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-   -   Connecting Lclock to Naim cd 3.5 ? (http://www.diyaudio.com/forums/digital-source/41992-connecting-lclock-naim-cd-3-5-a.html)

sinski 4th October 2004 10:57 AM

Connecting Lclock to Naim cd 3.5 ?
 
Hi,
I will get my Lclock soon. I was reading installation instructions on http://www.acoustica.org.uk/t/naim/35mods2.html and http://www.hifituning.de/pdf/naim.pdf.

There is a difference beetwen those two versions - on www.acoustica.org i have to remove only quarz and a smaller resistors (they are writing about 22K, but it is 10K) and connect the new clock to the 220K resistor, a resistor end which is closer to the cd front. On the picture 220K seems to connect pin 3 and 4 of 74HC04. Hope so ...

On www.hifituning.de i have to remove quarz, 10K and 220K and connect XO output to the pin 3 of 74HC04 - i think the pin 3 of 74HC04
is the place, where 220K was connected closer to the front.

I am confused ...
:confused:
Does anybody can help me ?

martin clark 4th October 2004 11:28 AM

Hifituning.de refers to the Naim CD3, which is not the same as the CD3.5.

The CD3 uses an 11.28Mhz clock and TDA1541 DAC.
The CD3.5 uses a 16.9344Mhz clock and the later CD7 chipset.
The 220K resistor doesn't matter much (it biases teh gate into linear region) - you can remove it if you wish.

If you have a 3.5, follow the instructions on acoustica.org.uk ;)

sinski 4th October 2004 12:49 PM

Hi Martin,

www.hifituning.de describe lclock installation for CD 3, CD 3.5, and CDS

220K "it biases the gate into linear region " - i have not idea what does it mean..., but for me "linear" sounds like this 220K resistor is doing something positive, stabilizing the circuit ?

sinski (Tomek...)

martin clark 4th October 2004 04:43 PM

Sorry, just read the whole hifituning.de document properly.

The two methods are basically the same: remove quartz, two small caps and one small resistor. Then it's up to you whether you remove the 220K resistor or not. This resistor does connect to pin 3 as you observe.

sinski 4th October 2004 06:20 PM

Hi Martin,

I was reading it properly :D an it is clear written that:

1. For CD 3 remove quarz, 2x22pF and 220K, connect Lclock out with pin 11 of saa7220
2. For CD 3.5 remove quarz, 2x22pF , 10k and 220K, connect Lclock out with pin 3 of 74HC04
3. For CDx there is not detailed description yet, one has to follow general installation desription
4. For CDS remove quarz, 2x47pF and 1K,connect Lclock out with pin 11 of saa7220P

http://www.hifituning.de/pdf/naim.pdf

and i am still confused

Regards, sinski

:confused:

martin clark 4th October 2004 08:05 PM

Why so confused?

The CD3 and CDS use the older Philips chipset, based around the SAA7220 decoder. For this device the clock is built around an inverter which is part of the Decoder. The SAA7220 then passes the clock signal to the DAC.

Althouhg they share the same case, the CD3 and CD3.5 are very different designs inside.
In the newer machines, the CD3.5, and CDX (I believe), the decoder is the later SAA7350. So, instead, Naim built the clock around an independant unbuffered inverter, which subsequently distributes the signal to both the decoder and the DAC. It's just a more refined arrangement.

sinski 4th October 2004 09:35 PM

Hi Martin.
I have not so much knowledge about this stuff as you.

I am just a simple diyer needing simple and clear description what&where&how and i am getting confused seeing two different advices for the same cd player.

If the 220K resistor has not connection to pin 3, then how will be the clock connected to pin 3 of saa7220, if i will connect the clock to one end of the 220K ?

Cheers, sinski

sinski 5th October 2004 08:31 AM

Hi Martin,
I was reading carefully installation instructions, but not carefully enough yours posts...
So - everything is clear - i remove 2 caps, small resistor and i leave (or remove if i want) the 220K, then connecting clock out wit pin 3 and it is done.
Thanks, Tomek

martin clark 5th October 2004 09:22 AM

That should work nicely :)

Edit:
One last thing - for the 3.5, it's easier to leave the 220K resistor in. Pin3 of the inverter is on the bottom of the board, but more space is available for fitting the clock on the top! The 220K is above the board, but connects to pin 3 by through-plated holes in the PCB. If you remove the resistor, you may have difficulty soldering yoru new clock signal wire into this tiny hole. It is easier to solder to the leg of the resistor left in place.

M.

PS. I will mark up those photos for you, but I have to get my Nait out of storage to check first. Sorry for delay!

sinski 5th October 2004 09:55 AM

Yes, i will do it this way.
I have another question - i think ALW wrote somewhere that clock cable should be as short as possible. In 3.5 i have to keep longer cable, because there is not a place for a clock directly over the old quarz. I saw at www.lcaudio.com that the new xclock 3 has instead of two simply cables one screened coax (RG174) cable. Does it make sense to change the two normal xclock cables against one coax cable ?

cheers, sinski


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