New Schiit / Preamps and Power Amp (was Putting the Schiit Signal Up)

Discussion in 'Preamps' started by purr1n, Oct 6, 2016.

  1. nedifer

    nedifer Facebook Friend

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    Possibly. Mine is dead silent though I haven't tried cranking it all the way. I do have a ground loop issue on the phono preamp, though, that I simply haven't had time to sort out. So it can happen.

    Do you have everything plugged into the same power source?
     
  2. Merrick

    Merrick A lidless ear

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    Unfortunately I do. I need to get some more power strips.
     
  3. nedifer

    nedifer Facebook Friend

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    My understanding is that you are better off having everything sourced from the same power source, but then my current phono preamp issue is the first time I've encountered a ground loop (in 3 decades of this, go figure...), so I am a bit of a noob at this.

    In the Saga manual, Schiit did mention the Ebtech Hum X Voltage Hum Filter as a possible solution, They seem to run ~$53 on Amazon. But I'm hoping I can find a cheaper solution to my own problem before resorting to that.

    Have you tried disconnecting your phono rig to see if the hum goes away? And cycle between active and passive mode?
     
  4. Merrick

    Merrick A lidless ear

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    My phono runs on batteries. Shouldn't that protect it from things like ground loops?
     
  5. Cspirou

    Cspirou They call me Sparky

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    I've never had a preamp or integrated that can auto-detect if an input is on. I'm sure it exists but I wouldn't be too concerned about that feature. You should also keep the fleawatt amp you have on max. The volume control on it is passive anyway so keeping it on max means it stays out of the way and let's the Saga do it's job. You should definitely plug all your components to the same power strip too.

    If the phono runs on batteries it probably isn't the problem. Do you hear the hum when you plug it in directly into the fleawatt?
     
  6. Merrick

    Merrick A lidless ear

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    Okay, did some quick checking to eliminate variables. Everything is still plugged into one power strip. The phono is the problem despite (or because of?) being battery powered. However, it's interacting in some way with the Saga, because when I plug it into the amp directly, I do hear what sounds kind of like static if the amp is at full power, much louder than I would ever play music if it were directly plugged in straight to the amp. I do not hear a constant hum. When I plug it into the Saga I get the hum at around 50% volume with no music playing.

    I have an external mono/stereo switch but I took that out of the chain and still got the same problem when the phono was plugged directly into the Saga, so it must be the phono.

    That HumX product may not be helpful here since the phono isn't drawing power from a wall socket.
     
    Last edited: Dec 1, 2016
  7. Merrick

    Merrick A lidless ear

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    Guess I'd need to get a ground loop isolator. I hope it doesn't degrade the sound in any way. Can anyone recommend any good ones?
     
  8. batriq

    batriq Probably has made you smarter

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    If you disconnect the turntable from the preamp do you still hear the hum? What if you completely take the joti out of the equation?
     
  9. fraggler

    fraggler A Happy & Busy Life

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    Out of curiosity, is that a TPA3116 based Fleawatt?
     
  10. Merrick

    Merrick A lidless ear

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    Well, I'm an idiot. Turns out it wasn't any kind of ground loop at all. The noise immediately went away when I moved the damn phono off of the Saga! I moved it away and now if I turn the Saga all the way up with no music playing, I get the same static type noise I get when I plug the phono directly into the amp and turn it to max. So I think I'm good. That's a relief!

    @fraggler Yes it is! This one, to be exact: https://fleawatt.blogspot.com/2016/09/beta-testing-amp-2-available.html
     
  11. Cspirou

    Cspirou They call me Sparky

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    Ah, it probably is a ground loop but going through the chassis. Maybe put some rubber feet on the phono if you want to stack it.
     
  12. fraggler

    fraggler A Happy & Busy Life

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    Nice, I will be particularly interested in your impressions as they evolve, as I am currently using a DIYish version of the same thing, including a stepped attenuator. Are you using the Saga primarily for the input and remote capabilities?
     
  13. Merrick

    Merrick A lidless ear

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    The Saga is for four things, first is to manage my multiple inputs. I've got the turntable and DAC right now, and have ordered a Pioneer Elite DV-79avi as a transport. I will be running RCA outs from the Pioneer to the Saga in order to get straight DSD playback from SACDs, as my Modi Multibit would first convert them to PCM. It's also for managing multiple outputs, the speakers and Jotunheim. The remote is third and very convenient, and the fourth is to add some tube element to my currently wholly tube-less setup. I realize it's only one tube and it's a hybrid buffer anyway, but it's better than nothing.

    The original plan was to wait for the Freya but after the surprise VPI opportunity, I decided the Saga was all that was prudent to get at this point. Eventually I can upgrade to the Freya and move a lot of this interim equipment into a second system.
     
  14. murray

    murray Friend

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    More likely to be electromagnetic induction from the preamp's power transformer. Especially considering the sensitive circuitry in the phono amp. Distance is the easiest cure there.
     
  15. Merrick

    Merrick A lidless ear

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    Yeah, I've got it on top of the power amp with no negative repercussions that I can hear. Simple fix, thankfully!
     
  16. nedifer

    nedifer Facebook Friend

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    Perhaps it was an interaction between the tube and the pickup on the stylus of the turntable?
     
  17. Merrick

    Merrick A lidless ear

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    Not sure what specifically would have caused it, I'm just glad the phono is so portable!
     
  18. zonto

    zonto Friend

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    "It will be very, very hard to get the production Vidars to [go into protection mode like the demo units did at RMAF]--where the show design ran 93 degrees C, the new design runs at 52 degrees C. No kidding." (source)
     
  19. fierce_freak

    fierce_freak Friend

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    I think I saw the specs somewhere, but I can't find them - what's the size of vidar? I know it's half-width, but what's the height and most importantly the depth?
     
  20. zonto

    zonto Friend

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    I haven't seen those specs. There are some pictures of a prototype in the Compendium in my sig, but those were also before the Vidar was redesigned with external heat sinks. @schiit?
     
    Last edited: Dec 11, 2016

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