Audio - Mains noise

[Fascinated Viewer]

Hi, I have a vinyl player from, I think, the 1980s not sure, as it does not exist anywhere online (Ion iTT02), and I also have this plugged into a Behringer phono preamp (PP400). The output is phono to 3.5 mm jack and plugs straight into my polaroid speaker. Yes, the same company that makes the cameras.

Anyways my issue is noise which is pretty sure the main noise as I hear this buzz which I think is from the preamp as I have unplugged the vinyl player from the preamp and the same noise is still there not sure why this issue happens. But it is annoying.

The speaker has a volume + and down, and I think I could be the speaker increasing the gain, which makes you be able to hear this noise am not sure and want to see what yall think bc I have no idea.

Note:
I have replaced the vinyl capacitors with newer ones bc there pretty dam old.

 

[Doodski]

I have replaced the vinyl capacitors with newer ones bc there pretty dam old.

What unit did you replace the caps in?

 

[Fascinated Viewer]

What unit did you replace the caps in?

The caps were in the vinyl player circuit board, and basically, the only board in there, bar the DC power terminals, i.e. vinyl player motor speed and on, off feature. The speaker wires if I remember correctly, just go from the tone arm into the female Phono connectors one of the tracks (copper trace terminals) decide to not work anymore, so I grabbed some solid wire and reconnected the trace

 

[Doodski]

The caps were in the vinyl player circuit board and basically, the only board in there, bar the DC power terminals

OK.

Without a source connected to the speakers connect the speakers to power and see if they have a buzz sound. If not then connect the pre-amp to the speakers and see if the buzz reappears. Check your cables for bad grounds. A bad ground connection in a cable will give a buzz sound.

 

[Fascinated Viewer]

So my speaker does not buzz. I know this for sure, as I have had the volume maxed out with no source but power connected, and it all seems fine. And I've replaced the caps in the speaker, too, cause it is a little old, and I wanted to minimize the factor of it being the speaker.

When I connected the preamp with no source connected to the preamp (preamp input), I heard the buzz. My samples seem fine, and the vinyl player is connected to the ground via the "12 v ground" on the preamp, and the noise is a lot better. I would like to try and get rid of it, but I doubt this may be possible. The Phono to 3.5mm jack cable is a Ugreen brand cable.

 

[Doodski]

So my speaker does not buzz. I know this for sure, as I have had the volume maxed out with no source but power connected, and it all seems fine. And I've replaced the caps in the speaker, too, cause it is a little old, and I wanted to minimize the factor of it being the speaker.

When I connected the preamp with no source connected to the preamp (preamp input), I heard the buzz. My samples seem fine, and the vinyl player is connected to the ground via the "12 v ground" on the preamp, and the noise is a lot better. I would like to try and get rid of it, but I doubt this may be possible. The Phono to 3.5mm jack cable is a Ugreen brand cable.

How loud is this AC mains buzz? Is it faint or is it obnoxious and easily heard?

 

[Fascinated Viewer]

I would say its faint and a bit obnoxious like its just annoying to hear. I could put this into adobe audition and play it back to you.

 

[Doodski]

I would say its faint and a bit obnoxious like its just annoying to hear. I could put this into adobe audition and play it back to you.

It appears the pre-amp is the cause of the AC mains buzz. Either that or the connection cable from the pre-amp to the speakers.

 

[Fascinated Viewer]

So I have moved my preamp up to my desk (away from mains power), and I only hear it when the vinyl player is plugged into the preamp. They are grounded in each other, and both do not use the grounding wire with the plug sockets. The vinyl player is not near any power sources, so I think it could be the transformer in the vinyl player?

 

[Doodski]

You should not hear a buzz when connecting the phono.

They are grounded in each other, and both do not use the grounding wire with the plug sockets.

Explain more for me. I'm a bit confused as per what the exact configuration is from your description.

The vinyl player is not near any power sources, so I think it could be the transformer in the vinyl player?

The phono transformer is likely not a source of the issue.

 

[Fascinated Viewer]

This is the audio i hear through the speaker but a bit quieter when the volume is increased on the speaker.

 

[Doodski]

This is the audio i hear through the speaker but a bit quieter when the volume is increased on the speaker.

Yes, a ground hum. Somewhere in the phono pre, the turntable and cables there is a bad ground.

They are grounded in each other, and both do not use the grounding wire with the plug sockets.

What do you mean by this. Is the ground on the RCA connection not connected/missing?

 

[Fascinated Viewer]

So this is the transformer in the vinyl player apologies. There are just caps in the phono amplifier which I have opened up to have a look at to see what's inside

(image of the vinyl player transformer for the motor and board)

 

[Fascinated Viewer]

Yes, a ground hum. Somewhere in the phono pre, the turntable and cables there is a bad ground.


What do you mean by this. Is the ground on the RCA connection not connected/missing?

Hi, this is the set-up I have to make things a little easier lmao. sorry for the confusion

 

[Doodski]

Hi, this is the set-up I have to make things a little easier lmao. sorry for the confusion

Thanks for the pic. Do you have a multimeter with Ohms/resistance range? If you have a meter then the grounds can be metered and see if there is anything obvious as a issue. Also placing the pre near AC power cables should not affect it to any substantial degree if everything is operating and designed properly.

 

[Fascinated Viewer]

Thanks for the pic. Do you have a multimeter with Ohms/resistance range? If you have a meter then the grounds can be metered and see if there is anything obvious as a issue. Also placing the pre near AC power cables should not affect it to any substantial degree if everything is operating and designed properly.

No, I don`t, but I can go to my university after the bank holiday on Monday and use there's they have a lot of equipment. I know that the vinyl player ground is connected internally to some metal to which the platter is connected. They have some table multimeters and some Keysight gear ngl I don`t know how to use it, so ill ask them lmao.

What should I look for in terms of range ? like whats acceptable/normal

 

[Doodski]

No, I don`t, but I can go to my university after the bank holiday on Monday and use there's they have a lot of equipment. I know that the vinyl player ground is connected internally to some metal to which the platter is connected. They have some table multimeters and some Keysight gear ngl I don`t know how to use it, so ill ask them lmao.

What should I look for in terms of range ? like whats acceptable/normal

For low resistance metering a 2 ohm range for a fancy more expensive multimeter and 200 Ohm for a general purpose meter is common for the low Ohms ranges and is what is required. What needs to be done is to meter the grounds and the + conductors from the head-shell to the RCAs on the pre. If you want to open the gear and do a thorough visual inspection of all the solder joints on the PCBs, @ the RCA connectors and the ground screws for tightness that will place you in a good position for when you may meter the gear with a multimeter. Things like the AC mains transformer and such are not going to be a source of the buzz. With this specific situation it will be something more simple but often convoluted to diagnose and find the fault but all-in-all this is probably not a difficult repair with a multimeter.

 

[Fascinated Viewer]

Okay, ill do that on Tuesday and probably let u know. Also, here are a few more photos of the connections, if they help at all (of the vinyl player)

 

[Doodski]

Okay, ill do that on Tuesday and probably let u know. Also, here are a few more photos of the connections, if they help at all (of the vinyl player)

Great pics... It helps a lot to see what the layout is. It's all pretty easily accessible so once a meter is available things should go pretty effectively/efficiently in diagnosing the fault.

 

[Fascinated Viewer]

Great pics... It helps a lot to see what the layout is. It's all pretty easily accessible so once a meter is available things should go pretty effectively/efficiently in diagnosing the fault.

Not sure how big of a factor corrosion is as I have noticed some green and dirty-looking metal which I think might be aluminium corrosion. it appears to be surface tho