Vox AC50 Stereo Amplifier User Manual


 
5
4. EQ and TONE controls
The TREBLE, MIDDLE, and BASS controls on this channel are of the interactive passive format
that is historic to VOX amplifiers. This type of EQ is sometimes nicknamed as the “tone stack” by
the nature that the three controls are drawn on a circuit diagram. Generally speaking, the position
of each control knob will influence the effect of the other two. Our advice is to set the three
controls at their midpoint positions and start from there. Experimentation is the key to finding your
tone. For starters though, turning the Middle control down will make the sound more “hollow”
particularly with high gain (distorted) settings, as typified on many modern heavy rock songs.
Turning the Middle up will make the tone fuller, smoother and produce a more “singing” tone.
Adjust Bass & Treble to suit.
The TONE CUT control is a classic VOX control that dates back to the very first VOX amplifier of
50 years ago, when it was the only form of tone control on the amplifier. In keeping with its name,
this control works by reducing (CUTS) the amount of high frequency content of the sound and
thus smoothes out and warms up the treble. When using this control please remember that as
you turn the control UP that you are actually turning DOWN the Treble.
5. REVERB
This control regulates the amount of the on-board spring reverberation required for Channel 1
only. Please remember that the reverb is controlled ON or OFF by the footswitch as well.
6. VOLUME
This control is set at the end of the Channel 1 preamp circuit, before it goes to the FX Loop,
Reverb, and Power Amp sections. As such it governs how loud the sound generated by the
Channel 1 electronics is going to be. Low settings of the control will mean the amp will be pretty
quiet, and higher settings will mean total mayhem has broken out! As the total sound level is
controlled by both the Gain and Volume controls (and the Output Master, but more on this later)
you will need to balance both the level and character of the sound with both these controls.
CHANNEL 2 SECTION
7. GAIN CONTROL
This control regulates the amount of signal amplification that is generated in the Channel 2
preamplifier circuit. The circuit design of Channel 2 is out and out mean, meaty and mighty – but
with a good measure of VOX thrown in as well! The basic sound of this channel takes off where
Channel 1 finishes; and by use of all of this channel’s controls you can achieve a variety of
sounds from gentle blues to classic rock to modern high gain wailing.
8. BRIGHT SWITCH
This switch brings in an extra capacitor (switch down) across the Gain control to boost the high-
mid and upper frequencies. The effect of this is dependant on the position of the Gain control –
lower settings mean that the switch is more active – higher positions mean that it is less active. A
good use of this switch is to give extra bite and clarity to muddy sounding humbucking pick-ups.
9. FAT SWITCH
This switch brings in some extra gain, and also focuses the mid range of the guitar and amp
which helps produce the “singing” tone when playing lead lines.
10. EQ and TONE controls
The TREBLE, MIDDLE, and BASS controls on this channel are of the interactive passive format
but have different characteristics than the classic VOX TB circuit that Channel 1 is based on. The
EQ is centered on different frequencies to enhance the higher gain capabilities of Channel 2.