Replace capacitors? Why?

Replace capacitors? Why?

Electrolytic capacitors generally consist of two long and thin aluminum strips, each welded to a lead of the capacitor, which are rolled up into a roll.

The two aluminum strips must not have any electrical contact with each other in order to function as a capacitor, which is why there is a somewhat wider strip of paper between the two aluminum strips. For special capacitors, more noble materials such as silk (in the form of fabric made from it or a kind of 'tissue paper') in question.

These absorbent strips are impregnated with a liquid called the electrolyte. Together with the paper strips, the electrolyte represents what is known as the dielectric, i.e. it separates the two types of charge, positive and negative, from one another.

The electrical value of an electrolytic capacitor results from the length and width of the strips, the distance between them (paper strips) and the amount of electrolyte present in the paper strip.

Although electrolytic capacitors with liquid electrolyte, which is the main focus of this shop, are hermetically sealed with a rubber stopper, the electrolyte manages to evaporate over time, e.g. which become hot and due to the increase in pressure inside due to heating up under load.
Storage conditions in a hot environment (attic) may also have played a role.

However, as the paper strips become drier, the capacitor loses capacity, more and more.
As a result, it is less and less able to perform the task originally intended for the installation site, if at all.
It is then as if there were no component at this point that could have a significant influence on what is happening (see below: Effects on hi-fi equipment).

You also often see electrolytic capacitors that have burst.
This can be due to incorrect formulation of the electrolyte liquid and/or heavy load and the associated self-heating.

Wrong dimensioning with regard to dielectric strength or this in connection with today's higher mains voltage can also lead to this.

Effects on hi-fi technology devices

Using the example of an analog amplifier, this may be caused by hum in the speakers (more and more missing filtering of the rectified mains voltage), imbalances in the two channels, distortion of the playback, failure of the protective circuit, which turns on the speakers after a while when switched on should notice (loudspeakers remain off for an eternity or turn on immediately without any protective effect).

CD players with their mainly digital signal processing are subject to unfiltered interference in the circuit due to defective capacitors, which, for example, make it more and more difficult to read the CD , make the player play "crazy" after a while or require a certain "preheating time" after switching on, before you can listen "normally" with it.

However, such players can no longer process the perfectly read-in information from the CD without problems . The effect is comparable to a CD that is badly scratched and where the player has to reconstruct (interpolate) the missing information, which can never succeed without loss.

Before a defective laser that can no longer be obtained is suspected as a source of interference, it may be worth installing a new set of capacitors or having them installed (unfortunately we do not offer this service).


Is it mandatory to recalibrate the device after installation?

In general, it is our position that if a unit has some adjustments to make and was perfectly adjusted at the factory when the capacitors were new and unused, the addition of a new capacitor set will bring it much closer to original condition than if only "the usual suspects" were replaced.

Over time, due to the aging of the electrolytic capacitors, the alignment shifted until the device was no longer functional.

When a completely new capacitor set is installed, the condition as in the factory is restored, although it must of course be said that both the old capacitors were subject to or are subject to the new manufacturing tolerances when they were new.

In the case of tuners, an adjustment is therefore definitely recommended if these electrolytic capacitors are in the HF-processing part of the circuit.