TUBE-TECH MP 2A
microphone pre-amplifier
Description
The TUBE-TECH microphone preamplifier MP 2A is a two-channel microphone and
instrument preamplifier.
Each amplifier consists of a microphone input transformer (with a static screen) with a
step-up of +10 dB, a dual tube preamplifier with a stepped gain (2dB/step passive and
10dB passive/active), an output amplifier with two dual tubes in push-pull and an
output transformer (with a static screen).
The microphone inputs are provided with a switchable -20dB attenuation PAD and
switchable +48 V PHANTOM-power, three selectable input IMPEDANCEs (600,
1200,2400 Ohm), and a PHASE reversal switch.
The microphone input is capable of accepting levels of up to +6 dBU (1.55V) at 40 Hz
without the PAD and +26 dBU (15.5V) at 40 Hz with the PAD, so the microphone input
can be used as a unity gain line amplifier.
The high impedance DI input is unbalanced and placed in the circuit directly after the
input transformer. The gain range for this input is +10dB to +60dB. When in use, the
microphone input is disabled.
A high pass filter (LOW CUT) for the microphone and the DI input is switchable
between off, 20Hz and 40Hz. It is advisable to use this filter in environments with high
levels of very low frequency disturbances.
Gain errors between the two channels are less than 0.5 dB at any gain setting.
The two amplifier circuits are completely separated and the cross talk between
channels is below -60 dB ranging from 20 Hz to 20 kHz.
An Overload indication (RED LED) lights up when the output level exceeds +26 dBU.
(130530)
