User Manual

6
WARNING! Before opening the upper lid of the amplifier make sure that power supply
has been disconnected AT LEAST 10 minutes allowing the electrolytic capacitors to
discharge fully. Disconnect power cord from the outlet!
CAUTION! The amplifier must be installed in such a way that free flow of hot air from
the tube is allowed. The amplifier must not be installed in a constrained surrounding
(i.e. tight shelves etc.)
CAUTION! The amplifier must be properly grounded during operation.
CAUTION! During operation the amplifier must be installed in such a way that the rear
power supplies are accessible.
CAUTION! The amplifier is an A category product. In a household it can influence
other electric appliances. In such cases the user is to take proper actions to mitigate this
disturbance.
CAUTION! Make sure that all screws holding the case together are properly in place
and tightened before carrying the amplifier with the handles.
CAUTION! Read this manual carefully. Fallow all of instructions during installation
and operation to avoid damage to the amplifier not covered by manufacturer´s
warranty! Do not attempt to perform any change of hardware or software!
3. GENERAL DESCRIPTION
3.1. HF part
In this amplifier a tetrode GU 84b is used in a grounded-cathode circuit (input into control
grid). This amplifier achieves excellent linearity by the voltage stabilization of the control
grid bias and the screen voltage. The power input is given to the control grid, using a
broadband input circuit with an input impedance of 50 Ohms. This adaptable input circuitry
ensures a good input SWR (better than 1.5:1) on all amateur bands.
The output of the amplifier is a Pi-L circuit. The ceramic capacitor for TUNE and LOAD are
divided. This enables the amplifier to be tuned exactly and makes it possible to easily return
to the previously set positions after band changes.