M907 — Summing/Output Module

M907 SUMMING/OUTPUT MODULE

Refer to drawing A 907-04-002

1) A1 Level Adjust

The A1 level adjust trim control allows setup of the console output level to standard operating levels for the A1 amplifier chain. This could be one of three busses from the console system: AUX 2 left, PGM 1 music left, or PGM 3 left.

2) A2 Level Adjust

The A2 level adjust trim control allows setup of the console output level to standard operating levels for the A2 amplifier chain. This could be one of three busses from the console system: AUX 2 right, PGM 1 music right, or PGM 3 right.

3) A1+A2 Level Adjust

The A1+A2 level adjust trim control allows setup of the console output level for the sum of A1 and A2 outputs. This provides a mono sum output.

4) A3 Level Adjust

The A3 level adjust trim control allows setup of the console output level to standard operating levels for the A3 amplifier chain. This could be one of three busses from the console system: PGM 1 voice left, PGM 2 left, and PGM 4 left.

5) A4 Level Adjust

The A4 level adjust trim control allows setup of the console output level to standard operating levels for the A4 amplifier chain. This could be one of three busses from the console system: PGM 1 voice right, PGM 2 right, and PGM 4 right.

6) A3+A4 Level Adjust

The A3+A4 level adjust trim control allows setup of the console output level for the sum of A3 and A4 outputs. This provides a mono sum output.

7) A5 Level Adjust

The A5 level adjust trim control allows setup of the console output level to standard operating levels for the mono A5 amplifier chain. This could be one of two busses from the console system; AUX 1 or MIX MINUS. All channels operate in a similar fashion, so the following description refers to channel A1 only.

Input

The signal originating from the external mixing network enters the module at connector P1 pin 2. The signal is routed through user programmable jumper LK5 and into the summing node of U1. U2, along with capacitors C21, C22, C152, C153 and resistors R18, R19, R20, R21, and R22 form a 30 kHz low pass filter with a -40 dB per decade roll off characteristic. The output of U2 provides a nominal level of -6 dBu at connector P2 pin 1.

Insert

An unbalanced insert point is provided between connector P2 pin 1 and P2 pin 2. This permits the insertion of an external equalizer, limiter or compressor into the main program channel.

Level Adjustment

From the insert point, the signal is returned to the module and is coupled to level adjust potentiometer R24. When the console is operated at operating levels of 0 dBu or +4 dBu, LK23 is shorted; for operation at +8 dBu, LK23 is opened. Trimming the output level is done by adjusting R24 which is front panel accessible.

Output

Output of the module is balanced through amplifiers U3 and U4. A 60 ohm output network provides two external stereo outputs for the console and a metering output for use by the console meter module (M909) and the monitor module (M905). M907 channels A1 & A2 (and A3 & A4) are combined to provide a mono sum output through U9 and U10. A single mono output is available for external use from the console system.

Power Supply

The power supply is decoupled through a passive decoupling circuit consisting of R1, R8, R153, R154 and C1, C6, C142, C143 for channel 1. Nominal power supply voltage at the amplifiers is 22 volts.

Configurations

The M907 is designed to be a universal output amplifier for the Renaissance series of consoles. To this end, it is possible to assign a summing bus to a particular output channel with certain restrictions. Tabulating these combinations:

Program 1L Music to A1 : LK 5 in position 1-2 Program 1R Music to A2 : LK 7 in position 1-2 Program 1L Speech to A3 : LK 9 in position 1-2 Program 1R Speech to A4 : LK 13 in position 1-2

Program 2L to A3 : LK 10 in position 1-2 Program 2R to A4 : LK 14 in position 1-2

Program 3L to A1 : LK 6 in position 1-2 Program 3R to A2 : LK 8 in position 1-2

Program 4L toA3 : LK 11 in position 1-2 Program 4R to A4 : LK 15 in position 1-2

Mix Minus buss to A5 : LK 17 in position 1-2

Aux 1 to A5 : LK 18 in position 1-2

Aux 2L to A1 : LK 12 in position 1-2 Aux 2R to A2 : LK 16 in position 1-2

*****All unused links in this group must be left open.*****

Program 1 Speech/Music Option

In console systems where the Program 1 buss is split and used in both the music and speech mode, the M907 can be configured to provide a sum of the music and speech buss after the module insert point. To do this, optional components R163, R164, R165, and R166 must be installed and printed circuit board links LK19, LK20, LK21, and LK22 must be cut. Alignment

A signal at normal console operating level should be brought up on the console on the program 1 music buss, and a reference taken for both left and right channels. Repeat this procedure for the speech buss, ensuring level equality.

