Schiit Mjolnir headphone amplifier
Sep 24, 2013 at 1:50 PM Post #2,821 of 3,541
   
You didn't miss it still for sale!

Check my sig  
wink_face.gif
   
 
Sep 24, 2013 at 2:56 PM Post #2,823 of 3,541
Sep 26, 2013 at 12:25 PM Post #2,825 of 3,541
So I've had my Mjolnir for about six months now, or something like that, and sometimes it hums and at other times it's silent.  I can't identify any pattern except the longer I leave it on the more likely it is to start humming.  Now my mains supply is pretty poor, with solid voltage and low distortion but lots of other issues such as DC offset, noise and so on.  I have a Running Springs filter, a balanced transformer, a PS Audio P3 (regenerator - but not a true one) and an Isotek Syncro (DC blocker).  I also have a true regenerator (AC>DC>AC), but it affects the sound quality and still doesn't keep the Mjolnir completely silent so it's been relegated to the PC.  If I daisy chain the first four of those together what could be getting through all of them to cause the Mjolnir to hum?  I'm hoping there's an electrical engineer who can answer that! :)
 
Everything in the chain is plugged into the same set of filters (except the PC which is plugged into the other regenerator).  I've tried assorted combinations and assorted sources, but with no luck.  The rest of the system and my other components are all silent (from 3' away), so it's just the Mjolnir that's humming.  I've tried disconnecting the PC from the hi-fi as well with no luck.
 
I also have an issue with the system sounding bright (through HD800s), again from time to time.  I don't think there's an exact correlation between the two (that I can tell), but the same underlying issue might vary in intensity and cause both problems.  I'm running balanced from the DAC and apart from power and headphones nothing else is connected to the Mjolnir.
 
The other filters all serve a function: when I moved in I assumed my hi-fi at the time was broken as it sounded so bad.  Without any filters at all (and before I bought the Mjolnir) I had a 24/88.2 recording from Linn turn into a digital screech that was literally painful - it was unidentifiable as music. The same song on the same system after midnight sounded fine and I've not had a recurrence of that particular problem since filtering up.  I believe it was caused by a combination of factors and I've dealt with probably all but one of them.  This last one is doing my head in though, so hopefully the Mjolnir's hum will suggest a solution.  Does anyone have any ideas?
 
Sep 26, 2013 at 12:33 PM Post #2,826 of 3,541
So I've had my Mjolnir for about six months now, or something like that, and sometimes it hums and at other times it's silent.  I can't identify any pattern except the longer I leave it on the more likely it is to start humming.  Now my mains supply is pretty poor, with solid voltage and low distortion but lots of other issues such as DC offset, noise and so on.  I have a Running Springs filter, a balanced transformer, a PS Audio P3 (regenerator - but not a true one) and an Isotek Syncro (DC blocker).  I also have a true regenerator (AC>DC>AC), but it affects the sound quality and still doesn't keep the Mjolnir completely silent so it's been relegated to the PC.  If I daisy chain the first four of those together what could be getting through all of them to cause the Mjolnir to hum?  I'm hoping there's an electrical engineer who can answer that! :)

Everything in the chain is plugged into the same set of filters (except the PC which is plugged into the other regenerator).  I've tried assorted combinations and assorted sources, but with no luck.  The rest of the system and my other components are all silent (from 3' away), so it's just the Mjolnir that's humming.  I've tried disconnecting the PC from the hi-fi as well with no luck.

I also have an issue with the system sounding bright (through HD800s), again from time to time.  I don't think there's an exact correlation between the two (that I can tell), but the same underlying issue might vary in intensity and cause both problems.  I'm running balanced from the DAC and apart from power and headphones nothing else is connected to the Mjolnir.

The other filters all serve a function: when I moved in I assumed my hi-fi at the time was broken as it sounded so bad.  Without any filters at all (and before I bought the Mjolnir) I had a 24/88.2 recording from Linn turn into a digital screech that was literally painful - it was unidentifiable as music. The same song on the same system after midnight sounded fine and I've not had a recurrence of that particular problem since filtering up.  I believe it was caused by a combination of factors and I've dealt with probably all but one of them.  This last one is doing my head in though, so hopefully the Mjolnir's hum will suggest a solution.  Does anyone have any ideas?
I don't think that true regenerator is necessary. I'd get a power conditioner with isolated banks and is also equipped with a voltage regulator.

I had the mjolnir prior to my HD800, the pairing is highly transparent but very thin sounding. I assume that's the brightness you hear.
 
