I am hearing a low frequency hum at higher volumes when using my turntable and upon searching as to why that might be I saw a video saying to be sure to have your turntable grounded to your pre amp, receiver,
or whatever, the problem is I see no ground lug on the stated turntable however there is a ground lug on my receiver?
Do I have an un-groundable turntable?
Thanks
Do I have an un-groundable turntable?
Thanks
No, your turntable is grounded, as is with cheap turntables, the shield of audio signal is alteady the ground. They connected it inside.
What you hear is likely rumble.
Can you place the stylus on the lp in the grove, but do not turn the motor on. Do you still hear the hum? Measure how much mV or uV on phono output.
Then use test record with empty groves, measure hum again, compare.
This is best way to find out where the hum is comming from. If its mechanical from lousy spindle or motor vibration, it will be hard to fix.
What you hear is likely rumble.
Can you place the stylus on the lp in the grove, but do not turn the motor on. Do you still hear the hum? Measure how much mV or uV on phono output.
Then use test record with empty groves, measure hum again, compare.
This is best way to find out where the hum is comming from. If its mechanical from lousy spindle or motor vibration, it will be hard to fix.
So get a couple feet of any sort of wire (I rob old lamps before I trash them), strip both ends, one end to receiver lug. Other end, tap any bare metal on the turntable while playing.
But it may be pickup proximity to amplifiers, power strips, other electrics. The pickup is shielded with a half-penny worth of MuMetal but that can never be perfect (the needle has to come in somewhere). How does the hum change as you move the needle to and fro?
If your TT starts to spin when you place the pickup over the record for a hum test, pull the AC line. Place the needle into the start of an LP grove.
Listen to hum, then reconnect AC, while listening. You got a few seconds of music signal free listening for rumble. Repeat, but lift the stylus during test.
If hum starts the moment AC is there, stylus up or down, you got the "usual" electric hum problem.
If "hum" is only there while the record is spinnig with needle down, it is mecanical noise.
If hum is present without AC to the TT as well, it is a different problem.
What model and make TT?
Listen to hum, then reconnect AC, while listening. You got a few seconds of music signal free listening for rumble. Repeat, but lift the stylus during test.
If hum starts the moment AC is there, stylus up or down, you got the "usual" electric hum problem.
If "hum" is only there while the record is spinnig with needle down, it is mecanical noise.
If hum is present without AC to the TT as well, it is a different problem.
What model and make TT?
I don't know why your unit makes hum, but I listened to the Giro almost 15 years ago and I remember it sounded just great!
And it is beautiful too. IMO
However it had a singular feature: its signal cable was "direct-wired" in a single piece from the cartridge to the RCA plugs with a separate GND wire (just as shown in the picture posted by @Galu).
So, if the supplied signal cable has not been changed or replaced you should simply connect the existing GND fork of the original cable to the GND lug on the rear of your receiver.
Please note that even so it is not sure that the possibly electric hum will disappear.
Here there is its user's manual. 🙂
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Could you say where did you get this information from?
Thanks 🙂
Please note that Unison Research Giro was an Italian-design turntable manufactured by the german Clearaudio and it wasn't a cheap turntable at all and it would be strange enough if just in such an important detail it had been built as an inexpensive table. 😳
As a matter of fact please note that its price illo tempore was about €4.000,00 with the arm and without cartridge and the table was highly appreciated all around.
However I believe it had not the commercial success that it would have deserved though.
Just if you didn't notice the TT chassis is made of acrylic and wood.
If the "ground" lead is not with the RCA leads just had one to the Tonearm base.
Dam ulogon you beat me to it
The usual, TT wires go directly to +- left and +- right of the cartridge. The tone arm metal is connected to the ground wire.
So you have 5 separate wires and no ground loop = hum.
Inside the tone arm the four +- wires are very thin and have no shielding. The shield it the metal of the arm, that is why it has to be grounded by wire number 5..
If for some reason your arm is not conductive, this is not even that bad, as the motor of your TT, which means AC line, is not connected to it and far away.
In some cases the cartridge and the unshielded wires can pick up noise, like mobile phones or even "green" light bulbs. Maybe something was altered inside your TT, during a cartridge change, some “tuning” or a wire is broken.
Tone arm wires are very fragile. Most critical are the solder points and the connector at the cartridge. Remember, when the arm moves, these wires are twisted.
Does hum get louder when you touch the tone arm to position it over the record?
So you have 5 separate wires and no ground loop = hum.
Inside the tone arm the four +- wires are very thin and have no shielding. The shield it the metal of the arm, that is why it has to be grounded by wire number 5..
If for some reason your arm is not conductive, this is not even that bad, as the motor of your TT, which means AC line, is not connected to it and far away.
In some cases the cartridge and the unshielded wires can pick up noise, like mobile phones or even "green" light bulbs. Maybe something was altered inside your TT, during a cartridge change, some “tuning” or a wire is broken.
Tone arm wires are very fragile. Most critical are the solder points and the connector at the cartridge. Remember, when the arm moves, these wires are twisted.
Does hum get louder when you touch the tone arm to position it over the record?
I note that Darren posted his question a week ago, but has not responded to any of our posts.
I would sure like to know if the ground lead, which is incorporated in the phono cable, is connected to the ground lug of his receiver, and whether or not he is still experiencing hum.
P.S. At "higher volumes", some hum will be heard if no music is playing, but it should not be audible when music is playing.
I would sure like to know if the ground lead, which is incorporated in the phono cable, is connected to the ground lug of his receiver, and whether or not he is still experiencing hum.
P.S. At "higher volumes", some hum will be heard if no music is playing, but it should not be audible when music is playing.
Let's cover the basics here:
-b
- is the "low frequency hum" at 60Hz?
- No: are you likely hearing rumble.
- Yes: you are hearing line noise (aka hum).
- What cartridge are you using?
- If the picture is of your actual system (versus a catalog image) then it looks like you have a wood bodied Grado or similar.
- Grado's (AFAIK) are generally unshielded.
- If so are you picking up hum from the motor?
-b
I had a personal family tragedy not long ago, anyone incensed with my no longer replying to this thread, this is the reason for my absence, I appreciate the help I was given here.
Maybe there is a ground loop in signal cable (if both ends of shielding are connected to - wire), or mechanical noise is transported from motor to tonearm via support plate on which the turntable sits.
It’s been quite a while since I responded to this forum , until recently I was unable to resolve the hum when using my turntable , recently I purchased a vintage receiver that I had when I was younger to go along with a couple of Dahlquist speakers I refurbished now when I use my turntable there is no hum, so the problem was with the receiver something in the phono channel.