Help with a Hum

post questions / problems regarding Cyrus kit here, or any other queries of a tech nature.
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johnandvirginia
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Help with a Hum

Postby johnandvirginia » Tue Sep 12, 2017 1:21 pm

My recent acquisition - the Rega RP6 + Lehmann Black Cube - sounds lovely but is spoiled by an annoying hum. Normally I would have connected the grounding wire from the turntable into the phono stage but there doesn't appear to be a grounding wire on the Rega!
Is there any way that I can connect a grounding wire so that I can stop the hum? Many thanks for any help.

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Re: Help with a Hum

Postby MiniCoupeman » Tue Sep 12, 2017 4:17 pm

First and very important. I have no tech knowledge at all! Now I have had similar problems in the past with various bits of kit and the advice I was given was to wire a plug to the earth teminal ONLY, and attach the other end to metal casework of the offending bit of kit. I believe this also works if it is attached to kit that is 'connected' i.e. Phono stage/Turntable. It is easy to try, apparently can do no damage and in my case, cured the hum.

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mickbald
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Re: Help with a Hum

Postby mickbald » Tue Sep 12, 2017 8:27 pm

On the Cube there is a ground point. Connect a wire on there and touch first the outer sleeve of the phono plug from the Rega. Then touch exposed parts (not anything inside the Rega) until the hum goes.

On my TT there is a ground lead running alongside the phono leads so you are probably looking to replicate this.

If this isolates the hum you need to work out how to connect a permanent fix. Come back for suggestions on how to do this.

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Re: Help with a Hum

Postby Lancashirelad » Wed Sep 13, 2017 6:24 am

H-FC 425 (July) has an ad for "Gutwire Audio Grounding Cables", seemingly these are connected between any spare input socket on a pre or integrated amp & a spare wall socket. I don't know how these are wired into the mains plug but experimenting with a donor IC might be worthwhile & surely much cheaper than the cable in the ad...

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ozzric
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Re: Help with a Hum

Postby ozzric » Wed Sep 13, 2017 8:56 am

Rega arms typically don't use a grounding fly-lead, preferring instead to simply ground the arm by connecting the arm body to one of the phono return paths (The -ve or screen of the phono cable).
I wont say this is an issue as such, but has known to be problematic and a separate earth bonding lead would be preferable. Even on new RP6's!

Image

Image

Here you see the black wire is the ground which connects to the headshell (RB250 Arm), onto a copper strip which grounds the arm body. The blue return wire is also connected to the strip, the ground wire, and the outgoing screen of the phono cable on the other side of this connector block.
Owners have done mods to cure the hum, which simply involves disconnecting the grounding strip from the return screen (Blue wire in this case) and running a separate ground wire from the copper strip/black wire externally to your amp or whatever.

Read This:
http://www.aqvox.de/REGA_250_300_Tonear ... a_mod.html

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johnandvirginia
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Re: Help with a Hum

Postby johnandvirginia » Wed Sep 13, 2017 10:57 am

Many thanks for suggestions. None of the simple ones seem to work and the difficult one scares me to death!!!! Perhaps I'll just keep the volume turned down!

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Re: Help with a Hum

Postby argustimewas » Wed Sep 13, 2017 8:39 pm

Surely your dealer can help?
Michell Orb SE / SME 309 / Ortofon Quintet Black
Phono X & PSX-R
CDXt Signature
DACXP Signature & PSX-R2
Mono X300 Signatures x 2
Spendor D7
Missing Link Binary Star coaxial, Atlas Navigator XLR, Mark Grant G1500HD RCA, Van Damme 6mm UP-LCOFC speaker cable
IMF x 3, R Andrews mains cables
X Arbour

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mickbald
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Re: Help with a Hum

Postby mickbald » Wed Sep 13, 2017 8:58 pm

A few more thoughts.

An earth hum is caused by a different voltage potential between devices causing current to flow between them. If you can remove any boxes and take the system down to a minimal set up that will help identify the problem.

Are you connected to any form of TV, Satellite, AV or the like? These often have floating earths and can cause a problem. Disconnect them and see if that helps.

Do you have any Ethernet power line extenders or other mains connected repeaters fitted. If so turn them all off as these can put noise onto the mains.

Lastly, if the phono leads are close to power leads this could cause the problem.

Sometimes hum is a bugger to fix, good luck.

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johnandvirginia
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Re: Help with a Hum

Postby johnandvirginia » Fri Sep 15, 2017 9:29 am

Yippee!! Many thanks! Re-routed the power lead to the phono stage away from other mains leads and hum almost totally eradicated! I can only reproduce a hum if I crank the volume up to levels that I would never use for everyday listening. So, again my thanks. John.


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