I am writing to submit my newly finished project below: This is my second Balance Zen pre-amp but is a complete set with casing. My previous project was posted at http://www.passdiy.com/gallery/bzls-p9.htm 1. In this version, I use one regulator to feed both channels. Supply voltage is set to +/-54V due to available transformer is only 55Vac. 2. Due to lower voltage, the current through each IRF610 is about 36mA (not 40mA). Temperature of mosfet is about 65 degC while 750 resistors (white) is about 75 degC. 3. No expensive component used except Rifa 10uF film capacitor for output couple. Total cost of parts (electrical and mechanical) is around USD$170. 4. Input use dip switches and two resistors to select attenution of x1, x0.8, x0.5, and x0.2. This is to adjust input source voltage level so that the output before volume is at about 2-3 Vrms to get best distortion and noise performance. 5. Gain resistor use 510//390 ohm, no pot. 6. Output use 10k Alps volume for each channel. 7. Also no selector as I only use one DAC with balance output. 8. Do not need any shield for transformer like my Aleph P, no hum and very weak noise at max output. 9. Photo show my aleph P on top and Balance Zen at bottom. Regards, Spencer Cheung
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