I've a Technics S:-1210 Mk II that has a low level (but quite noticeable) noise on the audio output that I think is either being induced into the cartridge but only when the stylus is in contact with the vinyl (or platter) or, is vibration, albeit not audible, that the transformer is causing in the platter?
Things I know and have checked:
1. It's not mechanical/bearing rumble - the noise is present when the unit is switched on but the motor not running/platter not spinning.
2. The stylus must be in contact with the vinyl or platter for the problem to appear. Just being near the vinyl/platter doesn't cause the problem.
3. All the grounding seems correct and intact - the problem was present when I got the unit which had the mod some people do with grounding via the signal grounds and no separate wire. I've re-instated the standard separate ground wire scheme but no change.
4. The noise is not plain mains hum - it sounds like there are higher frequencies imposed on top of mains hum and I can see that on a scope . It's not random noise.
5. All other wiring seems OK - the signal and ground wires all seem good.
6. The problem is on both channels.
7. I've tried a different cartridge - same result.
8. Everything works OK otherwise.
9. The platter itself does not appear to be grounded but grounding it made no difference. (I wondered if it acted as a screen to the power supply).
Any ideas?
Things I know and have checked:
1. It's not mechanical/bearing rumble - the noise is present when the unit is switched on but the motor not running/platter not spinning.
2. The stylus must be in contact with the vinyl or platter for the problem to appear. Just being near the vinyl/platter doesn't cause the problem.
3. All the grounding seems correct and intact - the problem was present when I got the unit which had the mod some people do with grounding via the signal grounds and no separate wire. I've re-instated the standard separate ground wire scheme but no change.
4. The noise is not plain mains hum - it sounds like there are higher frequencies imposed on top of mains hum and I can see that on a scope . It's not random noise.
5. All other wiring seems OK - the signal and ground wires all seem good.
6. The problem is on both channels.
7. I've tried a different cartridge - same result.
8. Everything works OK otherwise.
9. The platter itself does not appear to be grounded but grounding it made no difference. (I wondered if it acted as a screen to the power supply).
Any ideas?
check motor and transformer vibration mountings, maybe gone hard. the fact that you claim is only in the groove is mechanical coupling with something vibrating even in your rack
I'll check the transformer mountings - not sure the motor mounts are relevant as the motor is not running when the problem is present.
Tried that - no, it doesn't. It's making me think more that it could be vibration induced into the platter from the transformer. I just tried some different mats, felt, rubber etc. but not much change. The problem is noticeably worse at the outside of the platter, better near the centre.
I think Nico may have seen the problem.
You did not say where your turntable was located. If in a rack, the transformer in the power amplifier could be producing mechanical vibrations that are being passed on to the turntable.
You did not say where your turntable was located. If in a rack, the transformer in the power amplifier could be producing mechanical vibrations that are being passed on to the turntable.
"Could be other equipment in the rack vibrating like amplifier transformer. read my post 2"
Physical location makes no difference. No other equipment in "the rack". Same problem occurs when the unit is in other premises.
Physical location makes no difference. No other equipment in "the rack". Same problem occurs when the unit is in other premises.
I'm testing this in isolation using a pre-amplifier and headphones. No items such as power amps are nearby and the pre-amp runs off a plug-top located well away. The noise only occurs when the turntable is switched on. If it is off it still outputs audio but the noise is not present so I'd conclude it's the turntable's own power supply being the source of the noise.
"The noise only occurs when the turntable is switched on.
that is not what you said before"
Sorry if I was not clear but I thought my point no 1. in the original post said that but maybe not explicitly.
that is not what you said before"
Sorry if I was not clear but I thought my point no 1. in the original post said that but maybe not explicitly.
Sorry if I was not clear but I thought my point no 1. in the original post said that but maybe not explicitly.
If the turntable has an idler the motor may be running but the wheel is disengaged.
If the turntable transformer is hard mounted to the chassis then it is a design problem, it should be mounted by some anti-vibration mounting.
If the turntable has an idler the motor may be running but the wheel is disengaged.
If the turntable transformer is hard mounted to the chassis then it is a design problem, it should be mounted by some anti-vibration mounting.