6 – 10 Watt Stereo Amplifier Page 1 of 3 it 143 is a class AB stereo audio power amplifier designed for … Page 3 of 3 Circuit Diagram + Vin Gnd + + + + + + + + + Input 1 Input 2 TDA 2005 +-+-9 10 2 8 4 6 5 1 C1 … using a TDA2005 module. It is easy to construct and has a minimum of external components. The module has output current protection and thermal protection. This is the data book circuit which produces an excellent sound. The supply voltage required for this kit is 8 – 18V DC at 1 to 2 Amps. Maximum output power will only be obtained with a power supply of at least 2A at 15V DC, and using 2 ohm speakers (or 2 by 4 ohm speakers in parallel). However approximately 4W per channel can be obtained with only a 15V DC, 1A supply into 4 ohm loads. The power supply should be well filtered to reduce mains hum, the on board capacitors alone are not adequate for this purpose but are necessary to ensure stability. Extra filtering is unnecessary if operating from a battery. Construction. Follow the printed circuit overlay with reference to the circuit diagram where necessary. Add the lowest height components to the board first, starting with the resistors. Be careful to get the electrolytic capacitors in the correct way around and all parts in their correct positions. Be careful when soldering the IC not to use excessive heat. Use some heat sink compound between the heat sink & the IC. Also note if you intend to drive it very hard, it may require a bigger heatsink. The supplied heatsink is quite adequate for normal use. No damage will result, but the thermal protection circuit may limit the power output. Use shielded signal wire for the input connections, and at least 16/0.2 hook up wire for DC input and speaker outputs. Try to keep lead lengths as short as possible…

The circuit is straight forward. Most of the circuitry is contained within the amplifier module. C1 & C2 are input coupling capacitors and block DC, as do C10 & C11 which are the output coupling capacitors, and C7 & C9 which block DC from the feed back loop to the differential inputs. R3/R5 (and R4/R6) set the level of feed back. C10/R7 (and C11/R8) provide a high frequency load for stability where loudspeaker inductive reactance may become excessive. C4 and C5 provide power supply decoupling or filtering.

Kit 143. 6 – 10 Watt Stereo Amplifier Page 2 of 3 Specifications : D.C. Input : 8 – 18V at 1 – 2 A (15 – 30 VA minimum) Power output : > 8 W RMS / channel, 2 ohm load, 16V DC supply. > 6W RMS / channel, 4 ohm load, 16V DC supply. > 4W RMS / channel, 4 ohm load 12V DC supply. THD < 0.1% @ 1W, 4ohms. S/N ratio : > 80 dBA. Frequency response : ~ 15 Hz to 50 kHz, -3 dB Gain : ~ 30 dB maximum. Input level : ~ 150 mV for full output….

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