Oppo`s BDP105 - discussions, upgrading, mods...

[Erlend Sæterdal]

Originally Posted by Coris

This belong to an moded analogue (stereo) stage of 95... Is really very small.
Is just stupid to use something else than DC coupling for this analogue output (XLR/RCA) in a quite high end player. At last they should use non polarised caps. Such approach should look much more professional, than only throw on that outputs some usual 100µ caps.
With today components technology such design is just wrong!

What do you think a good quality eletrolytic cap does wrong as Coupling Cap ?

My exsperience is they are fine as long as there is a few volt on the input off the cap.

Actually I prefer them instead off MKP, MKT etc. Do not the treble from M.. !

[Coris]

Originally Posted by john curl

This last week, I met with the designers of the OPPO 105 analogue stage. They are competent, and well intentioned. However, the need for keeping cost within reasonable bounds, and adding features, limits what they CAN do themselves. I personally have used the 105: Stock, with STAX Lambda electrostatic headphones, and I will say it is the best player (of its type) that I have heard, including SACD.

OK, I will not contradict you about the competence of the Oppo electronic designers. When one meet face to face somebody, can get a more real impression about, than one who did not had that opportunity...
I know well enough how it works in such cases: there are someone else who have almost nothing of technical knowledge, but who decide how the professionals must do it (because costs, and so on). I really feel sorry for the professional people in such situation... But...

BDP95 had not those AC coupling caps on the analogue output, it were 200$ cheaper, and it were all right with the final stage in that DC coupling.
If the design it were done without AC coupling, the resulting cost of BDP105 should be lower (benefit).
This AC coupling do not improve in any way the output stage. This is obviously... It degrade the signal, no matter the caps quality. In this case is not even possible to think to have very high quality caps on that board. It is a cost case, right? And what for use caps there if is better without?
At last it may be used non polarised caps.
I can hardly understand the reason to isolate the output. It is a justification Oppo came out with, that it were reported in few cases (BDP95) that amp input it were disturbed in one way, or it were about offsett on input (!!!) on few of the amps types... So what? Oppo may customize a whole design, production of thousands of its products, degrade the analogue output stage quality on an new player model (which else it come with many others improvements...), only to be adapt it to just few types/cases of amps which it were designed in a very special way?
Such explanation (how it were presented) just do not hold... But anyway...

I will conclude now with an comment to john curl post.
I have now any doubt that the headphone output it may sounds exceptional. This output do not have AC coupling, the headphone channel final chip is very good in parameters (I know how it works...), it have a very high slew rate, and the headphone line it have paralleled 2 of the DAC channels on it... I believe you that it sound best.
I just did it before (in another case): I coupled the headphone out (adapted) to my amplifier. It were a very, very good sound out of that device... I used that connection for a while, but I found out further an even better way to do it... Just removed the headphone final amp chip... I think that all of us can agree with that "rule": less components/processing in the signal path, better that signal at the output.

It could be interesting to hear your opinion (as a beta tester) about the analogue outputs on XLR/RCA... Can you say the same about the player another analogue outputs?

But let`s wait the first reviews, and the firsts owners comments about this disputed subject...

[Coris]

Originally Posted by Erlend Sæterdal

What do you think a good quality eletrolytic cap does wrong as Coupling Cap ?

My exsperience is they are fine as long as there is a few volt on the input off the cap.

Actually I prefer them instead off MKP, MKT etc. Do not the treble from M.. !

