It is a well-known fact in the audio industry that capacitors make a big difference to the sound quality of an amplifier, but few people have spent much time researching the reasons why.
In essence, a capacitor is two large plates of conductive material, separated by an insulator. As the charge in one plate rises, it transfers across the electrolyte to the other plate and an ac current flows.
Electrolytic capacitors are electro-chemical devices and their internal chemistry prevents the use of low resistance material like copper.
So aluminium conductors with a higher resistance must be used and this makes the capacitor's internal design quite critical for audio applications. Also, capacitors are like batteries in that they have a limited operating life depending on the quality of their materials and their running temperature - a higher temperature gives a shorter life.
Makers of quality audio amplifiers should never cut costs on the capacitors as it drastically shortens the useful life of the amplifier.
A major improvement in audio capacitor performance came in 1984 with a DNM invention, the slit foil capacitor. Conventional capacitors, being made of large, coiled, thin strips of aluminium, are prone to induce eddy currents across their conducting surface. These currents prevent the capacitor from doing its job optimally, thus degrading subjective sound quality. By introducing a series of tiny slits in the foil conductors these eddy currents are dramatically reduced, so improving the subjective and measured performance. For such a simple alteration to the design of a capacitors the benefits are amazing. Use them in your power supply and you will hear the difference.
The slit foil capacitor is made exclusively by SuperTech and it is now used in quality hi-fi products the world over.