Kwak clock and Guido Tent oscillator in a TDA1541 zer-oversampled cd player

[Dr.H]

All,

Built the KWAK-clock 5 (AD8561, J309, single +5 V supply) and in my rotel rcd-955 (in zero-oversampling mode) I and several other listeners could not discern the difference in sound between using the KWAK clock and using the low-jitter crystal osc in a can that Guido Tent sells. Is this maybe due to the apparent lack of sensitivity to jitter of the 1541 DAC (apparently the dac is particulalrly sensitive to mechanical vibration though).

On a related subject, anyone have good suggestions on PS for these clocks? The KWAK uses a simple TL431 shunt regulator, while Guido uses something more exotic. See page three of this:

http://members.xoom.virgilio.it/hi_fi/xo_ita.pdf

I am trying ELSO's asynchronous reclocking stuff (using a 100MHz canned osc from Farnell though) and it works. Reclocked BCK has less overshoot/ringing. Have yet to listen though.

Finally, is there any benefit in passing the output (Q) of the 74HC74 to another 74HC74 and using the output from the second 74?

My 2c and questions.
Ryan

[Elso Kwak]

Hy Ryan,
The second flip-flop "in series" with the first one is to catch any missed transistions or to fight the metastability problem.
Thanks to my neighbour who has very young ears and hears his nephyw coming a mile away. My neigbour heard very faint bleebs when I was using the AD1865. I investigated the matter and found it might due to a metastability problem. When playing a continuous 3150 Hz tone the dropouts can be seen on the scope. Interestingly the TDA1543 is less sensitive to this phenomenon.
The dropouts disappeared after installing the second flip-flop. At least during the 15 minute time period of the testtrack.

As suggested earlier on these pages you might try version 6 of my clock that has more bass slam.

I am always a bit suprised when two clock-circuits reportingly sound the same but are of totally different construction......
I do hear differences between Lcaudio, Netaudio, Guido & my clock though....

Powersupplies for clock circuits have been discussed on this forum, also in connection with my clock, quite recently a thread started by fmak and aerlier.
Please use the search button.
I have tried as supply: LT1086-5, LT1086 with bypassed adjustment pin, Nicads, LT1021-5 reference with opamp and also simply the players +5V supply and more.

[joeling39]

Dr. H,

Could you tell me the order code for the 100MHz cystal you are using ?

Thanks.

Regards,
Joe Ling

[TNT]

A question:

Dosen't high freq. osc. have more jitter than lower freq ones. What is the benefit using high freq. osc's?

/

[Pjotr]

Originally posted by TNT
A question:

Dosen't high freq. osc. have more jitter than lower freq ones. What is the benefit using high freq. osc's?

Yes they have, mainly because they can only be made with overtone crystals, usually the 5th overtone. For frequencies above 100 MHz SAW oscillators are more appropriate. Lowest jitter can only be achieved with high quality fundamental crystals around 10 MHz when the frequency-determining element is a crystal.