Tube Tech MMC 1A MIC User Manual

TUBE-TECH MMC 1A

Mic-preamplifier and Multiband Compressor

Description:

The TUBE-TECH Mic-preamplifier and Multiband Compressor MMC 1A is a combined
microphone and DI preamplifier, a separate balanced line input and a three-band optical
compressor intended for recording directly to any recording media.

Mic -preamplifier:

The microphone preamplifier consists of a microphone input transformer (with a static screen)
with a step-up of +10 dB, two dual tube preamplifiers with a stepped gain switch, with
10dB/step (+20 dB - +60 dB) giving a total gain range of +20dB to +70dB.
The microphone input is provided with a switchable -20dB attenuation (PAD), switchable +48V
phantom-power, a phase reverse and has swithable input impedance (600, 1200, 2400 Ohm).

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, DI and line input is switchable between off, 20 Hz
and 40 Hz.

All inputs have a common stepped gain switch with 2dB/step (-10dB - +10dB).

Compressor:

The signal is fed to the two x-over networks, each made with a single RC circuit thereby
preserving optimum summation of the three bands at the output.
The x-over frequency between the low band and the mid band is variable from 60Hz to 300Hz
or 240Hz to1200Hz and the x-over frequency between mid band and the high band is variable
from 1,2kHz to 6kHz.

The signals from the three bands are then fed to the three separate side chain circuits, each
common for left and right channel. After processing, the three signals are fed to a gain control,
separate for each band and thereafter summed and send to the output gain, controlling the
entire output level for all three bands.
The compressors are of the optical device type. It has controls for ratio, threshold, attack and
release.

(050610)

Lydkraft ApS

Mose Allé 20, DK2610 Rødovre

Denmark

1

MIC-PREAMPLIFIER CONTROLS:

GAIN: The gain switch has a range from +20dB to +60dB in steps of 10dB.

IMPEDANCE: There are a selecting of three input impedances: 600, 1200 or 2400 Ohms.

PHASE: Reverses the phase of the mic input only.

PAD: This switch selects between 0dB or -20dB attenuation in front of the

microphone transformer.

PHANTOM: The +48V DC is supplied to the microphone input via two 6,81 Kresistors.

DI: The Direct Input is an unbalanced, high impedance input intended for various

instruments.
It goes directly into the mic-preamplifier (bypasses the input transformer)
and has a gain range of +10dB to +60dB

MIC/LINE: Switches between Mic/DI and the separate line input on the rear panel

LOW CUT: The highpass filter is selectable between off, 20 Hz (12dB/octave) and

40 Hz (6dB/octave).

MIC/LINE GAIN: All input have a commen gain switch with 2dB/step (-10dB - +10dB)

COMPRESSOR CONTROLS:

X-OVER LOW: Controls the frequency between the low band and the mid band.

Continuously variable from 60 Hz to 300 Hz

x4: Multiplies the “x-over low” frequency by 4, giving a frequency of

240Hz to 1200Hz

X-OVER HIGH: Controls the frequency between the mid band and the high band.

Continuously variable from 1,2 kHz to 6 kHz

RATIO: The ratio control varies the ratio by which the input signal is compressed.

If the ratio selected is 2:1, and the input signal increases 10 dB, the output
signal is only increased by 5 dB.
The ratio control is continuously variable from 1,5:1 to 10:1.

(041121)

2

Lydkraft ApS

Mose Allé 20, DK2610 Rødovre

Denmark