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4. OL Indicator
The OL (overload) indicator lights when the
amplifiers in the TH-12A are near the clipping point. It
is okay if the OL indicator blinks occasionally, because
this means that the transient peaks are just reaching
the maximum output of the amplifiers and you are
getting the most from your TH-12As.
If the OL indicator is blinking frequently or lighting
continuously, turn down the LEVEL control [3] on the
TH-12A or turn down the signal at it source
(e.g., the mixing console) until the OL indicator blinks
occasionally or not at all.
5. HIGH EQ
This control gives you up to 15 dB boost or cut above
12 kHz. The circuit is flat (no boost or cut) at the
center position (U). Use it to add sizzle to cymbals,
and an overall sense of transparency or edge to the
keyboards, vocals, guitar, and bacon frying. Turn it down
a little to reduce sibilance, or to remove high frequency
hiss.
6. MID EQ
This is a midrange EQ control that provides 15 dB of
boost or cut centered at any frequency between
100 Hz and 8 kHz. The MID EQ circuit is flat (no boost
or cut) at the center position (U). This frequency range
includes most vocals (male at the lower end of the
range and female at the upper end of the range), and
the fundamentals and harmonics for many instruments.
7. MID FREQ
This knob ranges from 100 Hz to 8 kHz and
determines the center frequency for the MID EQ filter.
This allows you to zero in on the precise narrow band of
frequencies you want to have affected by the MID EQ.
8. LOW EQ
This control provides up to 15 dB of boost or cut
below 80 Hz and it is also flat at the center
position (U). This frequency range represents the
punch in bass drums, bass guitar, fat synth patches, and
some really serious male singers.
9. EQ ON/OFF Switch
This switch allows you to bypass the EQ section.
When the switch is out (OFF), the EQ section is
bypassed and the EQ knobs have no effect on the signal.
When the switch is pushed in (ON), the EQ controls
may be used to tailor the frequency response of the
TH-12A.
10. POWER Switch
Use this switch to turn the TH-12A loudspeaker on
and off. The indicating LED above the POWER switch
lights when the POWER switch is on and AC power
is available at the linecord socket. A second power
indicator is located on the front of the cabinet.
11. Line Cord Socket and Fuse
Connect the detachable line cord to this IEC socket
securely, and plug the other end into your AC outlet.
Make sure the AC power is matched to the AC power
indicated on the rear panel (under the IEC socket).
The fuse is located behind the fuse cover, at the
bottom of the IEC socket. See the “Troubleshooting”
section on page 11 for information about replacing the
fuse.
