Please note that SML010FBDH12's Fv of 1.4v is at 10A, at operating currents this would be substantially lower. Also, Silicone Carbide Schottky's generally have zero reverse and forward recovery - this particular bridge is encased in a metal shield - admittedly it can not be easily sourced.... Together with 22000 caps I measure ripple voltage of about 5mv....
Hello,
I didnt want to start a new thread so here i go.
I have an oppo bdp95-eu that starts freezing when playing cd and blu ray. It is mainly used for dvd and blu ray and i only need the simple stereo output.
I can try to open it and see if i can clean the lens ( probably the reason) myself. I can ask for replacement at Oppo dealer here or i can get myself the latest 203.
203 might have some things that are nice but that will not be used. The 95 has a linear power supply for the analoque section so i am not sure the 203 will have better sound without modifications.
I always use choke input power supplies. But i think that will be to tricky to add inside the chassis.
Greetings, eduard
I didnt want to start a new thread so here i go.
I have an oppo bdp95-eu that starts freezing when playing cd and blu ray. It is mainly used for dvd and blu ray and i only need the simple stereo output.
I can try to open it and see if i can clean the lens ( probably the reason) myself. I can ask for replacement at Oppo dealer here or i can get myself the latest 203.
203 might have some things that are nice but that will not be used. The 95 has a linear power supply for the analoque section so i am not sure the 203 will have better sound without modifications.
I always use choke input power supplies. But i think that will be to tricky to add inside the chassis.
Greetings, eduard
My advice is getting a 203 while it still be on market... There is another (advanced) version/generation hardware, firstly. Everything in 203 is new and more performant than it is in 95. And it is 4k native...
Also you can try replacing the whole inside mechanism of your drive, rather than trying cleaning lens. BTW, the cause of your problems it can be very well the laser diode itself, which it got older, or out of parameters. That mechanism is to be found (yet) as kit, sold on Ebay or so. It is original and it works very well. Well, some skills may be necessary for such replacing operation. And courage as well...
Also you can try replacing the whole inside mechanism of your drive, rather than trying cleaning lens. BTW, the cause of your problems it can be very well the laser diode itself, which it got older, or out of parameters. That mechanism is to be found (yet) as kit, sold on Ebay or so. It is original and it works very well. Well, some skills may be necessary for such replacing operation. And courage as well...
AVCC Ripple
Hi Coris. Let me try to understand this. AVCC ripple is ~50mV before ADM7150 regulator and ~40mV after. Assuming AVCC is ~3.3V, then measured ripple is around 0.0012% or ~12 ppm. Is that right? So ripple is low both before and after AVCC regulator.
I think you measured +/-12V rail ripple last year ~200mV before regulators. So would you say the regulators have done ok job bringing 12V to 3.3V for AVCC?
Is there a AZ1117 regulator in between which helped this situation?
Hi Coris. Let me try to understand this. AVCC ripple is ~50mV before ADM7150 regulator and ~40mV after. Assuming AVCC is ~3.3V, then measured ripple is around 0.0012% or ~12 ppm. Is that right? So ripple is low both before and after AVCC regulator.
I think you measured +/-12V rail ripple last year ~200mV before regulators. So would you say the regulators have done ok job bringing 12V to 3.3V for AVCC?
Is there a AZ1117 regulator in between which helped this situation?
Original design is using the +12v rail for AVCC, regulating it directly from 12v to 3,3v. The 8,7v difference it goes in to heat dissipation...
Recently I tried to lower the main DC voltages (original 18v for +/-12v rails), which is the only convenient and reasonable solution to lower the heat dissipation on main regulators. It does not work. Why? Because the whole power system is monitored and controlled by dedicated safety circuits. This is a very good and professional approach, but in this particular case, it is an serious issue.
These monitoring circuits it detect power failure if the main analogue voltage is not as it was designed/programmed to be at 18v, and the device it fail to boot up.
I suspect the designers may being using the big ripple at the power system inputs, somehow in the power management, or monitoring system... It could be an explanation of a such big ripple, which is compensated further by regulators. Well, in a kind of compromise with an acceptable level of quality at the device outputs...
