The GSGH2 headphone amplifier is a portable unit usually battery operated but with provision for an external mains power unit. Designed to drive two pairs of headphones it provides individual level controls for each ear of each pair of headphones. Although optimised for medium to high impedance headphones ( 100 to 2000 ohms ) it is possible to use the GSGH2 with headphone impedances down to 8 ohms (the battery life is just significantly shorter). The headphone connectors are stereo jack sockets which will accept A or B gauge plugs. An internal link can be factory preset to provide the correct signals to drive normal stereo wired jack plugs or those wired with a phase reversed right ear.
A pair of multi- turn screwdriver operated potentiometers are provided to enable a wide range of input signals to be accommodated. Line up levels can be between -20dBu and +3dBu. Inputs are balanced, high impedance and are connected by a pair of 3pin XLRs. Both fixed plugs and fixed sockets are provided so that it is easy to loop through a number of these GSGH2 when many pairs of headphones are required.
Provided on the side of the unit is a switch to change the left input XLR from a balanced left input to an unbalanced stereo input. Then the left programme is on pin 2 and the right programme is on pin 3.
Two PP3 batteries are used to power the GSGH2. These batteries can be changed without using tools. Alkaline batteries are recommended for maximum life. Two 2.5mm DC connectors are provided for a external 18volt DC power supply unit. Because there are two connectors it is easy to loop through and power several GSGH2s from one power unit. Although an on/off switch is provided, the GSGH2 turns itself off if no headphone jacks are plugged into it. A front panel LED shows when the unit is on and also flashes to indicate when the batteries are getting low.