Tube Tech EQ 1AM User Manual

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TUBE-TECH EQ 1A, EQ 1AM

Equalizer

Description:

The TUBE-TECH EQ 1A is a full range one channel unit, featuring low and high cut filters with
a slope of 6 dB/octave or 12 dB/octave, low and high shelving filters and three overlapping bell
type bands with variable bandwidth.
The cut filters are designed around unity gain tube amplifiers (cathode follower) and the
shelving and the bell filters are designed around two tube operational amplifiers.
All seven sections have a separate in/out switch.
An all bypass switch is also provided.

The unit is all tube based except for the power supply.
Input and output have fully floating transformers.
All DC voltages are stabilized, except the anode voltage for the output stage.
The TUBE-TECH EQ 1AM has the same features as the EQ 1A and in addition, all pots on the

front panel has been substituted with 12 positions rotary switches, to give better precision and
repeatable settings.

(030507)

Lydkraft ApS

Mose Allé 20, DK 2610 Rødovre

Denmark

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CONTROLS:

LOW CUT:

The low cut section includes a frequency switch, a slope switch and an in/out

switch.

FREQUENCY: The -3 dB point at which the frequency response starts to decline. There are

a choice of six frequencies: 16, 25, 40, 60, 90, 130 Hz.
SLOPE: The slope can be switched between either 6 dB/oct. or 12 dB/oct.
IN/OUT: Switches the frequency dependent network in and out.

LOW SHELVING:

GAIN: EQ 1A: The gain control is continuously variable from 0 dB to 15 dB.

EQ 1AM: The gain control has 12 steps and is variable from 0 dB to 15 dB.

Steps: 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 15 dB

FREQUENCY: There are a choice of six frequencies: 22, 32, 45, 70, 100, 150 Hz.

The frequency where the boost or cut is 12 dB when the gain is at max.
BOOST/CUT: Determines whether the gain control shall be boosting or cutting.
IN/OUT: Switches the frequency dependent network in and out.

BAND 1-3:

GAIN: EQ 1A: The gain control is continuously variable from 0 dB to 20 dB.

EQ 1AM: The gain control has 12 steps and is variable from 0 dB to 20 dB.

Steps: 0, 1, 2, 3, 4, 6, 8, 10, 12, 14, 17, 20 dB

FREQUENCY: There is a choice of twelve frequencies:

Band 1: 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500 Hz.

Band 2: 0.25, 0.315, 0.4, 0.5, 0.63, 0.8, 1, 1.25, 1.6, 2, 2.5, 3.15 kHz

Band 3: 1.6, 2, 2.5, 3.15, 4, 5, 6.3, 8, 10, 12.5, 16, 20 kHz
BW: EQ 1A: The bandwidth control is continuously variable from 0.5 to 2.0.

EQ 1AM: The bandwidth control has 12 steps and is variable from 0.5 to 2.0.

Steps: 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.4, 1.6, 1.8, 2.0
BOOST/CUT: Determines whether the gain control shall be boosting or cutting.
IN/OUT: Switches the frequency dependent network in and out.

(030507)

LYDKRAFT ApS

Mose Allé 20, DK 2610 Rødovre

Denmark