Speakers Warble with Turntable

[N.Cotman]

Hi everyone,

My speakers warble when the volume is put up past about 30/40% while using my turntable. Even with a low volume, the drivers have a slight vibrate that I feel should not be there. The turntable is one of the cheap Sony USB ones (though I do not use that function).

I have played around a bit with speaker placement, and put padded feet to ensure there is as little vibration as possible, but still no luck. The turntable is sitting directly on top of my NAD receiver. That being said, I have also moved it to the side of it with the same results.

I purchased another turntable on the condition that I could return it if it did the same thing, and it did.

Any suggestions would be greatly appreciated, really wanna figure out whats going on!

Thanks,
Nick

 

[ImcLoud]

Which and receiver do you have, when you tried the new table, I take it you used the same cables? With issues like this I would start with the cables{all albums play the same?}, make sure the ground is good, and the equipment is all grounded correctly as well {as in the homes wiring}. Make sure all your settings are correct, ect... You have already showed its not the table since 2 do the same thing, next cheek the cables then the preamp...

 

[TLS Guy]

Which and receiver do you have, when you tried the new table, I take it you used the same cables? With issues like this I would start with the cables{all albums play the same?}, make sure the ground is good, and the equipment is all grounded correctly as well {as in the homes wiring}. Make sure all your settings are correct, ect... You have already showed its not the table since 2 do the same thing, next cheek the cables then the preamp...

It probably is the turntable. This sounds like acoustic feedback to me.

Reasons, include placing the turntable on a room egentone antinode, and the shelf the turntable is placed on plays a big part. Acoustic isolation of turntables is important and often a challenge.

In addition budget turntables have much poorer acoustic isolation and are much more prone to this problem.

If you have a sub, don't use it when playing the turntable, that will be your quickest fix.

 

[ImcLoud]

so you think he is going loud enough to get resonance from the tone arm?
How close to the speakers is the table? I do recall having an issue like this in my old house the speakers would vibrate the floor and the speakers would sound terrible {LP's of course}, I folded up a beach towel put it under the tt and the problem went away... TLS brings up a great point give it a try, isolate the tt in another room or different position...

 

[N.Cotman]

The receiver is a NAD 7100. There is no ground in my Sony, however the Nikko I bought and returned had a ground and, as you know, this made no difference. The speakers are mounted on stands about 2-3 feet on either side of the TT. They are also a little in front.

The whole setup is currently on a hardwood/ceramic tile floor. When I go back to school in September, the floor will be carpeted. Think this could make a difference? Thanks again everyone!

 

[mtrycrafts]

The receiver is a NAD 7100. There is no ground in my Sony, however the Nikko I bought and returned had a ground and, as you know, this made no difference. The speakers are mounted on stands about 2-3 feet on either side of the TT. They are also a little in front.

The whole setup is currently on a hardwood/ceramic tile floor. When I go back to school in September, the floor will be carpeted. Think this could make a difference? Thanks again everyone!

Where is the tone control set on the receiver for the bass? Is the house slab on grade or has a crawl space? Can you perceive floor movement when you walk on it, perhaps a curio cabinet pieces lets you know?
If not, Don't think the floor is an issue.

 

[markw]

It's acoustic feedback. The signal from the speaker is "read" by the turntable/arm/cartridge. fed back into the amp where it's amplifed and then fed out of the speakers where it's "read" (again) by the turntable/arm/cartridge combination, and fed back into the amp and blah blah blah ad infinitum.

Move the turntable further away from the speakers and/or put it on a more stable mounting to break that feedback loop.

 

[Ampdog]

Easy test: Place the stylus on a record on the turntable with the turntable stationary. Carefully turn up the volume until acoustic feedback starts, ready to decrease volume so as not to let the feedback get too much. You can do this with various tone control settings (bass; treble should not have an influence). In the unexpected event that the problem is not acoustic feedback, this would (not) show it up.

Do note that acoustic feedback need not only propagate through the floor, shelves etc., although those should be the first to be investigated. Acoustic feedback could take place directly to the turntable via air waves, probably then more so with the turntable lid removed.

 

[N.Cotman]

Ive raised it a little above my receiver on a temporary shelf, laid a towel under it, removed the dust cover when I use it, and switched the MC/MM switch on the back of my receiver to MM and have had drastic improvements!*

However, I think there is a ground issue. After I use it for a few minutes, a humming starts. If I touch it, it stops, then comes back after about 30 seconds. When I let go, the humming once again stops but then shortly comes back.

Note: there is no ground attachment on the turntable, just on the receiver.