Well, it may be quite much to "talk" about, to be answered this question...
First a such cap may have a large capacity to assure a very low pass. 100µ it may be quite right on the calculations, but one hear very well that is not enough... I`m quite sure that your self have experienced the difference, in bass domain, when is about an AC coupling, and an DC one...
An electrolytic cap is made as usually as an coil, and it have many foil turns inside. This mean quite high inductance in the signal path... There are few very expensive caps witch are made other way... Is not in this case we talk about... 105 have absolutely usual isolation caps on that outputs...
Such caps have parasitic inductance, resistance and those parameters are not very stable in time, specially when is to endure enough high frequency signals through... This may be an explanation for that low as possible voltage AC signals may goes through such coupling... The polarisation of such caps it present some parameters for the AC signal in one way (+), and not the same parameters for the signal in opposite way (-)... It is this good for an high fidelity signal which will goes through such caps? I do not think so at all...
Therefore the right design in this area is using non polarised caps...
The AC coupling caps in Oppo design of 105 model are not paralleled (as is to be seen in the presented pictures) with another small capacity caps, but with much better ESR/ESI parameters to improve the high pass of the AC coupling. Is this good for the signal high end spectrum? I do not think so at all...

Maybe are enough arguments for now... But all those thing are well known of the most of they who have something to do with electronics...

[qusp]

Originally Posted by Coris

I will conclude now with an comment to john curl post.
I have now any doubt that the headphone output it may sounds exceptional. This output do not have AC coupling, the headphone channel final chip is very good in parameters (I know how it works...), it have a very high slew rate, and the headphone line it have paralleled 2 of the DAC channels on it... I believe you that it sound best.
I just did it before (in another case): I coupled the headphone out (adapted) to my amplifier. It were a very, very good sound out of that device... I used that connection for a while, but I found out further an even better way to do it... Just removed the headphone final amp chip... I think that all of us can agree with that "rule": less components/processing in the signal path, better that signal at the output.

umm, John speaks of using Electrostatic headphones, lets just say that the headphone out on the BP would not sound very good driving them.... they need hundreds of volts, dunno if John was using an energizer or a dedicated amp, but either way theres no chance the BP had much of a hand in the amplification

the lambda are not my favorite stax, bass response is pretty tame, I prefer O2 MkII

[Coris]

Originally Posted by qusp

umm, John speaks of using Electrostatic headphones, lets just say that the headphone out on the BP would not sound very good driving them.... they need hundreds of volts, dunno if John was using an energizer or a dedicated amp, but either way theres no chance the BP had much of a hand in the amplification

the lambda are not my favorite stax, bass response is pretty tame, I prefer O2 MkII

I must say that I do not have experience with headphones so far... I start to use in the last time Sennheiser IE80 with my Note 2. The performance is quite impressive for both devices... Else I actually prefer to use speakers to listen. In my opinion, when is to use speakers, one feel quite different the sounds than when is only to send it right to the ears... But this it may be another discussion...
No mater what John use to use, the headphone line in BDP105 it may be better than the normal outputs. The design is different and it benefit of more DAC channels than the other outputs. I trust more this output than others...

[qusp]

I do a LOT of headphone listening, i'm pretty involved in headphone audio for work. IE8 are a bit bass heavy for me and I like slightly more bass than neutral with headphones

I agree, just pointing out that it would have had no effect on his opinion. on much of this we are on the same page. no matter how competent these designers are, theyve been muzzled by the lawyers and created a flawed analogue output, each of the 8 internal dacs has a phase and polarity flip and they have a DSP in this thing, it would have been possible for them to use 8 channel mode for the stereo out and cancel the DC completely before the output and still have balanced out, many different ways.

basically they were listening to the advisers, it has nothing to do with cost, a better job could have been done with the output for less money. ruining it for everyone just to cater for people with badly designed 'balanced' amps that have a different input impedance on negative and positive phases, thus causing offset.

but as I mentioned and Coris, even if they had to make that choice, using polar caps was a dumb move... not competent choices even if they are competent designers. there is no upside to that decision

[Extreme_Boky]

Originally Posted by Coris

OK, I will not contradict you about the competence of the Oppo electronic designers. When one meet face to face somebody, can get a more real impression about, than one who did not had that opportunity...
I know well enough how it works in such cases: there are someone else who have almost nothing of technical knowledge, but who decide how the professionals must do it (because costs, and so on). I really feel sorry for the professional people in such situation... But...

