The Top Hat M4 is a headphone amplifier/talkback unit housed in a 1U 19” subrack with 2 accompanying producer talkback boxes. Each Producer’s box is connected via XLR, has a gooseneck microphone and a series of one-way talkback destinations.

4 Headphone Amplifiers
The Top Hat M4 has 4 separate headphone amplifiers each with its own 3 channel mixer and interruptible talkback from the engineer and both producer boxes. Each headphone amp connects via a single XLR located on the rear panel.

4 Sources
The unit has facility for 4 sources; input 1, input 2, cue, and clean feed, connected to the rear panel via a D25 socket. Each source has a corresponding input gain POT located on the front panel.

3 Input Mixer Per Headphone Amp
Each headphone amplifier has a 3 input mixer to include either input 1 or input 2, an external input and cue or clean feed, for unique individual mixes. The left ear, both and right ear mixes are adjusted via corresponding POTS located on the front panel. Configuration is as follows;

1. Input 1 or input 2: selectable via the toggle switch, mixes into the left ear with volume adjustment via the 'left' POT.
2. Each headphone amplifier has its own unique external input: mixes into both ears with volume adjustment via the 'both' POT.
3. Cue or clean feed: selectable via the toggle switch, mixes into the right ear with volume adjustment via the 'right' POT.

All inputs connect via a D15 socket.

Headphone Amp Talkback/ Output
Interruptible (to the right ear mix) talkback using the white momentary push buttons on each headphone amp/ producers' box can be routed from 3 locations;

1. Producer Box 1 (indicated via the illuminated LED on the headphone amplifier)
2. Producer Box 2 (indicated via the illuminated LED on the headphone amplifier)
3. Engineer by pressing the white button on the front panel.

Master Talkback/ Output
There are 5 separate interruptible talkback circuits all using momentary push buttons;

1. RTB1 from both Producer 1 and 2 (Blue)
2. O/P1 from Producer 1 (Yellow)
3. O/P2 from Producer 2 (Yellow)
4. BASE 1 from Producer 1 (Red with a toggle switch for enabling button to ensure intended talkback interruption)