I hope I may find a way to trick the power monitoring circuits, to accept a lower main DC voltage. Not very easy, as it is no any documentation in this field...
Recently I tried to lower the main DC voltages (original 18v for +/-12v rails), which is the only convenient and reasonable solution to lower the heat dissipation on main regulators. It does not work. Why? Because the whole power system is monitored and controlled by dedicated safety circuits. This is a very good and professional approach, but in this particular case, it is an serious issue.
These monitoring circuits it detect power failure if the main analogue voltage is not as it was designed/programmed to be at 18v, and the device it fail to boot up.
I suspect the designers may being using the big ripple at the power system inputs, somehow in the power management, or monitoring system... It could be an explanation of a such big ripple, which is compensated further by regulators. Well, in a kind of compromise with an acceptable level of quality at the device outputs...
I hope I may find a way to trick the power monitoring circuits, to accept a lower main DC voltage. Not very easy, as it is no any documentation in this field...
The 25M Mhz clock it run the optical drive decoder/processor, beside it.
The HDMI interfaces are part of the main processor, which is clocked by 27Mhz. In 205 model, HDMI audio dedicated output is processed by its own (SI) processor, clocked by a 27Mhz resonator, in addition of a SAW 148,5 Mhz oscillator.
The HDMI interfaces are part of the main processor, which is clocked by 27Mhz. In 205 model, HDMI audio dedicated output is processed by its own (SI) processor, clocked by a 27Mhz resonator, in addition of a SAW 148,5 Mhz oscillator.
Indeed, the headphone output it sound very good in a stock device, as in a improved one as well.
The headphone section is enough complex. Many stages, and it have dedicated two of the DAC chip (paired) output channels tied together. First stage it use LM4562. Followed by a OP1632 stage (both fully differential stages). Then it follow a balanced to unbalanced conversion, using the TPA6120A2. In the end, the signal is outputted through a discrete buffer (power) stage.
Even though a so complex design (it was really necessary so many stages?), they could not prevent (or cared too much about) important oscillations which this stage it produce in 30 - 40Mhz range. TPA6120A2 chip is known for its instability, if special design measures are not taken into consideration. Well, Oppo designers had in mind a good (right) idea when they decided to use as feedback signal for TPA6120, the output of the final buffer. In this particular case, such (also right decision) it caused the whole stage to oscillate in Mhz range. These oscillations are of course not audible, but it is healthy, heaving it into a high quality device? I do not think so...
However, the stage it sounds great. In my opinion, this it is mainly because the buffered DC coupling output...
The headphone section is enough complex. Many stages, and it have dedicated two of the DAC chip (paired) output channels tied together. First stage it use LM4562. Followed by a OP1632 stage (both fully differential stages). Then it follow a balanced to unbalanced conversion, using the TPA6120A2. In the end, the signal is outputted through a discrete buffer (power) stage.
Even though a so complex design (it was really necessary so many stages?), they could not prevent (or cared too much about) important oscillations which this stage it produce in 30 - 40Mhz range. TPA6120A2 chip is known for its instability, if special design measures are not taken into consideration. Well, Oppo designers had in mind a good (right) idea when they decided to use as feedback signal for TPA6120, the output of the final buffer. In this particular case, such (also right decision) it caused the whole stage to oscillate in Mhz range. These oscillations are of course not audible, but it is healthy, heaving it into a high quality device? I do not think so...
However, the stage it sounds great. In my opinion, this it is mainly because the buffered DC coupling output...
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Hi Den,
Well, the power supplies (for digital stage) in Oppo devices are designed to be always on (connected to main power, and providing power at its output). The start of the device itself is controlled by its power management (software).
I provide soft start included in my DC blocking filters for important power applications (from 100w upwards), but in this case, for so low power (50w), it is really unnecessary...
Well, the power supplies (for digital stage) in Oppo devices are designed to be always on (connected to main power, and providing power at its output). The start of the device itself is controlled by its power management (software).
I provide soft start included in my DC blocking filters for important power applications (from 100w upwards), but in this case, for so low power (50w), it is really unnecessary...