P4 특징

Dual Channel (2채널)
current mode Microphone inputs (XLR)
current mode Line inputs on 1/4" Jack
20dB Pad
Phantom Power (48V)
Mic/ Line Switching
High pass filter (75Hz)
Limiter on/off
Limiter threshold sets from -10 to off
Compression mode for limiter
Dual outputs at +4 (Jack) and -10dB (Phono)

TECHNICAL SPECIFICATION

Microphone inputs suitable for all 200 ohm microphones. Input operates from microphone current. Input impedance equivalent to 1.1Kohms Input level +10dB to -75dB.

Line inputs 20Kohm balanced. Level +20 to -40dB

Main output 300 ohm source impedance (TRS jack), balanced. Max level +22dBu nominal level +4dBu

Secondary output (phono connectors) 600 ohm unbalanced. Max level +12dBu. Nominal level -10dBu.

Noise: Mic noise 126dB below input (50 to 70 dB gain) 20Hz-20KHz RMS. System noise approx 88dB below operating level.

Harmonic distortion within 0.01% except during limiting when distortion may rise to 0.5% depending on signal conditions.

LIMITER; Limit ratio approx 12:1, attack time depends on transient content; normally 200 microseconds. Release depends on content; normally 100mS. Compression mode increases attack to 1.5mS and release to 750mS

Designed specifically for broadcasting, commercial production and smaller recording systems, the P4 delivers great sounds. The P4 features two channels of:

TFPRO's unique current mode microphone input , developed to an amazing 70dB of gain, with a constant input control down to mute. The main advantage of this current mode input is in the guaranteed optimal performance from any microphone type, be it condenser, dynamic or even ribbon type.
Asymmetric limiter . An invention for broadcasting and digital recording, the new asymmetric limiter optimises signals by working to 'centre' a signal's balance, thereby optimising your recorder's recording resolution. The limiter also has a 'comp' button, that changes its behaviour to be more like a compressor.
'Superbal' balanced outputs calibrated to +4 plus additional -10dB outputs on phono connectors for convenient connection to some sound cards and consumer level equipment.

Front panel controls

Input gain. Smoothly controls microphone gain through 4 linked pre amplification stages.
20dB Pad/Phantom switch . This switch both enables the 48V phantom power and also reduces the input sensitivity by 20dB. This 'shifts down' the sensitivity of the pre amplifier to optimise it further for condenser microphones
Mic/Line switch . Switches between the Mic (XLR) and line (1/4" Jack) inputs.
High Pass filter . This switch engages the 75Hz high pass filter, for removing dangerous and troublesome LF from some microphone or instrument sources.
Limit On . This switch enables or bypasses the Asymmetric limiter function
Threshold . A rotary control for the threshold of the limiter circuit. 'Off' is the same as having the limiter bypassed. -10dB means the limiter will be fully operational for signals that exceed -10dB at the output.
Comp . This switch enables alternative attack and release shaping for the limiter dynamics, making it behave and sound more like a compressor.

Applications

Broadcasting

The P4 is perfectly suited as a main 'on air' microphone amplifier for radio broadcasting where maximum intelligibility is required; as the DJ mic amp on music stations, and for news and current affairs stations. The asymmetric limiter is an effective tool for maximising voice 'noticeability'.

Broadcast Commercial Production

The flexibility of the limiter and the clarity of the microphone amplifier make it a superb tool for commercial production where even more 'urgency' of voice can be created.

Home recording

For home recording, the P4 provides an ideal front end to a computer's sound card. With the current mode mic pre amplifier, a good result can be achieved from any musical source. Indeed, the pre amplifiers in the P4 are of such a high standard that mixing desk channels and pre amplifiers become redundant when comparing the sound and overload margin against the P4. The limiter provides a level of protection for your sound card against clip, so you can record at near optimal levels without the risk of ruining a take through overload. When used with a professional quality sound card, such as the E-MU 1212M , the capabilities of the TFPRO pre amplifiers become clear and the setup can be used to achieve recordings of the highest standards.

Location recording

The P4 is portable, so the same quality front end features can be taken anywhere, allowing for example two condenser microphones to record directly onto a portable recorder. With the need for a mixing desk eliminated, the advantage of the P4 in this situation is clear.

Live sound production

The current mode pre amplifier give obvious sonic improvement when using with dynamic mics on stage and when attempting to amplify instruments with specialist pickups. Time and again users of the current mode pre amplifier have reported how much easier it makes live engineering with instruments such as acoustic bass, violin, acoustic guitar etc; anything that may present an 'odd' impedance or large dynamics can be extremely difficult to control and sweeten using conventional pre amplifiers. In this situation the P4 is ideal, combining the current mode pre amplifier with a limiter capable of controlling these signals in a tiny package. Simply connect the Mic/instrument feed from the multicore to the P4, and feed a desk line input with the P4 output for immediate help in this situation.

녹음 샘풀은 http://www.tfpro.com/products/p4_extra/lim_comp.mp3에 있습니다. 가서 한번 들어 보세요.

This new limiter is very powerful indeed for voice. Human voice is predominantly 'one sided' when looking at an oscilloscope trace recording. This is mainly due to the constant movement of air in one direction while speaking. The problem is that loudspeakers cannot truly replicate this, and digital recorders, when presented with such a signal will tend to clip even though the amount of 'volume' may be quite low. Our new Asymmetric limiter will tend to 'pull' a signal into a more balanced form without causing distortion, enabling greater capability from your recording device