Tesoro Golden µMax Operator's Instruction Manual page 7

Adjust the SENSITIVITY
We are now ready to switch the detector into the Discriminate MODE. Go to the mode switch
and flip it all the way to the right and into the DISC position. The first thing that you will
notice is that the threshold hum stops. The discriminate circuit uses a silent search mode,
meaning that no sound will be heard until the coil goes over a target. The most common use
of the detector will be to hunt in the DISC MODE and switch to ALL METAL to pinpoint a
target. This will give you the advantage of ignoring unwanted targets and not having to listen
to the threshold hum until you are ready to recover a target.
The all metal circuit uses a single channel to detect various metals. The discriminate circuit
uses two different channels, then amplifies and filters the signals and then compares the two
to determine whether or not to beep at a target. While this is a great advantage for ignoring
unwanted targets, it can make the circuitry more susceptible to interference. A number of
outside conditions such as power lines, highly mineralized soil and wet salt sand can cause
interference. The SENSITIVITY knob is used to raise or lower the power to the operational
amplifiers, which changes the gain. Gain is the measurement of how much a signal is
amplified. The higher the gain the more depth and sensitivity to small objects a detector has.
Unfortunately, any small interference that is amplified can cause the detector to become
erratic. The SENSITIVITY control is used to find the best gain setting in any location without
letting the detector become unstable.
The SENSITIVITY knob is numbered from min to 10 and then has an orange area called the
Max Boost zone. For most normal hunting, anywhere in the numbered zone will work very
well. However, the Max Boost will allow you to increase the power to the operational
amplifiers to the point of overload. An overload situation will not hurt your detector, but it
will maximize the gain that is used by your detector. This can, in certain conditions such as
low mineralization in the soil, cause your detector to penetrate deeper into the ground and
become more sensitive to small objects.
Take some time to try waving targets in front of the coil with different sensitivity settings.
Notice that the higher the sensitivity setting, the farther away from the coil the target can be
and still get a response.
Check and Identify Discriminate ID Tones
Your Golden µMax detector has several different audio tones. As you were testing the
sensitivity, you may have heard some of these tones. In this section of the Quickstart, we will
take the time to identify each of the tones and what it means.
The first tone that we will talk about is the "saturation tone." When a target is too close to the
coil, it creates a very large signal. For most non-ID machines this is no problem. However,