Intermittent Noise Coming from Left Channel

[quietfactory]

Hello!

I'm not well-versed in audio matters regarding equipment, hence why I'm here. So heres the issue I've been having for months now: my left channel is making a weird noise, even if no audio is being played or if I set my volume to 0. Whether its my speaker or my open-back headphones, the noise persists. It's an intermittent in how often it happens & the duration also varies.

I own a Cambridge AXR85 integrated amplifier (refurbished), Pro-Ject Debut Carbon Evo Turntable, KEF Q150 bookshelf speakers, Sennheiser HD560s headphones, LG 32" UltraFine IPS UHD Monitor with FreeSync, & a 2021 Macbook Pro with M1 chip. I have an aux cord (purchased from Monoprice I believe) connected from my monitor to my amplifier when I'd like to hear audio from my computer. An HDMI cord connects my Macbook to my monitor as well.

I tried to google this issue & find a solution on my own. It mentioned grounding, electromagnetic interference, & other possible things. I have checked my grounding on both my turntable & IA. I purchased an Austere V Series Power (8 outlets) as suggested by a Crutchfield agent to see if that would help (it did not). I have checked all my connections into my speakers & IA + headphone jack input for both audio going in & out. I've moved all the wires with my headphones plugged in & heard no difference in the noise & how often it came through. I even unplugged the power cable to my IA with both my speakers connected & my over-ear headphones still plugged in to see what was going on & STILL this static/'burning' sound is coming through. This is both on AUX input & Phono. Although, I noticed that when I use Bluetooth with my IA via my phone, the noise is non-existent. I can't place if this is an electromagnetic, radio, or transistor issue. I've never used the tuner.

I've read some dozen forum threads throughout varies websites & such to see if I could find a solution. I noticed some of those same threads mentioned opening the unit & possibly soldering? I haven't any experience in that if it came down to one of my transistors being an issue. There is no audio shops in my city that specialize in audio equipment repair. The nearest place to take my IA for a diagnosis or repair is over 2 hours away. I called the business & left a message with no response. I'm running out of patience & options, someone please help me.

 

[spark1]

Disconnect everything from the amp except speakers. Turn amp on. Do you still get the noise?

If no, add the turntable. Noise?

If not, keep adding other input devices until you identify the culprit.

 

[RTally]

I even unplugged the power cable to my IA with both my speakers connected & my over-ear headphones still plugged in to see what was going on & STILL this static/'burning' sound is coming through. This is both on AUX input & Phono. Although, I noticed that when I use Bluetooth with my IA via my phone, the noise is non-existent. I can't place if this is an electromagnetic, radio, or transistor issue. I've never used the tuner.

Are you saying that you unplugged your integrated amp and, with it turned off, you still heard noise? Did you hear the noise through the headphones, the speakers, or both? Was your turntable and computer monitor still hooked up and plugged in? Were they turned on? When you swtiched to bluetooth with the amp off, you did not hear any noise?

If you hear noise from the headphones with the integrated amp turned off, I suspect that there is electromagnetic interference (EMI) being picked up by the amp. The source of EMI can be something located next to the amp or the equipment plugged into the amp, such as your computer or monitor. If the turntable and monitor are plugged in, the EMI could be coming through the power line from something plugged in somewhere else in the house. Since the noise is intermittent, you may want to see if the noise comes on when something else in the house comes on, like a refrigerator or microwave oven.

One way to troubleshoot these types of problems is to test one thing at a time. The idea is to start with the absolute minimum and add one thing at a time to see what you added that made the noise audible. This is made complicated because the noise is intermittent. If the noise lasts for several minutes, you can do the following as soon as the noise starts.

Starting with the headphones, you should not hear any noise when they are not plugged in (location should be same as when you hear noise). Next step is to add the integrated amp to the equation. With nothing except the headphones plugged into the amp (everything else unplugged), do you hear noise? Plug in the amp. Hear noise? Turn it on. Hear noise? Move input selector to different inputs. Hear noise. Plug in monitor. Hear noise? Remove monitor and plug in turntable. Hear noise? Connect turntable ground. Hear noise? Etc.

Another option is when you hear the noise, work backwards. With every thing connected as normal, start disconnecting everything while listening. Start with each input until nothing except the headphones is plugged into the amp. Once disconnected, leave it disconnected and move on to the next cable.

Hopefully, you will do one thing and the noise will be audible and when you undo it, the noise stops. Let us know what you did to make the noise appear.

 

[RTally]

PS: Welcome to AK. Glad to see you here.

Lots of members have experience troubleshooting equipment. I am sure we can at least identify the source of you noise.

 

[quietfactory]

One way to troubleshoot these types of problems is to test one thing at a time. The idea is to start with the absolute minimum and add one thing at a time to see what you added that made the noise audible. This is made complicated because the noise is intermittent. If the noise lasts for several minutes, you can do the following as soon as the noise starts.

Starting with the headphones, you should not hear any noise when they are not plugged in (location should be same as when you hear noise). Next step is to add the integrated amp to the equation. With nothing except the headphones plugged into the amp (everything else unplugged), do you hear noise? Plug in the amp. Hear noise? Turn it on. Hear noise? Move input selector to different inputs. Hear noise. Plug in monitor. Hear noise? Remove monitor and plug in turntable. Hear noise? Connect turntable ground. Hear noise? Etc.

Apologies for the late response, life you know? I've attempted the first bit of this diagnostic & found that when nothing but the headphones are connected while in the phono input, I hear the noise. Thing is, the noise doesn't happen unless I turn on the amp. Then, after I turn it off, the noise stays, even if the amp is unplugged. I'm not sure what to make of that. I also noticed something when plugging everything back in that I normally use in my setup. When I had my headphones plugged in, the amp on, & the aux cord plugged into the amp but not my monitor, it made a hum noise. Only when I had my hand(s) on my Macbook though. I theorize because it is made of metal, it may of caused conduction & the hum to be produced? I'm not sure, don't think my word choice is correct , but my understanding of the situation is I feel.