BDP95 had not those AC coupling caps on the analogue output, it were 200$ cheaper, and it were all right with the final stage in that DC coupling.
If the design it were done without AC coupling, the resulting cost of BDP105 should be lower (benefit).
This AC coupling do not improve in any way the output stage. This is obviously... It degrade the signal, no matter the caps quality. In this case is not even possible to think to have very high quality caps on that board. It is a cost case, right? And what for use caps there if is better without?
At last it may be used non polarised caps.
I can hardly understand the reason to isolate the output. It is a justification Oppo came out with, that it were reported in few cases (BDP95) that amp input it were disturbed in one way, or it were about offsett on input (!!!) on few of the amps types... So what? Oppo may customize a whole design, production of thousands of its products, degrade the analogue output stage quality on an new player model (which else it come with many others improvements...), only to be adapt it to just few types/cases of amps which it were designed in a very special way?
Such explanation (how it were presented) just do not hold... But anyway...

I will conclude now with an comment to john curl post.
I have now any doubt that the headphone output it may sounds exceptional. This output do not have AC coupling, the headphone channel final chip is very good in parameters (I know how it works...), it have a very high slew rate, and the headphone line it have paralleled 2 of the DAC channels on it... I believe you that it sound best.
I just did it before (in another case): I coupled the headphone out (adapted) to my amplifier. It were a very, very good sound out of that device... I used that connection for a while, but I found out further an even better way to do it... Just removed the headphone final amp chip... I think that all of us can agree with that "rule": less components/processing in the signal path, better that signal at the output.

It could be interesting to hear your opinion (as a beta tester) about the analogue outputs on XLR/RCA... Can you say the same about the player another analogue outputs?

But let`s wait the first reviews, and the firsts owners comments about this disputed subject...

I see highly optimised PCB layout, good ground segregation, steps undertaken towards reduction in cross-talk and... wide, thick PCB tracks that are optimised to produce correct impedance loading with the chosen decoupling capacitors’ values & types -> to provide good power supply rails' decoupling.

The reason for sound coupling capacitors is to provide DC segregation between the source and the amplifier / pre-amp. It had to be done. If you don't like this solution - remove the caps.

Many high end HiFi solutions REQUIRE these capacitors – the owners flatly refuse to use any component in their sound-chain that can cause any potential damage to their bellowed 100K + set-ups… OPPO does not want to be liable for any potential damage to 3rd party equipment AND does not want to bear repair costs under warranty, for their players as the result of direct coupling and potential damage back to the output stages inside the players.

Boky

[john curl]

Coris, I am a capacitor expert, and have long suggested on coupling cap free designs, BUT in the case of the 105, you are in error. The caps are necessary (unfortunately) but they are the best caps for the job that would fit. Ceramic caps would be FAR worse, sonically, and polypropylene caps would be too large.
The ONLY way around the caps is SERVOING, or changing the circuit design, and in my opinion, is not worth the change in performance, at least for this design.

[Erlend Sæterdal]

I think electrolyts are fine if they are god quality. In my I/V stage there is 8 coupling electrolyts 2 for each phase. 10 Vdc on them. I prefer this solution instead a more complicated design. But I still do not like IC in a product like this.

We heard the Oppo 95 in our Hifi Club and nobody wished to buy it. I am pretty sure it is the analog stage.

[Erlend Sæterdal]

Originally Posted by Coris

I must say that I do not have experience with headphones so far... I start to use in the last time Sennheiser IE80 with my Note 2. The performance is quite impressive for both devices... Else I actually prefer to use speakers to listen. In my opinion, when is to use speakers, one feel quite different the sounds than when is only to send it right to the ears... But this it may be another discussion...
No mater what John use to use, the headphone line in BDP105 it may be better than the normal outputs. The design is different and it benefit of more DAC channels than the other outputs. I trust more this output than others...