M404

MATCHED GA IN: 38db FREQUENCY RESPONSE: +0 . 5db from 2Ohz (effects controls at zero position) EQUIVALENT INPUT NOISE: -l15dbm (1ohz to 100Kh z bandwidth) HARMONIC DISTORTION: Less than 0 . 59 from 30hz to 20Khz (measured at +l8dbm output level) SOURCE IMPEDANCE: 150/600 ohms balanced or unbalanced INPUT IMPEDANCE: 150/600 ohms 10% INPUT LEVEL: -38db nominal, -20dbm maximum LOAD IMPEDANCE 600 ohms OUTPUT IMPEDANCE : 600 ohms (150 ohms available) +10% OUTPUT LEVEL: +l8dbm maximum PHASING: The low terminal number of the input pair and the 1 OW terminal number of the output pair are in phase EQUALIZING CHARACTERISTICS: In accordance with specified curves within 1 0 .

5db POWER REQUIREMENTS: 48 volts dc , regulated from M648 or equivalent 10OmA AMBIENT TEMPERATURE : to 60 DIMENS IONS: 1.58W X 6.625L X 6D (depth be low panel) inches WEIGHT: 1h2 lbs Net

Refer to schematic diagram 404-02-001 The M404 has three main active circuit sections low noise preamplifier , equalizer networks and output amplifier _ The equalizer section, resistor- capaci tor networks and FET isolation amplifiers_ has unity gain and is switched in and out between the pre- amplifier and output amplifier via switch SW4 _

The M404 is designed to mount directly on mixing console front panel The dimensions are such that the unit may be mounted in line with standard straight line mixing attenuator associated with each mixing channel cutout 1.56w X 6L and two tapped holes Will be required as shown in drawing 402-08-001 _ The escutcheon of the M404 will overlap the cutout and holes External connections are made to the 14 pin female ma ting connector in accordance with drawing 402-09-001 and Table 1 For optimum results, use insulated, shielded twisted pairs for both input and output wiring .

The optional external insert switch should be wired with shielded twisted pairs and located not more than 24 inches from the module Dress all audio cables apart Erom ac and power supply Wiring_ Ground shields at one end only and use separate ground return wire to the system common ground for the power supply and shields as shown in the System Wiring Diagram 404-09-002 _ The metal frame of the M404 equalizer should be bonced to the system ground _ In this case it is permissible to loop through each unit with common ground wire connected via pin "N" When used in system, such as an audio mixing console, the M404 equalizer should be operated from separate power supply than the ones used to provide dc power to program amplifiers, cue amplifiers or other similar units operating at high output levels The latter units produce large current swings and the possibility of instability, noise or crosstalk should be avoided in systems which combine high gain and wide-band amplifiers

The M404 has four operating controls These transient-free controls may be pre-set or adjusted during the operation of the unit_ The selectable frequencies associated with the HF and LF cut controls may be used independently or cumu latively to achieve multiple or combined effects, depending on the position of the HI-LO/Lo-Lo selector switch_ HF CUT X 1K Control This control produces rapid roll-off commencing at the high frequency audio spectrum to achieve low-pass filter characteristics The frequency designations indicated on the photo-etched escutcheon must be converted X IK (1000) to correspond to the operating frequency_ The nomenclature applies to the ~3db point on the attenuation curve E.G.

12=12,000 hz , 5=5,000 hz and 5=500 hz , etc _ In the OFF position the equalizer exhibits flat frequency response characteristics within 0 . 5db to 20Khz