User`s guide

used simultaneously. However, when using the Dual Tube EQ
to convert an unbalanced signal to a balanced signal (and vise-
versa) you will experience a level difference between the input
and output signals. This isn’t a big deal as you can compensate
with the Input and Output Level controls, but the front panel “0”
indicators will not be accurate unless using common connectors
(both XLRs or both 1/4).
Note: If you experience a hum when using both output connec-
tors simultaneously (one to the console and one to an instru-
ment amp), a ground loop may be the problem. To remedy this
problem, disconnect the ground wire (pin 1) from the XLR cable
plugged into the Dual Tube EQ’s output (or use a ground-lifted
audio cable). This interrupts the ground path and therefore
breaks the loop.
Mono (cascade) connections
When using the Dual Tube EQ as a mono, eight-band equalizer,
use the channel one connections labeled “Mono Input and
Output”. In this mode channel two may be used as a tube chan-
nel with input and output level controls.
Tube Replacement
The tubes in your Dual Tube EQ should last for many years.
The tubes used in your unit are carefully hand-sorted for perfor-
mance. In the event that you need to replace them, A R T sug-
gests that you do so with tubes available from A R T. These are
matched to the Dual Tube EQ and will yield consistent sonic
results. You’ll find these tubes to be very reasonably priced. You
can replace the tubes with other brands, however A R T has no
responsibility for the resulting sound quality. They may sound
better, they may sound worse. The choice is yours. Please real-
ize that unauthorized alterations to the Dual Tube EQ will void
the warranty.
Instruments and the Audio Spectrum
The following chart gives you an idea of where certain instru-
ments lie in the audio spectrum. If an instrument isn’t listed, use
the one which most closely resembles it. The descriptions in
quotations are references for you to experiment with. For exam-
ple, if you have a kick drum with no “click” from the beater, try
boosting around 2 - 2.5KHz. Since every instrument, micro-
phone and room is different, these are only approximations but
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