Crown Audio STUDIO AMPLIFIER owner manual Input Connection, Cable, Shielded, Twin-lead

Studio Reference I & II Professional Studio Amplifiers

3.3.4 Input Connection

The balanced inputs have a nominal impedance of 10 K ohms (5 K ohms unbalanced) and will accept the line-level output of most devices. Phone jacks are pro- vided on the back panel, while the factory-installed P.I.P.-FX provides female XLR input connectors (see Figure 2.2). Optional P.I.P. modules like the P.I.P.-BB and the P.I.P.-FPX can provide barrier block and phono (RCA) connectors. Various P.I.P.s are also avail- able which provide a wide range of input signal pro- cessing features (see Section 8).

Correct input wiring depends on two factors:

(1)whether the input signal is balanced or unbal- anced, and (2) whether the signal floats or has a ground reference. Figures 3.8 and 3.9 show the recom- mended connection techniques for each combination of source signal characteristics.

			– +
	INPUT		3
		1	2
Floating	Shield connected
source	to ground terminal
Output +				cable
	2-wire line cord		– +
				shielded
(or battery power)
	INPUT		3
		1	2
Grounded	Shield is not
source	connected			Twin-lead
	at this end
Output +
	3-wire grounded line cord
(or other ground connection)
			– +
	INPUT		3
Floating		1	2
	Shield connected to both
source	negative (–) and ground
	input terminals
Output +				conductorcoax
	2-wire line cord		– +		twistedpair
(or battery power)
			3

	Note: If two or more channels with				– +
	the same input ground reference				3
		are driven from the same
			INPUT	1	2
		floating source, connect
Floating only one shield to the
source		source chassis.
Output	–
	+

2-wire line cord

(or battery power)

– +

		INPUT		3
Grounded			1	2
		Shield not connected
source
		at this end
Output	–
	+

3-wire grounded line cord

(or other ground connection)

Fig. 3.9 Balanced Input Wiring

The amplifier’s built-in 1¦4-inch input phone jacks can be wired similarly for balanced or unbalanced, floating or ground-referenced sources. They have a standard tip-ring-sleeve (TRS) configuration: the tip is positive (+), the ring is negative (–) and the sleeve is ground (see Figure 3.10). Wiring for various sources follows the XLR wiring examples in Figures 3.8 and 3.9.

If you install a P.I.P. module other than the P.I.P.-FX, P.I.P.-BB, P.I.P.-FMX or P.I.P.-FPX, do not connect in- put signals to the phone jacks. The phone jacks are in parallel with the output of the P.I.P. module, so the source connected to the phone jacks can feed into the P.I.P. and generate a distortion in the output. The phone jacks can still be used as “daisy chain” outputs to feed the post-processed signal from the P.I.P. to the input of other amplifiers.

If the amplifier will be used in Bridge-Mono or Parallel- Mono mode, be sure to follow the instructions provided in Sections 3.3.2 and 3.3.3. Do not use the channel 2 input in either mono mode.

+

Grounded	INPUT	1 2
	Input ground	Single- or
source
	terminal not used

–

SHIELD

BALANCED

Output +

3-wire grounded line cord

(or other ground connection)

Fig. 3.8 Unbalanced Input Wiring

+

UNBALANCED

SHIELD

Fig. 3.10 Balanced and Unbalanced Phone Plugs

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