Sep 26, 2013 at 12:46 PM Post #2,827 of 3,541
 
So I've had my Mjolnir for about six months now, or something like that, and sometimes it hums and at other times it's silent.  I can't identify any pattern except the longer I leave it on the more likely it is to start humming.  Now my mains supply is pretty poor, with solid voltage and low distortion but lots of other issues such as DC offset, noise and so on.  I have a Running Springs filter, a balanced transformer, a PS Audio P3 (regenerator - but not a true one) and an Isotek Syncro (DC blocker).  I also have a true regenerator (AC>DC>AC), but it affects the sound quality and still doesn't keep the Mjolnir completely silent so it's been relegated to the PC.  If I daisy chain the first four of those together what could be getting through all of them to cause the Mjolnir to hum?  I'm hoping there's an electrical engineer who can answer that! :)
 
Everything in the chain is plugged into the same set of filters (except the PC which is plugged into the other regenerator).  I've tried assorted combinations and assorted sources, but with no luck.  The rest of the system and my other components are all silent (from 3' away), so it's just the Mjolnir that's humming.  I've tried disconnecting the PC from the hi-fi as well with no luck.
 
I also have an issue with the system sounding bright (through HD800s), again from time to time.  I don't think there's an exact correlation between the two (that I can tell), but the same underlying issue might vary in intensity and cause both problems.  I'm running balanced from the DAC and apart from power and headphones nothing else is connected to the Mjolnir.
 
The other filters all serve a function: when I moved in I assumed my hi-fi at the time was broken as it sounded so bad.  Without any filters at all (and before I bought the Mjolnir) I had a 24/88.2 recording from Linn turn into a digital screech that was literally painful - it was unidentifiable as music. The same song on the same system after midnight sounded fine and I've not had a recurrence of that particular problem since filtering up.  I believe it was caused by a combination of factors and I've dealt with probably all but one of them.  This last one is doing my head in though, so hopefully the Mjolnir's hum will suggest a solution.  Does anyone have any ideas?
 

I'm no engineer, but I have run into these issues myself and solved them. If the issues remain consistent from different outlets, a ground loop would be suspect, possibly the DAC too since you mentioned "screech" playback on a 24-bit file. I would experiment by taking a length of cheap speaker wire and connect one end to a screw on the DAC, and the other end to a screw on the MJ to see if that solves the problem. If it doesn't, try using a different PC or laptop and a different DAC if possible. Good luck!
 
Sep 27, 2013 at 12:05 PM Post #2,828 of 3,541
I've had the same issues with all my Schiit products and solved them by simply going to a 3 to 2 prong adapter with all of them with no other issues--
 
No more Hum--
 
Jack
 
Sep 27, 2013 at 10:00 PM Post #2,829 of 3,541
  I've had the same issues with all my Schiit products and solved them by simply going to a 3 to 2 prong adapter with all of them with no other issues--
 
No more Hum--
 
Jack

 
No more ground either.  
 
Sep 28, 2013 at 4:45 AM Post #2,832 of 3,541
  Is there no definite answer to this hum issue? Seems kind of weird that some are having this issue and others aren't. I'm definitely not, is this an amp issue or a home power issue?

Mine is dead silent as well.....been powered up non-stop for approx 6 months.....a few months ago people were thinking dimmers might be the problem.
 
Sep 28, 2013 at 12:12 PM Post #2,833 of 3,541
Mine is also dead quiet, I would check earthing firs,t this is nearly always associated with hum problems, initially I would remove the earth connection to the headphone amp and check if its better or has no effect
 
Sep 28, 2013 at 5:59 PM Post #2,834 of 3,541
The hum comes and goes, very occasionally it sounds as though it fluctuates slightly.  After it's been left off for eight hours and switched back on again the Mjolnir usually starts out silent, but once it's warmed up it starts humming again at some point and the hum generally persists afterwards to some extent.  I think it has gone away in the past whilst still switched on, but I'm not 100% sure about that.  The hum persists even with nothing attached to the Mjolnir (except power of course). I'm not comfortable removing earthing wires, so that option is closed to me unfortunately. 
 
I'm just running dc blocker/balanced transformer/regenerator/ at the moment as an experiment and the balanced transformer also hums a little at times so it's possible I just have an excessive amount of DC offset that the Syncro isn't completely dealing with.  Unfortunately I have no way to check that.  The balanced transformer is much quieter than the Mjolnir though and is usually silent even when the Mjolnir hums.  Given the P3 also blocks some DC and comes after the transformer and before the Mjolnir, that would mean the Mjolnir would have to be hyper-sensitive to DC offset for it to be the problem.
 
The one thing I believe would get through all my filters is high frequency noise (such as wireless or mobile phone networks) as I read somewhere the balanced transformer is limited in handling that issue.  The P3 does little to stop noise and the Syncro certainly won't, so is there some brick wall filter I can add as an experiment just to see if it stops the hum?
 
At this stage I'm assuming it's a home power issue, coupled with a very sensitive amp.
 
Sep 28, 2013 at 9:59 PM Post #2,835 of 3,541
I can and do rock my Mjo/Gun for hours on end with absolutely no hum or any other noise at all. Just deep black. I really want to try a Cyclops amp vs Mjo but it sounds so good (to me) that I am having a tough time coughing up the 1500 or so to go ahead and do it. I will someday... Been wanting to build two rigs anyway so that would be a start. Cant really see selling the Schiit as it is really sounding good (to me) but want to branch out and try some other gear also.
 

Users who are viewing this thread

Back
Top