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Oppo's BDP105 - discussions, upgrading, mods...
Oppo's BDP105 - discussions, upgrading, mods...
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Old 13th April 2018, 04:05 PM   #1791
inline_phil is offline inline_phil  United States
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Hindsight is always 20-20 and I did not take any when the mod was performed [wish I had]. At this time, I cannot do so until I get ready to tear into it again. But a cheap multi-meter is all that is needed to buzz out the redundant grounds.

I used the Audio + and - grounds on the edge connector as the reference points for the audio boards and the digital ground edge connector for the digital boards.

BTW, the multi-channel RCA jacks are already isolated on the inside of the rear panel. Someone understood how these grounds were causing audio degradation. Too bad they didn't do the same for the stereo audio RCA jacks at the factory.
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Old 13th April 2018, 04:06 PM   #1792
inline_phil is offline inline_phil  United States
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One probe to the PC board trace then put the other probe on the Audio + ground and then move that probe to the Audio - ground to assure that neither are redundant.
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Old 13th April 2018, 04:08 PM   #1793
inline_phil is offline inline_phil  United States
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Also, buzz out the traces on both sides [top and bottom]
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Old 16th April 2018, 08:51 AM   #1794
Staudio is offline Staudio  Russian Federation
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Quote:
Originally Posted by inline_phil View Post
One probe to the PC board trace then put the other probe on the Audio + ground and then move that probe to the Audio - ground to assure that neither are redundant.
Thank you! I'll try to make this mod.
As far as I understood, now you have only one ground point for all boards?
Or you leave only one ground screw, closest to the rear panel, for each board?
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Old 16th April 2018, 12:31 PM   #1795
inline_phil is offline inline_phil  United States
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One ground point for all boards. It's knows as a single-point ground, an old [circa 1970s] approach used in medical electronic equipment to keep eddy currents from forming.

Just imagine how much care must be taken to avoid such stray currents when an electrode from a device is placed on the heart or brain and the stainless steel table on which a patient is lying is connected to ground. One saline splash, one exposed body portion to this ground creates a return path to that device. A few milliamperes can cause irreparable damage and even death.

Now apply this concept to audio where ground currents recombine in random ways over whatever distance they travel through these multiple ground paths caused by these PC board screws. The electronic effect is phase smearing and increased noise [lower signal-to-noise ratio].

This identical effect is present in PC boards where computer layout programs do not account for the route of the ground path. Most programs [and universities] focus on the signal path and ignore the ground path. This same assumption was made with tube electronics and old automobiles where any convenient bare-metal was presumed to be a valid ground point.

If you want to lower noise, look at these grounds and study the paths they take. If there is a loop, just eliminate a path and the noise floor improves. In the past I have gone so far as to trace out the routes so-called ground planes take through in a PC board and are amazed at how many there are [on one I stopped counting at 100].

An Xacto knife lifting a trace segment creating a small gap is all that is needed. And if you make a mistake, you can always "put it back" with a solder bridge. But your multimeter will tell you that once the trace is cut and the reading goes to infinity.

This mod does not eliminate all ground loops, just the ones caused by the improper PC board grounding. And newer electronics use multi-layered boards so finding all of the built-in ground loops on such a PC board may not even be possible.

This mod is simple and it works. It costs pennies worth of parts and maybe as much as a few hours of your time. Plus it is simple to undo if you do not like the results but I can pretty much assure you that you will love it.

Remember that the RCA jacks on the stereo audio board also need tape on the chassis both internal and external [screw head isolation]. It wouldn't hurt to slightly enlarge these same screw holes holding the RCA jacks in place on the chassis to reduce the possibility of a ground through a misaligned mounting screw. DO NOT ENLARGE THE HOLES ON THE PC BOARDS since they may provide a path between the top and bottom traces.

Good luck and remember to take pictures and post your results.

Last edited by inline_phil; 16th April 2018 at 12:35 PM. Reason: clarification
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Old 16th April 2018, 01:28 PM   #1796
Staudio is offline Staudio  Russian Federation
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Originally Posted by inline_phil View Post
One ground point for all boards.
Does that mean, that you solder a wire to each board to connect it to ground point?
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Old 16th April 2018, 02:25 PM   #1797
inline_phil is offline inline_phil  United States
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No, the power supply cable for each PC board should already contain a ground.

Do not add wires between PC boards to ground the boards to each other
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Old 11th May 2018, 01:37 PM   #1798
The Turnip is offline The Turnip
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Question Question on diodes Oppo 105d

Hello everybody
A question about Oppo 105d
I have read here on the forum in various posts and even on the web in general.
There, I have noticed that changing the power supply diodes on the analog card can make a difference to the sound.
I have a good idea of ​​how the switch should be made and thought to start with this because I use Oppo mostly for music.
Against this, I am very very uncertain of the diodes and values ​​of these I will use. There is a plethora of everything.
The posts and articles I have read are a few years old now and I do not know if it might have come up with something newer / better to use.
If there is anyone out there who can advise me and share their experience of this change, I would be very grateful.
It is also very interesting to hear what the outcome of the change was.
If you have pictures on it, please feel free to post them. As you understand the text, I'm a newbie, but I can solder and screw.
What exactly this seems to be about.
(Well, I heard the news, there's good rockin' tonight.)
Thank you all.
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Old 13th May 2018, 10:29 AM   #1799
Coris is offline Coris  Norway
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Oppo's BDP105 - discussions, upgrading, mods...
Well, I am not very sure about how much noticeable improvement, the only replacement of the rectifier diodes, it may bring in this case. However, this is only a part of an improvement process (which it is more extended for the real and obvious results).

You can use Schottky diodes of 3-4A, and relative low voltage rating (40-60v). Such parameters it may also provide small enough component dimensions. Just cut the original diodes from their terminals, and solder the new one on that remaining terminals. Unsoldering/removing the original diodes from the board, it is not very easy, and it may damage the copper planes.

Last edited by Coris; 13th May 2018 at 10:33 AM.
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Old 15th May 2018, 08:41 AM   #1800
The Turnip is offline The Turnip
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Thank you Coris
I will carefully try to do it like this. Now i know more about the values of the parts.
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