Schoeps style transformerless circuit

7 responses

  1. Pablo Rodriguez Reyes | Reply

    Hi Jon, i have a few questions
    What are the symbols of a circle with a cross in the center?
    What about the 12v conection? Where i get that voltage from? Phantom power?
    What is the OSC?


    1. The circles with an x in the center are pads on the PCB. The “12v connection” is a voltage reference. The two 12 volts references are a connected in the ciruit but it keeps me from having to draw a line all over the schematic. Phantom power is delivered via the LXR connections, so it’s not shown on the schematic. OSC is the power connection to the oscillator PCB and has a matching pad on that circuit board.

      1. Pablo Rodriguez Reyes

        Ohhhh okay, thanks, i have to more questions, what about r4 and r5 values?, what is the hole in the XLR1 that have a G? Ground? And the one beat de Bias potentiometer?

      2. R4 and R5 are for a low-pass filter (per the notes on the schematic. They depend entirely on whether you want them at all and what your needs are. G is ground.

  2. Hi Jon, D1 and D2 are zener Diods right? which is the zener tension (Vz), the hole that is below the 1M potentiometer, what is it for?

  3. Small question, what would be the best way to match for hFE? I currently do not own any hardware for testing transistors and I assume the rinky dink 7 dollar component testers or cheap digital multimeters wont be accurate enough.

    1. I make a little circuit on a breadboard. And I doubt that the $7 component tester isn’t accurate enough. If you plug the same component in there twice and it gives you the same reading, it doesn’t matter if the actual number is correct, just that it’s the same relative value as something else that also gives you that number.

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