Aphex Systems 661 Stereo Amplifier User Manual


 
Tube Compressor/Limiter
Expressor
®
/Easyrider
®
withTubessence
®
Model 661
FRONT PANEL
(1-14 Active in Auto and Manual Modes)
1. The PROCESS IN / BYPASS Switch operates a
bypass relay (indicated by a yellow LED) that connects
the Main Audio input directly to the Output, completely
bypassing the 661. PROCESS IN (indicated by a red
LED) engages the 661 circuitry.
2. The SPR Switch controls the Spectral Phase
Refractor circuit. SPR can reverse the effect of accu-
mulated low frequency time delays caused by audio
passing through too many electronic stages.
3. The INPUT Control sets the amount of gain in the
661’s input stage.
4. The THRESHOLD Control sets the level above
which input signals will be processed by the 661’s gain
control circuitry in a manner defined by the settings of
the various AUTO or MANUAL controls.
5. The OUTPUT Control sets the amount of gain in the
661’s output stage, restoring level lost by compression
(make-up gain).
6. The LOW CUT Switch inserts a 6dB per octave low
cut filter with an 80Hz corner frequency into the
sidechain. This is most useful when using the 661 (two
in stereo link mode) to process a stereo mix-down of
base predominate material.
7. HIGH FREQUENCY EXPANDER (HFX) is a form of
dynamic equalization that boosts high frequencies
when gain reduction occurs. The HFX RATIO Control
sets the amount of equalization (6 dB per octave shelv-
ing) for the amount of Gain Reduction. At 1:1 there is 1
dB of High Frequency Expansion (or boost) for every
1dB of Gain Reduction.
8. The FREQUENCY Control lets you set the (HFX)
corner frequency of the shelving EQ anywhere between
2 kHz to 20 kHz.
9. The AUDIO LEVEL Meter monitors the Input and
Output level depending on the position of the switch
below the meters. A red CLIP LED at the right of the
meter indicates clipping.
10. The GAIN REDUCTION Meter shows the amount
of compression in 2dB steps with a maximum of 30dB.
11. UNLINK must be engaged for normal operation of
one 661. Depressing LINK or SLAVE when using only
one 661 will cause the unit to malfunction.
12. LINK is engaged when two 661’s are used in
stereo. Both 661’s must have the LINK switch engaged.
13. SLAVE is used when two 661’s are being config-
ured for a master/slave operation. Only the unit acting
as a SLAVE should have the SLAVE switch engaged.
The master unit needs to be in LINK.
14. The LED at the top of the POWER SWITCH illumi-
nates when the unit is powered.
The AUTO / MANUAL Mode switch determines if
the 661’s primary control parameters will be manually
adjusted by the user or automatically adjusted by the
661. In the AUTO (Easyrider) Mode the Fast / Slow
switch is active while Soft Knee, Ratio, Attack and
Release are defeated. In the MANUAL Mode, Soft
Knee, Ratio, Attack and Release are active, while the
Fast / Slow switch is defeated
AUTO MODE
When in the AUTO Mode the attack and release
characteristics of the Easyrider circuit are auto-
matically adjusted based upon the waveform of the
input. The SLOW/ FAST switch selects between two
ranges of the automatic release circuit.
MANUAL MODE
The SOFT KNEE Switch in the OFF position
results in a transition at threshold that is of the
abrupt Hard Knee type. In the ON position (indicated by
red LED), signals are processed more gradually and
the transition is less noticeable
The RATIO Control determines the amount of
change in output level for a given change in input
level above threshold. This is expressed as a ratio: rel-
ative input versus output. The range of this control is
1:1 to 30:1.
The ATTACK Control adjusts the time in which
the 661 will reduce the gain after an increase in
input over threshold. The range of the control is .05 to
100 ms.
The RELEASE Control adjusts how long it takes
the 661 to release gain reduction after a decrease
in input level. The range of this control is .04 to 4 sec-
onds.
BACK PANEL
1. VOLTAGE SELECTION AND FUSE
AC line power is supplied to the unit via an integral
receptacle/fuse holder on the rear panel which meets
all of the international safety certification requirements
and also doubles as a radio frequency line filter.
