kraken2109 said:

  I don't understand the problem here. They don't need an amp. The run loud enough for me off an mp3 player! Maybe yours are defective or something.

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There's a difference between being driven loud and driven well ... an iPhone will drive 600ohm DT880s pretty loudly, but they sound rubbish compared to when properly amped. The K601 / K612 needs an amp to perform at it it's absolute best. 
 
However, it doesn't need a lot of amping - I ran mine perfectly well off a FiiO E10 and in fact I couldn't tell the difference between that and with my M-stage. Both sounded better than directly out of my iPhone.  The difference isn't huge, but it is there, especially for demanding music (e.g. stuff with a wide dynamic range).

sinnottj said:

   
There's a difference between being driven loud and driven well ... an iPhone will drive 600ohm DT880s pretty loudly, but they sound rubbish compared to when properly amped. The K601 / K612 needs an amp to perform at it it's absolute best. 
 
However, it doesn't need a lot of amping - I ran mine perfectly well off a FiiO E10 and in fact I couldn't tell the difference between that and with my M-stage. Both sounded better than directly out of my iPhone.  The difference isn't huge, but it is there, especially for demanding music (e.g. stuff with a wide dynamic range).

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Bass response and soundstaging suffer as well when underpowered.  They can can also sound thinner.

sinnottj said:

   
There's a difference between being driven loud and driven well ... an iPhone will drive 600ohm DT880s pretty loudly, but they sound rubbish compared to when properly amped. The K601 / K612 needs an amp to perform at it it's absolute best. 
 
However, it doesn't need a lot of amping - I ran mine perfectly well off a FiiO E10 and in fact I couldn't tell the difference between that and with my M-stage. Both sounded better than directly out of my iPhone.  The difference isn't huge, but it is there, especially for demanding music (e.g. stuff with a wide dynamic range).

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I'm aware. I A/B tested between my phone, Cowon J3 and Denon reciever.

Ok well I can test again...off the asic of my motherboard (Asus z9pe-d8 WS using a realtek alc 898 link here...http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=28&Level=5&Conn=4&ProdID=325) or off my very ancient m-audio Black Box via USB 2.0.  I guess I could also test directly into my galaxy note.
 
As far as I can tell from the product literature, they have a resistance of 120 ohms...the akg k141 mkII's have a resistance of 55 ohms, that's I guess pretty close to my original studio mk I's.
 
I just think it's bizarre that I can't put enough signal through either through the headphone output of my m-audio speakers or the black box...but maybe I really do need a headphone amp (or xonar with a built-in amp). It just sucks that after having 3! (albeit budget) DACS, I have to go purchase another....
 
Will get back to you all after more testing, and thanks for the feedback! Really appreciated....

Ok I guess I have to pony up for a new soundcard or headphone amp....here's (in norwegian, but you can get the gist of it) a link to what I have available in my neck of the woods....https://www.komplett.no/k/kl.aspx?bn=11211
 
Sorry for being cranky, but getting yet a 4th DAC or amp seems a bit ridiculous.  My little brother, who is a pianist, collects DACS for his museum, all expensive (preferably) steinberg, etc...last count he had 8? expensive rackmount DACs....of course, one only works with this computer because of firewire, and the next one is perfectly portable, and the next is...weeehll you get the idea. I could justify this kind of thing as regards skis (I collect skis, but then they ARE completely different) and used to collect guitars (ditto again!) and tube amps (you guessed it!) but man a DAC is still just an asic/chip that someone in Taiwan plops on an integrated circuit board....
 
So do I go just a headphone preamp or an Asus Xonar? And can I get away with say a Xonar DGX for 50 bucks or do I need to splurge on a Xonar Essence XTC for 300+ bucks? Bearing in mind that surround sound for gaming would be nice, but most importantly the built-in headphone amp for the k612's.  Or do I simply go some Fiio amplifiers without the DAC (E11? E12?)....
 
Thanks again for the help with the newb...

Edit for kraken2109: They don't even get really loud....just medium to medium-loud, despite everything on full blast.....and I'm one of those people who despite playing a bit of guitar in my youth, has sensitive ears and prefers LOW VOLUME music....

Your DACs are not the issue, its the amount of synergy the K612 requires. Therefore, you need a standalone desktop amp... or even a portable amp like the E12. They will scale better with a desktop amp, though...

We've mentioned this numerous times, my friend. Its either you buy an amp... or just send the K612 back or sell it. That simple...

I don't mean to sound cranky, myself, but its not much more we can tell you.

Ok thanks received loud and clear! Thanks for the help!
 
