My Kwack clock implementation

[Andypairo]

First of all I want to thank Elso for sharing his project.

Of course my implementation doesn't claim to be state of the art, since it's made on veroboard without a great experience on HF layout, but I thought it could be nice to share my building experience and to receive a feedback from who has built it (and from Elso, of course!).

I borrowed (again 😉 ) a digicam and took a few shots.

Pic 1: the assembly

 

[Andypairo]

2nd pic: a closeup of the board

As you can see I used a MAX913 as comparator and also a J310 instead of J309 as JFet.
The crystal comes from Elso so it can't be bad

 

[Andypairo]

Pic 3 output waveform

Not bad at all, considering that for now I only adjusted the duty cycle roughly

 

[Andypairo]

Pic 4: voltage at the gate of the JFET.. a good sinewave

 

[Andypairo]

Last pic.. voltage at source of Jfet.. can someone explain why the waveform has a bump?

Should I try swapping the fet with another model or I'd better change the value of the source resistor (or what else)?


Cheers

Andrea / waiting for comments

 

[Andypairo]

to bump or not to bump...

While taking further measurements to get rid of this bump I noticed the extreme sensitivity of the node connected to the source to capacitive loading to ground... I should have realized that before (the cap to gnd is only 39 pF !) but all became clear whan I left out the cap and connected my oscilloscope probe (10x)... I got a nearly perfect sinewave!
Then connected the same probe to the output and.. nothing! The oscillator had stopped working...

Conclusion: the bump is probably due to the capacitance of the probe

Cheers

Andrea / who enjoys learning from building circuits😀

 

[Elso Kwak]

Kwak-clock

Hello Andrea,
You got decent squarewaves indicating a working clock. The "bumps" you mentioned are not important at all.
One of my first faults was connecting a 1x probe to a CMOS oscillator as it stopped working immediately. Yes ordinary probes have capacitance too.
I am using other kind of parts but I have seen pictures of the KC with all kinds of parts. Here is another one (not by me)😎

 

[zygibajt]

Hi,
I'm just finishing mine on vero board ,too.Had put it together week ago but waited for J309 to arrive (thanks Elso for J309,i just recived it a couple of hours ago).

I'm just not qiute sure how the pin-out of J309 is and how to put it into circuit.

I assume drain goes to + supply,source to crystal and gate to AD8651 and to ground trought 1Kohm resistor.

Is it correct??

Bartek

 

[Elso Kwak]

Pinout

Hi,
I'm just finishing mine on vero board ,too.Had put it together week ago but waited for J309 to arrive (thanks Elso for J309,i just recived it a couple of hours ago).

I'm just not qiute sure how the pin-out of J309 is and how to put it into circuit.

I assume drain goes to + supply,source to crystal and gate to AD8651 and to ground trought 1Kohm resistor.

Is it correct??

Bartek

Hello Bartek,
See this site for pinouts by Yeo :http://www.diyparadise.com/clock.html
It is Drain to supply, Source to 1k and Gate to crystal.😎

 

[zygibajt]

Thanks a lot.

Maybe i will put some photos tomorrow if I get the camera.

For now I will use it with CDP supply but will build separate this coming week.

Bartek

 

[Andypairo]

Re: Kwak-clock

Hello Andrea,
You got decent squarewaves indicating a working clock. The "bumps" you mentioned are not important at all.
One of my first faults was connecting a 1x probe to a CMOS oscillator as it stopped working immediately. Yes ordinary probes have capacitance too.
I am using other kind of parts but I have seen pictures of the KC with all kinds of parts. Here is another one (not by me)😎

Hello Elso,
do you think that a separate power supply is worthwhile or i can sticjk with the one of the CDP?

Cheers

Andrea

 

[Elso Kwak]

Re: Re: Kwak-clock

Hello Elso,
do you think that a separate power supply is worthwhile or i can sticjk with the one of the CDP?

Cheers

Andrea

Hi Andrea,
I tried both but found the raw supply of the player giving better sound. This is a rather unexpected result but I can live with that. Just follow the instructions I have sent you.
😎

 

[Andypairo]

Thank you, I'll probably install the clock in the following holidays...

Cheers

Andrea

 

[YongHo]

I Just wondering..

HI. Elso Kwak

I wanna make your KWAK-CLOCK-7
But I wanna use different PSU
I think high quality SHUNT REGULATOR will be fine

So I have to design SHUNT REG for KC7
But I dunno how much current needed for Oscillation(J309 and etc..) section. For AD8561(AD8611) section I can refer to Datasheet 😕

Would you tell me how much current needed at oscillation section(J309) 😉

Sorry for poor English
Merry Christmas !!

 

[krishu]

Hello,

thanks to Elso for sharing his knowledge.

I am looking around for the components, j309 seems to be difficult to buy. J310 is no problem here, so can I use this without
any problems?

Can anyone please name the thread where Elso postet the schematic for Elso Kwak 7, I downloaded the schematic, but missed to save the url. I wouzld like to link it at my website.

Thanks to all

Christian.