Hoses differ from radio interference in that they interfere with the operation of amplifiers, not radio receivers. Their sources are electrical, broadcast and telephone networks, cell phones, radio transmitters, powerful loads when switching on and off, and collector motors.
Instructions
Step 1
Regardless of the type of interference, try to shield all cables that carry audio from one device to another. Another way to deal with them is by using differential lines. To do this, install a differential transformer at the output of one device and at the input of another. The windings of these transformers, opposite to the devices, are connected to each other by the extreme terminals, and the middle ones are connected to the cases of the devices. The cable connecting differential transformers to each other must be shielded. Currently, there are solutions that allow differential input and output without the use of transformers.
Step 2
Use on the device from which the signal is taken, the output on which the signal has a large amplitude. On the device to which the signal will be sent, select the less sensitive input. In this case, the swing of the useful signal will exceed the swing of the interference. In general, always try to amplify the signal transmitted over the cable on the transmitting side, not the receiving side. Sometimes a step-up transformer can be used to increase the signal swing on the transmitting side, and a step-down transformer on the receiving side for matching. Both transformers must be suitable in terms of parameters.
Step 3
Try to place sources of interference away from the equipment and communication line, and if this is not possible, on the contrary, move the equipment and communication line away from the sources of interference. For example, if the cause of the interference is a cell phone or an electric drill, then it is easier to move the source of interference, and if, say, the welding machine is on the street, then it is easier to move the cable going to the amplifier.
Step 4
Avoid nonlinearities in the pre-stages of amplifiers. It is on them that, in particular, cell phone signals are detected, despite the fact that no diodes are shown in the diagram. If you want to artificially create distortion in an amplifier, for example, in order to simulate a tube sound, such an amplifier will be much more noise-immune if the stages, into which nonlinearity is artificially introduced, are located not at the beginning, but in the middle or end of the path.
