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Schiit Mjolnir headphone amplifier - Page 190

post #2836 of 3208

Storm, you should try plugging in at a different location to absolutely narrow down what's the cause.

post #2837 of 3208

With nothing in front of it.  Just straight wall.

post #2838 of 3208

Some more experiments:

 

I plugged the Mjolnir into the regenerator and it hummed.  I then disconnected the regenerator from the wall (pulled the plug) so that it was functioning as a battery back-up UPS - and the Mjolnir still hummed.  That means that either my problems are the Mjolnir itself, radiated EMI from somewhere, or the regenerator is putting out the same kind of AC problems that I'm getting from the wall.  Note that this regenerator has always been 100% consistent in the past but also 100% mediocre in terms of sound quality, so it's not inconceivable that the power it supplies is flawed in some way (in fact I know it is as the treble is a little rough and the midband lacks finesse when the whole system is plugged into it). The probability that it's also causing the Mjolnir to hum in the same way as the regular mains supply is the question.

 

I took the Mjolnir upstairs and plugged it into a socket in the bedroom, which is the quietest room in the house and on a different circuit.  It hummed as before.  I'm beginning to think it's just a noisy unit, but I'm sure it wasn't always this way.  I'm in the UK with a 230v version.  It would be interesting to note which versions other people have and whether they're noisy or not.

 

Having removed the Mjolnir from my system to experiment with it, I hooked up some old speaker amps to power my headphones.  These are 20 year old monsters with big toroidals and in desperate need of a service.  I can't use them to drive speakers due to the thinness of an adjoining wall with the neighbours, so they've been in storage for a while.  They work fine with the volume set to -60db apart from an audible hiss through the headphones.  Having set them up one of them hums with the same intensity as the Mjolnir (perhaps a bit louder), whilst the other is dead silent.  They're both plugged into the same DC blocker/filter combo.

 

NB: By hum I'm talking about mechanical noise emitted by the Mjolnir, which is audible from up to ten feet away in a quiet room (not through the headphones) and annoying within six feet.  It's higher pitched than a thrum, and lower pitched than a whine, if that helps :-)

post #2839 of 3208

Just a thought.  You may have already did this - not sure.  Try taking it to work or a friends house or somewhere other than your house.  Best place would be an audio shop where other amps are being used with no hum.

post #2840 of 3208

I've not tried it with the Mjolnir yet, but it's a good idea.  I did try that with a Lehmann BCL I borrowed, which hummed like a bastard here but was silent at the shop.  Trouble is, that was before I got the Syncro so it may have been caused by DC offset in that case so not comparable.  It was so loud I didn't even bother to listen to it and just took it immediately back to the store.

post #2841 of 3208

Made a discovery that I should have tried some time ago.  As the Mjolnir is on the end of the P3 I can adjust the voltage feeding it up and down in 1v increments with the P3's remote control.  At 230v - 240v the hum is similarly bad, and it's still bad below 230v, but by the time I hit 222v - 220v it is significantly diminished.  Unfortunately my local UK voltage is 240v - 250v so the P3 is operating way outside its recommended comfort zone outputting 220v.  The hum doesn't completely disappear at 220v but it's about half as loud (by my completely non-scientific calculations :wink_face:) and much less annoying.  The lowest voltage the UK P3 can do is 214v, which is slightly quieter still.

 

The DAC and source use switched-mode psus and don't care what the voltage is, so I'll leave it like this for the moment and hope nothing explodes!

post #2842 of 3208

I have a 230v UK version and no hum after the first few seconds of switch on. No special mains other than Russ Andrews cables.

post #2843 of 3208
Anyone try this amp with the HD800?
post #2844 of 3208
Quote:
Originally Posted by macbob713 View Post

Anyone try this amp with the HD800?
I have, I didnt like it--made the mid and upper range too thin.
post #2845 of 3208

I use mine with the HD800 and it's lovely after midnight, super smooth and transparent.  It does lack a little low-end grunt, but I'm used to small speakers so it sounds pretty normal to me.  The only issues I have are when the mains supply is noisy as some brightness and aggression creeps in, but that's true with all my amps to some extent.  Edit - some of that aggression comes from further up the chain with other devices being affected by the noise as well.  I'm having a really hard time getting my mains supply consistently good.

 

I've been running on 220v since my last post, with the Mjolnir on continuously, and if anything it's got quieter.  I can't hear anything from more than a foot away now, which is how it should be.  I just wish it did that at 240v.


Edited by Stormfriend - 10/7/13 at 1:43am
post #2846 of 3208

I'm really debating if I should buy a Mjolnir new or not.

Was going to buy a used, but it got sold as a stack with Gungnir.

Is the Mjolnir worth it with LCD2?(I got buffalo DAC)

post #2847 of 3208

Yes, yes it is.  Pretty sure I got the stack you were eyeing ;)

post #2848 of 3208

I have not been following the Mjolnir closely since I bought one shortly after Schiit released it. In reading some other threads, I have seen references to an "old" and "new" Mjolnir, suggesting the latest production versions are improved upon the originals. Could someone please explain to me what changes, if any, Schiit has made to the Mjolnir since its initial release, or how these changes affect sound quality? I would greatly appreciate it.

post #2849 of 3208
Quote:
Originally Posted by JeffA View Post
 

I have not been following the Mjolnir closely since I bought one shortly after Schiit released it. In reading some other threads, I have seen references to an "old" and "new" Mjolnir, suggesting the latest production versions are improved upon the originals. Could someone please explain to me what changes, if any, Schiit has made to the Mjolnir since its initial release, or how these changes affect sound quality? I would greatly appreciate it.

 

To the best of my knowledge there have not been any changes.

post #2850 of 3208

So on a whim I brought in the Gungnir and Mjolnir stack to see if I could free up some desk space without too much drop and... interesting results.

 

First things first.  This was not a fair fight.  $1600 v $7000 MSRP but this is Head-Fi so what the hell.  Secondly the Schiit stack is awesome given it's price tag and maybe more importantly really synergize with each other, cancelling out each other's potential faults.

 

So if we assume the GS-X mk2 and PWD2 are neutral, humour me :P  Then the Mjolnir is tilted up tonally and the Gungnir is tilted down.  Ie the PWD2 and Mjolnir is a little too forward  and illuminated and the Gungnir paired with the GS-X mk2 a little too laid back and dark.

 

But the Gungnir and Mjolnir really mesh well.  Since both "stacks" played best as a unit what do I think you give up for opting to keep several thousands in the bank?  Resolution and speed.  The GS-X mk2/PWD2 combo does a better job of digging deep into the recording and almost slowing things down during busy passages where the Mjolnir/Gungnir combo is turning towards hard times.  But it's the last 10% type difference, not a lopsided blowout.

 

So I can honestly now say my previous experience with the Mjolnir was in a large part the fault of the W4S DAC-2.  But partnered with a warm dac it really is something else.  Great dynamic swing and sense of air.

 

The Gungnir was also incredible and could bring life to a lot of the amps in the sub $1000 range that are often dried out and lacking down low.  I would however avoid pairing it to overly warm sources or you could fall into dark territory.  Headphone choice obviously plays a part here.

 

Should add.  Kudos to Schiit for having the balls to crank class A bias to reasonable levels.  Loves me some hot Schiit.  The Mjolnir gets quite hot.  Even the Gungnir is warm to the touch.  Love it!

 

Always drove me nuts that Burson had a massive heatsink for a case and set the bias to levels that barely warm the case sigh.


Edited by Solude - 10/12/13 at 5:34pm
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