User-configured links LK1, LK2, LK3, and LK4 are then installed in the 2-3 position. The correct mix of speech into music and music into speech is then achieved by adjusting trimmers R163, R164, R165, and R166 to required system levels. C1 To C14 Capacitor 22 uF/40 V Philips 035.57229 C15 " 220 uF/10 V ITT 220M010 C16 " SOT C17 " 22 pF Philips 638-10229 C18 " 10 uF/35 V ITT 10M35

C19 " 22 pF Philips 638-10229 C20 " 10 uF/35 V ITT 10M35 C21 " 1000 pF Aselco CQ92-MC-100-102M C22 " 1000 pF " " C23 " 0.1 uF/100 V Sprague K104K20X7RFVBWN

C24 " 47 pF Philips 638-34479 C25 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C26 " 47 uF/20 V ITT 47M20 C27 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C28 " 22 pF Philips 638-10229

C29 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C30 " 47 pF Philips 638-34479 C31 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C32 " 22 pF Philips 638-10229 C33 " 0.1 uF/100 V Sprague K104K20X7RFVBWN

C34 " 100 pF Philips 638-58101 C35 " 220 uF/10 V ITT 220M010 C36 " 22 pF Philips 638-10229 C37 " 10 uF/35 V ITT 1

M909 METER/MIX MINUS MODULE

Please refer to module layout drawing A 909-04-002.

1) Legend Strips

Two plastic covered designation strips for identification of the selector functions for the mono and stereo meter selectors.

2) Mono Meter Selector

Momentary switches SW7 through SW12 control the active solid-state switches for source selection to the mono meter. 3) Auxiliary Stereo Selector

Momentary switches SW1 through SW6 control the active solid-state switches for source selection to the left and right auxiliary meters. Meter Amplifiers

Main Meter Amplifier

Two identical meter amplifiers are employed for the main metering in the console. They consist of U28 and U29 and associated components for the left and right meters.

Dual operational amplifier U28 forms the nucleus of a balanced input/balanced output variable sensitivity buffer. Capacitors C74 and C75 prevent external bias from disturbing the meter circuit, while C82 and C83 protect the meter from any offset error present in U28. Trim control R129 is normally factory set to provide a 0 VU indication on the console meters at the specified system levels. Resistor R135 ensures the output impedance of the meter amplifier matches the VU standard (ANSI C16.5-1954).

Mono and Auxiliary Meter Selectors

The mono and auxiliary meters have six input sources, of which only one may be selected at a time. Referring to the schematic on sheet B909-02-002/2, each input is AC coupled to a separate 74HC4053 solid state switch. The outputs of the switches for the mono meter are all connected to the balanced summing amplifier U13. R46, R48 and R52 make up the `T' feedback for U13A with potentiometer R52 providing the gain adjustment for the mono meter output.

The left and right haves of the auxiliary stereo meter selector are identical to the mono meter selector.

Meter Select Logic

Refer to the schematic on sheet B909-02-002/1. The 74HC4053 switches are controlled by logic chips U1 through U6. Since both the mono and auxiliary stereo logic circuits are identical, only the mono meter selector will be described.

Microcontroller U1 reads the switches SW7 through SW12, which are software debounced, and outputs a 3 bit binary code for the depressed switch with the highest precedence.

The clock rate for U1 is set by the RC time constant of R11 and C7. U1 also requires a power on reset signal and this is provided by R17 and C5.

