5+5 Watt STEREO AMPLIFIER KIT

NOTE: CAREFULLY READ ALL INSTRUCTIONS BEFORE STARTING TO BUILD AND OPERATE THE AMPLIFIER KIT.

INTRODUCTION

The SA5W is a 5+5 Watt Amplifer kit using two mono amplifer circuits placed in duplicate on one Printed Circuit Board (PCB).
The SA5W PCB may also be cut down the middle to create two individual mono 5 Watt Amplifiers.
The amplifier circuit consists of a TDA1905 monolithic integrated circuit in POWERDIP package, intended for use as a low
frequency power amplifier in a wide range of applications in radio and iPods etc.

Specifications

Supply Voltage: 4 to 24Vdc (Note: below 10Vdc R4 must be fitted.)
Power output: 5 Watts per channel
Speaker Output: 6 Watt 4Ω with 12Vdc Supply ( 4.5W rms) Supplied with Kit.

6 Watt 8Ω with 16Vdc Supply (4.5W rms)
6 Watt 16Ω with 22Vdc Supply (4.5W rms)

Input Impeadance: 20k Ohms

For further details refer to www.datasheetcatalog.com and download data sheet TDA1905.

The kit is supplied with all components to build the SA5W Stereo Amplifier circuit board, including two 125mm
6W 4Ω speakers, DC 2.5mm pin panel mount power socket and 3.5mm panel mount stereo socket.
In addition you will require a wall mount Power Plug Pack Regulated to 12Vdc 1A.

Fig 1 - Assembled PCB CHANNEL A Speaker Output + to (+V) Red Speaker Output – to (0V) Black Signal Input + to (I/P) White Signal Ground to (0V) Screen CHANNEL B Speaker Output + to (+V) Red Speaker Output – to (0V) Black 12Vdc 1A Supply + to (+v) Red Supply ground to (0V) Black Signal Input + to (I/P) Red Signal Ground to (0V) Screen

Fig 2 - PCB SA5W

Bill of Materials - Per Channel

RESISTORS Designator Value Size

1x R3 1R 0.6W

2x R2 R4* 100R 0.6W Note* Fit R4 only when supply is less than 10Vdc

1x R1 10K 0.6W

1 x VR1 22K Trimpot

CAPACITORS

2 x C2 C6 220nF 50V 5 x 3.2mm

2x C1 C3 2.2uF 50V Ø 5x11mm 2.0 p-p

1x C4 10U 63V Ø 11mm 2.5 p-p

1x C5 47uF 63V Ø 8 x12mm 5.0 p-p

2 x C7 C8 1000U 35V Ø 13 x20mm 5.0 p-p

AMPLIFIER Chip

1x IC1 TDA1905A DIP16

Hardware per Kit

1x PCB - SA5W 5+5 Watt 101 x 56mm O/All 91 x 46mm c-c mounting holes

2x Speaker 6Watt 4Ω 125mm (5”) with 4x 120mm mounting holes

1x DC Socket 2.5mm pin Chassis Mount Power Socket

1x Stereo Cable 1.5m 2.5mm jack plug each end

ACCESSORIES

1 Wall Power Pack 12Vdc 1Amp

1m Red connecting wire 22AWG

1m Black connecting wire 22AWG

60mm single core Link wire

Assembly instructions

Before proceeding please take necessary antistatic precautions when inserting the amplifier IC1.
Insert and solder in all resistors, capacitors and the amplifier IC. Take care to follow good soldering practices.
Make sure all electrolytic capacitors are inserted correctly with the correct pin polarity. Refer to Figure 1 & 2.
Ensure adequate solder is applied to IC1 Pins 9 to 16 to ensure good heat conduction to the 0V copper plane.
Finally connect an insulated link wire for the (+V) supply rail between Channel A and B as indicated by the dotted
line on the PCB.

Fig 3 - Complete Assembled Kit

2x 125mm Speakers 6 Watt 4 Ohm

1.5 Stereo Lead with 3.5mm plug jack

2.5mm pin DC Power socket

12 DC 1 Amp Power Plug Pack

Assembled Amplifier PCB

Fig 4 – 5+5 Watt Stereo Amplifier Circuit Diagram

Fig 5 – Wiring Diagram

Fig 6 – Stereo Input Cable Diagram (Signal Input Option 1)

Fig 7 – Stereo Input Socket Diagram (Signal Input Option 2)

Wiring Instructions

When the PCB is completely assembled check that the polarity of all Electrolytic Capacitors are fitted correctly.
Refer to Fig 1 and Fig 2. Incorrect fitted capacitors will permanently damage if power is applied.

The wiring diagram Figure 5 shows the connections for the speakers, power supply and input signals.

1. First connect the signal inputs for Channel A and Channel B using one of two options.
Option 1; With the Stereo cable connected directly to the PCB refer to figure 6
Option 2; With the Stereo socket refer to Figure 7.
Terminals T5 the (+) Signal Inputs and terminals T6 the Signal Ground 0V, which is the Screen connection.
For Option 2 only one 0V signal ground is needed to be connected.
For Option 2 keep the wires short as possible.

2. Connect the supply socket as shown in figure 5, the centre pin positive (+V) and the outside barrel negative.
Check the power pack DC plug is connected accordingly.

3. Connect the Speaker wires, check the polarity of the speaker terminals, (+) connects to T 1 O/P and
(-) connects to T2 (0V).

4. Check all wiring is correct to the diagram Figure 5. Use a Multimeter to check the connections are correct.

Operation Instructions

1. Using a small screw driver set both VR1 Trimpots fully anti-clockwise for zero volume.

2. Plug in the Power to the mains supply and check the 12Vdc 1 Amp supply is providing +12V to the centre pin
and negative to the outside barrel.
Connect the Power pack DC plug into the Amplifier power socket.
Using a Multimeter check the supply to the amplifier is at 12Vdc across T3 (+) and T4 (-).

3. Using the stereo audio cable connect the amplifier input to the stereo output of the iPod or radio with
music playing at full volume.
First ensure first both VR1 Trimpots would to minimum fully anticlockwise.

4. Very slowly wind Channel A Trimpot VR1 a minute amount clockwise to increase the output volume of the
music to the Channel A Speaker.
Continue increasing the volume until the music is almost sounding distorted.
Place a mark on the PCB where the Trimpot arrow is pointing for maximum setting of the Trimpot.
Next wind Channel B to the same level of volume without distortion occurring.
NOTE: Do not wind the volume too high causing distortion.
Excessive distortion will cause permanent damage to the speaker.

5. The Amplifier is now fully operational. Control the volume using the iPod or radio volume control.