TIPS & ADVICE
A Word About 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.
You should consider the output impedance markings on your VAC Power Amplifier as follows:
"8 ohms" matches loads between 4 ohms and 8 ohms "4 ohms" matches loads between 2 ohms and 4 ohms "2 ohms" matches loads between 1 ohm and 2 ohms
Most loudspeakers vary outside of any one of these ranges, which is why experimentation is essential. We often find that matching a speaker's minimum impedance is more important than matching its nominal (average) impedance.
If you
Contrary to popular misconception, no power is lost due to unused output taps. Also, the amount of negative loop feedback in the amplifier does not change, being fixed at approximately 6 decibels for all output taps. For more information consult VAC Technical Monograph
TIPS & ADVICE
A Word About Output Stage Operating Mode (triode internal wiring option)
Triode amplification is the oldest form known, while partial triode
1)Somewhat more distortion at low power levels
2)Somewhat less distortion at moderate power levels
3)Reduced maximum power output
4)Output impedance matching is somewhat less critical
5)Increased damping factor.
The
VAC can provide directions allowing a skilled technician to convert the output stage to triode operation.