Topic: Modified C521BEE

[Music4Life]

Did anybody here who has this CDP or other brand/model tried to do
this mods?

Replace the stock OPAMP (NE5532 & LM6172) with OPA 627 with brown dog
adapter.

Any experience/review or comments. Thank you.

[rascal101]

All I can say is that this op-amp is way better than the 5532 or 6172. The specs are better and validated subjectively on various CDPs. You can try other Burr Brown or rather TI (Burr Brown was bought by TI), OPA2604, OPA2132, OPA2107 of which are dual op-amps. I believe the OPA2107 belongs to the same product family as the OPA627.

You can refer to this site ...

http://tangentsoft.net/audio/opamps.html

Based on experience, only other mod that I would agree doing for a CDP when warranty runs out.

[s2kov]

mas ok ba opa2107 sa opa627?

All I can say is that this op-amp is way better than the 5532 or 6172. The specs are better and validated subjectively on various CDPs. You can try other Burr Brown or rather TI (Burr Brown was bought by TI), OPA2604, OPA2132, OPA2107 of which are dual op-amps. I believe the OPA2107 belongs to the same product family as the OPA627.

You can refer to this site ...

http://tangentsoft.net/audio/opamps.html

Based on experience, only other mod that I would agree doing for a CDP when warranty runs out.

[rascal101]

To date, have tried OPA2107, OPA2132, OPA2134 and OPA2604. Subjectively, the OPA2107 is the best although I settled with the OPA2132.

[Music4Life]

Is the OPA 2107 a drop in replacement?
No extra parts needed?
How many IC's do I need to replace on my c521?
Where can I buy it?
How much?
Compare to the current stock setup, will there be a dramatic change in terms of sound quality? Please specify. Sorry for so many questions. Thank you.

[rascal101]

It is a drop-in replacement. You need two of these. Where to buy? RS Online or Farnell. Cost? I don't know.

Fortunately for me, didn't have to spend. TI sent to me a number of op-amps (OPA2132, OPA2604 etc etc) as free samples.

Sound improvement, I'd say from a 8/10 to a 8.5 - 9/10 (very subjective).

[rascal101]

If you want more dramatic improvements, you need to modify the op-amp stage circuit. This one though, you need a PCB and at least 4 op-amps.

For my old Sony CDP-M11, I traced out the schematic and removed the entire op-amp section including the filter circuit. Used recommended circuit from Sony application note. For reference see http://pinoydvd.com/board/index.php?topic=43433.0. You will notice, on the first picture at the bottom right 2 PCBs sticking out. This is the change that I did. I don't recommended it but should you want to go this way I can provide you with more information.

BTW, I had the op-amp section modified because Sony high end CDP X33ES and 555ES uses same DAC CXD2552BQ but only differs in their buffer amp + filter circuit implementation and use of expensive Elna caps.

[Music4Life]

If I replace the 2 stock opamp to OPA2107, what will be the upside and downside of this mods?

Will there be a cleaner sound? Less or more Bass? Too bright or too dark? Will there be complications in terms of voltage changes?

Pros? Cons? Thanks.

[Music4Life]

Another thing is, there is the OPA2107AP and
OPA2107AU.

What version do I need?

[rascal101]

To my ears, music is a bit more alive. Can't comment beyond that because after I did all the internal electrical circuit mods, I pursued a different track - external electrical circuit mods. I was still not contented with the sound and I thought the other proposed mods - vibration dampers, 75ohm termination at dig out etc are a complete waste of my time  They only look good in the forum or on paper. Straining my ear at 2am in the morning is not exactly what I call improvement. If there is improvement, I should hear during normal hours on a relatively quiet day. And verifiable by a comment from a female or double blind test.

You need the OPA2107AP which comes in the PDIP-8 (plastic dual in line) package. The OPA2107AU comes in SOIC-8 (small outline integrated circuit - this is surface mount) - not normally what is placed in a CDP or DVD.

Specs wise, max input voltage is +/-18V which is beyond what is typically supplied to this IC which is +/-12V. The offset voltage and bias currents are quite low. The slew rate is quite high at 18V/uS. The 5532 I believe is < 5V/uS.

Pros - good technical specifications, Cons - a bit expensive (may hover around the Php 600 - 800 per pc - could be higher, not 100% sure of this though).

[7Even]

OPA2107AP is 1,215 pesos in RS Philippines.

[rascal101]

Well, well, well ... that's the reason why I sold the OPA2107 samples and settled with the OPA2132 . I made some money and doing an upgraded differential circuit from Sony application notes I thought would be better than just doing an OPA2107 replacement. Of course, it also meant more work and, increased chances of making a very big mistake  . Anyway it was a 1991 CDP so I had nothing to lose ... Ok ok ... a few hours of sleep  .