Owner's manual

The Technical Stuff
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About “Class A”
Most electronic devices can be designed in such a way as to minimize a particularly unpleasant form
of distortion called crossover distortion. However, the active components in “Class A” electronic
devices such as the 710 draw current and work throughout the full signal cycle, thus eliminating
crossover distortion altogether.
Phantom Power
Most modern condenser microphones require +48 volts of DC (Direct Current) power to operate. When
delivered over a standard microphone cable (as opposed to coming from a dedicated power supply),
this is known as “phantom” power. The 710 provides such power when the Phantom switch is engaged
(placed in the +48V, up position) ( see #4 on page 5), applying 48 volts to to pins 2 and 3 of the
rear panel output connector.
While, in theory, this should result in no harm to the connected microphone even if it does not require
phantom power, problems can occur if the shield (pin 1) is broken or when using inexpensive
microphones that use the shield as their ground. The application of phantom power can even damage
those older ribbon microphones that have their output transformers wired with a grounded center-tap.
What’s more, the application of phantom power can often result in a loud pop (transient). For these
reasons, we strongly recommend that the Phantom switch be left in its off (down) position when
connecting and disconnecting microphones. Only turn the Phantom switch on if you are certain that
the connected microphone requires 48 volts of phantom power. If in doubt, consult the
manufacturer’s owners manual for that microphone.
Phase Inversion
The occasional need for phase inversion (changing the 710 front panel switch from INø to OUTø)
is best demonstrated by a common example: recording an open-backed guitar amplifier with two
microphones, where one mic is placed close to the front of the amp's speaker and the other near the
back of the amp. The waveform display of the first mic will show an upward peak when the speaker
pushes outward, placing positive sound pressure on the mic. However, the waveform display of the
second mic (the one behind the amp) will show a downward (negative) valley when the speaker pushes
forward, because from the back of the amp the speaker moves away from the mic, thus creating
negative sound pressure. If these two signals are mixed, the positive waveform from the front mic
combines with the negative waveform from the back mic to result in cancellation of much of the amp's
sound and a "thinning effect" that is sonically disappointing. However, if the phase of one of the mic
signals is inverted, the two signals will combine instead of cancelling, and the result will be much
fuller and sonically pleasing.