Nady Systems manual Applications, Specifications, USING THE HPA-4AS A HEADPHONE AMPLIFIER

APPLICATIONS

USING THE HPA-4 AS A HEADPHONE AMPLIFIER

Connect a stereo (L & R) program source (2 x 1/4” plugs) to the rear of the HPA-4 using one of the available 4 x stereo INPUT (3) pairs on the rear panel.

Connect a set of headphones using a stereo 1/4” cable to any of the HEADPHONE OUTPUTS (1) on the front panel of the HPA-4. Select the source signal from the rotary SELECTOR (4) switch for the channel in use. Set to an appropriate level for monitoring. (Note: If only the LEFT (MONO) channel input is used, the mono signal will be provided automatically at both the Left and Right sides of the PHONE (1) and LINE (2) outputs.)

Since the HPA-4 offers four independent channels, you can have four individual mixes for four musicians with a single unit. In studio recording applications, you can configure sub-groups, aux sends or single outputs of your audio mixer to feed signals independently to the HPA-4. This enables each musician to receive a specific configuration of instruments of their choice

in their headphones.

[Note - If four headphone outputs are not enough, you can interface and link any number of HPA-4’s for additional outputs (see be- low).]

USING THE HPA-4 AS A LINE DISTRIBUTION UNIT

To use the HPA-4 as a line distribution unit all you have to do is use the line output instead of the headphone output on the front of the unit for the line distribution signal feed. All other operation is identical as using the unit as a headphone amplifier.

Daisy chaining multiple HPA-4’s together for additional headphone/line distribution requirements.

It is very easy to chain multiple HPA-4’s together. Use appropriate single stereo 1/4” TRS to two 1/4” TS (2 x mono) adapter cables and make connections from the LINE DISTRIBUTION OUTPUT (2) channels on the front of your first HPA-4 unit to the stereo (L&R) AUDIO INPUTS (3) on the rear of your second HPA-4.

This effectively allows an additional (fully selectable) 4 headphone outputs and an additional 4 line outputs! You can continue to chain up to four HPA-4 units together using this same procedure.

SPECIFICATIONS

AUDIO INPUTS
Connectors	1/4" jack
Type	Unbalanced
Impedance	47k Ohms
Peak input level	+25dB
Gain control range	+35dB
HEADPHONE POWER AMPLIFIER OUTPUTS
Max.output level	300mW@32 Ohms (max 1W @ 32 Ohms)
Output impedance	22 Ohms
Max. gain	+20 dB
LINE DISTRIBUTION OUTPUTS
Connectors	1/4" jack
Type	Unbalanced/Parallel

DISTORTION, FREQUENCY RESPONSE,

S/N RATIO & CROSSTALK

FUNCTION CONTROLS
Volume	Per channel, variable
Signal selectors	Per channel, Variable
POWER SUPPLY
AC requirements	Selectable, ~100-120 VAC,
	~ 200-240V AC, 50-60 Hz
Power consumption	11.5VA
Fuse	100-120 VAC: 630 mA (slow-blow)
	200-240 VAC: 315 mA (slow-blow)
	100-240 VAC: 500 mA (slow-blow)
	5X20mm glass type
Power cord connector	Standard IEC receptacle
	with built-in fuse holder
PHYSICAL
Dimensions	1.75"X 19"X 8.5"(44.5X482.6X217mm)
Weight	6.93lbs (3.15Kg)

Distortion	0.02%
Frequency response	20Hz~20kHz, 0dB~-2B
S/N Ratio	Better than 80dB
Crosstalk rejection	>68dB@1kHz; 20dBinput

The specifications above are correct at the time of printing of this manual. For improvement purposes, all specifications for this unit, including design and appearance, are subject to change without prior notice.

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