Vox AC50CPH Stereo Receiver User Manual


 
6
CHANNEL 1 SECTION
3. GAIN CONTROL
This control regulates the amount of signal amplification that is generated in the Channel 1
preamplifier circuit, and as such sets the basic tonal qualities of the channel. The circuit design of
Channel 1 is based on the Top Boost channel of the historic VOX AC30. Therefore the basic
sound of this channel is classic VOX through and through. But by some subtle changes and
tweaks this channel will also give you some serious classic rock Crunch. Although different types
of guitars and pick-ups will give differing output levels and thus amp settings will vary between
different guitars, then generally the rule of thumb is that cleaner sounds are going to be between
Off (naturally!) and about 2 o’clock position of the knob. After that the channel preamp will slowly
start to go into crunchy distortion, with the maximum distortion at Full (of course!). Although this
channel is not seriously high gain (we’ve left that for channel 2) the distortion level can be seri-
ously satisfying.
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.