Front Panel Functions
1. Power Switch
On / Off Switch for mains power to the amplifier.
2. Standby Switch
Controls H.T. or high voltage to the valves to allow
them to attain correct working temperature before
playing. To prolong the life of the valves it is
always advisable to switch on the Mains Power
Switch (item 1) about 2 minutes before switching
on the Standby (item 2).
On switching off, the Standby should always be
switched before the Power Switch.
The standby facility is particularly useful live
between sets and before playing, as it allows you to
keep the valves operating at a functional
temperature but without any sound being
produced.
3. Presence Control
Adds higher frequencies to the guitar tone, creating
crispness and bite. Turning this up will make the
sound more cutting and further forward.
4. Bass Control
Controls the amount of low frequencies or bottom
end in your tone.
5. Middle Control
Dictates the middle register of the amplifier.
Turning this up will make your guitar sound fatter.
Conversely reducing the amount of middle in your
tone will result in a sharper and thinner guitar
sound for the classic ‘scooped’ tone.
6. Treble Control
Controls the high frequencies of the guitar tone,
making your guitar sound brighter when increased.
7. Volume I
Controls the overall output level of channel 1.
Note - this channel is voiced for a higher treble
response than channel 2.
8. Volume II
Controls the overall output level of channel 2.
Note - channel 2 is voiced for normal response.
9. Input Jack
Connects the guitar to channel 1.
10.Input Jack
Connects the guitar to channel 1.
Note - this input has less gain than item 9.
11. Input Jack
Connects the guitar to channel 2.
12. Input Jack
Connects the guitar to channel 2.
Note - this input has less gain than item 11.
Rear Panel Functions
1/2. Loudspeaker Jacks
With all valve amplifiers it is imperative that the
amp is connected to a load whilst in operation and
that the impedance selected on the amp matches
the total impedance of the speaker cabinet(s) being
used. For example, if the amp is running into a
single 16 Ohm cab, the amp should accordingly be
set to 16 Ohms. If running into two 16 Ohm cabs,
the amp should be set to 8 Ohms. If running into
two 8 Ohm cabs the amp should be set to 4 Ohms.
Note - The matching cabinet supplied with this
amp is wired for 16 Ohms.
Failure to comply with these points will result in
damage to the amplifier.
3. Output Selector
Matches amplifier output transformer impedance
to loudspeaker load impedance.
4. H.T. Fuse
See label for correct value.
5. Mains Input
Connects unit to power supply.
6. Mains fuse
See label for correct value.
JTM45 O/S Front and Rear Panel Features (continued)
