4. OL Indicator

The OL (overload) indicator lights when the amplifiers in the TH-15A 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-15As.

If the OL indicator is blinking frequently or lighting continuously, turn down the LEVEL control [3] on the TH15A 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.

8. LOW EQ

This control gives you 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 can be used to tailor the frequency response of the TH-15A.

10. POWER Switch

Use this switch to turn the TH-15A 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.

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.

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.

9