Axo APHEX EQF2 Parametric Equalizer Filter Instructions

EQF – 2
PARAMETRIC EQUALIZER/FILTER

EQF2 Parametric Equalizer Filter

• Tunable
  Peak/Shelf EQ

• Tunable
  Hi/Lo Pass Filter

• Modular
  (Retrofits to Industry Standards)

• Full Band
  (20Hz to 20kHz)

• Constant Bandwidth
  (1.5 Octave)

• Reciprocal Equalization
  Curves (Cut/Boost)

• Resolution
  (Expanded 600º Cut/Boost}

Well established in major studios internationally, the EQF-2 is available through the worldwide sales offices of Aphex Systems Ltd.
To fix that difficult guitar or that impossible bass drum, or simply to get that “just right’ sound, the EQF-2 has proven itself to be a powerful and creative tool.
The design engineers at Aphex are also experienced musicians and studio personnel, and they listen to what they design. One cannot determine what a piece of gear sounds like by looking at a graph. Tne EQF-2’s curves were chosen for the way they sounded not how they fooked. The ‘music first’’ ohilosophy carries through all Aphex products, because good music is what it’s all about in the first place.

SPECIFICATIONS

INPUT SPECIFICATIONS:

HIGH LEVEL INPUT Z = 34K OHM: MAXIMUM INPUT LEVEL = +30dBm
LOW LEVEL INPUT Z = IIK OHM: MAXIMUM INPUT LEVEL = +20dBm
OUTPUT SPECIFICATIONS:
HIGH LEVEL OUTPUT AT CLIPPING = +30dBm
LOW LEVEL OUTPUT AT CLIPPING = +20dBm
NOISE OUTPUT (INPUT SHORTED).
HIGH LEVEL OUT = -93dBm
LOW LEVEL OUT = -103dBm
TRANSFORMER (OUTPUT):
#JE t23 AL (OPTIONAL)
(OUTPUT SPECIFICATIONS WITH BIPOLAR 16 VOLT SUPPLY.)
FREQUENCY RESPONSE:
EQUALIZERS AND FILTERS OUT OF CIRCUIT: 0.1 dB, 10 TO 20.000 HZ.
EQUALIZERS AND FILTERS IN CIRCUIT, MINIMUM EQUALIZATION, MAXIMUM BANDWIDTH: -1 dB, 20 TO 20,000 HZ.
FILTER AND EQUALIZER CHARACTERISTICS:
HIGH PASS TUNING (2ND ORDER BUTTER- WORTH): = 20 TO 500 HZ FLAT PASS- BAND.
LOW PASS TUNING (2ND ORDER BUTTER- WORTH) 1 TO 20 KHZ FLAT PASSBAND.
LOW FREQUENCY EQUALIZER: 25 HZ TO 500 Hz +f2dB (PEAKING & SHELVING)
MID FREQUENCY EQUALIZER: 250 TO 5,000 Hz +12dB
HIGH FREQUENCY EQUALIZER: 1 KHZ TO 20 KHz +12dB (PEAKING & SHELVING)
TRUE RECIPROCAL BOOST/CUT SWITCHING ON ALL THREE EQ RANGES.
SEPARATE EQUALIZER AND FILTER IN/OUT SWITCHING.

DISTORTION AND TRANSIENT RESPONSE:
HARMONIC AND 1.M, DISTORTION ARE LESS THAN 0.1%
SLEW RATE: GREATER THAN 10 VOLTS PER MICROSECOND.
OVERSHOOT ANI RINGING: NEGLIGIBLE, WITH OR WITHOUT LOADING
MECHANICAL DATA:
THE EQF-2 1S AN ELECTRO-MECHANICAL RETROFIT FOR AENGUS, APS], AUTOMATED PROCESSES, MODULAR AUDIO PRODUCTS, AND MELCOR EQUALIZERS.
FRONT PANEL: 5.25 IN x 1.5 IN. (13.3 CM. x 3.8 CM.)
DEPTH: 6 IN. (15.2 CM.)
WEIGHT: 2 LB. (0.9 KG.)
POWER REQUIREMENTS:
±12 VOLTS TO ±18 VOLTS AT 75MA MAXIMUM CURRENT AND 1% OR BETTER RIPPLE.
EDGE CONNECTOR:
15 PIN. 4MM SPACING

