power level in triode is high enough that it will likely provide plenty of power for almost any speaker load.
3)Ultralinear operation – With this configuration, power levels near those of tetrode mode are achieved with low distortion levels that approach those of triode operation. For loudspeakers that demand very high levels of power, ultralinear should provide excellent sound and plenty of power.
The triode/ultralinear switch allows the user to operate the Tempest II in either of the two modes. In general, the sonic differences are subtle but for a given loudspeaker one mode is likely to sound better than the other. There is a complex relationship between the output transformer and the crossover network so try both and see which one works best in your system. This switch can be operated while the amplifier is playing but you will hear a small relay noise through the loudspeaker.
SETTING THE TUBE BIAS
Tools required: bias tool (provided with amplifier)
The output tubes (the big ones) need to be “biased’ with a grid voltage that controls the flow of electrical current through the tube. Tube biasing on the Tempest II has been designed to be both simple and effective. On some amplifiers biasing is done for two or more tubes simultaneously. With this method, the total current flowing through the group of tubes may be correct, but the current flow through any individual tube may vary significantly from the optimal value. With the Tempest II the bias is set individually for each tube so that the correct operating point is assured. An added benefit to this approach is that, should a tube fail prematurely, the single tube can be replaced without having to purchase a matched set. Use the following procedure to set the tube bias:
WARNING – There are dangerous and potentially lethal voltages inside this amplifier. Do not touch any part of the amplifier other than as described below. If you are uncertain about any of these instructions, please contact your dealer and have them bias the amplifier for you.
1)Allow the amplifier to warm up for at least 30 minutes.
2)Turn the preamplifier volume completely off so that no signal is entering the amplifier.
3)Remove the top cover. The bias tool is snap attached to the inside top of the deck lid.
4)Locate the rotary switch and associated small potentiometers (they are blue and have a small screw in the top). There are four, one for each tube. Note the biasing meter.
5)Position the rotary switch into the corresponding tube position (ie. V1 for output tube V1).
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