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.
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
2kHz 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.
A/M 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
A1 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
M1 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
M2 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.
M3 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.
M4 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.
