Updating Onkyo DX-706?
I own a Onkyo Integra DX-706 wich I have updated with LCAudio LClock 2 and shifted all analog opamps to LM6172. The LClock made some major improvements, but the opamps not so much.
I would like to make some new analog stage, but I cant find any information, servicemanual with scematic or datasheet on SM5813AP (dig. filter) and SM5861AP (single bit DA converter).
I did read the thread "Anyone tweaked the Onyko DX7711 integra CD-player?" http://www.diyaudio.com/forums/showt...ighlight=onkyo without any result.
Can any one help me on this one, please?
You will getsome advice.
you will get some help
by our "digital professor experts"
Elso and them.
They will come around and find this thread.
Elso will read about the concurrent's Clock,
and peranders will jump into the OP-amplifier thing directly!
you can not expect as much better sound quality
just by changing OP amp. Not that you can hear,
and it will even be har to measure - in some cases.
This is when you exchange a good OP-amp with a SUPER-expensive.
But when you have a very old like OP741 and some other
bad OPamps - than you can probably notice a slight improvement in Sound.
It all depends on what the level is - that your changes are made.
If you already is beyond human hearing, with your changes,
then it will not change anything you are able to sense, with your 5 senses.
(Somebodies than take their imagination to help - to "get the change")
:cool: ;) but this is a not so in your case :confused: :cool: ;)
/halo - mostly with his feats on the ground - not on the stars
Re: Updating Onkyo DX-706?
I think the digital filter is pin compatibel with Burr Brownīs DF1700.
If you use LM6172īs you should bypass the opamps better,thats one really weak point in the CDplayer...
Try the constant current source mod,you will not be disappointed.
halojoy and Nike
Thanks a lot, I am so buisy now, but I will be back to morrow.
Nike, I realy woud appriciate a scan from you.
Good Henrik brought up the DX 706, I also own one and use it as my only front end so I'm very interest in this thread!!!
Nicke, you would also make a big favor to me if you can send a copy of those scaned schematics.
I bought this CD new when they were current, more than 10 years ago, made some mods like adding 2 new PSU's, htere is room at the back besides the original trafo so now I have the original trafo for the digital section another for the clock plus other digital components and the third for analog.
Also changed opamps to AD827 with some apreciated sonic advantage plus output caps to Axons 2 x 5.6u for each channel. Replaced many caps and resistors.
Whats realy bad on this CD is the number of opamps used at the analog portion, 3 doubles for each channel!!!
My unit uses same NPC SM5861AP Sigmas DAC's (no surprise, he) I tried to get the specs for this at NPC site but they no longer publish the data sheets for those, I email to them requesting information they answered asking for what I would need them but finally there was a blank from NPC side.
Henrik, we need to do something with that output analog "stage", and also maybe to change those old Dac's and that DF as Nicke suggest.
Otherwise the DX 706 is an excellent built CD can't find a newer one built like that except if I go to ML or Krell of course but....
A suggestion about modifications...
One of the things I did that made a big difference was changing the resistors and caps in the analog stage.
Perhaps because the analog stage is a dual differential stage which uses 5%(or 10%...donīt remember which..) tolerance for the components.Or is it just better quality ?
Donīt ask me why .
Another thing I would do if I used the CDP today would be to modify the voltage reference for the analog regulatorīs(it is a version of the well known Sulzer type).Now it takes the 5 V reference from the output of the +5 V regulator for the DACs.I would replace it with a suitable voltage reference(National has several) fed from a constant current source.
Let us know about the result.
BTW I didnīt suggest that you should replace the digital filter,actually I think that it is the same as DF1700 but it is from NPC instead of Burr Brown.
You can read all about the mods I made here:Nickeīs mods
Nicke, What's your actual CDP these days?
For more info look here:http://www.diyaudio.com/forums/showt...5&pagenumber=1
I have made already some modification, temporary on my DX7711.
But, I still have left some things to do (I do not have too much time).
What I did is many of Nicke's changes, mentioned in Onkyo DX7711 thread.
1. Changed resistors (Holco)
2. Changed capacitors (Elna Cerafine)
3. Eliminated mute transistors
1. The opamps, what I use is OPA627 (all together 8 pcs, not cheap...)
2. Additional toroid trasformer for analog stage
3. Clock mod. not implemented yet
4. Voltage regulator update is not implemented yet
5. Another output caps (Elna Cerafine)
6. Silver Mica feedback caps
7. Copper shileding tape on receiver and DACs
So, I have still left many things, and when I have time, I'll implement those also.
The sound has changed already a lot.
It is more soft, and the clearance is better. I like more this sound, the previous was a bit aggressive for me.
There is some pictures about modification.
back side of pcb...
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