User`s guide

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One input jack per channel should be used at a time. Because
of its design, the Tube EQ can be hard-wired without having to
disconnect the XLR inputs when using the 1/4” jacks. In this case,
if no load is placed on the XLR input (no instrument or line-level
source connected) the 1/4” jack will function as if there was
nothing connected to the XLR input. However
, the inverse is NOT
true. If you are using the XLR input, you should not have any-
thing plugged into the 1/4” jack.
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Both balanced and unbalanced output connections may be used
simultaneously. However, when using the 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 sig-
nals. 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).
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: If you experience a hum when using both output connec-
tors simultaneously (one to the console and one to an instrument
amp), a ground loop may be the problem. To remedy this prob-
lem, disconnect the ground wire (pin 1) from the XLR
cable
plugged into the Tube EQ’s output (or use a ground-lifted audio
cable). This interrupts the ground path and therefore breaks the
loop.
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The tube in your Tube EQ should last for many years. The tubes
used in your unit are hand-sorted for performance. In the event
that you need to replace them, A R T suggests that you do so
with tubes available from A R T. These are matched to the 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 result-
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