I have finished stage 1 of mods to my Pioneer DV-588a DVD/SACD/Divx player. Since I will use the 588 to play DVD-Audio or SACD more often than I will use it for movies, the first mod on my list was an upgrade to the analog audio section.
The 588 uses 3 Burr-Brown PCM1742K DACs. These are 192/24 DACs, compatible only with PCM (not DSD). Thankfully, Pioneer uses the K grade which a spec'd to have 6 dB better S/N and DR, and lower THD than the non-K. These are typical basic budget DACs which have built-in I/V and some analog filtering, and their digital filters are only so-so. Although nobody here would choose these for a DIY project, they are not horrible, and I decided to leave them in place for now. I have bigger battles to fight.
Following the trio of DACs is a trio of dual opamps. The 588 uses a very similar analog section to other pioneer DVD players. Each channel gets a single opamp to perform 2nd order filtering and line-driving duties. The opamps are powered with a single +12 V supply. The virtual ground is generated with a very simple zener voltage reference. The opamps are generic "4560"s (no manufacturer markings). DC blocking caps on the ins/outs of the opamps are 100u/10V and 47u/16V respectively, all generic 'lytics. The filter caps are SMT ceramics, and they are quite small. Sadly, this type of thing is very common. I don't think that I am up to tring to solder the leads of films onto their tiny little solder pads.
My component selection was dictated largely by what I had on hand, since I wanted to do this on the cheap. I replaced all of the coupling caps with Nichicon Muse Fine Gold 47u/16V 'lytics. I replaced the decoupling caps in the analog supplies with Panasonic FCs. I replaced the opamps with much better units. I had considered the BB OPA2132 since I have some, but decided against that since they are FET input and the originals are bipolar. So I chose another TI-made opa to go in there, the ... RC4580. Don't laugh. This is absolutely not a JRC4580. It is a TI-designed and TI-made device intended to have similar specs (and frankly the specs are good) and in-circuit behaviour as the JRC device, so that it can be marketted as a drop-in replacement. But that says nothing about the sound. If you haven't heard the TI RC4580, then I don't want to see any comments about how I should have used this or that instead, or how could I have put such a bad sounding opamp in there. Got it?
Results of the mods: Me likes
. Without the possibility of A/B comparisons, I can't really say much more than that. It sounds good.
Next up:
- Remove muting transistors and reduce output impedance.
- Replace the 27M crystal with a good stable oscillator. Any suggestions?
The 588 uses 3 Burr-Brown PCM1742K DACs. These are 192/24 DACs, compatible only with PCM (not DSD). Thankfully, Pioneer uses the K grade which a spec'd to have 6 dB better S/N and DR, and lower THD than the non-K. These are typical basic budget DACs which have built-in I/V and some analog filtering, and their digital filters are only so-so. Although nobody here would choose these for a DIY project, they are not horrible, and I decided to leave them in place for now. I have bigger battles to fight.
Following the trio of DACs is a trio of dual opamps. The 588 uses a very similar analog section to other pioneer DVD players. Each channel gets a single opamp to perform 2nd order filtering and line-driving duties. The opamps are powered with a single +12 V supply. The virtual ground is generated with a very simple zener voltage reference. The opamps are generic "4560"s (no manufacturer markings). DC blocking caps on the ins/outs of the opamps are 100u/10V and 47u/16V respectively, all generic 'lytics. The filter caps are SMT ceramics, and they are quite small. Sadly, this type of thing is very common. I don't think that I am up to tring to solder the leads of films onto their tiny little solder pads.
My component selection was dictated largely by what I had on hand, since I wanted to do this on the cheap. I replaced all of the coupling caps with Nichicon Muse Fine Gold 47u/16V 'lytics. I replaced the decoupling caps in the analog supplies with Panasonic FCs. I replaced the opamps with much better units. I had considered the BB OPA2132 since I have some, but decided against that since they are FET input and the originals are bipolar. So I chose another TI-made opa to go in there, the ... RC4580. Don't laugh. This is absolutely not a JRC4580. It is a TI-designed and TI-made device intended to have similar specs (and frankly the specs are good) and in-circuit behaviour as the JRC device, so that it can be marketted as a drop-in replacement. But that says nothing about the sound. If you haven't heard the TI RC4580, then I don't want to see any comments about how I should have used this or that instead, or how could I have put such a bad sounding opamp in there. Got it?
Results of the mods: Me likes
. Without the possibility of A/B comparisons, I can't really say much more than that. It sounds good.Next up:
- Remove muting transistors and reduce output impedance.
- Replace the 27M crystal with a good stable oscillator. Any suggestions?
CarlosFM ...Done a bucket full of mods to the 575 that many of us have followed.
After trying several mods around the output stage I opted for a dedicated OPA627 fed with it's own supply,I stopped at the clock due to my pre/power amps need finishing and work as been busy with VOD rollout
The chassis and transport needs some beefing up too but care needs to be exercised not to foul any draw movement.
Here is CalosFM thread.
http://www.diyhifi.org/forums/viewtopic.php?t=205
After trying several mods around the output stage I opted for a dedicated OPA627 fed with it's own supply,I stopped at the clock due to my pre/power amps need finishing and work as been busy with VOD rollout
The chassis and transport needs some beefing up too but care needs to be exercised not to foul any draw movement.
Here is CalosFM thread.
http://www.diyhifi.org/forums/viewtopic.php?t=205
DragonMaster said:
I just looked at the register maps for the two devices and they are identical with the exception that the DSD1702 uses (for DSD purposes) a few of the bits which are "reserved" on the PCM1742. That means that the DSD1702 should be software compatible with the PCM1742.
However, I question the value of this mod. The specs on the DSD1702 are only very slightly better than the PCM1742K. Both list 106 dB DR and SNR. The 1702 betters the 1742 in: THD (0.0015% vs. 0.0020%), Stop-band Attenuation (60 dB vs. 55 dB), Pass-band ripple (+-0.03 dB vs. 0.02 dB). I think that the differences are too small to bother with.
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