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Schiit Jotunheim Review / Preview - Head-Fi TV

Discussion in 'Headphone Amps (full-size)' started by jude, Aug 26, 2016.
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  1. the finisher
    This appears to be a issue Schiit needs to deal with. I'm sure they watch this thread, but the sooner they know the better.
     
  2. Jason Stoddard
    This is really odd.

    Can you provide details of where you're experiencing this noise (what volume level, what components connected, what cables, etc)? Or do it via PM or email jason@schiit.com if you'd like.

    Also, can you post photos of how you grounded the lid? Because simply touching a wire to an anodized aluminum part won't form a ground. The top should be grounded through the contact of the pins with the unpainted steel chassis slots--the pins were specifically designed for us by Penn Engineering, the originator of this type of fastener, and we have shipped thousands of these products, including hundreds with phono boards, with no issues.

    Again, if anyone is having problems with hum and noise (at normal listening levels--all amps will have some residual hum and noise when turned all the way up), first try the troubleshooting steps at schiit.com to ensure you don't have a ground loop and it is not related to cables, etc), please contact us and we'll get it taken care of.
     
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    rlkeel0, the finisher, thebkt and 2 others like this.
  3. MWSVette
    A response from the man himself. It does not get any better than that....

    :)
     
    DavidA and the finisher like this.
  4. rutter
    I'll be getting an HDVA 600 today so that'll be the second amp I can compare the Jot to in terms of noise. I might even have to use the Jot's power cable with it so the environment should be exactly the same.

    I've run into some notable ear ringing I'm finding pretty strange. I even think my ears have rung without listening to music much, mostly just playing a game that doesn't even have background music.

    https://www.head-fi.org/threads/ear-ringing-with-certain-headphones.884243/

    The sixth post suggests amp distortion could be a factor. If there's any truth to that it would be pretty upsetting. I've been thinking of sending my Jot to the Th3Drizzl3 (I'll cover the shipping to and back) before Schiit, but in light of this recent suggestion resorting to asking Amir to have a look at it seems like a reasonable thing to do. It could be that the Jot and the HD800S are a really bad pairing, even though I've gone ahead and left both the Gumby and Jot on constantly in order to smooth things out as much as possible.
     
  5. Th3Drizzl3
    i scraped part of the underside clean so there was no coating and it was fresh i then wrapped a bare wire through one of the lids holes and was able to pull up on it pretty good against the bare area. and i grounded the outer rca barrel to the lid. also note without anything plugged in except power this noise was there. i tried with a topping d50 as well as the mimby both had noise. (again the other 2 jots i have here do not have noise) its a fairly steady hum that gets louder as the volume goes up. a humming not a whine. you mentioned the unpainted slots. the slots in this one were totally painted over. the paint went in the edge of the keyhole. once i scraped the paint away from the keyhole better the noise also subsided. i was going to solder a wire to the lid but turns out i did not have to. just by removing some excess paint it fixed the issue. im happy to answer anything i can. but im wondering if some of those pins are making better contact then others??

    edit: not that im saying anything good or bad about the guy (i dont want to get into an arguement here with anyone) looks like the guy over at asr forum also had the same idea someone just told me he basically did the same thing as i did to fix the noise. he also says it was gone for him doing this as well.
     
    Last edited: Jul 16, 2018
    Alcophone likes this.
  6. rutter
    CMX-2 arrived. Its indicator shows "line correct" and no difference is made to the background noise.
     
  7. Jason Stoddard
    Thanks for the additional detail.

    Since I'm now in the office, I pulled several Jotunheims off the line and checked chassis continuity. They're all good. So the pins are working as intended. I also checked the slot masking, and they are masked as intended. The masking is only on the edges of the slot, not on top, but they are showing bare metal as intended. This isn't to say that some might not make contact, but it's easy enough to add a check in production. I'll write that up today and get that rolling.

    However, here's the thing that's odd: I can't replicate your hum results.

    I took a chassis, unscrewed the screw that is used to ground the board to the bottom chassis, and put a top on it with no pins (literally taped it on). So the chassis was completely floating. The result: no exceptional hum and noise on the APx555 (just the standard residual power-supply stuff), see attached image. However, with the volume at midpoint, this one gave me extra 60Hz hum when the volume knob was touched. This was still 90dB+ down from the fundamental, however.

    I then screwed down the board to the bottom chassis to ground the bottom chassis alone, and put a top on it with no pins. So the top was completely floating, but the bottom was grounded. The result: same as above, except the noise floor was no longer sensitive to touching the volume knob. See attached image--results overlay.

    I then put a top on the grounded bottom chassis and verified it was grounded. The result: same as above, and the volume knob was still insensitive to touch. See attached image--all results overlay)

    image 2.png

    Again, if you're having problems with hum and noise on your Jotunheim (or any other product, or any other problem), contact us at info@schiit.com and we'll take care of it. If we can't replicate your problem, we always contact you for more information to see how we can help, and provide measurements from the AP or Avermetrics if needed.
     
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    CrownLands and Alcophone like this.
  8. Alcophone
    Hey Jason,

    Thanks for looking into it.
    Amir has created a separate thread with instructions, and a picture of the open Jotunheim. Unfortunately his side is down right now, but when it's back up, it might provide some further clues.
    Can you show a picture of what a Jotunheim is supposed to look like with the top off? And maybe highlight where there shouldn't be any paint/coating, both on the steel chassis and the aluminum top?

    Thank you!
     
  9. rutter
    Got the HDVA 600. Surprisingly to me it does have the same noise as the Jotunheim (the CMA400i somehow didn't). I'm using both the CMX-2 and Hum-X. It didn't come with its own power cable so I'm using the Jot's power cable. The USB and interconnect cables are Schiit, Gumby is the DAC.
     
    Alcophone likes this.
  10. Jason Stoddard
    It's pretty hard to show, it's literally just the inside edges of the slot. You can't even really see it here.

    IMG_1319.JPG
     
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    Alcophone likes this.
  11. Alcophone
    Aaah, that's good info. I expected the top part to be unpainted or something, which wasn't the case in Amir's picture. Thank you!
     
  12. Th3Drizzl3
    my next test will be to directly solder a lead to the under side of the lid and then solder it to ground. it will add a wire that will make the lid not fully removable but would be permanent.
     
  13. Th3Drizzl3
    jason this one had a decent amount of paint in the keyhole there was a bare spot but it was minimal. i used a exacto knife and scraped away the paint all the way around and then scraped the paint on top a bit. then when testing i did have a pretty solid ground.
     
    the finisher and Alcophone like this.
  14. Jason Stoddard
    Yep, the chassis we have here look correct, but I'm putting a "Jotunheim and Lyr 3 Chassis Grounding Test Procedure" together right now just to be sure in the future. (Lyr 3s use the same pins.)

    Thanks for the info!
     
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    thebkt, Th3Drizzl3 and Alcophone like this.
  15. Alcophone
    @Jason Stoddard Amir's site is back up. I'll mail you the link to his dedicated thread, but it looks like he's indeed suggesting to sand the inside of the keyhole. That wasn't clear to me before.
     
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