| pozo1992 |
Hi there,
I am dealing with both, CD player mods and playstation tuning. So recently I had the idea to combine both worlds, i.e. to use the PSX 67.737MHz oscillator as part of a clock generator for my pioneer CD player. The nice thing about the PSX clock is that it has four times the frequency of my CD player (16.9344MHz). Now by dividing the PSX clock by four using two toggle flipflops of ACT type I could get a decent clock for my CD.
My plan is the following: Desolder the oscillator from the PSX, add a 74ACT74 and some means for supplying these and try with my pioneer CD. Intention is to make the circuit as small as possible with very short interconnections using SMD components. Remember we are dealing with very high frequencies.
First measurements on the oscillator are encouraging: Frequency accuracy is fine, 1ppm!!!
The manufacturer of the PSX oscillator is KDS.
Anyone tried this? Please comment. IŽLL keep you updated.
p.s.: Did I discover the source of the "PSX sound"? |
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| pozo1992 |
Hi gents,
now I have the first prototype running. Attached you can see a pic of it.
It measures very well: Inital accuracy: 16.934375MHz which is approx. 2.5ppm. Rise and fall times are around 2ns. Please see also the two attached scope pics. Please note the special arrangement for attaching the scope probes in order to get accurated results.
The supply delivers 3.3V for the PSX oscillator and 5.0V for the 74ACT74 gates. It is based on a TL431 circuit with NPN transistor.
So far I did not test the impact on the sound. Later I intend to use it in my Pioneer PD-S802 and test the sound against a KC7 clock and one of my own creations. |
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| pozo1992 |
| And a last the 67MHz oscillator signal before and after the 47R coupling resistor: |
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| Nanook |
| er how does it sound. I don't know the jitter of the 802 or 54 . I have a PD-54 which is essentially a 802 .. |
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| Elso Kwak |
| use some modern logic family ACT yeck... |
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| pozo1992 |
Hi Nanook,
first of all: Each of the clock circuits I have tried in place of the original one were better than it. The most important thing is to omit the HCMOS IC that is distributing the clock signal among the DACs and the decoder chip. The clock is able to drive them without effort. Done that its difficult for me to hear a significant difference between the tested clock circuits. My intention about the PSX clock was to see how far you can go in terms of technical optimisation and what I can personally hear.
So after all its a matter of taste..... |
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