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Thread: Marantz cd50 distorted unclear audio after mod

  1. #1
    Join Date: Nov 2011

    Location: Gold Coast - Australia

    Posts: 78
    I'm Sam.

    Default Marantz cd50 distorted unclear audio after mod

    I had a spare CD50, that i messed up the traces a little and repaired. Anyway, i was happy that I least got some distorted sound out of one channel.

    Mind you, i had to use some old opamps that I left in the with a box of throw outs, ? could they be damaged or some issue with soldering?

    Thanks Sam

    Amps: Technics SU-V9, SU-V8 (black and silver), V8X, V4X ( 2 black, 1 silver) , G50 and SU-500
    Source:Technics SL-P990, P350, P477a,PG440a, Marantz CD40, NEC CD620 - TDA1541A, Philips CD753, Klein DAC, tuner and turntables Technics
    Speakers: Technics SB-6, Coral CX-5, ESM bookself (seas tweeters), Celestion Sl-6 (copper domes)

  2. #2
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,757
    I'm Chris.

    Default Likely singles not duals, or orientation

    Hi Sam
    Best to using some solder wick, de solder the op amps you placed in.
    The technique with solder wick is to wet it with solder , then within about 3
    seconds the solder wick will mop up any excess solder -in the process
    clearing the holes, enabling easy removal. Using turned pin DIP adapters
    you can then choose and trial different opamps with ease ,

    With the player normally in front of you, orientation to place each dual op amp
    back, is Pin 1 facing toward the right, that is furthest from the transport
    toward the right. The small half circle on the op amp indicates Pin 1
    is on the left of the op amp- sometimes indicated with a circle.

    Many options for dual opamp, like LM4562, LM833, LM6172 ,
    with an adapter you are free to trial. A humble TL072 available
    everywhere will confirm the CD50 is otherwise working OK

    With a multimeter you can also check for positive voltage at Pin 8
    and negative voltage at Pin 4. that is with negative probe to the copper ground plane
    Note how well these players were made with respect to grounding
    on the top pcb,

    Cheers / Chris

  3. #3
    Join Date: May 2008

    Location: Surrey

    Posts: 7,103
    I'm Rob.

    Default

    I had this recently with my CD63. I was awaiting some Burson discrete op-amps and fitted some old ones I have had for years. One was ok, but the other sounded dreadful, distortion etc. Not sure what had happened to it before I put it away. I always put 8 pin DIL sockets in if I am intending to op-amp roll do you don't have to keep soldering and de-soldering.
    Buy Bose...And get your parking validated!.

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  4. #4
    Join Date: Nov 2011

    Location: Gold Coast - Australia

    Posts: 78
    I'm Sam.

    Default

    Hi Chris,
    I found my DIP adaptors, so I can swap opamps. Only have 1 new OPA2134, which I was going to use for my phonostage in my amplifer but decided to put a LME4990860 instead.

    Thanks for the solder tip, i couldve killed or damaged the old ones getting them out with heat. I remember the direction of the opamps, LME/LMs have a little indent, I noticed some smds just writting or a slash.

    Jaycar, which I think is also in NZ, stock opamps, like the TL072. LM833N etc. For now I could use one new one? or would i need 2 to check?

    The Test the RCAs can be ground also?

    Thanks Regards
    Sam

    Quote Originally Posted by Light Dependant Resistor View Post
    Hi Sam
    Best to using some solder wick, de solder the op amps you placed in.
    The technique with solder wick is to wet it with solder , then within about 3
    seconds the solder wick will mop up any excess solder -in the process
    clearing the holes, enabling easy removal. Using turned pin DIP adapters
    you can then choose and trial different opamps with ease ,

    With the player normally in front of you, orientation to place each dual op amp
    back, is Pin 1 facing toward the right, that is furthest from the transport
    toward the right. The small half circle on the op amp indicates Pin 1
    is on the left of the op amp- sometimes indicated with a circle.

