Tube Tech MP 1A Mic. Preamplifier and DI - Manual

Lydkraft ApS
Mose Allé 20, DK 2610 Rødovre
Denmark
1
TUBE-TECH MP 1A
microphone pre-amplifier
Description
The TUBE-TECH microphone preamplifier MP 1A is a combined two channel
microphone and DI 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 (5dB/step, passive
and 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.
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 for the microphone and the DI input is switchable between off, 20 Hz
and 40 Hz. 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.
040902