High-Level
Hookup
The auxiliary inputs are high impedance. Thus you may use any input as a source for the MP-3. If you
are using a low impedance source, a low impedance termination is recommended for better sound. A
single-ended source can also be used, by applying the signal between either pin two or pin three of the
input XLR, and ground. The unused input (pin three or pin two, respectively), may have to be shorted out
to prevent noise. Pin two of all the XLR inputs is the noninverting input, per industry standard.
The tape outputs are high impedance. Use a high-quality cable for best results and keep the cable as
short as possible. The minimum drive impedance is 20K-ohms. The tape 2 output is inverted while tape 1
is non-inverted.
The tape monitors are a single-ended, non-inverting, high impedance input.
MP-3 tube locations
NOTES ON TUBES
1) The 12AT7s in the upper left of the board are the most critical
6) NEVER use Tweek® on vacuum tubes.
for low noise phono operation.
7) Long live analog!
2) The constant current source tube is outside of the signal path.
3) Matched sections in the 12AU7 of the high level section will
reduce DC offset during operation of the front panel GAIN TRIM control.
4) Tube damping rings are recommended.
5) Do not remove tubes while unit is operating. Hazardous or lethal voltages are present!