Operation

This section of the manual provides a description of all operating controls and indicators and their use in the system, and step-by-step procedures for the various modes of operation.

3.1 CONTROLS AND INDICATORS↑ TOP

Table 3-1 Tape Transport Controls and Indicators

⤢ zoomLine drawing of the MX-5050BII tape transport deck — reels, threading path, and the pushbutton panel — with its numbered call-outs (1 through 25) matching the Index No. column of Table 3-1.

Located inside the head cover is a switch for selection of either of the two playback head stacks. Flip the head cover "up" for easy access.

⤢ zoomLine drawing of the head-cover inset, with the 2T/4T P.B. HEAD switch (Index No. 17) and heads H1-H4 shown open.

Index No.	Name	Function
1	POWER Pushbutton Switch	In the depressed position, power is applied to the equipment, and the VU meters illuminate.
2	CUE Lever	In the up position, the system operates normally. In the fast forward and rewind modes, moving the lever downward permits variable control of the tape lifter to enable audio monitoring. The lever locks in the full down position.
3	Elapsed Time Indicator	A C.P.U. controlled LED display of elapsed tape time in hours, minutes, and seconds, ± 9 hr. 59 min. 59 sec. max. The pushbutton resets the display to (0.00.00).
4	MEMORY Pushbutton Switch	Depress this switch and the MX-5050B will enter the STOP mode when the elapsed time indicator displays (-0.00.00) in the rewind mode.
5	F. FWD Pushbutton Switch	Used to select the fast forward mode to run the tape from left to right at high speed. This mode may be entered into from any other mode except the edit mode.
6	REWIND Pushbutton Switch	Used to select the rewind mode to run the tape from right to left at high speed. This mode may be entered into from any other mode except the edit mode.
7	STOP Pushbutton Switch	Used to stop the tape transport and cancel the existing mode of operation.
8	PLAY Pushbutton Switch	Used to select the play mode, or used in conjunction with the RECORD pushbutton switch.
8	(Continued)	Pressing the PLAY pushbutton during the fast forward or rewind modes stops the tape, then automatically starts the play mode.
9	RECORD Pushbutton Switch	Used in conjunction with the PLAY pushbutton switch and the RECORD channel selector. With the desired channel pushbutton switches depressed, simultaneously pressing the PLAY and RECORD pushbuttons' initiates the record mode and the red indicator illuminates. In the play mode, when the RECORD pushbutton is pushed, the unit enters the record mode. (This is called "Punch in".) In the record mode, when the PLAY pushbutton is pushed, the unit enters the reproduce mode. (This is called "Punch out".) Punch in and Punch out are used for overdubbing in conjunction with the sel. rep. function.
10	Record Indicator (red)	Used to indicate the record mode.

Transport record indicator	Amplifier record indicator	Transport	Recording
dark	dark	non rec. mode	x
blinks	illuminated	non rec. mode	x (ready)
remains illuminated	dark	rec. mode	x
remains illuminated	illuminated	rec. mode	o

Blinking means that the amplifier is in the record-ready mode. Recording is being carried out when the record indicators of both the amplifier and the transport remain illuminated.

11	EDIT Pushbutton Switch	Used to initiate the edit mode to aid in cutting out unwanted tape.
11	(Continued)	When the EDIT pushbutton is depressed the green indicator illuminates and power is disconnected to the takeup reel. When the play pushbutton switch is then depressed it causes the supply reel to rotate and tape to spill off on the takeup side of the transport. Other operations are halted.
12	EDIT Indicator (green)	Illuminates when the EDIT pushbutton switch is depressed.
13	Large/Small REEL Pushbutton Switch	An alternate-action pushbutton switch used to select the supply and takeup-reel tape tension for either large or small reel-diameter hubs. Place the pushbutton in the "in" (Small position) for reels with EIA hubs (2-1/4 inch hubs). Place the pushbutton in the "out" (Large position) for reels with NAB hubs (4-1/2 inch diameter hubs). (THE SAME SIZE REELS SHOULD BE USED ON BOTH TURNTABLES.)
14	HIGH/LOW Speed Pushbutton Switch	An alternate-action pushbutton switch used to select operating speeds. (15/7.5 ips) When machine is converted to a low speed version, this switch selects tape speeds of 7-1/2 ips or 3-3/4 ips. Refer to page 5-1 for conversion procedure.[sic]
15	PITCH CONTROL	Used to control tape speed. The capstan's speed can be controlled within ± 7 % of the selected speed. When the PITCH CONTROL knob is pulled out and turned clockwise, capstan speed increases. When pulled out and turned counterclockwise, capstan speed decreases. PITCH CONTROL FUNCTIONS IN BOTH THE RECORD AND PLAY MODES.
16	PITCH CONTROL Indicator (red)	Lights when the PITCH CONTROL switch is pulled out (Variable).
17	Reproduce Head Selector Switch	Used to select the appropriate reproduce head stack to conform to the type of tape to be reproduced. (Refer to Sec. 1.1.3.)
18	NAB Hub Reel Hold Down Knobs	Used to attach EIA or NAB hub reels to the reel table. (Refer to Sec. 3.2.1.)
19	Supply Reel	Used to supply tape for reproduction or recording.
20	Tension Arm	Used to eliminate tape tension fluctuations.
21	TACHO Pulse Generator Roller	Used to generate the pulses for the elapsed time indicator.
22	Takeup Reel	Used to take up tape.
23	Pinch Roller	Used to correctly transmit the rotation of the capstan to the tape.
24	Tension Arm with Safety Switch	Used to eliminate tape tension fluctuations. When tape is exhausted, supply and takeup reel rotation is automatically stopped by the safety switch attached to the tension arm.
25	Capstan Shaft	The shaft used to keep speed constant while in the reproduce and record modes.

