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

Yes, that is a definite possibility. But I have not able to find any SAWs @108MHz.

The 74HC4040 is rated 90MHz "maximum operating frequency". I imagine that is input freq. Do they make them higher than that?

I do know this much, we need to come up with a working solution, or else the '105 will be inferior to the '95 - based on what I have here.

Cheers, Joe R.

there is special seria AC usually 50% faster, for example, 74AC4040 is rated 140MHz
 
btw, SAWs oscillators are good enough and only and they aren't best possible on jitter and phase noise, look, for example, at one 100MHz ultra low jitter (compare datasheets) and it's not so expensive (€21.76) farnell SKU - 1904495

also if you need cheap 25MHz TCXO with good frequency stability (jitter - no data) you could look at this one farnell SKU - 2063962
 
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.

John, are you saying that this is the best SACD player you've ever heard?
 
I meant an good quality standard 108 Mhz oscillator (not SAW)...
I think I will try first an upper frequency oscillator than 27Mhz to see what may happen... What about if it function well with 30Mhz and you may find an SAW 60Mhz...? For example.

Only interested in a SAW solution.

106.25MHz "no longer stocked" by Element14, but others may have some. Divide by 4 equals 26.56MHz. Needs a suitable high freq divide chip.

62.5MHz - some may be floating around. But... only if desperate.

I did see a 52.5MHz SAW somewhere, it was listed but not stocked and they are made. divide by 2 equals 26.25Mz.

I have seen nothing else around that is anywhere near suitable. These things are made for mainly high freq operation like microwave, networking, industrial. That may be the problem, but also why it's been ignored for audio - so we look to be leading the rest. It would be nice if we could start something new - and the DIY crowd showing the way that DAC/player manufacturers should be going?

Cheers, Joe R.
 
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I have been actually frustrated many time about those high quality oscillators for audio use, which is very difficult to be found it on the marked, or not produced at all. The providers/manufacturers have an very wide and good marked in audio/video field, but do not produce such things... Hard to understand...
 
No, it is not the best, but it is pretty good.

Hi John

For the money, how can anybody complain? I can't think of anything near the price that offers the same all round value.

Even when people can't afford anything added done, I still recommend Oppo.

But there is potential in them that is not exploited and would add cost. I have clients who heard their '95 first and then got our work done on them, and they are gob-smacked when they hear the difference - and some ask why they couldn't sound like that out of the box? Just not possible.

Cheers, Joe R.
 
My customers feel the same way. Stock the Oppos are good. But after I perform my extensive mods then they go completely nuts. There is a lot of info on my website about modding and a description of the first level of mods for the 105. I will have the advanced mods listed in a couple of weeks. Every single one of the things mentioned all make a sonic difference. Please feel free to use any of my ideas. Even for monetary gain. You too Joe! Enjoy!
 
I have been actually frustrated many time about those high quality oscillators for audio use, which is very difficult to be found it on the marked, or not produced at all. The providers/manufacturers have an very wide and good marked in audio/video field, but do not produce such things... Hard to understand...

The answer is simple. They cannot place part or circuit 3 times price of just a good one 'because they're making money and the mass production is taking a place plus there are some standards around of good and enough quality or needs for some level of performance.

look at price and stated jitter
http://www.taelektroakustik.de/fileadmin/pdf/testberichte/Hifi_News_Review_DAC8.pdf
the jitter is 30ps
ok, it is not correct comparison but anyway:
EPSON SAW oscillator has rms jitter - 3ps
my offered ABRACON oscillator to try instead of EPSON SAW has rms jitter 0.1ps max (bandwidth 12kHz - 20mhZ) if we'll take full bandwidth the value will be worse but it's special oscillator especially for low jitter needs and it's available at farnell
 
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look at price and stated jitter

I say don't look at the price and stated jitter.

May I put it this way, when we originally did I work on the Terra Firma clock (sorry, but I am not trying to advertise here) we came across something that caught even us by surprise. We drove a clock from a servo controlled voltage source and tuned it down to a suitably low, or so we thought, frequency. Then I got the bug and tried it ten times lower, and the improvement was not subtle, but a delay occurred, so you have to wait at least 15 seconds for the voltage to come up to speed. Then we tried ten times lower, and now had to wait quite a few minutes, then finally we went ten times lower still, and this time had to wait from one day to the next... and it further improved. We then had to design something that shortened that time. This was a logistic problem only.