The tally LEDs for switches SW7 through SW12 are controlled by U4, a CD4051 8 channel analog multiplexer. The three bit binary code from U1 determines which channel of U4 is turned "ON". Current flows through current limiting resistor R19 and through the "ON" channel of U4 to the appropriate LED.

Grounding the control line on pins 9, 10 & 11 of the 74HC4053 will connect the associated input to the summing amplifier. The 8 channel analog multiplexer U3 operates in manner similar to U4 except that the "ON" channel of U3 grounds one of the control lines to the 74HC4053 switches. The remaining control lines are pulled up by R18, which turns off the remaining 74HC4053 switches for the mono selector. Mix Minus

Refer to the schematic on sheet B909-02-002/3.

The mix minus portion of the M909 consists of U30 through U34 and associated components. The telephone input is configured as a simple differential input amplifier whose signal is summed with all four mix minus outputs. The mix minus inputs are configured so that the like numbered output does not receive the associated input.

Each mix minus output is electronically balanced for direct coupling to a bridging output load. Power Supply Decoupling

The active decoupling network consisting of Q1 through Q5 and associated components regulates the incoming power for use in the module. Diodes CR1 and CR2 prevent module damage in the event of power supply voltage reversal. The decoupling network drops the ±23 volts down to a nominal ±18 volts. Transistor Q3 further decouples the ±18 volts down to +5 volts for use by the CMOS logic circuitry.

C1 Capacitor 22 uF/25 V Siemens 85200 C2 " 22 uF/25 V " " C3 " 22 uF/25 V " " C4 " 22 uF/25 V " " C5 " 22 uF/25 V " "

C6 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C7 " 330 pF Philips 638-03331 C8 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C9 " 330 pF Philips 638-03331 C10 To C21 " 6.8 uF/16 V ITT 6.8M16

C22 " 220 uF/10 V " 220M010 C23 " 220 uF/10V " " C24 " 47 pF Philips 638-34479 C25 " 47 pF " " C26 " 22 uF/35 V ITT 22M35

C27 To C38 " 6.8 uF/16 V ITT 6.8M16 C39 " 220 uF/10 V " 220M010 C40 " 220 uF/10V " " C41 " 47 pF Philips 638-34479 C42 " 47 pF " "

C43 " 22 uF/35 V ITT 22M35 C44 To C55 " 6.8 uF/16 V ITT 6.8M16 C56 " 220 uF/10 V " 220M010 C57 " 220 uF/10V " " C58 " 47 pF Philips 638-34479

C59 " 47 pF " " C60 " 22 uF/35 V ITT 22M35 C61 To C73 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C74 " 6.8 uF/16 V ITT 6.8M16 C75 " 6.8 uF/16 V " "

C76 " SOT C77 " SOT C78 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C79 " 0.1 uF/100 V " " C80 " 47 pF Philips 638-34479

C81 " 47 pF " " C82 " 10 uF/25 V ITT 10M25 C83 " 10 uF/25 V " " C84 " 6.8 uF/16 V ITT 6.8M16 C85 " 6.8 uF/16 V " "

C86 Capacitor SOT C87 " SOT C88 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C89 " 0.1 uF/100 V C90 " 47 pF Philips 638-34479

C91 " 47 pF " " C92 " 10 uF/25 V ITT 10M25 C93 " 10 uF/25 V " " C94 " 10 uF/25 V " " C95 " 10 uF/25 V " "

C96 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C97 " 0.1 uF/100 V C98 " 82 pF Philips 638-58829 C99 " 22 pF " 638-10229 C100 " 33 uF/16 V ITT 33M16

C101 " 10 uF/25 V " 10M25 C102 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C103 " 0.1 uF/100 V " " C104 " 82 pF Philips 638-58829 C105 " 10 uF/25 V ITT 10M25

C106 " 82 pF Philips 638-58829 C107 " 10 uF/25 V ITT 10M25 C108 " 0.1 uF/100 V Sprague K104K20X7RFVBWN C109 " 0.1 uF/100 V " " C110 " 82 pF Philips 638-58829

C111 " 10 uF/25 V ITT 10M25 C112 " 82 pF Philips 638-58829 C113

M909 METER/MIX MINUS MODULE

Meter Section

Input Sensitivity: 0 to +4 dBu (for +4 dBu output).

