Front Panel Facilities

ABM, RPM-1, MAG 300 & ELECTRIC BLUE 180

ABM/RPM-1

MAG 300

Electric

Blue 180

INPUTS

On the MAG 300 and Electric Blue 180, there are two choices of instrument input, these are marked HIGH and LOW.The HIGH input is high sensitivity and also high impedance to suit the output from PASSIVE basses.The LOW input is low sensitivity and lower impedance to suit the output from ACTIVE basses.The ABM has a single instrument input provided, linked to a PASSIVE/ACTIVE selector switch (switch out=PASSIVE, switch in=ACTIVE).

INPUT CONTROL

The INPUT control sets the signal level through the preamp in conjunction with the INPUT LEVEL VU Meter (Electric Blue 180 uses a LED display).This is adjusted to give a reading of 0VU on the meter (yellow LED on Electric Blue 180) for average playing dynamics with occasional peaks into the red (red LED on Electric Blue 180) region. Please note that this setting may require re-adjustment after modification of the EQ controls.

PUSH FLAT / SHAPE (ABM/RPM-1 only)

With this button in its OUT position a fixed E.Q. is superimposed on the preamp to give a bright but punchy character to the sound. Pushing this button IN returns the preamp to a Flat frequency response. This function may also be controlled from a footswitch. For the footswitch to operate, this button must be in its OUT position.

VALVE DRIVE (ABM/RPM-1 only)

This routes the signal either through a clean Solid State amplification section (control on zero) or through a Dual Triode Tube amplification/overdrive section to add either tonal character, i.e. warmth with the control set at 9 o’clock, a slight edge in the sound at 12 o’clock, through to an increasing degree of Tube distortion/overdrive as the control is advanced to maximum. A Mix of these two amplification sections can be achieved with this control. N.B.The degree of Tube distortion with this control will also depend on the setting of the INPUT control.

VALVE DRIVE IN/OUT (ABM/RPM-1 only)

This push button switches the valve drive section IN or OUT.This function may also be controlled from a footswitch. For the footswitch to operate this button must be in its OUT position.

DEEP (Electric Blue 180 & MAG 300)

With this button IN, a fixed E.Q. is superimposed on the preamp to give a BASS boost to the sound.This gives +8dB at 50Hz.

BRIGHT (Electric Blue 180 & MAG 300)

With this button IN, a fixed E.Q. is superimposed on the preamp to give a TREBLE boost to the sound. This gives +10dB at 10kHz.

E.Q. IN / OUT

This button switches the Equalisation section IN or OUT, i.e., the Bass, Middle and Treble controls and the two sets of sliders (rotary controls on Electric Blue 180) placed between these.This facility is footswitchable on the ABM/RPM-1 range via a socket on the rear panel. For the footswitch to operate this button must be in its out position.

EQUALISATION

This consists of BASS, MIDDLE and TREBLE controls with two sliders (rotary controls on Electric Blue 180 & MAG 300) placed in between.This can be used in a number of ways:

• Firstly as a very simple Bass, Middle and Treble tone control section as found on older traditional amplifiers. This is done by leaving the two sets of sliders (rotary controls on Electric Blue 180 & MAG 300) set in their centre positions and using only the BASS, MIDDLE and TREBLE controls to alter the overall tone.

•Secondly, if more control is required, then the sliders (rotary controls on Electric Blue 180 & MAG 300) can also be used to tailor the E.Q. in the regions between the main tone controls.

This provides a very versatile Equalisation section that is simple to understand and operate, yet provides a wide degree of variation. It retains the simplicity of a three-control tone section but provides the flexibility of a graphic equaliser.

SUB HARMONICS

This section consists of an IN / OUT switch and a LEVEL control.When switched IN, Sub Harmonics an octave below the notes being played are produced.The level of these Sub Harmonics relative to the straight bass sound can be adjusted using the LEVEL control.This is very effective in thickening the sound and you will find in use that only a small degree of this lower octave is required to really fill out the sound and provide a character to the sound that is not possible by any other means.The degree of Sub Harmonics is also dependant on the setting of the BASS control.This facility is footswitchable on the ABM/RPM-1 range via a socket on the rear panel. For the footswitch to operate the Sub Harmonics must first be switched into circuit with the front panel push button.

DIRECT INJECT (D.I.)

A balanced D.I. is provided on the front panel rugged metal latching XLR socket.The ABM/RPM-1 features a push button placed below the XLR that allows the user to choose either a Pre E.Q. / Pre Sub signal or a Post E.Q. / Post Sub and Effects signal (the Pre E.Q. signal also includes the Shape facility, if this is switched into circuit) – EBs and MAGs feature a Post E.Q. / Post Sub and Effects signal.The output signal from this XLR socket is set to a level and impedance suitable for connecting directly into the Microphone input of a mixing desk for either Direct Injection into the PA system or for recording.This must ONLY be used into a Balanced Microphone input. It is not intended for any other type of connection.This has a floating ground that is referenced to the mixing console it is plugged into and should not need ground lifting. It is also unaffected by Phantom Powering on the Microphone input. Make sure your XLR plug does not have the shell of the plug internally connected to the ground signal or this will connect the system to the chassis ground of the amplifier and may cause problems with hum.

PUSH TO MUTE (ABM/RPM-1 only)

When pushed IN this button mutes the output from the preamp to the power amp, mutes the output from the D.I. socket and mutes the output from the Sub Out socket as well.This leaves the output from the TUNER / LINE socket still available to allow muted tuning. An LED is provided next to this switch to indicate when the amplifier is muted.This operates only from the front panel MUTE push switch, i.e. pressing this button mutes all sound from the amplifier and allows a tuner connected to the TUNER / LINE socket to operate for silent tuning. Release the button and you are back in action again.