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Digital Drive Upsamplers, DACs, jitter, shakes and analogue withdrawals, this is it. |
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Digital Drive Upsamplers, DACs, jitter, shakes and analogue withdrawals, this is it. |
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In Reply to: Rubidium clock for Philips TDA1540?? posted by Tube747 on January 26, 2017 at 05:07:24:
Hi,
> I want to modify my vintage Philips CD104 player that has Philips
> TDA-1540 14 bits DAC (I2S instead of SSPDIF for least jitter) to
> link with external clock unit.
Why? Adding a decent quality internal clock would be much easier.
> Do you think I can use a Rubidium clock unit for this particular
> playerwith TDA-1540 DAC chip??
These kind of clocks have a 10MHz output. So not directly.
What is more important to understand is how rubidium clocks actually work. They use a CRYSTAL OSCILLATOR to generate the actual clock signal which is "pulled" to the precise frequency linked against the rubidium frequency normal using a very slow PLL.
In other words, the jitter and short term accuracy (which arguably is what matters for audio) of ANY rubidium clock is no better than the cyrstal clock inside.
Some Rubidium clocks (e.g. Sanford Research SRS-10) have very good crystal oscillators, better than anything I have ever seen in any CD-Player or DAC, some others - well the clock already in your CDP is likely better.
At any extent, you would need a further frequency synthesizer to get the correct audio clock from the 10MHz, by the time you have added this to a Sanford SRS-10 you will likely have spend 3k - 5k (or maybe a 5th of that at surplus prices) and you have two huge 19"Boxes.
Meanwhile a credible internal clock with the correct frequency and at best marginally worse jitter can be had for 100 - 500 USD.
Also, be aware how the circuitry in your CDP routes the clock. You need to fundamentally change that, as the internal clcok routing mangles the best clock you can send in to "awful" by the time it has passed through the various daisy chained super noisy IC's.
So you probably need to add a re-clocker circuit between digital filter and DAC and develop an additional clock distribution circuit to integrate a clock correctly for maximum benefit (also if you use external Rubidium Clock & Clock Synthesizer).
I'm not sure I would put so much effort into this machine.
Thor
At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?
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Follow Ups
- RE: Rubidium clock for Philips TDA1540?? - Thorsten 02:29:47 01/28/17 (0)
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