Connecting the PA640

INSTALLATION (cont'd)

I When making connections to the PA640 be sure the power cord is unplugged. Proceed as follows:

Stereo Mode Connections

1.Using good quality RCA type patch cables, connect the L and R OUTPUT jacks of the driving preamp to the CH1, CH2, etc. LINE INPUTS jacks on the PA640. Do this for each amplifier pair. Refer to Fig. 6.

2.Slide the BRIDGED/STEREO switch to the STEREO position.

3.Using good quality speaker wire, connect the individual speaker leads to the 4-terminal "SPEAKERS" connectors on the PA640 as shown.

4.Even though the PA640 is 2-Ohm safe in Stereo Mode, make sure the impedance presented to the speaker terminals by the speakers (or any combination of speak- ers) is 4-Ohms minimum.

5.Be sure to observe correct polarity by connecting the "+" and "–" terminal from each channel on the PA640 to the corresponding "+" and "–" terminals on each speaker. This will ensure correct "phasing". See Fig. 6 and Speaker Phasing below.

VIDEO

AUDIO

LEVEL

C H 1

3V .2V

Preamp Outputs

ZPR68, etc.

RCA Type

Patch Cords

Set

BRIDGED/STEREO

Switch to

STEREO position

BRIDGED

C H 2

STEREO

Since the connectors are removable, you may unplug them for ease of lead assembly.

6.As a rule of thumb, use 18 gauge speaker wire for speaker runs up to 30', 16 gauge up to 70', and 14 gauge up to 150'. The 4-terminal connectors accept wire sizes up to 12 gauge max.

7.Strip the insulation back about 1/4" and twist the strands on each lead to prevent fraying.

CAUTION: After lead ends are inserted and the screws tightened down, be sure there are no free strands that could cause shorting!

Speaker Phasing

To obtain stable imaging and full bass response, it is imperative that stereo speakers be connected "in phase" with each other. You can verify this as follows:

1.If the "+" (positive) and "–" (negative) terminals on your speakers are correctly marked, and visible, and you have wired the system as shown in Figs. 6 and 7, then the system will be "in phase". No further action is required.

LINE INPUTS

PA640 Input Panel

PA640 Speakers & AC Panel

CH2	CH1
+ –	– +

PROTECTION

+B R I D G E D –

S P E A K E R S

Be sure speakers are connected with correct polarity as shown.

–

Wall speakers,

shelf speakers, etc.

Amplifiers & Preamplifiers

	Most manufacturer's identify the positive terminal with a		Left	Right
	red binding post, a "+" sign, or a red dot.
2. If you are unsure of the markings, you can verify the			Fig. 6 STEREO Mode Connections
	phasing. Using a mono sound source, such as AM radio,
	alternately reverse the leads to one of the speakers. Pick
	the connection that delivers a solid center image between
	the speakers along with best bass response.
		
				7
	PA640			7