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gabrielbecheanu 20th January 2011 05:39 PM

Onkyo DX 6850=DX 706 upgrade
I have a CD made by Onkyo model DX6850 (DX 706 American version) and I would like to make him an upgrade. I study the service manual and I decide to upgrade the digital part of the CD player. One of the difference between DX6850 and 6870 is the clock generator.
I found on EBay an oscillator on the right frequency Vanguard Ultra precision Golden TCXO, 0.3ppm 16.9344MHz - eBay (item 120627335095 end time Jan-26-11 05:42:02 PST)

Any suggestion about my idea to install the new oscillator on the CD player, I will see any differences?

aparatusonitus 20th January 2011 06:23 PM


Originally Posted by gabrielbecheanu (
Any suggestion about my idea to install the new oscillator on the CD player, I will see any differences?

Simple answer is no, deal with the digital power supply don't want LM7805 as voltage regulator there...use J-fet CCS -> TL431 -> good elcap//film//ceramic for digital supply decoupling at devices pins as possible.

gabrielbecheanu 20th January 2011 07:14 PM

Thanks for the info.
I put this question because a friend of mine put another clock in his TEAC VRDS 10S CD player and I sow a huge improvement.
I believe that through this change that I'll enhancing efficiency and performance of this CD player
I made some changes, I changed NJM5532 with OPA 2134 and have removed the muting transistors

aparatusonitus 21st January 2011 06:41 PM

You can put rubidium clock inside if you want, but it will not perform one zilch better then simple crystal clock until you deal with grounding and power supply...and remember clock psu is analog psu, not digital!

gabrielbecheanu 21st January 2011 06:49 PM

To modify the PSU is too much for me at this time, I must study about CD players modification.
I try to find some tutorials to modify this CD but no one made something like this for this CD player.

gabrielbecheanu 5th March 2011 10:16 PM

1 Attachment(s)
Hi aparatusonitus
I Received A few days ago the TCXO clock But as you said i think i must start to improve the digital power supply. I sow some pictures on the web But I Would like more specific advice to upgrade this CD. I have the service manual for all Three models (6850,6870,6890) I think you know me better than me all the differences between those CD players.
Can you give me more advice in this project?
An interesting pictures

mlloyd1 7th March 2011 09:06 PM

it's probably too late for me to say this, but i'll do it anyway :-)
you want a low jitter clock (to help achieve low jitter, the clock will require use of a low noise power supply).
you don't need a "high accuracy" clock - accurate frequency of operation and low phase noise/low jitter are two different things. Search around here more for some helpful background.

I have a DX-706 and DX-6800 myself. To me, a lower jitter clock improves the sound of my DX-706. At the moment, my DX-706 uses the Hagerman clock (info here: Hagerman Technology LLC: HagClock Audio CD Low Jitter Precision Clock Oscillator DIY Kit). Again, search this site for ideas and information about other clocks.

good luck,

gabrielbecheanu 7th March 2011 09:23 PM

Thanks mlloyd1
As you know our CD player can be easily upgrade to DX6870. The main board are the same except some missing parts and transformer. I think I will start to upgrade the power supply an use two transformers instead of one.
I will like to know more how to modify this CD player. I think this CD player has more to offer.
Best regards

gabrielbecheanu 5th February 2012 05:28 PM

Today I almost finish to upgrade the CD player. I have to put four more components near to the Optocoupler two resistor and two capacitors one near to the new oscillator and one near to the Optocoupler. The reason that I donít put them is that i donít know the value of them. This components are not in the service manual, the only way is to find a (6870 708) and see the value of them
Any one who has a 708 CD player can tell me the value for these components.

After that the upgrade will be complete
Best regards

SoNic_real_one 5th February 2012 06:01 PM

Gabi, I would replace also the Opamps that you have.

I am talking about Q403, 404, 405, 406 - NJM5532 were great back then, but today there are better options. I suggest LM4562.

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