Weird noise in tweeter

[Sopper]

I experience weird computer-like noise coming from the tweeter.
For this problem to solve I use to break down it to parts

This video shows the annoying noise
The strange thing is, when I lay my finger on both speaker banana plugs at the amp side, the noise is reduced by a lot.
This setup contains just 1 Tundra mono amplifier, connected to power and 1 speaker cable connected to 1 speaker.

Anyone an idea what is causing this noise and how to fix it?

https://drive.google.com/file/d/1NAiezq ... share_link

[Spannko]

Is it possible that you’re picking up some kind of digital transmission and when you put your finger on the phono plug you are grounding the noise? You could try pushing on the plug with the same pressure but using an insulator to prevent the grounding.

[Sopper]

Is it possible that you’re picking up some kind of digital transmission and when you put your finger on the phono plug you are grounding the noise? You could try pushing on the plug with the same pressure but using an insulator to prevent the grounding.

Yes, I’m picking up something for sure, since it only happens on the left side of the setup.

I thought about what you suggested, but am clueless about what sort of material this could be

[Spannko]

Any non-conductive material will do, a piece of wood for example or a BIC biro, using the non-pointy end!

[Spannko]

Alternatively, you could have a loose ground on the socket and when you press on the plug you’re temporarily connecting the ground again?

Also, I notice that when you touch the plug, you’re also bridging the left and right grounds. So you could be connecting the left channel ground to to the right channel ground via your finger?

[Sopper]

Alternatively, you could have a loose ground on the socket and when you press on the plug you’re temporarily connecting the ground again?

It happens with both Tundra mono
So it would be very weird to have ground broken on both amplifiers

Both amplifiers connected to speaker are fine at the right side of the setup
Both are bad when on the left side 🤔

[lejonklou]

Have you connected the power amp to the pre amp (both powered up)?

[Sopper]

Have you connected the power amp to the pre amp (both powered up)?

No, this is just poweramp and speaker connected

[lejonklou]

That likely explains it.

With no preamp connected, the input of the power amp is left floating and makes the amp prone to pick up disturbances.

[Sopper]

That likely explains it.

With no preamp connected, the input of the power amp is left floating and makes the amp prone to pick up disturbances.

It is less with preamp connected but it is still hearable and annoying

[Spannko]

Have you tried replacing your DIY cables with Linn Silvers?

[Sopper]

Have you tried replacing your DIY cables with Linn Silvers?

Offcourse…
It’s not the cables
All cables I tried, same story

[Spannko]

How is your mains supply configured?

[Sopper]

How is your mains supply configured?

It’s not the mains either
Tried all inlets in the room
I have a dedicated audio power line

All I know is that I’m picking some interference up at the left side. It’s not equipment, cable or power related. I cannot find the source of this interference and also don’t know how to find it if it’s not something visible.
The restaurant beneath me, I checked there and there is nothing close that can be picked up.

So if I cannot find the source I cannot solve the problem
All I can do/try is to reduce the noise
Lifting the speaker cable helps, but not in a logic way; lifting further (higher) results in increase of interference. 30cm height seems the least interference at the moment

Is there any measurement equipment that can detect interference? Or a company who can measure it?

[tpetsch]

How is your mains supply configured?

It’s not the mains either
Tried all inlets in the room
I have a dedicated audio power line

All I know is that I’m picking some interference up at the left side. It’s not equipment, cable or power related. I cannot find the source of this interference and also don’t know how to find it if it’s not something visible.
The restaurant beneath me, I checked there and there is nothing close that can be picked up.

So if I cannot find the source I cannot solve the problem
All I can do/try is to reduce the noise
Lifting the speaker cable helps, but not in a logic way; lifting further (higher) results in increase of interference. 30cm height seems the least interference at the moment

Is there any measurement equipment that can detect interference? Or a company who can measure it?

As an experiment:
You can try running an extension cord from other outlets in the house to the system and see what happens.
You can try lifting the ground on the AC cord and see if this has an effect.
Did you swap left & right speaker cables at the amp and did the noise move to the other speaker?

[Sopper]

As an experiment:
You can try running an extension cord from other outlets in the house to the system and see what happens.

Done this, no effect

You can try lifting the ground on the AC cord and see if this has an effect.

Not sure if this is safe to do?

Did you swap left & right speaker cables at the amp and did the noise move to the other speaker?

Good one, I need to do this, I’ll report back

[Sopper]

Meanwhile I have ordered an EMF meter
Hopefully I can determine the root cause of this interference

[tpetsch]

As an experiment:
You can try running an extension cord from other outlets in the house to the system and see what happens.

Done this, no effect

You can try lifting the ground on the AC cord and see if this has an effect.

Not sure if this is safe to do?

Did you swap left & right speaker cables at the amp and did the noise move to the other speaker?

Good one, I need to do this, I’ll report back

It's perfectly fine to lift a ground temporarily to check/listen for AC ground faults, I've done it dozens of times on shop calls and my personal Linn, Naim and other gear over the years, not sure where you are but here in the US we have cheater plugs that make lifting a cord ground a 5 second & very simple test, remove the plug from the receptacle, add the cheater -see pic-, plug back into the wall and listen to the system again to see if the issue stayed or went away. ...But I completely understand if you're not comfortable doing this.

Another thing you can try is to remove all RCA source inputs to the preamp including a TT ground if using one, then if the noise goes away start adding each source interconnect back one at a time until the noise returns.

[lejonklou]

That likely explains it.

With no preamp connected, the input of the power amp is left floating and makes the amp prone to pick up disturbances.

It is less with preamp connected but it is still hearable and annoying

If you, instead of connecting the interconnect to the preamp, short out the pin to the barrel and leave the other end connected to the power amp, does the noise go away?

[Sopper]

I will short the input of the Tundra and report back