Flynnyfalcon Posted February 2, 2016 Posted February 2, 2016 Hi all, I've been doing a little reading on this and so far haven't been able to come up with a definitive solution. I have a faint and sometimes (intermittent) not so faint audible hum coming through my speakers when using my turntable. It appears a grounding issue, but I can't seem to find out why. Cabling all appears to be good and solid. My setup is: * 12V Battery source, into stock and fairly new Clearaudio Concept * Stock Clearaudio phono cables into RCM Sensor IC Phono Stage * Vermouth Black Pearl interconnects from phono into Leben amp. * Issue has arisen with different carts. If I touch the cabling plugs, the hum seems to disappear, especially so when touching the Vermouths which are as good as brand new. The hum was also there with previous phono cabling setups so I know the Vermouths are not at fault. I have pulled apart the Clearaudio cables and they look good. I have buzzed them with the multimeter and their is no crosstalk. I have physically moved the cables to see if other nearby cabling is causing the hum, with no definitive answer appearing. The grounding cable from the TT is your basic multi strand cable with a spade on the end, which is solidly tightened to the phono. The noise not noticeable when playing music but no doubt my noise floor is greater than it should be so I want to get rid of the issue. Everything appears to be connected currently, where should I look next? Thanks.
Happy Posted February 2, 2016 Posted February 2, 2016 Tried moving the phono away from the amp and/or tt? Sent from my iPhone using Tapatalk 1
Deano_malaysia Posted February 2, 2016 Posted February 2, 2016 Hi sounds like the cable is maybe picking up interference from another source, is the phonostage near a power cable? 1
Flynnyfalcon Posted February 2, 2016 Author Posted February 2, 2016 There is probably 40-50cm between the Amp and the Phono. The Phono's power supply is on the shelf below the Phono, so approx 30cm. Close proximity power cables is something I hadn't considered. Will look over it this eve.
andyr Posted February 2, 2016 Posted February 2, 2016 Comments in blue, below. Andy Hi all, I've been doing a little reading on this and so far haven't been able to come up with a definitive solution. I have a faint and sometimes (intermittent) not so faint audible hum coming through my speakers when using my turntable. It appears a grounding issue, but I can't seem to find out why. Cabling all appears to be good and solid. My setup is: * 12V Battery source, into stock and fairly new Clearaudio Concept What do you mean by this? People generally say the TT (or the phono stage it's plugged into) is the 'source'. Do you mean the Clearaudio TT is powered by a 12v battery (rather than being plugged into the wall)? * Stock Clearaudio phono cables into RCM Sensor IC Phono Stage Are the RCA sockets on the RCM Sensor IC Phono Stage connected to the case (unusual) ... or isolated from it (usual case)? * Vermouth Black Pearl interconnects from phono into Leben amp. Similarly, are the RCA sockets on the Leben connected to the case ... or isolated from it? * Issue has arisen with different carts. If I touch the cabling plugs, the hum seems to disappear, especially so when touching the Vermouths which are as good as brand new. The hum was also there with previous phono cabling setups so I know the Vermouths are not at fault. I have pulled apart the Clearaudio cables and they look good. I have buzzed them with the multimeter and their is no crosstalk. I have physically moved the cables to see if other nearby cabling is causing the hum, with no definitive answer appearing. The grounding cable from the TT is your basic multi strand cable with a spade on the end, which is solidly tightened to the phono. Is the RCM Sensor IC Phono Stage mains powered? If so, does it have an IEC socket for the mains cable ... or does it have a captive 2-wire mains cord. The noise not noticeable when playing music but no doubt my noise floor is greater than it should be so I want to get rid of the issue. Everything appears to be connected currently, where should I look next? Thanks. 1
Happy Posted February 2, 2016 Posted February 2, 2016 There is probably 40-50cm between the Amp and the Phono. The Phono's power supply is on the shelf below the Phono, so approx 30cm. Close proximity power cables is something I hadn't considered. Will look over it this eve. The tt is away from the amps? The cartridge often picks up stuff from the trannie.
Flynnyfalcon Posted February 2, 2016 Author Posted February 2, 2016 - The original wall wart power supply is no more, the TT is running on a 12v battery. - The sockets I'm assuming are isolated/insulated. I'm away from the phono at the moment, but it's a well designed phono so I would expect this to be the case. I might be able to find a pic to confirm. - At the amp end, I'm not 100% sure, again I'd have to take a look. - The Phono is mains powers and yes does have a removable IEC cable.
rocky500 Posted February 2, 2016 Posted February 2, 2016 (edited) Found some pics if they help at all. RCM Phono stage. Clearaudio Concept turntable 12V power connector Clearaudio original PSU Edited February 2, 2016 by rocky500 1
blybo Posted February 2, 2016 Posted February 2, 2016 I used to get this until @@cheekyboy was swapping carts for me and pulled a plug off it's wire, green iirc. Much swearing ensued. When he re soldered the wire to the plug, and one other he thought looked suspect, the issue disappeared completely.
Flynnyfalcon Posted February 2, 2016 Author Posted February 2, 2016 I used to get this until @@cheekyboy was swapping carts for me and pulled a plug off it's wire, green iirc. Much swearing ensued. When he re soldered the wire to the plug, and one other he thought looked suspect, the issue disappeared completely. Hmmm, that's a thought... Being such fine wires, I'm sure slight misuse could cause a problem. I shall investigate.
tesla13BMW Posted February 2, 2016 Posted February 2, 2016 My PSU1 linear power supply for the Graham Slee Reflex M will induce a hum into the phono if it is too close and oriented the wrong way. Certainly worth rotating in the horizontal and vertical plain. The fact that it is fain and sometimes loader seems to point towards there being a constant low level interference with a higher level sometimes. When the high level occurs has something turned on dimmer lamp, fridge, air con, etc? 1
Flynnyfalcon Posted February 2, 2016 Author Posted February 2, 2016 Hey Tesla, will definitely look into this as well. I have a smallish cabinet so evenly spacing things out has been a compromise. What your saying does make sense.
andyr Posted February 2, 2016 Posted February 2, 2016 Hey Tesla, will definitely look into this as well. I have a smallish cabinet so evenly spacing things out has been a compromise. What your saying does make sense. Don't forget to think about the other issue that Tesla mentioned - "When the high level occurs, has something turned on ... light dimmer, fridge, air con, etc?". Andy
lovetube Posted February 2, 2016 Posted February 2, 2016 Hi all, I've been doing a little reading on this and so far haven't been able to come up with a definitive solution. I have a faint and sometimes (intermittent) not so faint audible hum coming through my speakers when using my turntable. It appears a grounding issue, but I can't seem to find out why. Cabling all appears to be good and solid. My setup is: * 12V Battery source, into stock and fairly new Clearaudio Concept * Stock Clearaudio phono cables into RCM Sensor IC Phono Stage * Vermouth Black Pearl interconnects from phono into Leben amp. * Issue has arisen with different carts. If I touch the cabling plugs, the hum seems to disappear, especially so when touching the Vermouths which are as good as brand new. The hum was also there with previous phono cabling setups so I know the Vermouths are not at fault. I have pulled apart the Clearaudio cables and they look good. I have buzzed them with the multimeter and their is no crosstalk. I have physically moved the cables to see if other nearby cabling is causing the hum, with no definitive answer appearing. The grounding cable from the TT is your basic multi strand cable with a spade on the end, which is solidly tightened to the phono. The noise not noticeable when playing music but no doubt my noise floor is greater than it should be so I want to get rid of the issue. Everything appears to be connected currently, where should I look next? Thanks. what you describe means you have some earthing issue. hunt it down Duc
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