BOGNER
AMPLIFICATION
4
The Vox AC30 is an example of a Class A amp. A good general description of class A might be:
harmonically richer (2nd and 3rd order harmonics) than A/B, more sweetly compressed, a little less note
distinction than A/B (more "melted together", shall we say) yet more "musical". Class A/B is head-roomier,
punchier, louder and of course less "squished" sounding. In Class A the amp draws full current all the
time even if you do not play, the amp runs hotter and tube live might be shorter then in Class AB.
To the left of the A/AB switch is the Output
Power Half - Full
switch.
The function of this switch is to cut two power tubes out of the circuit and knock the amp down to half the
watts. This enables you to crank the amp up to redline, and only hurt your immediate neighbors, not the
ones at the end of the block. When using the half power switch, reset the ohms switch to 1/2 the actual
value of the cabinet. (A 16 ohm cab should be set to 8 ohms, an 8 ohm cab to 4, don't use a 4 ohm cab in
half power).
Further left on the rear panel, you'll find the
Old/New
style switch. This control functions as a
pentode/triode selector. In "new" position, the Ecstasy's power section is operating in pentode, which
means all elements within the power tubes are working. In the "old" or Triode mode only 3 out of 5
elements within each tube are working. This cuts power, but it also "smoothes and sweetens" the sound,
and of course, limits headroom. Triode mode is more sensitive to imbalances and if you hear a slight hum
is probably the result of the power amp tubes.
These 3 power amp operation switches - Class A/AB, Full-Half power and Sound Style Old/New all cut
power or watts. By using these controls together, you can get almost any wattage or power level you
want, from a max of around 120 (Class AB, Full power, "New"), down to about 7 watts (Class A, 1/2
power, "Old"). Please note that cutting the power in half does not mean half the volume, I would say it is
only about 20% less but tone, headroom and feel changes as well. As matter of fact, if you switch from
Class AB to A you might even have slightly higher volume even so the wattage is lower, this is because in
Class A the power amp is more sensitive to the input gain, back the channel volume off until it matches
the gain level it had in Class AB and then volume should be lower. Best reduction for volume is to use
less and smaller speakers with combination of the above.
Many pro players sometimes like to "slave" their amps by running a
line out
from their amplifiers, through
effects, to another stereo power amp. A "line out" is an output from the head that is line level, suitable for
feeding the input of an effect or power amp. This is also known as "slaving". The difference between a
line out and a send, (which is also line level) is: A send is a pre amp out and a line out comes after the
power tubes. The way this works is; run the Ecstasy head to a speaker cab "dry" (speaker cable from
speaker out to cab, nothing in loop),
then
run a shielded cable from the line out jack (rear panel, left side)
to an effect input. Run two shielded cables from the stereo outputs of the effect to the inputs of a stereo
power amp. Run the speaker outs of the power amp to two more cabs. Turn them all up and be blown
away! You are now successfully "tri-amping". Some guys like to mix only effect in their "wet" speakers,
others like a little "dry" in there, too. Of course, it all depends on your application. If the extra speakers are
to be used as a guitar monitor for your drummer, you'll most assuredly want some dry sound in it. If the
speakers will all face the same general direction, you many not want dry in the effects speakers. You
decide. We like them both ways. You can also use the line out to feed a mixing board, a recorder or to
send signal to another amp to power more speakers. In this case it is best to use an EQ in between so
you can shape the tone.
Notice next to the line out jack there is a Trim pot (optional individual for each channel) and three push
buttons, "Ch.1 Ch.2 Ch.3". The buttons will switch channels if you are without your footswitch or Medusa.
The trim pot is a line out level control. This gives you the ultimate flexibility for slaving. >>>
