Triode/Ultralinear Modes - DYNACO Stereo 80 Owner's Manual

Triode/Ultralinear Modes

The Ultralinear mode is usually considered to be the "normal" mode of operation. The overall power
rating of the amplifier is specified for Ultralinear mode.
In Ultralinear mode, the screen grid of each output tube is connected to a tap on its associated output
transformer. When Triode mode is selected, the screen grids are (instead) connected to the plates of their
respective output tubes.
Operating the amplifier in Triode mode reduces the amplifier output power to about 1/2 of that in
Ultralinear mode. Triode mode also softens the clipping characteristics of the amplifier so it seems to
need less output power. Triode mode produces more lower-even order harmonics, whereas Ultralinear
mode produces higher-odd order harmonics.
Some people prefer Triode mode; some people prefer Ultralinear mode. The choice of which mode to use
is also often influenced by the sonic characteristics of the speakers being used.
You can listen and compare to determine which mode sounds best to you for your chosen music material
and speakers.
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