7
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.). During extended
operation the tube ventilation grid can reach high temperature. Do not touch it!
The amplifier must be properly grounded during operation
.
During operation the amplifier must be installed in such a way that the rear side remains accessible.
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.
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 Compartment
his amplifier is using ceramic tetrode FU-728F or GU84B ( GU78B )
in a grounded-cathode circuit
(input into control grid). The OM2501HF (OM3501HF) amplifier achieves excellent linearity by the
voltage stabilization of the control grid bias and the screen voltage. The power input is fed
to the
control grid, using a broadband input circuit with an input impedance of 50 Ohms. This adaptable input
circuit 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 variable capacitors for TUNE and LOAD are separate. This
enables the amplifier to be tuned exactly and makes it possible to easily return to the previously set
positions after band changes.
T
