Resource for calculate, building and measuring Hi Fi Loudspeakers and more...


 
Thursday, 27 April 2017
1733 users online


Bookmark and Share


Clock's:   L C Audio  -  TentLabs  -  AudioKit  -  EffectiveAudioMod  -  Audiocom International  -  NewClassD  -  Kwak Clock


 LClock XO Precision CD Master Clock Generator

The L C Audio module is used in my player...

LClock XO

This module with a precision Master Clock Generator can improve the sound quality of almost any CD player from the cheapest to the most costly. - Why?

99% of all CD players on the market are equipped with a cheap CMOS crystal Oscillator, with a high level of analog input noise. The crystal oscillator produces the reference frequency by changing state at a rate of i.e. 16.934.400 times per second. The oscillator works by making the crystal unit filter the output signal of a CMOS gate, and sending it back to the input at a phase shifted sinewave of some 100 mV amplitude. This is enough to make the gate shift states in a fairly stable manner. However as the 100 mV signal is mixed with an analog input noise of 100 uV (MicroVolts) this causes the oscillator to shift state slightly before or after it was supposed to. Since there is a ratio of 1000 between 100 mV and 100 uV, the raw signal to noie ratio can be calculated to 40 dB. At 16,9 MHz raw clock frequency the division ratio to reach the audio sampling rate of 44,1 times 8 ( 352,8 kHz ) is 48. Thus the jitter level is also attenuated by 48 times or 33 dB. The total (time domain) signal to noise ratio is then 40 + 33 or 73 dB. Not at all enough to use the DAC chips potential of some 95 - 100 dB of S/N.

The time noise is also called jitter.

Since a crystal oscillator only requires one single inverter to work, most CD makers use the other 5 inverter gates in the 74HCU04 IC for other purposes, such as switching and buffering. However, this causes switching noise on the supply rails. Since the analog trigger level of a gate is one half the VCC voltage, half of the switching noise is transferred directly to the input of the Crystal Oscillator.
This creates even more jitter, one of the most unfreindly phenomenon in digital audio equipment.
Sound will be harsh and Stone Cold. Sound Stage is narrow, and uninteresting, music becomes what is known as: DIGITAL! 

Lets take a look inside Your CD players control signals:

This is what the clock signal in Your CD player looks like:

Now :  ...compare with the signal of an LClock : 

In CD's with a signal processor - integrated crystal oscillator, (Such as the SAA7345, SAA7220 or NPC SM5864) there are not only 5 other gates creating jitter, but hundreds, making the problem even worse.

CD producers like SONY, Arcam, Kenwood, Pioneer and Rotel are becoming aware of how serious the Jitter problem really is, but still they are not solving the problem adequately. In their 1999/2000 models these manufacturers all use cheap CMOS or transistor oscillators with standard high-noise voltage regulators and cheap 50 c crystal units.
We use only fine handcut precision crystals, ultra lownoise regulators and GHz high frequency transistors for LClock2.

That makes a difference!
The LClock XO is a credit card size SMD Circuit to fit into Your CD player, and it contains a super low jitter master clock, to replace the existing oscillator. The time domain S/N is as high as > 120 dB, so You are sure to exploit the full potential of Your CD players DAC system.

The XO Clock is a very cost effective way to improve the sound of almost any CD player, no matter the price level. 

This is what it does to sound:

  • Firmer and more distinct Bass.
  • Wider, deeper and higher soundstage.
  • Better definition and placement of instruments in a multiinstrument session.
  • Cleans up hairy treble performance.


Technical Data Sheet:

Frequencies Precision
8.4672 2 ppm. MHz
11.2896 2 ppm. MHz
12.2880 2 ppm. MHz
16.9344 2 ppm. MHz
18.4320 2 ppm. MHz
22.5792 2 ppm. MHz
24.5760 2 ppm. MHz
27.0000 2 ppm. MHz
33.8688 2 ppm. MHz
45.1584 2 ppm. MHz
Jitter Level 2,5 ps (max.)
Power Supply Noise 1.8 uV (max.)
Power Supply Rejection 92 dB (max.)
Power Supply Influence on Frequency 0,01 ppm / Volt(max.)
Current Consumption 60 mA
Supply Voltage Range 9 - 26 Volts DC
Thermal Performance 10 - 50 deg. C
Size 50 by 80 mm.

But Maybe You don't bother with these technical terms, and - like more than 2000 other music-addicts in Scandinavia and most other places in the world - just want to get the wide musical perspective, the high definition and the firm, distingtive bass reproduction Your CD player can only offer with an LClock XO upgrade.

Remember, if You have just a little experience with electronics or have a friend with a few skills, this would be adequate to get Your machine upgraded to supreme performance. Its easy and it takes only 15 to 20 minutes on most models.
 

What is the procedure for installing an LClock?