Table 3-2 shows the location and function of each control and indicator on the record/reproduce electronics control panel.

Table 3-2 Record/Reproduce Electronics Controls and Indicators

⤢ zoomLine drawing of the record/reproduce electronics control panel — input knobs, VU meters, and pushbutton row — with its numbered call-outs (1 through 15) matching the Index No. column of Table 3-2.

Index No.	Name	Function
1	LINE/MIC INPUT Level Control	Used to control the recording level line input (outside knob) and microphone (inside knob) of the corresponding channel.
2	VU Meters	Indicate the record and playback level of the corresponding channel depending on the mode of operation and position of the MONITOR SOURCE/TAPE switch (Index No. 13 in this table). The meters are illuminated when the recorder is turned on.
3	Peak Indicators (red)	Used to show signal peaks. When the input signal exceeds the standard level by 15 dB, the peak indicator lights. At a frequency of 700 Hz, the magnetic flux at the standard level is 185 nWb/m. When the peak indicator lights, the level is 1040 nWb/m. This trigger level may be adjusted.
4	OUTPUT Level Controls	Used to control the playback level of the corresponding channel. (Control is deactivated when the SRL switch is in the "SRL" position.)
5	SRL Switch and Indicator (red)	In the "SRL (Standard Reference Level)" position, the red indicator is illuminated. The playback level is then determined by an internal preset potentiometer. The SRL can be selected by the Record level switch on the rear panel as follows:

RECORD LEVEL	Standard Reference Level
	Flux Level	Based on
L	185 nWb/m	Ampex Operating level
M	250 nWb/m	MRL reference fluxivity of 250 nWb
H	320 nWb/m	BASF or MRL IEC reference level

In the normal position, the reproduce level is controlled by the OUTPUT controls of the corresponding channel.

DO NOT TURN THIS SWITCH OFF UNLESS YOU TURN THE LINE OUTPUT LEVEL CONTROLS (INDEX NO. 4 IN THIS TABLE) DOWN TO THE MINIMUM LEVEL WHILE A SIGNAL IS BEING OUTPUT TO OTHER EQUIPMENT, TO PREVENT POSSIBLE DAMAGE.

6	RECORD Selector Switch and Indicator (red)	Used to select channels for recording, and used in conjunction with the PLAY and RECORD pushbutton switches (Index Nos. 8 and 9 of Table 3-1). In the "out" position this switch prevents activation of the channel record mode.
6	(Continued)	In the "in" position it permits the channel record mode to be entered into and the red indicator is illuminated.
7	SEL/REP Selector Switch and Indicator	In the SEL. REP. (Selective Reproduction) "out" position, the signal on the tape is reproduced normally. In the SEL/REP "in" position, the green indicator is illuminated and the signal on the tape is reproduced by the record head (rather than by the reproduce head) to permit recording on one channel to synchronize with the other channel.
8	RECORD BIAS Adjustment Control	Used to adjust the amplitude of the bias current in accordance with the tape being used for optimum performance. Used in conjunction with the Test OSC function (Index No. 12 in this table).
9	RECORD EQ Adjustment Control	Used to adjust record equalization of corresponding channels and speed modes (HIGH or LOW).
10	RECORD LEVEL Adjustment Control	Used to make fine adjustments when different types of tape are to be used.
11	PHONES Jack	Receptacle for headphones. Used to monitor the input or output signal as selected by the Monitor SOURCE/TAPE selector switch (Index No. 13 in this table). (Load impedance: 8 ohms or greater)
12	TEST OSC Push-button Switch	When the left button is held down, a 1 kHz Test tone is generated and fed to the line input circuit. The right button (which locks down) generates a 10 kHz tone. These tones are used for cue tone recording and Record Bias adjustment (Index No. 8 of the table).
13	MONITOR SOURCE/TAPE Switch	In the "out" (SOURCE) position, the input signal is fed to the LINE OUT connectors, the PHONES jack, the VU meters, and the peak indicators. In the "in" (Tape) position, the signal being reproduced is fed to the LINE OUT connectors, the PHONES jack, VU meters, and the peak indicators.
14	EQ Selection Indicator	Located on the amplifier front panel are 2 LED EQ Selection Indicator Displays which indicate the position of the NAB or IEC EQ switch which is located on the back of the unit.
15	Record Level Selection Indicator	Located on the front amplifier front panel are 3 LED Record Level Selector Indicator Displays which indicate the position of the Record Level Selector switch which is located on the back of the unit.

