HPA-6

  Stereo 6 Channel Headphone Amplifier - User Guide

INTRODUCTION

This unit has two stereo line level inputs feeding six discrete headphone stations, plus a further stereo Auxiliary input feeding the first two stations (see option below).  Signals connected to this Auxiliary input will be added to the signals present on inputs A and B, and is intended to be used for 'click tracks', a cassette or CD/Minidisc/iPod player during rehearsals, or perhaps adding reverb to vocals etc. when no Aux. sends are available on the desk.

Bass and treble equalisation is available on input B signals, and each of the six headphone stations has push buttons to select signals from the A or B input, and to mono their own signal.  The front panel input sockets are also duplicated on the rear panel.  All six headphone stations can drive headphones from 8 to 2,000 ohms, the lower the impedance the greater the volume.

CONNECTIONS

1.  POWER: UK models are supplied with a Eurolead, fitted with a 13 amp U.K. mains plug.  Export models come with a Eurolead with bare wire termination, fit a suitable mains plug for your countries power supply socket.  Connect this lead to the rear panel inlet socket.  Always replace a blown power fuse with one of the same value: for 220v-230v 50Hz, 1.6A 250v, and for 110-120v 60Hz, 3A.

2.  STEREO INPUTS A & B: Connect line level stereo unbalanced input signals to either or both of these TRS jack sockets.  Both inputs will feed all six stations, and duplicates can be found on the rear panel.

3.  STEREO AUX INPUT: This is the same as 2, except that it feeds inputs 1 and 2 only, and is mixed together with A & B signals.  It is also duplicated on the rear panel.  Uses include adding a 'click track' to the foldback signal, practising a part by playing along with an ipod or CD, etc.

4.  STATIONS 1-6: Connect stereo headphones from 8 to 2,000 ohms impedance.  A split lead (or better, an MTR 4 or 8 way stereo splitter box, model "PS-4" or "PS-8") can be used to increase the number of headphones per station, but do not allow the total impedance seen by any one station to fall below 8 ohms.

5.  EARTH SWITCH: If hum occurs due to an earth loop with other equipment, use the rear panel earth lift slide switch to separate the technical earth from the mains earth.

OPERATION

Switch on the power, and set A & B input volumes to approx. 5 on the dial.  Set each station's volume to zero (fully left), put on headphones and select either A (out) or B (in) on the source button.  Increase volume to the desired level.  If a mono signal is being input (or if one earpiece is removed from the ear), press the mono button.  On input B, bass and treble equalisation is provided, adjust to taste.  Remember that increasing bass and treble will also increase volume, and that decreasing bass or treble can help the clarity of certain sounds, particularly in overdub situations.  The three peak led's close to the inputs will show green, and will turn to red when the input signal begins to approach overload.

C A U T I O N
This unit is capable of providing continuous very high sound pressure levels.  Medical opinion agrees that exposure to high levels of sound can temporarily - and in continuous cases over a period of time PERMANENTLY - damage your hearing.  We cannot control how you use this product so, Please Be Sensible.  We must refuse any responsibility for hearing damage.

SPECIFICATIONS
A, B & Aux. input impedance:        20Kohms unbalanced stereo
A, B & Aux. input sensitivity:          25 volts nominal
Maximum output:                         2.0 volts = 500mW into 8ohms, 4.7 volts = 35mW into 600ohms,
                                                  4.8 volts = 10mW into 2,000ohms
High/Low e.q:                              ±13dB @ 10kHz/100Hz
System Gain:                               28dB, e.q. flat
Hum & noise, unweighted:           -85dB
T.H.D.:                                        .08% @ 1kHz
Frequency response:                    10Hz - 20kHz, ±3dB
Dimensions/Weight:                     483w x 205d x 44h (mm)/4Kg

OPTION
The Aux. input can be factory retro-wired to feed all, or any combination of, the six headphone stations.

MTR Ltd, Ford House, 58 Cross Rd, Bushey, Herts, WD19 4DQ   UK
Tel: +44-(0)1923-234050   Fax: -255746    e-mail: mtrltd@aol.com    www.mtraudio.com