Rane AVA 22D 2000 version - Manual (Page 4)

Manual-4
600 OHM USER INFORMATION
The AVA 22d’s Inputs are specified for a nominal +4 dBu input, which is a voltage referenced level of 1.228 Volts RMS.
(0 dBu = 0.7746 Volts). At this voltage level, the AVA 22d provides 16 dB of headroom. Users who wish to operate the AVA
22d in 600 ohm systems must provide their own 600 ohm input resistor across the input terminals. This enables the AVA 22d
to accept a +4 dBm input and allows delivery of +4 dBm to a 600 ohm load. Confusion among 600 ohm users of the AVA 22d
may occur if one assumes the input and output impedances of the AVA 22d are 600 ohms – they are not. Therefore, when
evaluating the AVA 22D do not assume that +4 dBm equals +4 dBu unless you have ensured that all input and output imped-
ances in your test setup are 600 ohms.
Advantages of Hi-Z in/Lo-Z out systems:
(from Audio System Design and Installation, by Phillip Giddings, Howard W. Sams, 1990, pp. 129-130.)
1. Less distortion in output due to smaller output current needs.
2. Lower noise pickup by interconnecting lines due to lower source impedance.
3. Greater lengths of cable may be driven for a given high frequency roll-off.
4. Many pieces of equipment can be driven from one output without the use of distribution amplifiers and with no concern for
matching or level changes.
5. Better reliability resulting from less heat generation due to less power drawn from the output stage.
6. Because of the AVA 22d’s 200 ohm output impedance, the addition of a 600 ohm load termination drops the delivered
voltage by about 2.5 dB.
7. Greater signal voltage swing as 6 dB of signal is not lost in the (600 ohm) source impedance.
8. Smaller currents reduce inductive coupling and crosstalk between cables.
AVA 22d CONNECTION
When connecting the AVA 22d to other components in
your system for the first time, leave the power supply for last.
This gives you a chance to make mistakes and correct them
before any damage is done to your fragile speakers, head-
phones, ears, or brains. The AVA 22d passes audio while it is
unpowered by virtue of its fail safe bypass relays (when the
AVA 22d functions as a wire). Turn the system volume down
before plugging in the AVA 22d’s power.
INPUTS
The AVA 22d’s Inputs are electronically balanced. Use
only balanced wiring. Pin 2 is “hot” per AES standards.
OUTPUTS
The AVA 22d’s Outputs are balanced line drivers. Pin 2 is
“hot” per AES standards.
REMOTE RECALL TERMINALS
Each Channel of the AVA 22d has two nonvolatile
Memories, “A” and “B”. Connecting a switch between the
GND and MEM terminals permits remote stereo recalling of
the Memories. Only a change in the switch position is sensed.
When the switch closes, both Channels’ Memory B’s are
recalled. When the switch opens, both Memory A’s are
recalled. See Operating Instructions for more details or an
option.
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