In audio electronics design friends, I believe we are not unfamiliar to the front stage potentiometer. But making audio electronics design, pre-potentiometer resistance is determined to make a novice design is very distressing problem! Common pre-Pot is how much? Select the number resistance potentiometers in order to meet the design requirements of the circuit it?
Today, Granville electronic potentiometer resistance on this issue to determine the analysis.

Generally speaking, the audio amplifier circuit class potentiometer resistance is usually 50K or 100K. Potentiometer is a sliding contact-type variable resistor! Whose resistance changes depending on the needs can be divided into linear potentiometer (antilog) three kinds of potentiometer potentiometer logarithmic, exponential type.
In fact, the sound volume potentiometer is a logarithmic potentiometer, its resistance is generally between 47-100 kilohms. During construction, mostly carbon brush chip or wire brush style. The multi-filament high-end potential, the potential of such a performance far superior to common reed potentiometer. The actual choice, we should be determined before the device according to the direction of the output impedance of the amplifier. Example: Most of the audio CD, DAC, DVD, deck, etc., the output impedance close as 100K, so the first stage of general potentiometer 100K; and most of the previous stage output impedance is 50K, so the multi-stage amplifier volume potentiometer to 50K; In this case, Granville electronic reminder, where some special types, such as: 10K - 470K has. This approach is to be able to try before and after impedance matching, reduced distortion. Usually coaxial output line, the output device in the output interface to 75 ohm resistor in series or in parallel, DAC in the input interface 75 ohm resistor in series or in parallel, coaxial cable impedance is 75 ohms. It is the same reason, but also for impedance matching.
Volume potentiometer as a pre-load, the general design of the output impedance matches the design stage before the actual application that allows a certain range selection. The original use of potentiometers 50K instead of 100K, in conditions not very good situation is acceptable.
Today, newcomers are designed for stereo volume potentiometer resistance level before selecting a certain direction and there is no idea of ??it?
If you need more, please login http://www.591ccc.com Learn More Oh!