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Low Jitter Clock For CD Player – Upgrade Module

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On September 7, 2011

In Uncategorized

Do you have one of those expensive CD players that use a simple quartz oscillator to provide the clock? Anyways, the clock upgrade is no doubt the most important upgrade to any CD player. Otherwise you will never hear that nice smooth analog like sounding from your gear.

What you need is a low phase noise clock source to feed the CD player.
Searching the web will come out with many ways to upgrade your CD player. Some of those upgrades come at substantial costs. Many sources simply don’t provide enough data to prove those high costs in my opinion.

So i searched and searched for a nice clock project to upgrade mu trusty Arcam Alpha 5 CD player. This one was already upgraded with a nice new TDA1541A S1 DAC chip so I was impatient to reveal its true potential.

So finally I came across a nice article about The Flea Clock from Pink Fish Media. An very interesting project indeed. What that project aims at is in reality an ultra low noise PSU to power up a Tent Labs oscillator. So my project was based on that one from PFM forum.

I just had to change some things to fit my personal needs.
First – the oscillator was unable to drive any substantial capacitive loads, so I needed to buffer the outputs. Buffering is an easy task. A simple inverter would do the job. In this project I’m using two 74VCH1G04 ic’s to provide me two outputs.
Second – i wanted a oscillator with real measured parameters showing the phase noise and jitter performance since I had no way(equipment) to measure the jitter myself. Few manufacturers that in My opinion are suitable for the task:

Fox Electronics HC-73 series oscillators:
http://www.foxonline.com/pdfs/FXO_HC73.pdf

EuroQuartz XO-91 series oscillators:
http://www.euroquartz.co.uk/Portals/0/xo91.pdf

Silicon Labs Si510 series oscillators:
http://www.silabs.com/pages/DownloadDoc.aspx?FILEURL=Support%20Documents/TechnicalDocs/si510-11.pdf&src=DocumentationWebPart

In my case I’m using 11.2896MHz oscillator to feed the digital filter’s XIN pin(pin 11 on SAA7220 chip). This is the most basic way to feed the new clock to your CD player. Simply remove the quartz form the player and the two caps and the resistor. Here is how I did it:

 A more advanced reclocking to your player can done using a flip-flop to reclock the I2S bus before fitting it to the TDA1541A chip. Here is how its done:
This method has one major disadvantage. It uses one IC to process all three wires of the I2S bus. A better way is to use three IC’s but it’s cost and space consuming.
Possibly the best way is to feed the clock separately to the digital filter(SAA7220) and the DAC chip (TDA1541A). The DAC chip itself requires half the frequency provided to the digital filter. So we need to divide the clock coming from the module. This can be done again using a flip-flop:
In my opinion this is the better sounding reclock. Anyways, a wide field for experiments is available.
So this is the final result. Here is the clock module PCB fitted into my Arcam Alpha 5 CD player
Ultra low jitter clock fitted into Arcam Alpha 5 CD player
The module itself is powered by a preregulated PSU using a LM317 vreg providing 18VDC. I’m using a small transformer to power the whole thing up. This is the better way to do it. One can still use the already available supply rails from the CD player but 18VDC is the minimum voltage required in order the module to work.
A complete schematic for this module is available HERE.
WARNING – This design is provided to the DIY community for free and is intended for personal use only. Therefore the commercial usage is NOT allowed.
*************THANK YOU FOR READING THIS ARTICLE**************

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5 Comments

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  1. Giro

    hI, interesting concept.
    In drawing theres a transistor prior to 12v regulator, what is it for?
    Thanks

  2. Dmitry

    Hi Ventsislav

    Interesting and practical useful article. Thanks for posting.

    I’m trying to feed all three chips (7210, 7220 and 1541) from one low-jitter clock. When I do it for 7210 & 7220 and simply by-pass 7220 by connecting pins 2 of 7220 & 5141 (without feeding 1541 with Q/2) – it works just fine. When, however, I’m using the flip-flop module (as per your suggestion in the article) and provide the clock Q/2 to #2-4 of 1541 directly – it doesn’t ‘sync’, producing huge distortion. I checked all schematics ten time and don’t see a problem there.

    Any idea of why the above can take place or advice would be really appreciated.

    Best regards,
    Dmitry

  3. Lucian

    Hi.
    I bought for my CD-371 one low jitter clock module from ebay but it seems it doesn’t work. I took out all clock related components around saa7220 and just connected main clock output to pin 11. The cd is spinning chaotically in both directions and never stop. If I try to connect also the ground of the module to cd player ground the spinning stops but then the rectifier diodes on the module go crazy hot (actually first time it burnt the CD player fuse). The module produce a nice stable 5.00 V for powering the TXCO and … that’s were my measuring capabilities are ending: I don’t have a scope to see the output of the module.
    If I put back the old clock the CD is working fine (except for the ERR message while trying to read TOC of the CD but that’s a different issue I guess)
    Any ideea please? Thanks.

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