23 Power Tube Fuse
24 Noise Gate Threshold Level
A tip from the designer:
IMPORTANT note; please read and heed
This red LED lights up to indicate one of the internal power tube fuses (4 pcs.) has
blown. You can continue playing, but the amp's performance will be diminished.
Normally the loss of a power tube results in an unbalanced signal.
Be sure to have a specialist look over the power amp as soon as possible; the fuse
probably blew because of a defective power tube. Once a fuse has blown, it must be
replaced by a new fuse.
This control activates an onboard Noise Gate serving to suppress any excess noise
generated when both
and
are active. To this end, twist the knob
clockwise, near or just beyond the 9 or 10 o'clock position.
In addition the Noise Gate can be controlled remotely (on/off) via a footswitch
connected to jack 20 (for details refer to chapter 20) or via the ENGL Custom
Footswitch Z-9 (refer to chapter 19 for details). If you want to control the Noise Gate
remotely via footswitch, you must set the Threshold knob to 10 o'clock or beyond.
Use this knob to set a threshold value (that is, the noise level) at which the Noise Gate
activates to suppress the signal within the 9 to 5 o'clock range. The further you twist
the knob to the right, the higher the signal level at which the Noise Gate kicks in. If you
set the knob to the 5 o'clock position, the Noise Gate reacts to extremely high levels
(suppresses high noise levels), meaning that there's not much of a margin between the
guitar signal and background noise.
Noise is a definite no-no in many situations. For example, studio etiquette demands
that you keep a lid on extraneous noise during short breaks. It's in the nature of high-
gain rigs to generate undesirable peripheral noise in overdriven (high gain) channels.
This is attributable to the physical properties of an amp's constituent components, in
particular its active components. That's right; those cherished tubes are the culprits.
The Noise Gate is a tool that lets you silence this noise during breaks by way of signal
mute circuit. Note that electric guitars pick up interference signals, and these are
amplified tremendously at high gain levels (Lead channel with
activated).
The most common source of noise is 50 Hz or 60 Hz (hertz/cycle) mains hum,
particularly when the guitar is positioned near transformers and power units. Because
in worst-case scenarios this humming can attain extremely high levels, the Noise Gate
can hardly distinguish between the musical signal and noise. This makes it hard to find
the right Threshold setting. It is entirely possible for this humming and other noise to
rise to a level that deactivates the Noise Gate and therefore becomes audible. My
advice is to stay as far away from transformers and power units as space allows.
: The
may open up inadvertently
when the
is activated, the high-gain Lead channel is selected, and the
volume exceeds the Threshold knob setting. At very high volume and gain settings,
this may generate instant feedback, particularly if your guitar is facing the speakers.
Rather than musical and controlled, this is the shrill, unpleasant and potentially
harmful variety of feedback squealing that sends your audience and fellow musicians
packing. Though the amp is not more susceptible to feedback when the
is
activated, the fact that it suppresses extraneous noise means you can't hear those
Lead
High Gain
High Gain
Noise Gate
Noise Gate
Noise Gate
13
