Pioneer sx 434 grainy sound ?

Discussion in 'Pioneer Audio' started by dadix, Feb 10, 2019.

  1. dadix

    dadix New Member

    Messages:
    38
    Hello .I bought an receiver sx 434 a few days ago but it seems to me that it has a grainy sound. Is this sound Pioneer's sound or is something not working well?
     

     

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  2. kaplang

    kaplang Works for me ! Subscriber

    Problem not the sound you should expect.

    Does it have the same sound for AM , FM or anything hooked to it like a turntable?
     
  3. dadix

    dadix New Member

    Messages:
    38
    Yes. It has the same sound for tuner and amp. I don't have TT.
    All parts are original.
     
  4. ivandezande

    ivandezande Super Member

    Messages:
    1,960
    Location:
    Twin Cities
    It's 40+ years old and untouched, can't say I'm surprised. If it biases and visually looks fine, that's probably how it sounds.
    It has known noisy transistors in it.
     
  5. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    22,226
    Location:
    Glen Burnie Md.
    I've had my 434 from new. Never sounded "Grainy". It did start sounding tired and less articulate about 7 years ago. A transistor replacement of trouble prones in the whole thing, plus capacitors (electrolytics) brought it back to it's normal self. I use it with a pair of Minimus 7's in my RV trailer (it beats the factory installed JVC BPC every which way but loose!) now. There are a few 434 rebuild threads on here, and if I'm not mistaken a recap/transistor parts list thread. It's 45 years old, it's tired, and more than likely needs an overhaul. If you have the opportunity to compare it with a SX-535 or 636 do so. They sound basically the same, just with more wattage. Check the FUSES in the back (inside the rectangular plastic housing) 1st. 250V 3A AGC fuses (fast blow!) These can be gotten at Home Depot or Lowes.

    Service Manual and Schematic HERE. If it's a US (Single Voltage)model it should have a sticker on the back panel with "KCU" on the Back. Get the correct schematic to match. https://www.hifiengine.com/manual_library/pioneer/sx-434.shtml

    Parts list here.
    Transistors part list only. http://audiokarma.org/forums/index.php?threads/pioneer-sx-434-noise-on-both-channels.811021
    Full parts list by Avionic from 2016. http://audiokarma.org/forums/index.php?threads/pioneer-sx-434-cap-list-map.736342/#post-9981580

    I honestly would bump the voltage of the Main Filter caps to 35V as the originals are 25V and the working voltage when new was 24V, and bound to be a little more now with higher voltages. 647-UHE1V332MHD6 is 3300uf 35V in Nichicon with 10000 hour rating, and a little cheaper than the closest comparable Panasonic.
     
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  6. dadix

    dadix New Member

    Messages:
    38
    I realy like the sound of this and now I am looking for an 737 . Is it sound of 737 different than 434 ? More open or cleaner, warmer or better stereo separation or sound stage?
     
    Last edited: Feb 14, 2019

     

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  7. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    22,226
    Location:
    Glen Burnie Md.
    The 737 is more detailed if you want to call it that. Better Tuner, mpx, amps, more options for accessory gear. Think of the 434 as a 6cyl 66' Chevy II, and the 737 as a 66 4bbl small block V-8 Malibu with AC. The 1010 as a 66 or 67 Impala SS with the Big Block 427.

    Basically the whole series sounds similar across the board, with more controls, power and headroom in each succesive model. Features per dollar,(bang for the buck) the 737 is the sweet spot for the x3x series.
     
  8. dadix

    dadix New Member

    Messages:
    38
    So, I have to buy one and decide ...
     

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