Hi all,
I scored a Marantz CD94 from UK and seems to be a non modded unit. Still has the old capacitors intact with no leak and performs well. I am thinking if upgrading opamp to OPA626AU would give a significant improvement. The reason I ask if the op amps for 4 is around 100 dollars. I also have Burson V6 but only 3 (took it for Xonar Essense audio card) so what option would you go. OPA627 or buy one more burson v6 and go all out? Thank in advance
I scored a Marantz CD94 from UK and seems to be a non modded unit. Still has the old capacitors intact with no leak and performs well. I am thinking if upgrading opamp to OPA626AU would give a significant improvement. The reason I ask if the op amps for 4 is around 100 dollars. I also have Burson V6 but only 3 (took it for Xonar Essense audio card) so what option would you go. OPA627 or buy one more burson v6 and go all out? Thank in advance
If you leave out the low-pass filter, you need only two opamps.
I use 2 x OPA627 class-A biased, it works well.
I use 2 x OPA627 class-A biased, it works well.
Thank you lcsaszar. I am still amateur so can you help me which ones in the board are low pass filter one. I also tried looking on how to bias but didnt get much sucess. Could you share the steps. If I use discrete opamp do i still need to bias it? also what do i lose if I dont change the low pass filter opamp. thank you
Why not leave it standard and preserve value, and only fix when it needs fixing? Just my serving suggestion.
Noted. Just that seeing so many praising this with all the mods I get tempted. My experience in DIY is building nigel speed controller for lenco l75 which I got from europe. Had to do it to use in US. Due to age I got feedback that I will benefit from recap but I would still keep it stock until I see any cap bulge or leak. I think just adding IC socket would help me in future rolling. I wont touch TDA1541 for now. I have the non A version.
The LP filter is usually the second opamp in each channel. Class A biasing is essentially forcing higher idle current through the output stage. I used a 1.5k resistor between the output and negative supply. The effect is marginal.
Don't expect ground-shaking differences... The improvement is likely to be more in minor details.
You could also use LM49720 or LT1028 too.