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    Operating voltage for output section of ST-70

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    SuperB

    Posts : 15
    Join date : 2012-01-01

    Operating voltage for output section of ST-70

    Post by SuperB on Mon Jan 02, 2012 2:25 pm

    Hey!
    Since I want to separate the power supply for driver and output section on the ST-70. And I want to run 440V on the output tubes (EL34), what is the operating current should I settle for 440V.

    Also, I want to put a OPT with 5K primary to replace the A470. What is circuit change require?

    Thanks!

    tubes4hifi
    Admin

    Posts : 1286
    Join date : 2008-11-30

    Re: Operating voltage for output section of ST-70

    Post by tubes4hifi on Mon Jan 02, 2012 3:23 pm

    if you allow 50ma of current for each EL34 output tube, then you'll need a total current of 200ma.
    you shouldn't need any changes for the output transformers, other than possibly fine-tuning the negative feedback capacitor value.

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