JTM45 O/S Front and Rear Panel Features (continued)
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
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.
Connects the guitar to channel 1.
