Phono pre hum



  • mhardy6647mhardy6647 Posts: 19,075
    edited November 2017
    Probably worth noting that figuring out what to ground to what generally has to be determined empirically in cases like these. :)

    Also, perhaps, worthy of note. My Marantz (Clearaudio) TT-15S1 came with two ground leads -- one for the tt proper (connected, I suppose, to the platter mount) and the other to the (detached) motor.

    As I intoned, oh so gravely, earlier: grounding is both art & science :|
  • jdjohnjdjohn Posts: 429
    mhardy6647 wrote: »
    As I intoned, oh so gravely, earlier: grounding is both art & science :|
    And trial and error :D Glad Bob is sorted. Another good reason to keep a few spare wires around.
  • mhardy6647mhardy6647 Posts: 19,075
    Mark my words:

    Bag o' clipleads.
    1001 uses!
    Collect 'em, trade 'em, give 'em to your friends!
    They make great stocking stuffers, too!

  • lightman1lightman1 Posts: 9,863
    Hardy-ed up another thread....
  • msgmsg Posts: 4,270
    Hey, look who it is!
  • mhardy6647mhardy6647 Posts: 19,075
    lightman1 wrote: »
    Hardy-ed up another thread....

    I'm here for youse guyses.

    Think of me as Johnny Clipleadseed.

    I should keep little gift bags of 'em here at the ol' casa.
    This could be you! (borrowed images, no warranty express or implied. Always keep one hand in your pocket when working with HV.)


  • pitdogg2pitdogg2 Posts: 10,868
    Man those pictures just scream FIRE B) :*
  • msgmsg Posts: 4,270
    To me, that bottom one screams, "Ouch Ouch! Hot! Ahh! My fingers!"
  • Viking64Viking64 Posts: 3,294
    I have no idea what any of that is.

  • mhardy6647mhardy6647 Posts: 19,075
    Amplifier breadboards of various flavors.

  • msgmsg Posts: 4,270
    I like my breadboards toasted and flavored with Vegemite.
  • muncybobmuncybob Posts: 1,873
    mhardy6647 wrote: »
    It might make a difference if it is only 'asleep'.
    If you get bored some time, try unplugging the player from the AC mains and see if it changes the noise signature on your phono preamp any.

    So I was curious to see if this made any did not. I also tried other areas to ground and still no improvement over the Oppo ground. The power strip itself(Panamax M4300-EX) has a ground lug so I made another ground wire(now up to 3) and no difference. So, this is as good as it will get and that's fine. Thanks again for all the help, tunes are sounding much better :)
    Yep, my name really is Bob.
    Parasound HCA1500, Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, "upgraded" Polk SDA 2B.
  • mhardy6647mhardy6647 Posts: 19,075
    Yeah, so your hum/noise is due to circuit &/or power supply, it seems.

    One other thing you could try if you get really, really bored (and if you haven't) is to either open circuit the inputs (no cables installed) or (probably better short the inputs (shorting plugs or cables with both leads connected together) and see what the "absolute" noise level of the preamp is. Shorting the inputs would isolate the preamp pretty well, such that any noise you hear is from the preamp (or - it is still possible - being induced into it from external EMI sources).

    High gain vacuum tube circuits have a tendency to be noisy. Even solid state circuits aren't immune from the hiss of "shot noise" at high gain.

    I will close by mentioning that even I ultimately settled on a (gasp!) solid state phono preamp at my house. :|


    (legacy photo of an experiment with the aforementioned ss phono preamp & Silk SUTs -- and plenty of clipleads!)
  • lightman1lightman1 Posts: 9,863're gonna burn your house down one day.....Safety First! :p
  • mhardy6647mhardy6647 Posts: 19,075
    Point taken, your being a pro & all... but, in my defense, everything there is low voltage DC (well, other than the audio signals, which are AC on the order of 100s of microvolts on the "innie" side & a volt or so on the outie side).
  • FestYboyFestYboy Posts: 2,786
    Wow, an "innie" AND an "outie" @mhardy6647 you must be proud :p
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