Step Volume Potentiometer Overview

If the volume potentiometer is only used to adjust the volume, the problem would be much simpler. But in fact, the volume potentiometer is the only way for the signal to pass. Its importance is often underestimated. Audio technology has always been committed to creating zero-distortion components, but in reality this is a dream. What we pursue is actually the lowest level of compromise.
VR, as the name suggests, is a variable resistor. Generally, the machine is used to adjust the signal size. In audio, it is used for volume control, left and right balance, high and low bass knobs... All of them. This component is a continuous adjustment step (sliding type), with very poor stability and easily affected by temperature and humidity. For other information, please refer to the relevant instructions of electronic components. When VR is a new product, most people's ears are slow to detect the sound, but after using it for a while, you will feel that the sound of the left and right channels will drift and the instrument cannot be accurately positioned. After a while, there will be noise when rotating the potentiometer. Only then will you suddenly realize it, and the overall sound will get worse and worse. Some people blame this and that, change the machine, change the line, and try all kinds of treatments in a hurry. It is also in vain.

The volume potentiometer can be a general potentiometer, such as ALPS.Noble, etc. Or you can buy a Swiss Elma frame, add 0.1% Holco precision resistors to form a step-by-step potentiometer (the choice of rich people, this potentiometer costs two thousand dollars), or make a step-by-step volume switch yourself. The advantage of the former is that it is easy to buy, but the sound quality of commercial products that cost only tens of yuan is not very ideal, and the error between the two channels is usually not small, which seems to be inconsistent with the spirit of HI-FI; if you buy high-end products, the price is quite high. In view of this, high-end expensive machines use 24k gold-plated contact switches with 24~60 fixed resistors welded on them to ensure more stable quality. The latter uses a multi-segment band switch (usually more than 20 segments) and welds resistors of different resistance values ​​to simulate the action of the potentiometer. The advantage is that the error between the two channels is very small, and when the higher-grade resistors are used, the sound quality is relatively better. The disadvantage is that multi-segment band switches are not easy to buy, and the price of good quality ones is not cheap;

There is no doubt that this type of switch-type stepping resistor is much better than potentiometers. It is generally used by Cello, Krell, Mark Livinson, Jadis, MBL... and my MATISSE. The multi-stage series switch is welded with fixed resistors. This design can greatly reduce the size of the parallel type and can have continuous multi-stage volume switching (generally about 20~60 stages). It is no different from the traditional cheap VR in use, but the sound quality is indeed incomparable to VR. The disadvantage is that because it is a multi-stage series type, the number of fixed resistors is amazing, about 100, and at the same time, the error of ultra-precision resistors must be 1%. Holco, Vishy Dale, Philips... resistors can be used. At the same time, the quality of SW must be good, which is why this kind of thing costs you 3,000 to 6,000 yuan. You can buy finished products at various audiophile parts stores. If the VR you use is not a general specification, you have to make it yourself. You can substitute the formula of 20 Log Av and step by about 0.5~0.8dB per segment.