Why am I saying this? Because what we did made no difference to the jitter spec and we heard the same improvement with all kinds of clocks/oscillators, even cheap ones - and it allowed us to clearly hear differences too.

We realised that this all had to be about rock-like stability, absolute pure DC and expunging ultra-ulta-low frequency noise.

The key word is stability.

So when I came across SAW oscillators and the claim that because of their superior stability than conventional oscillators, they can work up to much higher frequencies than conventional types. These are BAW types, although rarely stated if ever stated. It's only that SAW oscillators work very differently that they say they are called SAW.

But can you see that some lateral thinking is being applied here, the notion that the higher you go, the greater the stability required, and what is stability if it is not that of a waveform which is more stable relative to a Ground... DC. Or the result is extremely low frequency noise. It fitted our conceptual thinking aligned to TF.

So when I was this stability highlighted I got that instinctive urge to ask the question and simply ordered and I was suitable floored.

So, to repeat... don't ask about the price or the jitter spec... just try it!

I suspect you won't regret it. Hey, you have little to loose and I might be the one with egg on my face. So, I am the brave one here, OK?

Cheers, Joe

PS: Some time later, Paul Miller in the UK did indeed do a measurement that revealed "low rate, uncorrelated or noise-like jitter" - we contacted him and the equipment was worth a mountain of loot. But it shows it does exist.
 
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You too Joe! Enjoy!

You bet, and the satisfaction you get back is a real bonus too. It seems I get these beautiful bottles of wine quite regularly, somebody gave me a Pinot Noir (from New Zealand) today. I like Pinots. :D

I'm just about to read what you've done to the 105, thanks. Read what you did earlier on the 103.

Cheers, Joe R.
 
Joe Rasmussen

thank you for your patience and having time to explain what you wanted to say by saying use SAW

due to other principles of operation are involved noise has other distribution figure or even different nature all that leads to more dramatic sound advance compared to just to use expensive especially low jitter oscillator 'cause as you researched jitter doesn't always matter
of course, I'll try SAW type, thank you for sharing your experience
 
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Can you or Coris confirm my impression, reading between the lines, that Oppo has left left DC on the outputs, as DC bias to be seen by those caps? That may not be a bad idea as caps generally do better with some DC bias. But, in which case you have to find a way to remove the DC offset and you can't just get rid of the caps, as some seem to have suggested.

My own solution will be the same as the '95 which is DC coupled. The question is whether to sacrifice the headphone amp - I can disable all the I/V ICs, I can run 4x paralleled using jumpers. As these will each see a common 3R3 to ground-plane near DAC (reference point where things cancel), picking up anything stray has to be about as minimal as it gets. I will get same performance as '95 I suspect.

Still would like further confirmation that we are definitely back to 27MHz as was the usual standard in the past with Mediatek/Oppo.

I may possible get my first '105 this coming week.

Cheers, Joe R.

It is very possible to get DC offset 0,000 with right components and right design. The resistors involved in analogue stage after the DAC are crucial. Not at least the right opamps... In production process (producing thousands of PCBs) this is just not possible... Or it may cost the final product a fortune...
I think is not very easy to work around (jumping) the output of the ESS9018 in 105. One do not know what design it may be under the chip or in the internal layers of the PCB. The solution is to lift up all the output pins of the DAC and do another connections. This it may be very risky and involve an very big amount of precise work. I`m not at this moment very sure what procedure is to be followed... In the 95 model the (stereo) outputs were already coupled 4+4...
This mod it seems to me for the moment a very difficult task... It still to be analysed this mod I suppose, to be found it the right way(s).
But at last one may not be very obsess about coupling all together the outputs channels. It may work well as Oppo have designed/assigned the outputs of the DAC chip, if another mods are do it right in another stages... We will see...
 
The stock 105 has no offset voltage before the output coupling cap.....I just measured my unit and all outputs are 5mv or under. The circuit is just the usual: IV converter for each phase and then another opamp to sum. When you sum you get rid of the DC offset (relative to the matching of the four resistors in the summing stage). This is how the 95 was and they used NO coupling caps. You can remove the caps, if you like. The balanced outputs use a differential driver that has reference to ground so has no voltage on their outputs as well. However, it is better to get rid of the summing opamp altogether and use a better IV converter then straight out through a coupling cap...way better. When you sum you are just adding the sound of another opamp and its passive components used (resistors, caps, solder joints). Less is better!