3.2 OPERATING INFORMATION↑ TOP

3.2.1 USE OF THE REEL HOLD DOWN KNOBS↑ TOP

NAB hub reel hold down knobs are used as follows:

When an EIA hub (2-1/4 inch diameter hub) is used;

(1) Remove the NAB reel hold down knob by turning the inner knob counterclockwise.

(2) Place the reel on the reel table.

(3) Place the reel hold down knob on the reel and fix it by turning the inner knob clockwise.

When an NAB hub (4-1/2 inch diameter hub) reel is used;

(1) Place the reel hold down knob on the reel table and lock it by turning the inner knob clockwise.

(2) Place the NAB hub reel on to the reel table and fix it by pulling and turning the outer knob.

⤢ zoomExploded line drawing of a reel hub assembly showing the inner knob, outer knob, and base with leader lines identifying each part.

Fig. 3-1 Reel Hold Down Knobs

3.2.2 PRE-OPERATING PROCEDURE↑ TOP

After the equipment has been installed, as described in Sec. 2 of this manual, and the operator has become familiar with all the operating controls and indicators, described in Tables 3-1 and 3-2, prepare the recorder for operation as follows.

(1) Place the POWER switch in the "on" position. The VU meter lights will illuminate.

(2) If metal reels are to be used, use reel-adjusting discs (shims) between the reels and the turntables. Place a reel of tape on the supply (left-hand) turntable. Note that the reel must turn counterclockwise as tape is pulled off the reel. Place the same size empty reel on the takeup (right-hand) turn-table.

(3) Thread the tape as shown in Fig. 3-2, and place the end of the tape in the slot of the empty reel.

(4) Set the HIGH/LOW SPEED switch to the desired tape speed.

(5) Set the LARGE/SMALL REEL switch to conform to the size of the reel hub diameter being used. Place the switch to the "out" (LARGE position) for NAB hubs (4-1/2 inch diameter) or to the "in" (SMALL position) for EIA hubs (2-1/4 inch diameter). (THE SAME SIZE REELS SHOULD BE USED ON BOTH TURNTABLES.)

(6) Set the reproduce head selector switch (Index No. 17 in Table 3-1) to the appropriate position as determined by the track format of the tape to be reproduced.

(7) If desired, connect a headset or monitor speaker/amplifier to the PHONE jack.

⤢ zoomLine drawing of the tape transport deck with supply and takeup reels and a threading path traced across the heads and capstan.

Fig. 3-2 Tape Threading

3.2.3 REPRODUCTION↑ TOP

To reproduce, proceed as follows:

(1) Perform all steps in the pre-operating procedure.

(2) Set the channel RECORD selector switch(es) to the "out" position.

(3) Set the reproduce head selector switch to its appropriate position.

(4) Set the channel MONITOR selector switches to their TAPE "in" positions.

(5) Press the PLAY pushbutton to begin reproducing the prerecorded tape.

(6) Adjust the channel OUTPUT level control(s) for the desired output level or set the SRL switch to the "SRL" position.

(7) When the desired program has been reproduced, press the STOP pushbutton.

3.2.4 NORMAL RECORDING↑ TOP

To record normally, proceed as follows:

(1) Perform all steps in the pre-operating procedure.

(2) Set the desired RECORD selector switches to the "in" position for the channel(s) selected for recording. The corresponding red indicator(s) will illuminate to indicate the selected channel(s). Simultaneously the tape transport RECORD indicator will begin to blink.

(3) Set the corresponding MONITOR SOURCE/TAPE switch to the "out" (SOURCE) position.

