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The best speaker to use with this audio amplifier is a 4 ohm, 8 watt, 4" to 6" size speaker. A small one comes with some of the kits, but it does not give the best audio compared to using a larger speaker. Some of the kits may contain a LM383, but it is identical to the TDA2002. Same pin out and electrical characteristics. Most ham CW and SSB communication is between 300 Hz to 3000 Hz. The following is a chart reprinted from the SGS data sheet intended to aid the designer for fine tuning the audio amplifier. |
| Part | Value | Purpose | Larger Value | Smaller Value |
| C21 | 2.2 mfd | Input DC decoupling | Noise at switch-on, switch-off | |
| C22 | 470 mfd | Ripple rejection | Degradation of SVR | |
| C25 | 0.1 mfd | Supply bypassing | Danger of oscillation | |
| C24 | 1000 mfd | Output coupling to load | Higher low frequency cutoff | |
| C26 | 0.1 mfd | Frequency stability | Danger of oscillation at high frequencies with inductive loads | |
| C23 | 39 pf | Upper frequency cutoff | Lower bandwidth | Larger bandwidth |
| R7 | 220 ohm | Setting of gain | Increase of drain current | |
| R8 | 2.2 ohm | Setting of gain and SVR | Degradation of SVR | |
| R9 | 1 ohm | Frequency stability | Danger of oscillation at high frequencies with inductive loads | |
| R6 | 39 ohm | Upper frequency cutoff | Poor high frequency attenuation | Danger of oscillation |
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