Shure FP31 Mixer

The FP31 is a portable electronic news gathering (ENG) electronic field production (EFP), or film production, mixer that provides the quality and features needed for remotes.

Features

Inputs

• Three transformer-coupled, 3-socket XLR-connector inputs; each switchable to low-impedance microphone or line level
• Lo-Cut filters available at each input to reduce extraneous low-frequency interference
• (Phantom) simplex or A-B power for condenser microphones available at each microphone input
• Built-in tone oscillator for level checks or line tests
• Slate microphone with automatic gain control (AGC) for take identification or for emergency use
• Slate tone for identifying take locations during editing

Outputs

• Two transformer-coupled, 3-pin XLR-connector outputs, each switchable either to low-impedance balanced microphone or to 600-ohm balanced line level
• Tape output to feed tape recorder input or other unbalanced Aux-level input
• Front and side panel stereo headphone jacks (8 to 2,000 ohms, and 3.5 mm jacks) with separate Phones level control. Either or both jacks can drive Aux or unbalanced line-level inputs. Four separate sources can be driven from these two headphone outputs.

Controls and Indicators

• Active, feedback-type input gain controls permit direct input of high-level sources without input attenuators
• Built-in Limiter with adjustable threshold -prevents output clipping of mixer or input overload of amplifier, telephone line or tape recorder
• LED indicator flashes with Limiter operation or to signal overload with Limiter defeated
• Professional VU meter, factory set for 0 VU = + 4 dBm, internally adjustable for other VU levels
• VU lamp, stays illuminated while pushbutton is depressed, automatic 5-second turnoff after button is released.
• Battery check function with readout on VU meter
• Master gain controls level at Line/Mic and Tape outputs as well as tone oscillator level
• Phones level control adjusts output at both headphone jacks

Power

• Mixer is powered by two standard 9V alkaline batteries that also supply simplex power for condenser microphones
• Extreme!y low battery drain provides 8-hour minimum battery life under normal conditions
• Separate 9V alkaline battery supplies A-B power for condenser microphones; third battery is not required if power is not used
• Spring-loaded battery compartment prevents incorrect insertion of batteries; batteries available for replacement instantly when compartment door is opened
• Mixer can be powered from any 11 to 18 Vdc source such as: standard belt pack, automotive electrical system, video tape recorder, or ac power converter

Mechanical characteristics

• Extremely rugged and durable construction
• Very small size and light weight
• Carrying case and detachable shoulder strap supplied
• All input and output connectors are professional standard types

Performance

• Reliable operation under wide extremes of temperature and humidity
• Extremely low noise and low RF susceptibility permits use near microwave transmitters and in strong hum fields
• Wide, flat response, extremely low distortion, and up to + 18 dBm output level provide studio-quality performance in a portable mixer

Specifications

Frequency Response

30Hz to 20kHz ± 2 dB

Distortion

Less than 0.25% total harmonic distortion at + 4 dBm, 50 Hz to 20 kHz

Noise

Less than -129 dBV equivalent input noise

Common Mode Rejection

65 dB minimum at 100 Hz, -30 dBV input

Tone Oscillator

1 kHz nominal at + 4 dBm, Master at approx. 7

Slate Tone

400 Hz, 1 sec, each time button is depressed

Slate Microphone

Electret condenser, omnidirectional, with AGC, activated while slate button is depressed

Phase

3-pin Input & Output connectors in phase; pin 3 in phase with tip of phone & mini jacks

Control Interaction

Less than 1 dB with any control combination

Output Isolation

Shorting one output shall cause no more than 8 dB level drop at 1 kHz at other output

Overload and Shorting Protection

Shorting outputs, even for prolonged periods, shall cause no damage. Microphone inputs will not be damaged by signals up to 3 volts.

Dimensions

48.3 mm Hx160mmWx 135mm D(1-7/8x6-5/16x 5-5/16 in.)

Net Weight (less batteries)

1 kg (2.2 Ib)

Supplied Accessories

Removable shoulder strap, carrying case