Enhancing DVDs & CD Players performance - Modifications

[Hari Iyer]

Always wondered the difference between an entry level DVD player and an top-of-the art DVD players & CD players.

I have taken the example of my Pioneer DVD player DV-373-S as most of my analysis is based on this DVD player.

Looking at the circuit diagram of the DVD player you can see that the DAC used in this DVD is PCM1742 from Texas Instument (Burr-Brown). But if you carefully analyze the data-sheet of this chip it is again 24bits/192KHz DAC but other specifications are,
Dynamic Range - 100dB, Signal to Noise Ratio - 100dB, THD-0.02%, (refer attachments for more details).
Further analysis of advance chip in this series are PCM1792 again a 24bits/192KHz DAC with specification like,
Dynamic Range - 129dB, Signal to Noise Ratio - 127dB, THD-0.0004%, (refer att achments for more details).
Hence the PCM1792 is a better chip in various aspects compared to PCM1742 in performance.

Also looking at the DVD ckt diagram you can see that the output of the DAC goes as the input to an OP-AMP (Operational Amplifier). The Pioneer DVD uses a op-amp BA4560 which is a very entry level op-amp with very modest specification. Further analysis of other high quality op-amps will give you excellent performance for e.g. the LM4562 from National semiconductor chip. I have attached the datasheet for all the modifications suggested.

Caution: The PCM1742 (16 Pin) and the PCM1792 (28pin) are not pin compatiable and also the associated circuits are required to be changed as the PCM17412 gives a voltage output directly but the PCM1792 gives a current output which needs to be converted to voltage output. This conversion circuit is also provided in the datasheet. You will also need to map the pins from PCM1742 to PCM1792 and also provide dual power-supply for the op-amp (the pioneer DVD used a cheap single supply option for the op-amp). These modifications will have to be done separately on a add-on PCB and the wires soldered to the DVD PCB and connected by a connector to the modified PCB.
The above activity is a skilled activity which only a experienced DIY can only take because most of the components are surface mounted and will require skill soldering and DIYers should be proficient in circuit analysis, digital design, Linear circuit design and the likes. But as information sharing point of view i can tell that most of the higher-end product only have this basic difference between the entry level and the high-end level and nothing else. The above modification will cost not more than Rs.3000/- including the (DAC chip - 1no, op-Amps - 4 nos, passive componetns - resistor, capacitors, voltage regulators etc, & PCB). Considering the cost of a high end DVD and the entry level DVD this is a fraction of the cost. Again a caution do not attempt these modification without knowledge of the internals. You could end up ruining the existing player or even a possibility of an electircal shock as most of the players used SMPS supply and the primary is not isolated from the mains.

Cheers,

 

[Hari Iyer]

adding attachments

 

[captrajesh]

Thank you for heeding to my suggestion Hari Iyer.

My another humble suggestion is to also include entry / mid level CDPs

 

[jls001]

The whole idea of Lampizator rests on the same thing you found out. That the DAC chips are mostly good. In fact Lukasz Fikus of lampizator fame has listed a huge number of high-end and low-end CD players using the same DAC chip. It is the difference in the analog portion of the circuit that makes the sonic difference. The ideas in Lukasz Fikus Lampizator make for very interesting reading, and the circuits suggested are directly implementable for people with sufficient circuit skills.

 

[kpn]

Okay what if a micro controller is controlling the DAC chip, so by changing the DAC chip like what you are saying, will it give a better performance, or the micro controller also has to be replaced with a new one and has to be reprogrammed. Because certain functions in some DAC chips can only be invoked through software than through hardware.

 

[spirovious]

Nice work done Hari.

 

[keith_correa]

Has anyone tried biasing the opamp into Class A?

 

[linuxguru]

Has anyone tried biasing the opamp into Class A?

I've done that on the MyRef Rev C/E monoblock, but not on a CD/DVD player yet.

FWIW, I have developed a Class-A single-opamp module called the LF01 that can use just about any SOIC-8 single-opamp, biases the opamp into Class-A and drives a Class-A discrete output stage. I've tested the LM318, NE5534A and the OPA627AU on the LF01, and they all work fine - however, there may be compensation changes required in the external circuit into which it is plugged.

Most CD/DVD players use a dual-opamp as the I/V converter or buffer after the DAC, so the LF01 won't work there. However, I have a fully-discrete dual-opamp module also under development, for these kinds of applications.

 

[rohitmusic]

Reviving an old thread

Ad I discovered my brother has his Pioneer DV 393 DVD player which I think should be similar to the 373.

What is the easiest way to mod this? I mean without doing too much of soldering etc - can i just swap the dac chip to some better one?

(disclaimer: I have no prior experience modding any dvd player)

Thanks in advance!

 

[rohitmusic]

Any inputs form this thread apply?

1) This DVD uses a 24 bit/ 192KHz DAC of make Burr-Brown chip nbr BB-1742.
2) The output of this chip goes to the op-Amp which is a entry level Dual op-Amp - chip nbr BA4560 of SOIC package. This op-Amp can be replaced by a very high performance op-AMP from National Semiconductor LM4562MA of SOIC package for improving the performance of this player directly.
3) Also noticed that the DC by-pass capacitor used after the op-AMP is 47 microfarad 16v electrolytic capacitor. This shoud be replaced by the same capacitor of Bi-polar type.

Can you suggest some chip for 1)
Can I directly go ahead and replace 2) and 3)

Thanks!

 

[doors666]

why would you put so much of effort and money when most of the dvd players give you digital outs. use an external dac.

 

[rohitmusic]

The real point of excitement here is that we can make a simple/al cheapo/consumer grade DVD player sound "better". That is why would love to try this out.

(I already have a dedicated setup with all components in place. This is just to explore what can be achieved in a very modest cost so more people can cross over to the "HiFi" world.)