Mundorf E-Cap audio and signal coupling capacitors are bipolar electrolytic capacitors. They are used in applications where film capacitors are not suitable for space or cost reasons, as they are generally much more compact than their film counterparts. In particular, they are widely used in crossover filters.

There are two ranges of E-Cap capacitors. The PLAIN range consists of the ECAP70 (BG50) and ECAP50 models. Capacitors in this range are made of smooth foils and therefore allow low losses for better sound quality.

These capacitors are bipolar and have a second aluminium foil for resistance to AC voltage, making them suitable for AC audio signals.