I feel a bit obliged to comment here as it appears SOME of your intial comments may have come from my responses to your previous posts (although seriously misquoted).
The CA audio products (like many others) use IC opamps (monolythic integrated circuits) in their analog output stages. From my direct listening experience, some of the criticism leveled at the CA CD players (like the 840C I own) of "bright" sounding sonic signatures may be directly related to these opamps. If you feed the digital output (upsampled or native) to an outboard D/A with a well designed class A discrete component analog output stage, many of these sonic abberations are abated. In the 840, CA uses the OPA 2134 series opamp which is considered by many to be a mid level amplifier. My comments are limited to the CA 840 with which I have direct experience. By the way, I have noted similar characteristics in an Parasound P3 preamp which uses similar OPA2134 opamps. There is considerable info on the sound of opamps in the headphone community if you want to see how many audiofiles view and rank various opamps. The 2134s are considered medeocre at best.
The biasing in opamps is typically never Class A due to power consumption considerations (more important to the vast majority of opamp users not in high end audio). The need for these amps to drive low impedance loads almost always requires them to employ class AB output stages. IMHO these will never sound as good as a WELL DESIGNED pure class A discrete stage. I am not alone in this opinion. Just ask John Curl what he thinks of IC opamps as high end audio devices.
Regarding the swapping of opamps, this may or not be easy or possible. Firstly, the opamps in the CA products are surface mounted. R/R these amps requires special desoldering equipment to keep from destroying the pc board. They are not mounted in the familiar 8 pin DIP sockets or packages. Secondly, replacing a lower bandwidth IC like the 2132/4 with a very high speed version like the 627 may create severe oscillation problems due to the very high bandwidth of the 627. The bypassing and power supply layout suitable for a 2132 may not prevent oscillation if a 627 is used in its place. So be careful of mods that might look good on paper but be a dissaster in practice.
And, just because a circuit is discrete does not make it necessarily superior to an opamp. I am refering to the Burson "discrete" opamps which have been measured and found to have significant distortion. Much worse than even the 2134 and particularly inferior to the 627/637 series.
The CA audio products (like many others) use IC opamps (monolythic integrated circuits) in their analog output stages. From my direct listening experience, some of the criticism leveled at the CA CD players (like the 840C I own) of "bright" sounding sonic signatures may be directly related to these opamps. If you feed the digital output (upsampled or native) to an outboard D/A with a well designed class A discrete component analog output stage, many of these sonic abberations are abated. In the 840, CA uses the OPA 2134 series opamp which is considered by many to be a mid level amplifier. My comments are limited to the CA 840 with which I have direct experience. By the way, I have noted similar characteristics in an Parasound P3 preamp which uses similar OPA2134 opamps. There is considerable info on the sound of opamps in the headphone community if you want to see how many audiofiles view and rank various opamps. The 2134s are considered medeocre at best.
The biasing in opamps is typically never Class A due to power consumption considerations (more important to the vast majority of opamp users not in high end audio). The need for these amps to drive low impedance loads almost always requires them to employ class AB output stages. IMHO these will never sound as good as a WELL DESIGNED pure class A discrete stage. I am not alone in this opinion. Just ask John Curl what he thinks of IC opamps as high end audio devices.
Regarding the swapping of opamps, this may or not be easy or possible. Firstly, the opamps in the CA products are surface mounted. R/R these amps requires special desoldering equipment to keep from destroying the pc board. They are not mounted in the familiar 8 pin DIP sockets or packages. Secondly, replacing a lower bandwidth IC like the 2132/4 with a very high speed version like the 627 may create severe oscillation problems due to the very high bandwidth of the 627. The bypassing and power supply layout suitable for a 2132 may not prevent oscillation if a 627 is used in its place. So be careful of mods that might look good on paper but be a dissaster in practice.
And, just because a circuit is discrete does not make it necessarily superior to an opamp. I am refering to the Burson "discrete" opamps which have been measured and found to have significant distortion. Much worse than even the 2134 and particularly inferior to the 627/637 series.