Whirlwind THS R Talkback Headphone Box

The RTS compatible THS R has both main and talkback microphone outputs. The microphone signal is always live at the main output unless the Talkback or Cough switch is depressed. If power to the THS R is lost, the mic signal will still pass with dynamic mics and with condenser mics if phantom power is provided from the host console. Two types of onboard condenser microphone power are available, enabling seamless switching when talkback is activated. A three way switch selects either phantom or "T" power and is recessed to avoid accidental turn off. A momentary Cough switch silences both the mic out and the talkback out when depressed. The announcer's microphone is sent through a preamp and line driver that deliver line level signal to the talkback output when the momentary Talkback switch is activated. The Talkback switch also mutes the mic out. There is a level control for fine adjustment of the audio sent down the talkback line.
The THS R receives both power and input audio through a female 3 pin XLR from a "Wet" RTS compatible IFB system. Positive 24-30VDC power and interrupt audio are on Pin 2 and non-interrupt audio is on Pin 3. Pin 1 is power ground and audio shield. The headphone section of the THS R has two inputs. Each input has a volume control and dip switches to send the signal to the left and/or right headphone earpieces. When an input is assigned to both ears, level adjustments affect both left and right ears equally. Both 3.5mm and ¼" TRS jacks are provided for hookup flexibility. Headphones with impedances ranging from 30 to 150 Ohms can be driven to full volume. 600 Ohm headphones can be used with a slight reduction in volume due to "Wet" IFB current limitations.
Transformer isolation is provided for both IFB inputs and the talkback output. The high quality audio transformers provide signal and power isolation and ground loop reduction for both the interrupt and non-interrupt inputs as well as line balancing for the talkback output.
The THS R can also be locally powered. A rear panel switch selects "Wet" IFB or external power supplied by a 12 VAC power adapter, model # PS12AC1A, included with the unit. Typical current consumption from the IFB line is 85mA. Maximum draw is 110mA.