1  = CHASSIS GND
2 = HIGH LEVEL OUTPUT
3 = LOW LEVEL OUTPUT
4 = OUTPUT LOW SIDE
5 = POWER COMMON
6 = SPARE
7 = SPARE
8 = INPUT LOW SIDE| 9 = LOW LEVEL INPUT
10 = HIGH LEVEL INPUT
11 = GAIN TRIM
12 = POWER IN
13 = POWER SUPPLY COMMON
14 = POWER IN
15 = SPARE
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*GAIN ADJUSTMENT IS ACCOMPLISHED BY RESISTOR TO POWER COMMON. GAIN INCREASES AS FOLLOWS:
4.7K = +2 dB, 1.6 K = +4 dB,
0.62K = +6dB, 0.1 K = +8 dB

EQF – 2 BLOCK DIAGRAM

EQ- F 2 SIGNAL PATH

EQF – 2 HI PASS

EQF – 2 LOW EQ

EQF – 2 MID EQ

EQF-2 DC OFFSET CALIBRATION PROCEDURE
If it ever becomes necessary to replace one of the op-amps, this procedure will renull the overall d.c. offset of the EQF-2.
See drawing for test points.

1. Attach noise filter to input of oscilloscope.
2. Set scope on 5mv. per division scale and DC.
3. Ground scope to an audio Gnd. on EQF-2 test cable.
4. Turn all EQ knobs fully clockwise.
5. Attach test lead from noise filter on scope to either of the center pins of SW2 (“EQ” switch) on EQF-2.
6. Engage “Filter” on EQF-2 and adjust “Position” knob on scope for center or “0” line of the screen. This is your DC reference.
7. Disengage “Filter” and adjust “Trimpot One” on EQF-2 so line matches with reference. When aligned properly, line will not move when “Filter” is engaged/disengaged.
8. Engage “EQ” on EQF-2 and adjust “Trimpot Two” so line matches with reference. (As in step #7).
9. Double check that when “EQ” or “Filter” is engaged or disengaged the line stays stationary.

NOTES ON ABOVE

1. If DC is so far out of alignment that it cannot be calibrated by either trimpot, try swapping some of the #351 IC’s around (usually #2 with #9 or #1 with #9 works best). After moving IC’s around re-calibrate DC.
2. If possible, avoid calibrating so trimpot is at end stops. You should have enough adjustment left in trimpot to be able to pass reference line by at least 5mv. If this is not: possible see “Note One”.

EQF – 2 DC OFFSET ILLUSTRATIONS

DC CALIBRATION HINT
To aid in getting accurate DC readings with high scope sensitivity, we recommend constructing a simple low pass (noise) filter as described below.

R – 1 MODULAR INTERFACE
The R-1 is a compact rack mount package designed to hold ten EQF-2 or CX-1 size packages. The R-1 backplane provides barrier strip access to all inputs and outputs; power and ground are bussed.

PS – 1 POWER SUPPLY
The PS-1 is a rack mount power supply designed to complement the R-1 in looks and function. Its ± 16V @ 3.0 Amps will adequately power anything the R-1 can hold. Your modules are protected by built – in Over Voltage Protection and illuminated circuit breaker/power switch.

• SUPPORTS 4 APHEX AUDIO MODULES
• ALL PATCH POINTS ON REAR (¼” and T-T SIZES)
• SELF-POWERED FOR 115-230V
• EXTREMELY COMPACT AND PORTABLE FOR THE ENGINEER/PRODUCER ON THE GO
• HI/LO LEVEL SELECT FOR EACH INPUT/OUTPUT

SPECIFICATIONS

DC SUPPLY — REGULATED ± 16V @ 500mA
POWER REQUIREMENTS — 115-230 V.A.C., 25 WATTS
SIZE – 5.75″ H x 11″ W X 7.75” D (EXCL. KNOBS)
WEIGHT – (EMPTY) 9 lbs., 2 oz.

7801 Melrose Avenue
Los Angeles, California 90046
213-655-1411.
TWX:910-321-5762

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