Problem with Kwak Clock power supply

[Bernhard]

Am I wasting time with clocks, or wasting time measuring things?

Did you compare sound with original and your clock ?

 

[Bricolo]

No, I still didn't have the time to put it in the player
My exams are in a week, I'll do this later

 

[Bernhard]

But you have time to browse the forum and measure your spikes etc.

 

[Bricolo]

exactly

 

[Guido Tent]

Re: Re: Re: Re: Re: Re: Re: Confused?

Hi,

I have no 470R here, but that's how it looks with the comparator connected directly to a coax with a 50R at the scope (no resistor between coax and comparator)

http://www.diyaudio.com/forums/showthread.php?postid=378023#post378023

better add a resistor

regards

 

[Guido Tent]

Re: Re: Re: Re: Re: Re: Re: Confused?

That's odd.
Why do people anways use 47R or 470R for 50Ohm transmission lines?
The nearest E24 value is 51/510

the series resistor at the source is far less critical than the coax impedance, and the termination impedance, which SHOULD match the coax

Adding exactly 50 ohm by the way does ignore the output impedance of the driver......

Measure it and you will see!!

regards

 

[f.k.l.chan]

Leo,

I cannot judge jitter performance based on a spectral analysis

cheers

Hi Guido,

I think you misunderstand my question, just want to know which noise level is more important to audio playback, like this datasheet showed in the phase noise characteristics of this link http://www.raltron.com/products/pdfspecs/clock_cx71_72_73.pdf
it shows -70dB at 10Hz, -95dB at 100Hz, -120dB at 1kHz, -140dB at 10kHz and -150dB at 100kHz.

Leo

 

[Guido Tent]

Hi Guido,

I think you misunderstand my question, just want to know which noise level is more important to audio playback, like this datasheet showed in the phase noise characteristics of this link http://www.raltron.com/products/pdfspecs/clock_cx71_72_73.pdf
it shows -70dB at 10Hz, -95dB at 100Hz, -120dB at 1kHz, -140dB at 10kHz and -150dB at 100kHz.

Leo

Leo,

That datasheet gives spectral information. Again, I cannot judge the clock quality based on that parameter. Jitter needs to be measured using a time domain analyser, in my opinion. Only then I know what is cooking.

best regards

 

[Bernhard]

Elso & Guido,

did you do measurements with and without your clocks in the analog domain ?

Can you post any results please ?

 

[f.k.l.chan]

Leo,

That datasheet gives spectral information. Again, I cannot judge the clock quality based on that parameter. Jitter needs to be measured using a time domain analyser, in my opinion. Only then I know what is cooking.

best regards

time domain analyser is something like HP 5731A? impossible for me to buy one

 

[Guido Tent]

Elso & Guido,

did you do measurements with and without your clocks in the analog domain ?

Can you post any results please ?

Hi,

I used to do something like that, and will do new tests in future.

I will not post any results.


regards

 

[Guido Tent]

time domain analyser is something like HP 5731A? impossible for me to buy one

Hi

I understand. I heavilly invested in an HP53310A and an Audio Precision APone, which also gives answer to the fact that I do not publish results.

regards

 

[Bricolo]

Re: Re: Re: Re: Re: Re: Re: Re: Confused?

the series resistor at the source is far less critical than the coax impedance, and the termination impedance, which SHOULD match the coax

Adding exactly 50 ohm by the way does ignore the output impedance of the driver......

Measure it and you will see!!

regards

Here's the output signal with a 1kR/50R/50R probe (series resistor, coax, termination resistor)
20mV/div (the probe's attenuation is 20x)

 

[Bricolo]

And now directly connected to the coax
200mV/div

 

[Bricolo]

And with a Tek 1/10 probe
0.5V/div

Not that bad...

 

[fmak]

And with a Tek 1/10 probe
0.5V/div

Not that bad...

-----------------------------------------------------------------------
Probes vary, not a good way. Use coax with matched impedances. What is your bandwidth.

I get excellent sq wave with Valpey Fisher VF series and excellent sound.

 

[Bricolo]

the scope is 100Mhz

 

[Bernhard]

I will not post any results.

So I guess your results are similar to mine:

No difference between CDP clock ( Saa7220 +crystal ) and your clock.

But: Very big difference between DAC chip X and DAC chip Y.

My conclusion regarding clocks is clear.

 

[pro]

I have made this experiment. I have left the crystal with resistance and condensers to their place close to the SAA7220. I have found a bridge metallic that it connects the SAA7220 to the SAA7210, I have removed it and I inserted two plug. In the plug I insert the Kwak clock or a branch thread and feel the difference. The change feels also my son to it that it has 4 years. The CDP is a CD582 Philips, the dac is TDA1541A without oversampling, conversion I/V is passive, the output stage is discreet opamp jfet-fet. I do not have an oscilloscope, therefore I do not know as my Kwak works clock, but however the difference with original one it is remarkable.
Salutes.

 

[fmak]

the scope is 100Mhz

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Probably ok for 11.xxMhz only, not for 16.9xx to show true waveform.