Note – Important! After turning off the amplifier, wait at least one minute to turn it back on. Do not turn it on then off and then on again in quick succession. Doing this will not allow the power supply to discharge between on/off cycling and may result in transient noises.
USING AN EXTERNAL PREAMPLIFIER
The Tempest offers the flexibility of adding an external preamplifier should the user wish to do so. In the external preamp mode the Tempest preamp is completely bypassed and only the power amplifier section is used. To set up the Tempest for use with an external preamp perform the following steps.
1) Remove the cover
WARNING - This amplifier uses voltages that could cause injury or death. Never open the amplifier while it is plugged in, and always wait at least one hour after turning the unit off to unplug and open the unit. Lethal voltages can remain in the electronics after the unit is unplugged
2)Locate the four small shunts on the control circuit board as shown in figure 1.
3)Using a needle nose pliers carefully remove the four shunts from the locations marked “int pre” and move them to the adjacent locations marked “ext pre.”
4)Rotate the selector knob to preamp on the front panel.
5)Connect the external preamp to the inputs on the rear panel marked preamp.
TRIODE ULTRALINEAR SWITCH
This switch is located on the back panel of the amp. See Figure 2. The output transformer of a tube amplifier acts as the electrical interface between the very different impedances of the loudspeaker and the tube circuitry. There are three fundamental ways that the output transformer can be connected to the tube circuit.
1)Tetrode or Pentode connection – In this configuration, the highest power level is achieved but at the expense of significantly higher distortion levels. Practically speaking, this mode of operation is sonically inferior and has been disregarded in the Tempest II design.
2)Triode connection – With this configuration, the lowest level of distortion is achieved but at the expense of output power. In the case of the Tempest II, its
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