Upgrading & modding new Oppos, BDP-93 & BDP-95 - Page 11 - diyAudio
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Old 1st January 2012, 05:00 AM   #101
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Location: Sydney
I agree. There's one important element that's been omitted from your observation - ground plane potential uniformity / ground plane noise. If done properly, a local decoupling can achieve an excellent result - much greater than implementing only very low noise voltage regulators.

Power supply pins on all IC’s should sit at ground noise potential – not higher than that, if a local decoupling is executed properly. Then, there’s actually only one question: How low is the ground plane noise?

I dislike kits that consist of many modules, like buffalo and similar – with these, it is impossible to achieve ground potential uniformity – the main reason why Coris achieved suboptimal results in BD95 with placid / placid bp. There’s the heat as well, which renders these modules useless in consumer electronic products, unless a special care is taken to dissipate the heat (fans!); I don’t think many DIY-ers are aware of this “heat-factor” when they are ordering shunt regulators on line.

Low noise power supply regulation should be executed on the main board; shunt types can also be used, but catered at design stage from the get-go, as heat generators) – only then the low nose benefits of such power supply can be distributed to where it is really needed – at all IC’s / discrete stages – this is the whole idea.

Boky
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Old 1st January 2012, 11:48 AM   #102
Coris is offline Coris  Norway
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For sure, the ground potential uniformity is (have to be) a must for good results. Shunt regulator can be a good solution, but is not when is about a main PSU. It is working very well and are quite efficient if are used as local regulators (right beside the chip/device of interest). In such case is about quite low currents and heat dissipation can be minimal. One may chose the right solution, because is very possible to obtain very good results with a serial one...
Yes, in case of BDP95, the placement of the DAC chip and some other devices are quite far from the main PSU. A good ground plane, with a low potential is a problem here. Also the ground plane is to be designed accordingly. Is not only about have a coper plane as well...
I adopted a solution with a 1,5 square mm silver ground wires (shortest as possible) from main (+/-) PSUs, which meet together in the chosen common (radial) GND point . It works well so far for me.
The main PSU is only to be a main one, and the local supplementary regulation is applied in the points of interest. I chosen serial low noise chip regulators, because they are more practical and easy to apply. Even more,such type regulators tolerate very well large decoupling capacities (which also are a must in some cases) in my opinion.

Last edited by Coris; 1st January 2012 at 11:50 AM.
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Old 14th January 2012, 04:36 PM   #103
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@All,

a question regarding to the Oppo 93.

Based on your experience, how great would an replacement of the OPA 5532 vs LM4562 (=LME49720) affect the analog audio performance ?

BR - Sony123
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Old 15th January 2012, 07:12 AM   #104
Coris is offline Coris  Norway
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Quote:
Originally Posted by sony123 View Post
@All,

a question regarding to the Oppo 93.

Based on your experience, how great would an replacement of the OPA 5532 vs LM4562 (=LME49720) affect the analog audio performance ?

BR - Sony123
I have to say that improvements in audio performances it not may come to much only from the replacements of the op amps. What is used in Oppo`s devices are enough good quality active components. What is the weak part of those Oppo players is the power system, and the quality of the clock oscillators. Actually (as I guess...) Oppo 93 have only an switching PSU which supply for the audio stage too... This is not very good solution.
If you will try to improve the power system, with good/consistent local decoupling for the involved components, and maybe replace the respective clock oscillators with another ones (better specs), then will for sure be an quite big improvement in the analogue audio output (and video too).
You may try to replace only the main oscillator for the DAC chip with another one (80 or 100 Mhz) and you will have at once an improvement (with the same op amps).
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Old 9th February 2012, 04:45 AM   #105
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Default full linear power mod and TCXO( OCXO) mod for OPPO 93/95

Click the image to open in full size.I I I am happy to report to I have modified OPPO 93 with full linear power and i replaced 20( HDMI part ), 25 ( CPU ) MHZ with 2.5 PPM TCXO.
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Old 9th February 2012, 12:12 PM   #106
marce is offline marce  United Kingdom
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Some interesting and quite deep discussion on de-coupling here, further on in the thread are numerous links and comments on digital supply decoupling.
paralleling film caps with electrolytic caps
Digital systems generate thier own noise, I would also look up simultaneous switching noise, and the numerous data sheets, app notes and white papers on how to controll it.
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Old 9th February 2012, 03:30 PM   #107
Coris is offline Coris  Norway
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Quote:
Originally Posted by Jae Hong Lee View Post
Click the image to open in full size.I I I am happy to report to I have modified OPPO 93 with full linear power and i replaced 20( HDMI part ), 25 ( CPU ) MHZ with 2.5 PPM TCXO.
Nice! Can you reveal your sources for the 2,5ppm oscillators? Some impresions about picture/video improvements, concerning replacement of 20Mhz clock - HDMI?
(Is something wrong with your picture attached here. Not possible to open).
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Old 9th February 2012, 11:33 PM   #108
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http://blog.paran.com/blog/list/list...?pmcId=pcaudio

here is the link of my fully modfied oppo 93.
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Old 10th February 2012, 12:04 AM   #109
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Join Date: Feb 2012
Full linear power mod was very difficult task.

It took about 6 months from scratch.

I am audio and home theater enthusiasts over 30 years have Ph.D. in digital TV broadcasting field.

I have built nearly all of my audio gear by myself and published 4 books in Korean for building tube/FET amplifiers.

Anyway, I installed 3 PCBs
Main PCB: replacing original power board ;
It has troidal transformer supplying linear power to +5 V, +,-15 V


Sub PCB and daughter PCB :
It make linear + 1.0V, 1.1V. 2* 1.8 V and 3.3 V
( originary it was done by DC-DC converter )

I intended to change 3 crystals to OCXO ( 0.01 PPM );

I ordered to make 20,25 and 27 Mhz OCXO to nearby Korean manufacturer.
Each cost about 200 $ !!!! ( minimum order is 5 for each frequency ).

It takes 4- 6 weeks to deliver.

I am waiting now.

For the time being only 20 and 25 MHz are replaced with TCXO ( from digikey )

27 MHz is placed under main PCB.


I am very happy to the stunning result

It can compete more than 95 % of Ayre Dx-5 ( my opinion ).

Picture has vivid color and no noise , edge is sharp.

I am using JVC X-3 projector for 2D and 3D movies.

In my humble opinion, my machine is best in the world as far as 3D source player.

Avatar , alice in Wonderland and IMAX 3D video source is really wonderful with this modified OPPO 93.

I will keep post again
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Old 10th February 2012, 06:24 AM   #110
Coris is offline Coris  Norway
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Many thanks for informations. Nice job! I think too that is very big potential in those machines, if the right components/concept are used...
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