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Opamp upgrade to Technics SL-P990 cd player

Sam Mcdonald
Intellectual 330 points
Other Parts Discussed in Thread: LM4562, OPA2604, OPA1652, OPA1642, OPA1612, PCM56

Hello,

I have a Technics SL-P990 CD player with a few opamps. The service manual mentions the operational amplifers, though a Japanese website said the opamps were "Op-amp "M5238FP" Mitsubishi made in I / V conversion" . Which would be most suited to replace this opamp and which should I change?

I have some LM4562 smds spare, but there could be some better ones suited to the above opamp

Thank you

Sam

from the service manual

IC805,806,807, 808 are IC Buffer AMP M5238FP

IC 809, 810 are IC Amplifer NJM5532 ( near adjustment screws)

IC 811,812 are IC Filter NJM5532

IC 813, 814 are IC Amplifer M5238FP

  • 0
    TI__Guru* 93105 points

    Hi Sam,

    TI does have a line of precision audio op amps specified for high-performance audio applications. Likely, there are some that will provide a higher level of performance than you may be receiving from the original op amps. Since I don't know what you are specifically after in terms of better ones, I think that you may be best qualified to review the amplifiers and make a selection. I am providing you with a link to our webpage that has the audio op amp selection guide:

    I hope this is useful to you.

    Regards, Thomas

    PA - Linear Applications Engineering

  • 0 in reply to Thomas Kuehl
    Intellectual 330 points

    Hi Thomas
    Thank you for your reply and links.
    I was able to find a pdf on the orginal op amps. they are j-fet. They op amps are in IV conversion whatever that means. Maybe another TI JFET would be good, like the OPA2604 or whatever suits the IV conversion and orignal
    pdf1.alldatasheet.com/.../M5238FP.html

    Thank you
    Regards
    Sam

  • 0 in reply to Sam Mcdonald
    TI__Guru* 93105 points

    Hi Sam,

    The OPA2604 is an earlier generation TI/ Burr-Brown audio operational amplifier. Some of our newer amplifiers will probably provide higher performance; lower noise, lower distortion. Take a look at the OPA1642 and OPA1652 JFET audio op amps. They might be a good choice:

    www.ti.com/.../OPA1642

    Regards, Thomas

    PA - Linear Applications Engineering

  • 0 in reply to Thomas Kuehl
    Intellectual 330 points
    Hi Thomas,
    The OPA1642 would be a great choice in the iv conversion and it seems to be good with the old M5238 similar specs, but much better. It appears the OPA1642 is liked for it superior sound. Last time you helped with with my phonostage. I ended up using both OPA1612 and in another amplifer the OPA1642. I will just work out which ones to replace in the cd player.

    Thanks again
    Regards
    Sam
  • 0
    Prodigy 10 points

    Sam...

    Great project... I did the same thing to my SL-P999.  Do you have an original remote for the 990?  If so, Is it a EUR64729?  If it is, is there any chance of getting you to download the hex codes from the remote so they can be converted and loaded into a universal remote? You can contact me directly at:  thx1326@swbell.net.

    Thanks in advance... good luck with the project!

    PS... I might also suggest that you replace PCM56P DAC's with BurrBrown PCM61P's.  Drop in replacement.  More airy and better soundstage and a bit quieter.

  • 0 in reply to David Sherfy
    Intellectual 330 points
    Hi David,
    Thank you for the reply. I write to your email, and yes i have two P990 players, one remote doesnt work, but model numbers are EUR64713 for both remotes? if that helps. I have no idea how to download hex codes.

    Thanks for the tip but i cant find any PCM61Ps are mouser, i was amazed they still had the pcm56 there. Pretty damn good players the high end Technics.

    Regards
    Sam.