Stylus picking up external noise/sound

[A K Bhattacharjee]

This is happening with one of my turntables namely Sherwood. It is observed that whenever the stylus is placed on a record, it picks up near by noise/sound. To check I placed the stylus on a record/mat without spinning the platter. It also happens with different carts.Even slight tapping the tt body or touching it, the stylus picks up the noise. It is very much disturbing & I feel it. Any help?

 

[raj12345]

Check earthing from turntable to griund it appropriately.. Check nearby magnetic fields near ti turntable.. Check RCA cable if its faulty..

 

[analogadikt]

This is happening with one of my turntables namely Sherwood. It is observed that whenever the stylus is placed on a record, it picks up near by noise/sound. To check I placed the stylus on a record/mat without spinning the platter. It also happens with different carts.Even slight tapping the tt body or touching it, the stylus picks up the noise. It is very much disturbing & I feel it. Any help?

Looks like you are experiencing acoustic feedback. This happens when there is inadequate isolation of the tt. What sort of base this TT has? A plastic one? Is there any built in isolation system like springs or damped feet? Detailed pictures of the tt and the overall setup shall help. Meanwhile you can experiment by shifting the tt around the room. If you have long interconnets, then keep the tt in another room and check what happens.

Regards,

 

[A K Bhattacharjee]

Yesterday after reconnecting the wires, I noticed that the problem is reciprocal to volume of the amp.

 

[kuruvilajacob]

I also feel it is because of lack of isolation since this is happening even in idle position. Try isolating the TT and you may get rid of this problem

 

[Hiten]

This is happening with one of my turntables namely Sherwood. It is observed that whenever the stylus is placed on a record, it picks up near by noise/sound. To check I placed the stylus on a record/mat without spinning the platter. It also happens with different carts.Even slight tapping the tt body or touching it, the stylus picks up the noise. It is very much disturbing & I feel it. Any help?

When you say it picks up near by noise/sound is it like humming sound ? Sometimes transformer inside the turntable vibrates, motor vibrates and you get noise/sound. Which Model is this ? If it is reciprocal to amplifier volume do you have speakers near the Turntable ?

 

[Hiten]

sorry just saw you put stylus on platter not moving. so it is not motor noise. Here is my little M.S.E.

This is cheap philips turntable, a wooden piece was placed on plinth with stylus touching it. The turntable was isolated (If I remember napkin cloth, rubber feet, and wooden shelf) The speakers were NOT near and no directly facing the turntable. Still when I opened the dust the minute vibrations/noise was fed to speakers it passed on through closed room and fed in to turntable dustcover which FURTHER amplified it.

 

[A K Bhattacharjee]

It sounds like bhum bhum if the body of the tt is touched. It is more when touched underneath. Nothing will be heard until the body is touched or the volume is increased. At +3 volume hum is clear & very loud.

 

[arj]

can you calculate the resonance frequency for the tonearm and cartridge combination ? the frequency should be between 8-12. if it is lower/higher it can capture footfalls and external sounds and resonate
You will need to know the Tonearm effective mass, the cartridge weight and cartridge compliance

Cartridge Resonance Evaluator - Vinyl Engine

www.vinylengine.com

once you enter the effective mass of the cartridge it will give you the cartridge compliance and weight combination.

 

[A K Bhattacharjee]

Thanks to all for valuable advice/suggestions. My amp requires some treatment. TT is absolutely o.k with my other amp.

 

[raj12345]

Usually tonearm have 6 wires including two black wires for grounding tonearm tube and stand respectively.. Check your tonearm wires are 6 in all and are grounded at common point as with cartridge ground wires i.e colored green & blue. This is always a main cause of cartridge picking external noise & humming..

 

[A K Bhattacharjee]

Yes Raj, wires are six & well connected. Now the problem which is still persisting is even changing amp, hump remains when the body of the tt is touched. I am thinking of re- soldering of the black wires. With Yamaha amplifier hum is coming from one channel & it is very loud. Local technician tried to reduce it with a pf capacitor but did not succeed. May be the pre-amp section has some fault.

 

[raj12345]

Check the Earthing of your amplifier as well as your turntable..
1. Connect a wire from your turntable body (metal) to amp ground usually located behind.
2. Tight clamp your TT Headshell to Tonearm..
3. Move all AC wires beyond Analog Output RCA of Turntable as well as seperate & far from the Speaker wires..
4. Keep TT away from Amplifier
5. It will be better you change your RCA of TT first and then change Tonearm wires if required
6. It may also be caused due to non-impedence matching of cartridge and phono preamp
7. Check the shorting of Tonearm as well as RCA cable wires.

 

[Hari Iyer]

This is what I did in the past 6+ months part by part to remove hum/ hiss from my Thorens TT.

1. The original TT wiring was single core with the shield connected to cartridge. I made this 2 core shielded and the shield connects to phono preamp ground.
2. The TT chassis, platter was not grounding and the entire chassis behaved like antenna and simple tapping would get amplified. I grounded the chassis, platter and tonearm with a wire and connected them to amplifier ground. Signal shield ground was separated routed and grounded to phono preamplifier ground.
3. With this 90% of the noise vanished. Still there was some ground loop issue causing some hiss/ hum when I place my ears next to the speakers which was driving me nuts. For this I installed an audio isolation transformer at the phono preamp input. Now the 2 core wires coming from the cartridge goes to the input of the audio transformer and the output of the transformer goes to the phono preamp input. This removed all noise from my TT. Earlier turning the fan regulator, switching on a tube light ( choke type), ringing of the door bell will cause huge noise in my setup. With the audio isolation transformer they have vanished 100%.
4. Now there is a very very minor 100Hz hum caused by power supply. I am planning for a common mode choke + inductors + active RC filter through transistors by using a capacitance multiplier for my power supply. Hope that will reduce the 0.5% noise in my TT.

I am not sure how much of a DIY guy you are, but isolation transformer are available for purchase. Buy good quality ones as it affects both low and high frequency response. I was lucky to get NEC audio transformer.

Hope this helps.