AD828 PreAmp Module

AD828 PreAmp Module Audio Amplifier Amp

Stereo Dynamic Microphone Guitar Instrument Audio Video Signal Preamplifier

     The AD828 PreAmp Module is a 2 channel (stereo) preamplifier board that boosts the low level audio signal coming from dynamic microphones, guitars and similar instruments. At the centre of the board is a 2 channel op-amp IC marked AD828; the left (L) and right (R) channels are amplified separately. It runs from a single DC 3.8V - 15V supply and, at 33mm x 25mm, fits easily inside an existing device or a small enclosure.

     When a microphone or guitar is connected directly to a recorder, mixer or power amplifier, the signal is often too weak. This board raises the signal to a level that recording and amplifier inputs can use. 4 x 10µF and 2 x 100µF electrolytic capacitors are fitted on the board; connections are made through the IN (R / GND / L), OUT (R / GND / L) and VCC (+ / -) solder pads on the board edge.

     There is no supply (regulator) circuit on the board. Sound quality depends directly on how clean the supply is; use a quality regulated power supply or a battery for high performance.

Key features:

     2 channel (stereo) design: The left and right channels are amplified separately; two microphones, a stereo source or two separate instruments can be boosted with one board.

     Wide supply range: Works from DC 3.8V - 15V; it can be powered by 5V USB, a 2 cell lithium battery (7.4V), a 9V battery or a 12V adapter. Operating current is approximately 15mA.

     Small and light board: At 33mm x 25mm and 4gr it fits inside a microphone box, pedal or speaker; it is fixed with 2 mounting holes.

     Labelled connection points: The IN, OUT and VCC pads are marked R / GND / L and + / - on the board; wires are soldered directly.

     Capacitors fitted: 4 x 10µF 16V and 2 x 100µF 16V electrolytic capacitors are soldered on the board; no extra parts are needed to run it.

Features:

• Product type: 2 channel (stereo) microphone and instrument preamplifier board
• Model: AD828 Module
• IC: 2 channel op-amp marked AD828 (SOIC-8 package)
• Number of channels: 2 channels (L and R)
• Operating voltage: DC 3.8V - 15V (single supply)
• Operating current: approximately 15mA
• Supply regulator: none; a regulated, clean supply is required
• Input connection: IN - R / GND / L
• Output connection: OUT - R / GND / L
• Supply connection: VCC - + / -
• Capacitors: 4 x 10µF 16V, 2 x 100µF 16V (SMD electrolytic)
• Suitable sources: dynamic microphone, guitar and instrument output, low level audio signal
• Components: SMD parts
• Connection type: solder pads (no pin header fitted)
• Operating temperature: -10°C - 80°C
• Mounting: 2 mounting holes
• Colour: Red
• Dimensions: 33mm x 25mm
• Weight: 4gr

Usage information:

• Connect the supply to VCC + and -, the source (microphone or instrument) to the IN pads, and the recorder or amplifier input to the OUT pads. For a single channel, connect only the L or R pad together with GND.
• Power the board from a regulated source between 3.8V and 15V; the AD828 manufacturer ratings are given for 5V and higher supplies, so 5V - 15V is preferred. If hum is heard at the output with a switching adapter, use a battery or a linear regulated supply.
• Use shielded audio cable at the input and output; connect the cable shields to GND and keep the board away from power wiring.

Applications:

•  Dynamic microphone preamplification
•  Guitar and bass guitar signal boosting
•  Boosting instrument and electric saz outputs
•  Karaoke setups
•  Audio interface and recorder input
•  Podcast and voice over setups
•  Announcement and intercom systems
•  Signal boosting before a mixer or power amplifier
•  Home made amplifier and speaker projects
•  Audio circuit training and experiments

Things to consider:

•  There is no supply (regulator) circuit on the board. The capacitors on the board are rated 16V; voltage above 15V can damage it; do not reverse the + and - supply wires.
•  Sound quality depends on a clean supply. Using a quality power supply is necessary for high performance.
•  The board is for dynamic microphone and instrument signals. The 48V phantom power needed by condenser microphones is not provided.
•  The output is not intended to drive speakers or headphones; connect it to a power amplifier, mixer or recorder input.

Package contents:

•  1 x AD828 PreAmp Module
•  Note: Power supply, microphone and connection cables are not included.