2. LINK provides two different methods of linking the
VCA control between two 661’s: Stereo Link and
Master/Slave. To link two 661’s, insert a 1/4” TS cable
into the LINK jack on both units.
3. SIDECHAIN ACCESS provides a 1/4” TS jack to
send the output of the 661 into an external processing
device and a return 1/4” TS jack for returning the out-
put of an external processing device into the 661.
4. The OPERATING LEVEL Switch on the rear panel
selects the nominal operating level to either +4dBu or -
10dBV. This switch sets the dynamic range of the 661’s
circuitry to best match you standard operating level,
and also sets the 0dB calibration of the front panel
AUDIO LEVEL Meter to equal the reference level
selected.
5. Two servo balanced INPUT Connectors are provid-
ed, choose either a 3-pin XLR female connector or a
1/4” TRS phone jack.
6. Two servo balanced OUTPUT Connectors are pro-
vided, choose either a 3-pin XLR male connector or a
1/4” TRS phone jack.
7. A WIRING TABLE is printed on the back panel for
assistance in the proper wiring of connectors.
PROCESS
IN
BYPASS
SPR
0
-2
-4
-6
-8
-1
0
+2
+4
+6
+8
+1
0
INPUT
dB
-7
-9
-12
-17
-25
-3
0
-5
0
+3
+9
+2
0
THRESHOLD
dB
0
-3
-6
-10
-11
-1
2
+3
+6
+10
+14
+1
8
OUTPUT
dB
Easyrider
TM
AUTO
SLOW
FAST
MANUAL
SOFT
KNEE
4
3
2.5
2
1.3
1.0
5
6
7
10
3
0
RATIO
20
1
0
5
1
.5
.05
3
0
4
0
6
0
80
1
00
ATTACK
mSEC
.22
.16
.1
.
0
6
.
0
5
.
0
4
.4
1
2
3
4
RELEASE
SEC
SIDECHAIN
LOW
CUT
.5
.4
.3
.2
.1
OFF
.6
.7
.8
.9
1.
0
HFX RATIO
HIGH FREQUENCY EXPANDER
FREQUENCY(kHz)
-30 -24 -18 -12 -6 0 +3 +6 +9 +12 CLIP
30 24 20 16 13 10 8 6 4 2
AUDIO LEVEL
GAIN REDUCTION
INPUT
OUTPUT UNLINK LINK SLAVE POWER
8
6.4
4.6
3.2
2.4
2
10
14
16
18
20
EXPRESSOR
TM
with
Tubessence
®
RETURN
SEND
OUTPUT
INPUT
MODEL 661
EXPRESSOR
MADE IN USA
APHEX SYSTEMS LTD.
SUN VALLEY, CA
U.S. PATENT NO. 5115471
OTHER PATENTS
ISSUED OR PENDING
AC 100/120/220/240V 50/60HZ 20 WATTS
FUSE: 100/120V=0.375A 220/240V=0.25A (250V SLOW BLOW)
TM
SERIAL #
CHASSIS
GROUND
59887
COMMERCIAL
AUDIO EQUIPMENT
®
SIDECHAIN ACCESS
TIP/SLEEVE - UNBALANCED
MAIN AUDIO
1/4"
SLEEVE
TIP
RING
GROUND
POS
NEG
XLR
PIN 1
PIN 2
PIN 3
OP
LEVEL
+4
-10
LINK
TIP/SLEEVE
UNBALANCED
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE
THIS DEVICE TO RAIN OR MOISTURE. DO NOT REMOVE
THE COVER. NO USER SERVICABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED PERSONNELONLY.
ATTENTION: AFIN D'EVITER DES CHOCS ELECTRIQUES,
N'ENLEVEZ PAS LE COUVERCLE. IL N'Y A AUCUNE
PIECES D'ENTRETIEN A L'INTERIEUR. REFEREZ LES
REPARATIONS A UNE PERSONNE QUALIFIEE.
ATTENTION: RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR
L
I
S
T
E
D
1 23 76 4 5
1 2 3 4 5 6 7 8 9 11 12 13 10 14
BACK PANEL
FRONT PANEL
A/M
A1
M1
M2
M3
M4
A/M M1 M2 M3 M4A1