    Many options for dual opamp, like LM4562, LM833, LM6172 ,
    with an adapter you are free to trial. A humble TL072 available
    everywhere will confirm the CD50 is otherwise working OK

    With a multimeter you can also check for positive voltage at Pin 8
    and negative voltage at Pin 4. that is with negative probe to the copper ground plane
    Note how well these players were made with respect to grounding
    on the top pcb,

    Cheers / Chris
    Quote Originally Posted by Puffin View Post
    I had this recently with my CD63. I was awaiting some Burson discrete op-amps and fitted some old ones I have had for years. One was ok, but the other sounded dreadful, distortion etc. Not sure what had happened to it before I put it away. I always put 8 pin DIL sockets in if I am intending to op-amp roll do you don't have to keep soldering and de-soldering.
    Hi Rob
    Good news i found my dil socket adaptors, so I can swap in a new OPA2134 ( only 1) or use the LM4562 out of the board of a CD84 player which is a part machine now I have the working CD74, since you experienced the same, i hope that swapping will solve the problem

    Amps: Technics SU-V9, SU-V8 (black and silver), V8X, V4X ( 2 black, 1 silver) , G50 and SU-500
    Source:Technics SL-P990, P350, P477a,PG440a, Marantz CD40, NEC CD620 - TDA1541A, Philips CD753, Klein DAC, tuner and turntables Technics
    Speakers: Technics SB-6, Coral CX-5, ESM bookself (seas tweeters), Celestion Sl-6 (copper domes)

  5. #5
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,757
    I'm Chris.

    Default

    Hi Sam
    You will need both opamps in place, suggest 2x LM833 until you
    get a more exotic pair. The LM833 is actually very good and will
    surprise you just how good.

    Yes you can use the RCA as a ground for testing, Remember
    to have your meter set for ohms before attaching probe.
    Ohms setting on your meter being very high impedance.

    Cheers / Chris

  6. #6
    Join Date: Nov 2011

    Location: Gold Coast - Australia

    Posts: 78
    I'm Sam.

    Default

    Hi Chris,
    I just got some cheap TL072s with a cheap adaptor socket from Jaycar, sound - no audio but cracklling popping sound. I hope I didnt fry the TDA or something, as I was re doing the NOS, though least there is some sound i guess. I will check soldering or try to revert back to non NOS on the TDA.

    LM833N in the Technics SL-P477A is awesome sounding with the slimcII 2 upgrade. I only forgot to replace the 2 bipolars - 22uf 16v, , only ES i have is 100uf 35v, which I think wouild be too much capacitance /voltage maybe.

    http://theartofsound.net/forum/showt...ich-to-changer

    Thanks
    Cheers
    Sam

    Amps: Technics SU-V9, SU-V8 (black and silver), V8X, V4X ( 2 black, 1 silver) , G50 and SU-500
    Source:Technics SL-P990, P350, P477a,PG440a, Marantz CD40, NEC CD620 - TDA1541A, Philips CD753, Klein DAC, tuner and turntables Technics
    Speakers: Technics SB-6, Coral CX-5, ESM bookself (seas tweeters), Celestion Sl-6 (copper domes)

  7. #7
    Join Date: Feb 2014

    Location: Huntingdonshire

    Posts: 1,413
    I'm Andrew.

    Default

    When doing the nos mod did you remember to add the mute link and lift pin 11 on the SAA7210?

  8. #8
    Join Date: Nov 2011

    Location: Gold Coast - Australia

    Posts: 78
    I'm Sam.

    Default

    Hi Andrew I did add the mute link cable, but the 34 spc is very brittle and breaks, so maybe another wire. Currently I have no sound from it since the other opamps it was making a loud buzz. I might end up keeping it for parts - laser

    Amps: Technics SU-V9, SU-V8 (black and silver), V8X, V4X ( 2 black, 1 silver) , G50 and SU-500
    Source:Technics SL-P990, P350, P477a,PG440a, Marantz CD40, NEC CD620 - TDA1541A, Philips CD753, Klein DAC, tuner and turntables Technics
    Speakers: Technics SB-6, Coral CX-5, ESM bookself (seas tweeters), Celestion Sl-6 (copper domes)

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