Upgrading Philips DVD 963 SA

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#221
current leakage

Hi,

I would like to ask a question regarding electronic which I have no knowledge of.
here we go:

when I bought my DVD963SA, I never knew there was a current leakage. Unitl one day I use a "test pen" to touch on the screws on the chassis and notice that there was a current leakage. But strangely, the leakage does not "bite".
I look around the inside of the player and found that the leakage is from the mounting of the transformer or the power supply.

my Question is. Should I isolate the power supply electronic from the chassis, ie put some rubber spacer between the electronic plate and the chassis and earth the chassis?
will this create any problem for the sound quality?
Or is the leakage intentional?

Please advice.


PS: I must re-iterate, I am have no electonic back ground. Thank you.

🙂
 
#222
Bypassing the muting transistor

ChuckT said:
Make sure to bypass the muting transistor by soldering the output end of the coupling cap directly to the rca out. It makes a very large difference with improvement to the soundstage and smoothness.
Click to expand...

Hi ChuckT/or other brothers,

Pls advise is it need to de-solder the original connection between the RCA out and the muting transistor out. And any bad effect for this bypassing, eg. noise generating during skipping songs, or pause/stop. If yes, is the noise serious?

Thanks in advance.

😕
 
#224
Output transistor bypassing

Hello Air,

Pls advise the details of de-soldering the transistor. Is it just take the transistor away, or any other better methods?

And is there any listenable difference after bypassing these transistor.


By the way, is there any brother has a schemetic diagram for 963SA that could email to me!

Thanks in advance.

:smash:
 
#225
Here's what I did, one leg of the coupling cap (I use Blackgate NP 33uf/16v) and solder one leg to the board (the signal output hole) and the other leg directly on the RCA out. This is probably the easiest and most direct.
No side effect, didn't notice any clicks when switching songs.

I consider this the top 3 simple tweaks for this machine.
 
#226
ChuckT: Did you use the original RCA out, or did you add a new one? If you used the original, I hope that you disconnected it from its original contacts. If you didnt, you still got the muting transistor, and only bypassed an resistor.

kingslui: Yes, I just took the transistors away. At the same time I removed them, I was changing op-amps, so I can not tell what difference removing the transistors did, but at least, it isnt for the worse 😉
 
#227
Hi air, I connected to the original RCA, you are right, the signal still go back to the muting transistor. But nevertheless, there was still improvement to sound as previously, the same cap was just replacing the orignal coupling and it didn't sound as good. Maybe I should put a copper wire between the muting transistor pins.
 
#228
Bypassing muting transistor

Thanks Chuckt and Air.

I see. So I am planning to connect the output cap directly to a new RCA (by desoldering the cap's output from the muting transistor)and see what is the difference .

By the way, I have changed two philips' original output cap in golden color to Blackgate's 100uf 16V non-polar. But Chuckt's mod is using 33uf. Which one is better?
 
#229
#230
Muting trans removed

Got the muting transistors removed. Word of advice: do it before putting the huge BGs coupling capactors, the latter leaves little room for re-work.

The impact? Its definitely smoothly, slightly. Maybe the changes in the caps have already made the negated the full effects of the removal, or it could be that I am getting deaf. 😀
 
#231
Thanks again Air for your very helpful schematic diagrams.

I have bypassed the muting transistors by connecting the 100uF caps, 470 ohm , 10K ohm and 1n caps to another PCB board and a new RCA sockets (by removing the components ouputs boards).

And it sound better I believe.
 
#232
The DV667As AKA DV536A .

I have a Pioneer DV667AS . I found that it has dc shift in between audio tracks. So if the preamp is dc coupled , I get a thump after every track when I guess the mute comes on momentarily.
If I ac couple the preamp , there is no problem.
Would anyone have a circuit diagram of the dac circuit in the 667. I did find Burr Brown DAC's on this machine. This machine is sold as the DV536A also ( I guess in the US).
Thanks,
Cheers.
 
#235
Guido Tends clock upgrade Post #234
Hi all,
did anyone build in Guidos now available clock upgrade? Any feedback?
regards
Stephanr

On Friday I sent Guido the payment and shipping costs for a TentLabs clock upgrade for the Philips DVD963SA. On Saturday I got an email from him saying that what Philips has been making changes in the hardware of the DVD963SA over time and that there are a number of different versions of the player. Rather than having to design a clock upgrade for each of the the several different versions of the of the DVD963SA, Guido said that "We are currently prototyping a universal upgrade that will fit any hardware."

As soon as he completes the prototyping of the universal clock upgrade and has finished units for sale, I'm getting one. The combination of Guido's technical expertise, his extensive protyping and product development, and the build quality of the completed product - are all worth waiting for.

I will let you know how much of a difference it makes in my player's sound.

lwr
 
#236
Balanced outputs?

As I was reading my service manual for the dvd963sa, suddenly it hitted me.. Why haven´t anyone built a complete new ouput stage (from ad1955) for this player?

In the datasheet of ad1955, there is a simple schematic on how to make a differential output from the dac.
--> ad1955 balanced out
--> dvd963sa output


This is almost what we can see in the schematic of the dvd963sa, but I was thinking about building it on a different pcb, so I can easily compare it to the original output, and use wich opamps I want to. The pcb would also include an single ended output, as my preamp right now does not have differential input.

Anyone else thought about this, and any comments? I was thinking about using TI´s opa627 as both i/v and line stages.
 
#237
Re: Balanced outputs?

air said:
As I was reading my service manual for the dvd963sa, suddenly it hitted me.. Why haven´t anyone built a complete new ouput stage (from ad1955) for this player?

In the datasheet of ad1955, there is a simple schematic on how to make a differential output from the dac.
--> ad1955 balanced out
--> dvd963sa output


This is almost what we can see in the schematic of the dvd963sa, but I was thinking about building it on a different pcb, so I can easily compare it to the original output, and use wich opamps I want to. The pcb would also include an single ended output, as my preamp right now does not have differential input.

Anyone else thought about this, and any comments? I was thinking about using TI´s opa627 as both i/v and line stages.
Click to expand...

Hi Air,

Yes I've also been thinking of building a new output stage for the 963SA. Actually I already have started getting the parts and building the circuit. I will be a direct heated triode, fully battery powered, 'cost no object' output stage. It will be quite bulky so I have to buld it in a seperate enclosure. I have bought a second 963SA (defective drive unit) for little money and this will be the seperate case for the actual output circuit. Battery's and transformer will be located at a 'hidden' place (to bulky).
I do not like the sound of opamps, so thats why I go the 'tube' way.....

See a picture of it on top of a Pioneer PD-S901.


There is also this other link where you can find different output stages for the 963SA.

http://www.audioxtension.com/rev/963sa/963.htm


Regards,

Saffier
 
#238
Picture output stage

Sorry, forgot the attachment...
 

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