All data below based on LM386N-4, 8 pin DIP with 1.25w package dissipation, and max PSU of 22v
Current datasheet from TI: https://www.ti.com/lit/ds/symlink/lm386.pdf?ts=1612350151545
Maximum power without heatsink, sorted by speaker output in ohms:
4 ohms (Figure 7 on datasheet) = Max 0.35w @ 6v (clean 0.25w) [Min 0.35w @ 6v]
* Need heatsink above 11v
* PSU recommendation: 7.2v NIMH or 7.4v Li-ion
8 ohms (Figure 8 on datasheet) = Max 0.85w @ 12v (clean 0.5w) [Min 0.3w @ 6v]
* Need heatsink above 14v
* PSU recommendation: 9.6v NIMH or 11.1v Li-ion
16 ohms (Figure 9 on datasheet) = Max 1.6w @ 16v (clean 1.2w) [Min 0.2w @ 6v]
* No heatsink required
* PSU recommendation: 11.1v Li-ion, 12v SLA or 14.4v auto power
Current datasheet from TI: https://www.ti.com/lit/ds/symlink/lm386.pdf?ts=1612350151545
Maximum power without heatsink, sorted by speaker output in ohms:
4 ohms (Figure 7 on datasheet) = Max 0.35w @ 6v (clean 0.25w) [Min 0.35w @ 6v]
* Need heatsink above 11v
* PSU recommendation: 7.2v NIMH or 7.4v Li-ion
8 ohms (Figure 8 on datasheet) = Max 0.85w @ 12v (clean 0.5w) [Min 0.3w @ 6v]
* Need heatsink above 14v
* PSU recommendation: 9.6v NIMH or 11.1v Li-ion
16 ohms (Figure 9 on datasheet) = Max 1.6w @ 16v (clean 1.2w) [Min 0.2w @ 6v]
* No heatsink required
* PSU recommendation: 11.1v Li-ion, 12v SLA or 14.4v auto power