low level hum from turntable source.

Zog

Active Member
Have an old Pioneer PL514 turntable.

This is connected via a pre-amp to my main AVR (as the latter has no phono source) using standard RCA from the pre-out to the CD input. There is also a ground from the turntable to the rear panel of the pre-amp.

Two issues .
1/ There is a very low-level hum when listening to the turntable. It is relative to the volume, but is only audible on fairly quiet tracks.

2/ Bit of a volume difference between this source and other using the main AVR exclusively. As I am using the pre-out, the volume on the pre-amp cannot be adjusted. It can come as a bit of a shock when you switch sources.

Thanks in advance for ideas.
 

silversurfer24v

Well-known Member
I had a hum on an old Dual turntable I use and it was recommended to change the rca plugs, if you wiggle the cables or handle the rca plugs does it get louder, I cut them of and soldered new plugs on and now silent, something to check out
 

Mark.Yudkin

Distinguished Member
Both symptoms are fairly normal, especially on older equipment. You can possibly reduce the level of the low-level hum, as well as addressing the volume difference, by purchasing a new pre-amplifier (you didn't identifier your pre-amplifier) and/or cartridge.

Some AVRs (you didn't identify yours) offer an option to adjust the gain of each input separately; this feature can be used to even out level differences of different equipment.

I don't think it's a faulty connection because that would generate a rather more audible hum level than you describe.
 

andybebbs

Active Member
I would say it was a cable problem change your rca cables.
 

noiseboy72

Distinguished Member
Hum suggests mains interference is getting into the cabling somewhere. Good cable management can help with this.

Keep mains and signal cables as far apart physically as possible. Avoid the cables crossing, but if they have to, do so at 90 degrees. Do not run cables alongside each other. Keep cables as short as you can. No more than 1M from the turntable to the pre-amp. If you need more length, extend after the pre-amp.

If the pre-amp has an external power supply, move this as far away from the pre-amp as possible.

In terms of the level imbalance, check if your preamp has internal or external gain matching settings. Some have a set of switches which change the gain and impedance, and this can have a big effect on the hum level and overall volume.
 

daddy999

Active Member
Check the earth, then the RCA cables and keep the turntable as far away as possible from the speakers.
 

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