC. The amount of jitter depends entirely on the clock signal at the DAC chip input. There is no......

In fact, one could use a cheap device like the raspberry pi running Squeezeslave, and if it is clocked externally by the DAC, it should sound the same as a Touch.
Jack

This is very helpful. Thanks so much for your explanation Jack!

CFT