Formula Sound ASP4 User manual

ASP4
4 CHANNEL MIC PREAMP
USERSMANUAL

ASP 4 Microphone preamplifier
Introduction
The ASP 4 is a 4 channel microphone preamplifier, each channel having balanced input and
outputs on XLR connectors, features include phantom power (48V or 18V), LF Filter, Mute,
phase reverse, line level setting, 50dB gain range, volume control and level meter.
Factory setting
The roll off frequency of the LF Filter has 5 internal settings, factory setting is position 3 which is
70Hz. The other settings are 35Hz, 50Hz, 110Hz, and 150Hz.
The phantom power has 2 internal settings, factory setting is 48V. The second setting is 18V.
Gain is factory set to about 30dB and is adjustable via the back panel.
To change the settings ensure the power is disconnected, remove the 3 screws either side of
the top cover and the 2 screws on the top cover (retain for refitting).
Move the jumpers shown in appendix 1 to the required positions for the settings you require, the
silk screen legend on the PCB indicates setting.
Refit the covers.
Front and rear panels
Set up
The 4 channels are marked channels 1 –4 and each channel is independent with its own
controls, indicators and settings. All switches are illuminated when on, the back panel switches
also have LED’s on the front panel to indicate when they are on.
When using with microphones, connect a microphone to an input, if phantom power is required
select phantom power by pressing the front panel switch on the appropriate channel.
If phase reverse is required select phase reverse by pressing the switch on the back panel, this
will reverse hot and cold connections on the input XLR. (phase reverse LED on the front panel
will also light).
Set the front panel volume control to 3/4 clockwise position then talk into the microphone and
adjust the gain control on the back panel (adjacent to the input XLR) until the LED level meter
reads 0dB.
PUSH PUSH PUSHPUSH

For line level input press the “LINE” switch on the back panel for the required channel (Line LED
on the front panel will also light).
Set the front panel volume control to 3/4 clockwise position. Connect the line level source and
adjust the gain control on the back panel (adjacent to the input XLR) until the LED level meter
reads 0dB.
Selecting “Mute” on the front panel will mute the audio on that channel.
Selecting “LF Filter” on the front panel will introduce an LF Filter into the signal path, the LF filter
rolls off at up to 24dB/octave.
The LED meter indicates output level, the clip LED will come on if the output goes above
+18dB.
Formula Sound Limited
Unit 23; Stadium Business Centre
North End Road
Wembley
HA9 0AT
Tel [phone] Fax [phone] Email [email protected]
www.formula-sound.co.uk

ASP 4 SPECIFICATION
Four channels each with balanced XLR input and XLR output connections that may be strapped
for unbalanced use. Each channel operates independently and has the same specification.
Frequency response (LF Filter out) 20Hz –20KHz +/- 0.5dB
Distortion (THD and noise @ 1Khz) <0.005% at +10dBu
Noise (20Hz –20KHz) 150R EIN <125dB
Input impedance > 2K ohms balanced
Gain adjustment range (Mic) Min +10dB Max +60dB
(LINE) Min -25dB Max +25dB
Phantom Power Factory set +48V
May be switched to +18V
LF Filter (rolls off at 24dB/octave below set frequency) Factory setting 3 is 70Hz
Setting 1 35Hz Setting 2 50Hz Setting 3 70Hz Setting 4 110Hz Setting 5 150Hz
Mute (or volume control fully anticlockwise) <100dB
LED meter indicates output level -10dB, -5dB, 0dB, +3dB, +6dB
Clip indicator (output level) >18dB
Phase reverse Reverses hot and cold on XLR in
Power 230V (internally switch for 115V)
250mA slow blow fuse (500mA)
Dimensions 19” rack mounting 1RU
W 482mm, H 44mm, D 200mm
Finish Front and rear panels are black
Anodised with silk screen legend.
Covers are plastic coated steel.
Formula Sound Limited reserve the right to alter the specification without notice

FORMULA SOUND LIMITED
UNIT 23; STADIUM BUSINESS CENTRE; NORTH END ROAD; WEMBLEY; MIDDLESEX; HA9 0AT
TELEPHONE [phone] FAX [phone]
www.formula-sound.co.uk email [e-mail]
E.U. CERTIFICATE OF CONFORMITY
We declare that the products listed conform to the following directives and standards
89/336/EEC amended by 92/31/EEC and 93/68/EEC
BS EN 50082-1 BS EN 50081-1
PRODUCT TYPE
ASP 4
The CE mark was first applied in 1995
Signed
B. J. Penaligon General Manager
Attention
The attention of the specifier, purchaser, installer, or user is drawn to the fact that good wiring practice must be
observed when connecting the above equipment. Good quality connectors and screened cables must be used for all
audio connections. Twin screened cables should be used for all balanced lines.
THIS EQUIPMENT MUST BE EARTHED
CONSULT THE USERS MANUAL FOR TECHNICAL DETAILS