As far as summing more of the outputs together....well, the jury is out on that one. Some find that using them single is best. The traces for all the outputs are usable and if you want you can put them all together....without any surgery or removing of parts. There are many, many more important ways to improve the sound than the possible paralleling of the outputs. Please don't get hung up on one area.
 
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Thanks for infos. 5mV is an very good offset. I still wonder why they use separation caps in this model, if it were just fine as it were (DC coupling) in 95 model...
Else I fully agree: are many ways to improve the player before thinking to sum the output channels. No, I`m not hang on this area. It ware my thoughts, answering/commenting the Joe`s post...

I found it at Digikey an 54 Mhz oscillator (PN 1253-1054-1-ND) which is specified as "Type SO (SAW)"... I can not see in the data sheet something about SAW type... I think I will give it a try anyway to this and another similar one 27Mhz.
 
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Why am I saying this? Because what we did made no difference to the jitter spec and we heard the same improvement with all kinds of clocks/oscillators, even cheap ones - and it allowed us to clearly hear differences too.

Thanks for this, Joe. I just read the related material on your web site. Please correct me if I'm wrong, but it occurs to me that (following your "jitter is analogue" image) that jitter frequency would be (as with analogue waves) inversely proportional to 'wavelength'--in the time domain, presumably the number of clock cycles affected per 'cycle' of jitter (with jitter amplitude being the amount of phase shift per clock cycle). So very low frequency jitter (also called 'wander,' I believe) would, if this model holds, be that which shifts the signal across the largest number of clock cycles. If this is true, then it makes perfect sense that, other things being equal, the lower the frequency of jitter, the more distortion of the signal it would cause. A 1-Hz jitter component would affect, for instance, 44.1 thousand samples of a Red Book CD signal. A two-Hz jitter component would affect 22.05 thousand, etc. The additive effect of several low-frequency jitter components (even allowing for statistical cancelling out of some the huge sum of phase shifts) could, even if jitter amplitude were held constant across the jitter frequency spectrum, result in a potential for dramatic timing errors in signal reconstruction at all audio frequencies. Whereas higher-frequency jitter, affecting comparatively few clock cycles, would be more likely to inflect harmonics/timbre higher in the audio band, and their additive effects would be smaller.

It would be interesting, if adequately sensitive test and clock-perturbing equipment exists, to do listening tests on the effects of injecting different very narrow frequency bands of jitter on the same audio signal (clocked by something like the Rubidium clock), followed by the testing the effects of "stacking" several of those narrow bands of jitter, particularly at relatively low frequencies.

In any case, such a model would seem to confirm both the efficacy of ultra-low noise power supply design and construction (to power the digital circuitry) using known techniques, as well as of the discovery and implementation of clocks with optimum inherent stability (thus synchronous oscillators--rather than PLL--based on SAW devices would be candidates?). Given successful execution in these two areas, then one could look at minimizing sources of random rather than periodic jitter, such as thermal noise, etc.

I'd welcome comments on all the above--I am no specialist in this field and I could be way off base, or this could all be old hat to those in the know, but if it is, I don't think its impact on audiophile gear design has really hit home yet.

Thanks--this my first post, so please set any flamethrowers to "low."
 
PS to the above: I do realize that the actual clocks involved are running in the MHz range, so that a 1-Hz jitter/wander component would actually affect potentially millions of clock cycles, but it would still affect the number of signal samples corresponding to the sampling rate . . . .
 
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Hi Chris
In 95 the output channels of stereo stage DAC it were coupled together 4+4 with common I/V stage and the resulting signal it were amplified accordingly and distributed to XLR and SE outputs.
In the BDP-105's stereo board design, the 4 pairs of DACs in the ESS9018 DAC are allocated as: 1 pair for the RCA outputs, 1 pair for the XLR outputs, and 2 pairs stacked for the headphone amplifier. It seems that every type output it have its own I/V stage.

I looks like the headphone stage benefit most of this design... But let`s not be very obsess of this new stacking of DAC in the last model... It may be good enough. I did not took yet my self an close look on this aspect. Very soon...
 
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