Frequency Response: ±0.1 dB 20 Hz to 15 kHz.

Noise: Greater than 80 dB below unity gain +4 dBu output.

Harmonic Distortion: Less than 0.05% from 20 Hz to 15 kHz.

Input Impedance: Greater than 15K, balanced.

Source Impedance: 600 ohms or less, balanced.

Output Impedance: 3600 ohms.

Channel Separation: 65 dB.

Mix Minus Section:

Frequency Response: ±1 dB 20 Hz to 20 kHz.

Noise: Greater than 80 dB below an operating level of +4 dBu.

Harmonic Distortion: Less than 0.05%.

Source Impedance: 600 ohms or less.

Input Impedance: 15,000 ohms unbalanced.

Output impedance: 60 ohms or less, balanced.

Load Impedance: 600 ohms or greater, balanced.

Crosstalk: 65 dB or greater, 20 Hz to 20 kHz. (Mix minus input to mix minus output)

Overall Specifications

Power Requirements: ±23 volts DC, 100 mA.

Ambient Temperature: 0 to 50 degrees Celsius.

Dimensions: 1.5" wide x 16.2" high x 6.6" deep. (38mm x 410mm x 168mm).

Weight: 525 grams (19 ounces).

GENERAL

M909 METER/MIX MINUS MODULE

The M909 Meter/Mix Minus module provides source selection and buffering for the meters in the console system. In addition, the module can generate up to four mix-minus outputs from the console.

Five meter buffers are included in the module. Two of these are permanently assigned to monitor a stereo program feed; normally console Program 1. One meter has a six button pre-selector associated with it. The remaining two buffers have an additional six button pre-selector for utilization as a auxiliary stereo metering system. All meter inputs are actively balanced. All audio is selected through solid-state logic controlled switches.

Mix minus feeds are generated in the M909 too. To use the mix minus outputs, the mix minus buss in the console is assigned to all input channels except the telephones. The mix minus output from the M907 is connected to the balanced telephone input of the M909. Each telephone input module's post fader direct output (M901) is brought to the M909 individually. The appropriate mix minus feeds are generated internal to the M909 for use by up to four telephone hybrids. OPERATIONAL

M907 SUMMING/OUTPUT MODULE

(Note: 0 dBu = 0.774V rms)

Gain: (Bridging) 10 dB nominal, +14 dB +/-0.5 dB maximum in two steps. Trim control is provided.

Frequency Response: +/-0.2 dB from 10 Hz to 20 kHz.

Dynamic Range: 110 dB.

Noise: 84 dB below +4 dBu nominal output level (20 Hz to 30 kHz).

Harmonic Distortion: Less than 0.01% from 20 Hz to 20 kHz at +27 dBu output.

Less than 0.02% from 20 Hz to 20 kHz at +27 dBm into one 600 ohm load.

Source Impedance:

Summing: 10,000 or 15,000 ohms, unbalanced. Insert: 600 ohms or less, unbalanced.

Input Impedance:

Summing: Less than 3 ohms. Insert: 6500 ohms unbalanced.

Program Output Impedance: 60 ohms, balanced.

Load Impedance: 600 ohms or greater, balanced.

Output Level: +4 dBu nominal, +30 dBu maximum . +27 dBm maximum.

Channel Separation: 80 dB or greater at 1 kHz.

Power Requirements: +/-24 volts DC, 105 mA nominal.

Ambient Temperature: 0 to 50 degrees Celsius.

Weight: 425 grams (15 ounces). GENERAL

M907 SUMMING/OUTPUT MODULE

The M907 is designed to receive up to five separate mixed feeds from the mixing busses of the Renaissance series of radio consoles. The signals are independently processed and amplified to standard user configurable line levels. The outputs of the M907 supply the main program output channels of the console system and provide bridging feeds for the monitoring section and metering sections of the console. OPERATIONAL

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