Inquiries of ONKYO T-9090II Tuner

Discussion in 'Tuners' started by rainywind, Aug 25, 2017.

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  1. rainywind

    rainywind New Member

    Messages:
    3
    Hi, I hope someone on this forum might be able to help me.

    Does anyone know:

    What is the function of L001,L002,L003,L004,L005 (Induction coil)and Q001(Triode) in the T-9090II’s circuit?

    What is the function of L107,L159 in the T-9090II’s circuit?

    How to improve the sensitivity and selectivity in these circuit?

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  2. jdurbin1

    jdurbin1 Tandberg enthusiast Subscriber

    Messages:
    8,366
    Location:
    San Diego
    By improve, do you mean modify so as to raise the performance above what the manufacturer provided, or to optimize the adjustments to get the best performance from the existing circuit?

    If the latter, following the procedure in the service manual is the best course: https://www.hifiengine.com/hfe_downloads/index.php?onkyo/onkyo_t-9090_ii_service.pdf

    (note: you'll need to register first, then login in order to access that file - it's free though)

    If you are looking to improve on the original performance, no suggestions... beyond my expertise.

    Welcome to Audiokarma, also!


    John
     
  3. Punker X

    Punker X AK Subscriber Subscriber

    Messages:
    3,880
    Location:
    Panic in Detroit
    Been my experience with this tuner it would be hard to improve, other than changing the ceramic filters. Supplies of those are getting very limited of the good ones. A professional alignment will yield the greatest improvement here. This truly is one of the most sensitive and selective tuners made. Messing with it I feel could be a mistake. Where is room for improvement in the audio circuits to increase fidelity. New opamp and better coupling caps. Beefing up the power supply is also a good idea.

    Coils and amp in the first part of your question are for the RF frontend.

    Data sheet here for the super narrow chip, http://nice.kaze.com/av/LA1235.pdf
     
  4. rainywind

    rainywind New Member

    Messages:
    3
    Thanks John
    My tuner still in very good condition, but I hope that its performance can be further pushed through the improvement of the front end circuit...
     
  5. rainywind

    rainywind New Member

    Messages:
    3
    Errrrrr....
    Has anyone ever applied technologies such as secondary frequency conversion to these tuners?

    secondary frequency conversion in Kenwood L-02t:
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