Manual-4
600 OHM USER INFORMATION
The AVA 22’s Inputs are specified for a n4 dB
u
input, which is a voltage referenced level of 1.228 Volts RMS.
(0 dB
u
= 0.7746 Volts). At this
voltage
level, the AVA 22 provides 16 dB of headroom below 8 kHz. Users who wish to
operate the AVA 22 in 600 ohm systems must provide their own 600 ohm input resistor across the input terminals. This
enables the AVA 22 to accept a +4 dB
m
input and allows delivery of +4 dB
m
to a 600 ohm load. Confusion among 600 ohm
users of the AVA 22 may occur if one assumes the input and output impedances of the AVA 22 are 600 ohms – they are not.
Therefore, when evaluating the AVA 22 do not assume that +4 dB
m
4 dB
u
unless you have ensured that all input and
output impedances 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. About 14 dB 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. In the event that a 600 ohm load termination is used the delivered voltage will only drop by about 1 dB (20 log[R1/
(R1+RS)].
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 22 CONNECTION
When connecting the AVA 22 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 22 passes audio while it is
unpowered by virtue of its fail safe bypass relays (when the
AVA 22 functions as a wire). Turn the system volume down
before plugging in the AVA 22’s power.
INPUTS
The AVA 22’s Inputs are electronically balanced. Use
only balanced wiring. Pin 2 is “hot” per AES standards.
OUTPUTS
The AVA 22’s Outputs are balanced line drivers. Pin 2 is
“hot” per AES standards.
REMOTE RECALL TERMINALS
Each Channel of the AVA 22 has two nonvolatile Memo-
ries, “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.
Ω
