Heathkit IM-48 Audio Analyzer

The Heathkit IM-48 Audio Analyzer is a unique instrument. It combines
three important and useful audio test devices. The instrument functions
as an audio wattmeter, a high sensitivity AC VTVM, and an intermodulation
analyzer. Noninductive load impedances of 4, 8, 16, and 600 ohms are built in.

SPECIFICATIONS

Frequency Response:
	AC VTVM . . . . . . . . . . . .	 10 Hz to 100 kHz +/- 1 db
	Wattmeter . . . . . . . . . . .	 10 Hz to 50 kHz +/- 1 db
	I.M. Analyzer High Pass Filter.	 2 kHz to 12 kHz
	I.M. Analyzer Low Pass Filter .	 10 Hz to 600 Hz

Sensitivity:
	AC VTVM . . . . . . . . . . . .	 10 millivolt full scale maximum
	Wattmeter . . . . . . . . . . .  .15 millivolts full scale maximum
	I.M. Analyzer . . . . . . . . .  .04 volts minimum high frequency signal
					 required or .17 volts of LF and HF energy mixed 4:1

Range:
	AC VTVM . . . . . . . . . . . .	 01, .03, .1, .3, 1, 3, 10, 30, 100, 300 volts RMS full scale
	DBM . . . . . . . . . . . . . .	 -40, -30, -20, -10, 0, +10, +20, +30, +40, +50
					 reads from -65 to +52 dbm
	Wattmeter . . . . . . . . . . .	 15 mw, 1.5 mw, 15 mw, 150 mw, 1.5 w, 15 w, 150 w full scale.
					 Maximum continuous power - 25 watts, intermittent power, to 50 watts
	I.M. Analyzer . . . . . . . . .	 1%, 3%, 10%, 100% full scale

Input Impedance:				
	AC VTVM . . . . . . . . . . . .	 1 Mohm or 4,8,16,600 ohms switch selected
	I.M. Analyzer . . . . . . . . .	 1 Mohm or 4,8,16,600 ohms switch selected
	Wattmeter . . . . . . . . . . .	 4,8,16,600 ohms internal load, 10 kohms across
					 external load

Output Impedance:
	Low and High Frequency
	Output. . . . . . . . . . . . .	 3 kohms (600 ohms when shunted with 750 ohm resistor)

Internal Generator Frequencies:
	Low Frequency . . . . . . . . .  60 Hz
	High Frequency  . . . . . . . .  Approximately 6 kHz

General:
	Multipliers . . . . . . . . . .  Precision type
	Meter . . . . . . . . . . . . .  4-1/2” streamlined case with 200 microampere movement
	Meter Rectifier . . . . . . . .  Germanium diode bridge
	Tube Compliment . . . . . . . .	 12AT7, 12AU7, 12AX7, 6C4, 6X4

	Power Supply. . . . . . . . . .  Transformer, full wave rectifier
	Power Requirements. . . . . . .  105-125 or 210-250 VAC, 50/60 Hz, 30 watts

	Dimensions. . . . . . . . . . .  13” wide, 8-1/2” high, 7” deep
	Net Weight. . . . . . . . . . .  9 lbs