differential clock

[Bernhard]

I have built a differential oscillator and after testing a few mods, I could post a schematic if there is any interest.

The outputs will drive the + and - inputs of the comparator to achieve better psu noise rejection.

Or one output drives a reclocker at raw clock frequency, while the other output is divided down to word clock or whatever.

[malay]

Certainly! Very interestingly and rather in time!

[Bernhard]

Here is the schematic from my working prototype.
Next step is to add more parallel FETs.
For conversion to square, I intend to use AD9687 which has ECL outputs.
And use ECL as far as possible for the rest of the DAC.

[Bernhard]

Added the AD9687 and it looks very good.
AD9687 with only 2,7 ns propagation delay is much faster than AD8561 that has 7 ns.

[Bernhard]

[malay]

Very beautifully Bernhard!
How this beauty influences a sound? As it is beautiful?
It is possible to describe in a few words. Judging by frequency it for TDA1541?

[QSerraTico_Tico]

Not very original as Wildmonkeysects already invented it in 2002:
ECL oscillator just won't oscillate

[Bernhard]

Originally Posted by QSerraTico_Tico

Not very original as Wildmonkeysects already invented it in 2002:
ECL oscillator just won't oscillate

Thanks, I did not see this.
Anyway, I did not claim an inventionjust a schematic and he did not invent it either.
Coupling caps should be used for exactly 50% duty cycle and referencing the comparator to its own ground pins, not somewhere else.

[Bernhard]

Originally Posted by malay

Very beautifully Bernhard!
How this beauty influences a sound? As it is beautiful?
It is possible to describe in a few words. Judging by frequency it for TDA1541?

Thanks, this beauty has not been connected to a DAC yet as I have not finished the comparator part and the shield.

I am listening to the previous version with less ideal grounding and it sounds a bit better than a pair of industrial clocks, however I have no specs or datasheets from manufacturers.

The influence on sound...
The clock is located inside the DAC and it fixes all the typical degradations caused by SPDIF & bad CD player clocks, for example corrupted tonal balance, irritating sound, lack of precision and separation.

I don't like the superlative vocabulary that is used regularly in this place

The clock frequency has nothing to do with TDA1541, it is just comfortable to divide down to what my transport expects as word clock.

What is important with any clock: The oscillator part must be shielded. Otherwise it will pick up all the noise it can get, you can see it on a spectrum analyzer.
Industrial clocks are not put into hermetically sealed metal cases for fun or for the shiny look.

There are clock modules offered for audio tuning, that have discrete oscillators on pcbs and no shield. Just forget about it.

[bordins]

Thanks for the post.

I wonder what special about this differential clock, compared to popular ones such as KC7 or Tent clocks.

I came across some simulation on 3 different clock circuits, published by DeepColor. (PDF)