(4) Adjust the corresponding LINE/MIC INPUT level control(s) so that the VU meter(s) indicates 0 for most audio peaks. (It is advisable to adjust the channel input levels so that the peak indicator lamps, located in the VU meter housings, blink occasionally.)

(5) Push the elapsed time indicator pushbutton to reset the display to (0.00.00).

(6) Press the PLAY and RECORD pushbuttons simultaneously to start recording on the selected channel(s). The tape transport RECORD indicator will cease blinking and instead will remain illuminated.

(7) While recording, the input signal of each channel can be compared with the signal reproduced on each channel by pressing the MONITOR switch to the "in" (TAPE) position.

(8) After recording is completed, but while still in the record mode, once again press the PLAY pushbutton to enter directly into the play mode without stopping the tape transport (punch out). After punching outs, if desired, press the RECORD pushbutton to enter directly into the record mode without stopping the tape transport (punch in). If further recording is not necessary, press the STOP pushbutton to stop tape motion and deactivate the record mode.

3.2.5 RECORDING WITH SELECTIVE REPRODUCTION↑ TOP

The selective reproduction function causes the reproduced audio to be derived from the record head rather than from the reproduce head. This permits a recording to be made on another channel synchronized (in phase) with the channel being reproduced. To record with selective reproduction, proceed as follows.

(1) Perform all steps in the pre-operating procedure.

(2) Perform all steps in the normal recording procedure for the channel to be recorded.

(3) Rewind the tape to the point where selective reproduction is to begin.

(4) Set the selective reproduction (SEL/REP) switch to the "in" position for the channel to be monitored while the recording is being made.

(5) Set the RECORD selector switch to the "in" position for the channel to be recorded.

(6) Set the MONITOR selector switch to the "in" (Tape) position for the channel being monitored.

(7) Set the MONITOR selector switch to the "out" (Source) position for the channel to be recorded.

(8) Adjust the LINE/MIC INPUT level control so that the VU meter indicates 0 for most audio peaks. (It is advisable to adjust the channel output levels so that the peak indicator lamps, located in the VU meter housings, blink occasionally.)

(9) Press the PLAY pushbutton to start tape motion. At the point where overdub is desired press the RECORD pushbutton to start recording on the selected channel(s).

(10) When recording is complete, press the STOP pushbutton to stop tape motion and deactivate the record mode, or punch- out by pressing the PLAY pushbutton.

NOTES:

1. If this unit is a full-track model, the SEL. REP. function is not included.
2. The pitch control is used to finely adjust one track with another track(s). It can be used in both the Record and Reproduce modes.
3. The SEL. REP. mode has priority over the Record mode in this unit. (While the SEL. REP. pushbutton(s) is (are) pushed, the corresponding channel(s) can not enter the record mode.)

3.2.6 FAST WINDING↑ TOP

For fast-winding operations, and for editing or cueing, press the F. FWD. or REWIND pushbutton as appropriate. These pushbuttons can be pressed alternately without having to press the STOP pushbutton between fast-winding operations. These modes may be entered into from any other mode except the edit mode. Pressing PLAY during a fast-winding mode causes the tape to automatically come to a stop and then enter into the play mode. In a fast-winding mode, the tape lifters are automatically actuated and lift the tape away from the heads. To monitor the tape in a fast-winding mode, the position of the tape lifters can be varied by operation of the CUE lever. Thus the distance of the tape from the heads may be varied to control the signal level from the tape.

3.2.7 EDITING AND SPLICING TAPE↑ TOP

For editing and splicing operations, the CUE lever can be used in fast-winding modes to quickly locate the desired program material. In addition, there is an EDIT mode of operation, used as follows:

Depressing the EDIT pushbutton while in the play mode removes power from the takeup reel and causes the tape to be spilled off on the takeup side of the transport. This mode is used to fasilitate cutting out unwanted tape. The edit mode can also be entered into from the stop mode by pressing the PLAY pushbutton while the EDIT pushbutton is in its depressed position.

The tape-splicing block (Fig. 3-3) mounted on the head cover can be used to hold the tape for ease in cutting the tape with a single-edged razor blade and applying splicing tape. Use 7/32-inch wide splicing tape (3M Co., No. 41). Never use cellophane tape. The tape splicing block has the following features:

⤢ zoomLine drawing of the tape-splicing block showing the head-stack indicator marks, the tape-guide channel, and the diagonal and vertical cutting guides.

Fig. 3-3 Tape Splicing Block

1 Head-stack indicator marks: Indicates location of the individual head stacks. 2 Tape-guide channel: Holds the tape for ease of cutting and splicing. 3 45° cutting guide : Used to guide tape cutter for a diagonal cut. 4 90° cutting guide : Used to guide tape cutter for a vertical cut.