VAC Phi 220 - Manual (Page 17)

15
Tips: Impedance Matching
We strongly suggest that you experiment with the three available impedance connections for the
best sonic match with your system. Since no loudspeaker represents an unchanging impedance at
all frequencies, it is impossible to assert with certainty which output tap is appropriate to use. In
many systems an amazing difference in sound will exist between the various impedance taps.
The available connections on your Phi are:
Labeled Use with speakers of
8 ohms 4 to 8 ohms
4 ohms 2 to 4 ohms
2 ohms 1 to 2 ohms (Phi 220 only)
Since the impedance of most loudspeakers vary over a wide range experimentation is essential.
Most speakers have a rated impedance of 4 or 8 ohms. We recommend starting with the 8 ohm
connection; after you know the sound if that connection, try the 4 ohm connection. Choose the
connection that sounds best to your ears.
If you bi-wire your system (run separate speaker leads from the amplifier to the high and low
frequency transducers) you may discover that two different impedance taps work best.
Contrary to popular misconception, no power is lost due to unused output taps.
For more information consult VAC Technical Monograph 90-9.