OPA275 is a JFET input opamp and it sounds decent. OPA2604 is not an improvement. Maybe replacing them is not a very good idea ? I would never replace them for bipolar types for offset reasons. Although I never use sockets maybe it is a good idea to use those in this machine to try stuff out without damaging the PCB.
BTW muting transistors really have influence on sound quality as capacity varies with voltage on them. Removing them will give better results in most cases. Micro-relays are way better but they're too slow when uncorrectable errors occur. They are good for muting power on plops and clicks though. Good thing is that they connected emitter to signal lines. I have seen worse.
My advice is to replace the output caps for MKT ones with 5 mm pitch like the Wima MKS2-XL types. Worthwhile upgrade, better than most electrolytic caps.
BTW muting transistors really have influence on sound quality as capacity varies with voltage on them. Removing them will give better results in most cases. Micro-relays are way better but they're too slow when uncorrectable errors occur. They are good for muting power on plops and clicks though. Good thing is that they connected emitter to signal lines. I have seen worse.
My advice is to replace the output caps for MKT ones with 5 mm pitch like the Wima MKS2-XL types. Worthwhile upgrade, better than most electrolytic caps.
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Hi Jean-paul, what would be your advice regarding those transistors : keeping them or removing them ? They are smd transistors.
I was planning some Elna ARS-A (super gold) 100uF or some Elna Cerafine BP 10uF. Do you think Wima should better them ? In this case what value should be fine ?
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Hi, I always remove them but be prepared that if you have scratched disks you can hear severe clicks/plops. Since I am cautious with all my stuff it was never a problem in my case. I would add a small relay for muting the outputs at power on and off.
I prefer MKT/MKC/MKP film caps over electrolytic caps anytime (except when they're BG). They never need replacement as there is no electrolyte that dries out.
MKS2-XL exist in 10 uF. I have bought the very last batch of MKS2-XL 22 uF 16 V a few years ago from Wima and use those with good results. Largest cap with 5 mm pitch in the world !
I prefer MKT/MKC/MKP film caps over electrolytic caps anytime (except when they're BG). They never need replacement as there is no electrolyte that dries out.
MKS2-XL exist in 10 uF. I have bought the very last batch of MKS2-XL 22 uF 16 V a few years ago from Wima and use those with good results. Largest cap with 5 mm pitch in the world !
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