PassLabs-X2 preamp.pdf | | PASS
X2 SERVICE MANUAL
REV 2,3
PASS LABORATORIES 24449 FORESTHILL RD. FORESTHILL, CA 95631 TEL (530) 367-3690 FAX (530) 367-2193 www.passlabs.com
The Pass Labs X2 is a high performance audio preamplifier, intended for maximum performance in reproduction of music. It is a simple design, consisting of dual complementary input JFET transistors driving dual complementary MOSFET output transistors connected in the patented Super-Symmetry topology. Figure 1 shows the block diagram of one channel of the preamplifier. There are three unbalanced inputs and one balanced input. The balanced input is converted to single-ended via a differential amplifier. The signal from all four inputs is presented to the Select and Tape Mon switches. The wiper of the Select switch attaches to the input volume control, and its wiper feeds one input of a balanced gain stage. The output of the balanced gain stage is the output of the preamp. The balanced input and balanced output active stages of the circuitry ar |