Rotel RCD-02 Kwak-Clock upgrade

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#61
Elso, can you explain us how to adjust the duty cycle to 50%

My scope doesn't give the duty cycle of a signal, and since the waveform is a little assymetrical it's not very simple to do


That's what I did:
-scope input set to ground: set the spot on zero volt
-scope on AC: set the sensitivity to have a good resolution, and the time scale to have 2 periods displayed
-now, uncalibrate the timebase, in order to have a period on, say, 4 divisions.
-after that, turn the clock's pot in order to have the waveform crossing the X axis on 0, 2 and 4 divisions


Is this the good method?
 
#62
Hi,
Any idea what speed scope is needed to see the waveform properly? We have a 40MHz one in the house, and we tried it on that, and you could make out some kind of repetitive pattern, but it was too crammed in and blurry to make out very well. It's working fine now so would any further adjustments make it run the cdp better?
Thanks,
Steve
 
#67
Duty cycle

Bricolo said:
Elso, can you explain us how to adjust the duty cycle to 50%

My scope doesn't give the duty cycle of a signal, and since the waveform is a little assymetrical it's not very simple to do


That's what I did:
-scope input set to ground: set the spot on zero volt
-scope on AC: set the sensitivity to have a good resolution, and the time scale to have 2 periods displayed
-now, uncalibrate the timebase, in order to have a period on, say, 4 divisions.
-after that, turn the clock's pot in order to have the waveform crossing the X axis on 0, 2 and 4 divisions


Is this the good method?
Click to expand...


Hi, I meant adjusting the pot untill you get equal positive and negative sqaures. (Most symmetrical wave form.) It is almost self explanatory.😎
 
#69
had all the parts lying around to make one for some time but the idea of p2p wiring stalled my progress

i have a small fotoboard2 pcb etching setup at home, and i just want to make one clean no b.s. kwak clock that will last me a while

so are there any pcb track layouts i can (secretly) get from anyone anywhere ?

regards keegan
 
#71
Elso,

I was saying that THIS isn't what I call a symmetrical squarewave

attachment.php


And I don't know how to adjust the duty cycle on something like that.
 
#76
From what I gather, you turn the pot until the flanks of the wave are equal distances apart. As Elso says, the cdp only uses the flanks as a reference, so it shouldn't matter too much about the symetricalness about the time axis. I think you just try and get the time between each time the wave crosses over the center equal. AD8561 (i think thats the number, cant be a****d to look it up at the moment) is a comparator, and I think the 2k pot adjusts the reference voltage, at which point the comparator switches. The input from the jfet into the comparator (pin 2) i think is a sine wave, so by varying the reference voltage at pin 3 you can adjust at what point the comparator output switches from high to low output, and hence the duty cycle. From looking at the schematic i think thats how it works, however i could be very wrong!
Steve
 
#77
ELSO!

I'm building the second clock of your design for my other player.

What do you think is better resistor,metallised (metal film) or carbon resistors?

I built my first clock with cheap metal film 1% resistors,becouse I have a good stock of them.But maybe carbon resistors willl do better?

I would like to know your opinion.

Bartek
 
#80
Carbon Resistors in KWAK-CLOCK

zygibajt said:


Just what i thought.Non magnetic are better at digital/high frequency signal circuits.
Click to expand...


Hello, Carbon composition resitors known as Allen Bradly have lower inductance but much higher noise than metalfilm resistors.
Also the stability of the carbon composition is very poor.
I doubt you will hear any difference using a carbon comp. resistor. But you can try. The only position that makes sense to me is the 1k source resitor and the 47 Ohm in the output.😎
 
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