What makes an Excellent Electrolytic Capacitor?
"Electrolytic capacitors determine the lifespan of a power supply"
We are often asked what kinds of Capacitors we use in our repairs and upgrade kits. We thought it might be useful to explain some of the factors leading to our decision choices. The first thing to note is that it’s somewhat pointless chasing a specific named manufacturer as there are a number of factors that make one capacitor a more appropriate choice over another, especially in non-audio path applications. As Valhalla, Axis and Lingo boards are all power supplies that are not in the direct amplification audio path the choice of capacitors will not be audible so the desired characteristics are for long life.
There are a number of factors which can help extend a capacitor’s life but perhaps the most important is temperature. Having capacitors operating in a warm or hot environment can result in electrolyte drying up and shortening the capacitor’s lifespan. It’s crucial to replace to use 105 °C rated capacitors to extend the life of your repair. That’s our number one consideration – all the capacitors we supply are the high temperature 105 °C versions. Even a 10 °C increase in the operating temperature of an electrolytic cap cuts its estimated lifetime, which shows the importance of keeping an electrolytic cap’s temperature at the lowest possible levels.
Linn Axis and especially Valhalla power supplies run hot! It’s particularly unfortunate that Linn chose to site the large voltage-dropping resistors so close to the 47uf electrolytic smoothing capacitors.
The next most important factor is rated operating voltage. If an electrolytic capacitor is subjected to its maximum rated voltage it will tend to heat up and its lifespan will be reduced for the reasons outlined above. It’s wise to up-rate the working voltage specification as this will prolong the capacitors working life, for example, where Linn specifies 250v parts we tend to supply 350v parts (space permitting).
Effective Series Resistance
Effective Series Resistance (ESR) is another important factor. In general, the lower the ESR the better the quality of the capacitor. The higher the ESR the more heat will be generated inside the electrolytic capacitor.
Finally, the manufacturing quality should be considered. At Valhalla Electronics, the majority of the capacitors we use for our Linn Axis, Linn Valhalla repairs and update kits are from manufacturers such as Supertec, Panasonic or Nichicon.