General perception
Reducing or suppressing noise in a vinyl sound system to an acceptable level is difficult and multi-step. Even the lowest noise phono stages can produce annoying noise if set up incorrectly. This article is not for turntables like Victrola, Crossley.
Phonostage
The first thing to notice is that the signal strength from the cartridge (turntable) is only 1/1000 of the signal from a CD player or DAC. That’s why the interference becomes more severe. Phonostage MM has a gain of 40dB at 1kHz (gain = 100). However, because of the RIAA Equalization process, the gain at 60Hz will be ten times greater (gain = 1000). Electrical noise level 0.000005V produced audible noise. With MC cartridges, this phenomenon is ten times worse. We will need to find and fix each system’s fault, especially in complex audio systems.
Sources of Interference
Noise sources often come from wires, tonearms, or cartridges, mainly due to impure currents or interference from magnetic fields, high-frequency waves, and radio waves.
Symptoms and Treatment Solutions
Below is a list of noise symptoms in an audio system and what causes them most often. Here we will only deal with electrical noise errors.
- Light hiss:
This sound is quite ordinary. That is what we want in a turntable sound system. A good system will have lower hiss than groove noise.
- A little explosion:
The cause is usually due to scratches
- Occasional beeping sound:
The connection is not good; it may be caused by a loose connector, wire, or socket. An open weld can also cause it.
- Pop a loud voice:
The “beep” sound when powering off or on the machine. In many cases, the hardware must interfere with by soldering more capacitors to the amplifier’s power input. However, for most people, this is not possible. It is best to turn down the volume on the amplifier and then turn off other push-button devices.
- Buzzing:
The phenomenon of buzzing due to magnetic infection. That is usually due to the proximity of power transformers, isolation transformers, or a ground loop caused by too many ground lines in a system.
- Emit a light, steady buzzing sound:
Because the tray system is not properly grounded or not grounded. Usually occurs in systems that are not grounded (by 3-pin).
- Whisper:
Caused by motors in nearby equipment. Refrigerators or electrical appliances with motors will cause interference when plugged into the same power line, causing low-frequency interference while they are operating.
- Hissing:
Due to high-frequency interference from refrigerators, TVs, washing machines, infecting the total electrical system and audio system
- Catching radio waves:
Usually happens with semiconductor phono that is not well anti-interference. Because the system lacks ground, you will accidentally turn into an AM/FM radio reception antenna when touching the metal tonearm.
- Howl:
The tray hums, the size gradually increases. That is caused by vibrations caused by placing the speaker and turntable close together. There is no isolation measure for the tray and speakers; it is easy to burn the amplifier circuit if the volume is loud.
- Chilled sound, lost high mid and treble:
The load impedance is too large, so the sound is muffled.
- Glare:
Usually occurs with MC needles. Needle MC uses load impedance, not load capacitive like MM needle; if we let the load capacitance be too high on the phono, it will cause high-band resonance and push the high mid and treble tones up, causing harsh glare and thin sound. It is recommended to put the minimum load capacitance if an MC needle is used.
How to diagnose and “first aid.”
Thoroughly dealing with the above errors is very difficult, especially when there are many overlapping problems. You can check simply by the following ways:
– Touch the metal parts that should be grounded, such as grounding pins, tonearm, connection cover, chassis. If the noise level changes, that means you will need to pay attention to handling that area. The first thing you should do is test the grounding.
– Unplug the phono stage input wire to see if the noise is gone.
– Switch between channels to see which channel is causing the error.
– Change the position and orientation of the phono stage to see if the hum changes. That helps to find out exactly which device is causing the error.
– Plug the cord into another outlet.
– Turn off the fluorescent lights to see if the buzzing stops?
– For systems using 2-prong (2-prong) wires, check that the ground is connected.
– Try isolating phono stage, turn off WiFi router, tablet, laptop, and smartphone near the system.
Methods to do
Start by placing the turntable and phono stage away from the power amplifier and speakers, and place them on a sturdy and sturdy surface. Plug all electrical equipment into the same socket using an outlet or line filter. Run the cord short and separate it from the other wires (not tied in bundles). Finally, place noise sources such as isolation transformers, voltage stabilizers, refrigerators, and TVs as far away from audio devices as possible.