[78-L] turntable hum mystery

[neechevoneeznayou at gmail.com]

Yes, I switch off the power to the TT and the hum disappears, tho the 
music continues until the table stops completely.

Thanks Doug

joe salerno

On 11/9/2012 2:45 PM, Doug Pomeroy wrote:
> Joe,
>
> Can you turn off the turntable motor without turning off your phono preamp?
> That would allow you to rule out vibration from the motor as a source.
>
> Doug Pomeroy
> audiofixer at verizon.net
>
>
>> Message: 2
>> Date: Thu, 08 Nov 2012 16:46:10 -0600
>> From: "neechevoneeznayou at gmail.com" <neechevoneeznayou at gmail.com>
>> Subject: [78-L] turntable hum mystery
>> To: 78-l <78-l at klickitat.78online.com>
>> Message-ID: <509C3632.1030800 at gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> Listers,
>>
>> Last time I posted about hum on my turntable, it was solved by checking
>> the ground connection. It was loose, and tightening it made a huge
>> improvement.
>>
>> Later I was thinking I was hearing much hum from the records. Surely
>> they didn't record that much hum in so many records did they? Upon
>> further investigation, it appears not to be from the records. It is only
>> when the table is on and the stylus in contact with the record. Lift the
>> stylus even the tiniest bit and the hum goes away. Turn the thing off,
>> even with the stylus on the record, and the hum goes away.
>>
>> So how is the hum getting into the system? Neither vinyl or diamond are
>> conductors of electricity. So I've ruled that out. Bad p.s. caps giving
>> off EMR that the cartridge is picking up? Seems unlikely, in that
>> picking up the stylus even the tiniest bit causes the hum to cease. If
>> the leak were in the air I would expect the hum to remain as long as the
>> cart was within a certain proximity.
>>
>> Whaz goin' on here?
>> --
>> Joe Salerno
>
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-- 
Joe Salerno