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Balanced and Unbalanced Input Lines

Recording and broadcast studios use balanced connections almost exclusively because of their inherent ability to reject noise and hum, assuring the best sound. Certain high quality preamplifiers and surround controllers built for residential use utilize balanced connections with XLR jacks for the same reasons. The P 3’s balanced outputs enable you to take full advantage of the inherent noise rejection capability and superior sound quality of Parasound Halo power amplifiers.

Unbalanced connections with RCA jacks are found on all home audio equipment. RCA jacks and two- conductor wires are less costly than the additional circuitry, higher priced XLR connectors and three- conductor wiring required for balanced connections.

In an unbalanced line, the positive audio signal appears at the center pin of the RCA jack and the negative signal on the outer shield wire, which also functions as the ground connection. Unbalanced interconnect cables are vulnerable to hum from an AC line, or other noise, such as RFI (Radio Frequency Interference), which can be reproduced through your loudspeakers. Since the unbalanced line’s ground also carries the audio signal, there is no way for the connected amplifier or preamplifier to distinguish between the audio signals you want and unwanted noise emanating from external sources.

Balanced lines are superior because they utilize separate conductors for audio and ground: two inner conductors carry the positive and negative audio signal, and a third outer wire connects the grounds and also shields the two signal conductors. When the positive and negative signals appear at the component receiving the signal they are equal, but 180 degrees out of phase with each other with respect to ground. To send and receive balanced signals requires special differential circuitry.

A differential input circuit amplifies only the difference between the positive and negative signals. For example, when a 1 Volt signal arrives at a balanced input stage, the differential input “sees” a positive 1 Volt minus a negative 1 Volt, or 2 Volts total. External hum and noise that somehow get into a balanced line is common to both its positive and negative conductors with respect to ground. Therefore, it’s canceled, or rejected, by the differential input circuit.

This phenomenon of rejecting noise signals common to both positive and negative conductors is called common-mode rejection. Differential inputs are specified according to how well they reject signals common to both conductors. This is measured in dB and is called the common mode rejection ratio or CMRR.

Direct Inputs

The P 3 direct inputs have the shortest signal paths with the fewest parts from the input to the output to avoid any contamination from collateral tone control or record output circuits. As a result, you can’t alter tone or make recordings from components that are connected to Direct Inputs 1 or 2.

External Loop In / Out Connections

The left and right channel External Loop In/Out jacks come from the factory with jumpers installed. When these jumpers are removed, you can "insert" signal- processing components into the internal signal path of the P 3. This includes signal processors such as surround decoders, equalizers, and spatial enhancers. The External Loop also lets you patch in a second audio record/playback system such as computer-based CD-R, CD-RW, and MP 3 burning and monitoring components. You can also use the External Loop to add in sound effects, narration, or music on videotaped movies.

Output Connections

There are two pairs of output jacks on the rear panel of your P 3, one balanced pair and one unbalanced pair. When a source is playing, both outputs are active. You can connect both output pairs simultaneously to two amplifiers if you wish.

Balance

You can change the balance a maximum of 12 dB in either direction. Usually, you should not need to change the balance level from its 0 dB middle position, but if your listening area is closer to one speaker or the other, you can compensate for this with the balance control so one speaker does not sound louder than the other does.

Balanced Output Connections

Use the balanced output to connect your P 3 to a power amplifier with balanced inputs such as the Parasound Halo Series amplifiers. Like the Balanced Inputs, the Direct Balanced XLR inputs provide the highest-quality audio transmission of the P 3's outputs. As mentioned earlier, balanced circuits provide superior hum and noise cancellation and can even eliminate hum created by ground loops, especially in long wire runs.

Bass and Treble Level Controls and Tone Button

The bass and treble controls offer adjustment of overall tonal balance. The Bass controls allow you to boost or cut low frequencies +/- 10 dB in 2 dB steps. The Treble controls allow you to boost or cut high frequencies +/- 10 dB in 2 dB steps. To preserve sonic clarity, use these controls sparingly and only for recordings that sound better with them. You will find that very slight adjustments can add a degree of warmth, richness, clarity and airiness. However, greater adjustments may obscure musical detail, and