Ok so it's not the DAC's, so need suggestions/help for a headphone amp.  The Fiio E12 is 1495 nok or usd 246 over here. Any suggestions for alternatives (both cheaper and more expensive?).  Or should I go with one of the asus xonar  soundcards with built-in headphone amps? Which of the xonar line can drive the k612's?
 
OK am just going to rule out multi-thousand dollar tube headphone-amps iff you were wondering...
 
Will have a look over at musician's friend etc...
 
WAS going to purchase a pair of steelseries 9H but weell, just loved my k141's too much.

Sorry, I'm not familiar with how much juice the built in amps in the Xonar sound cards can provide.

Headphone amps to consider for the K612 in the $200-$300 range:

Schiit Asgard 2
Matrix M-Stage
ifi Micro iCAN

Those are the only desktop amps I've owned...

Ok thanks will check them out...listening now full blast out the back of my mobo, via spotify (ok yes pretty ****ty sampling) but it's more than bearable...medium to loud listening volume...and tried full blast out of my m-audio studio speakers, again same thing...these cans need a lot of juice!
 
Will have to check out sweetwater as well...there must be lots of headphone amps out there...

Just get the Asgard 2. You can thank me later

I think my old man has a pair of old Denon headphone amps sitting in aus...prbly also absurdly overpriced....1 input, 1 output, vintage around the 80's....but reminds of the schiidt and other amps...there must be a way to ghetto mod say almost any half-decent amp to serve my purpose. Did ask for a quote and help from schiidt because weell the story was too cool and of course the name was cool as well.  
 
Still there are limits...300 bucks for a headphone amp? Ditto the others? Point of diminishing returns...I can understand spending a lot on cans, or even a kick-ass tube amp, but a headphone amp? Maybe iff they had glowing tubes.....
 
Edit: buying a mixing board of my little bro (again one of prbly 6?) so hopefully they have enough juice to drive these things...a small Mackie...
 
Edit 2: a decent pair of Schiidts or other imported headphone amps..let's say they cost 300 bucks..well for me they work out to nearly 550 bucks after shipping and then sales tax or VAT (value added tax of 25% after shipping) on top of that...wow that's starting to get pretty damn expensive! So thus the numerous posts etc and annoying the schiidt out of people...one of the costs of living in Europe (ok I won't mention threat of invasion by Putin!)...not to mention the extra markup....whinge whinge...

Weeell Ghetto Mod here! Older pair of tiny mini-stereo Sony amp/cassette/cd player (almost a ghetto blaster, just not quite so portable). So out of front jacks on the pc straight into rca jacks in the sony...Weell the sound isn't great, but at least I have a bigger amp! It was never a great amp to begin with, but not too too shabby (ancient Sony FH-311 integrated hifi!)...even has a decent equalizer!
Have a feeling the fiio and Schiidt and other dedicated headphone amps would be better...but at least now I have some decent volume control...without everything set 11! 
 
Not exactly the thing you can put in your pocketses of course! But don't discount the value of older hi-fi gear! Anyone want to buy lots of older cassettes and a mint sony walkman professional cassette player/recorder (WM-D3)? Has played lots of the Police, and other assorted 80's music! Used exclusively with the best tapes of course...
 
Ok will go back to checking out my ghetto-blaster setup here...
 
Edit: well they can drive supposedly 200w, but they're not terribly musical, and can barely drive my phones...oh well back to the drawing board....just a bad headphone out...sound really good on speakers for what they are...

Quick question. Do you have a A/V stereo receiver in the house? Try that... and report back...

Well that's what I'm listening though at the moment here in Norway...my folks have the Denon receiver back in Sydney...maybe I just need a better source..will try some cd's.  
 
Edit the ****ty old sony FH-311 little 'boom box', but it's usually pretty ok through speakers...ditto my computer through my m-audio reference speakers...hoping the mackie mixer will sort this...or these cans are just too clean for me...think I need better source music...better than spotify and cd's anyway...
 
Edit 2: a quick A/B with the old studio 141's which keep cutting out (need yet another resoldering job!)...well when the 141'a work, they're warmer, nicer in the base, and more encompassing.  However they're definitely less detailed than the k612's. They also need much less to drive them, and basically sound better with less driving them. 
 
OK all very subjective! Maybe I should have just gone less 'studio' and more for a less critical-listening pair of cans...although I thought! the k141's were already pretty ok as regards studio use! 
 
Edit 3: Wow those 141's just rock! My L5-CES sounds BOMBER through them....have to fix again soonest! What a great pair of cans! So musical! (the original ones)...
 
Edit 4: Think I just like the semiaural cans best...the k612's are definately more detailed, but somehow prefer the old 141 semiaural sound...seems closer. Also darker, warmer and smoother. The k612's are just too brittle for me...
 
Who knew there was such a huge a difference between cans? Reminds me of early days discussing tubes for amps (dude no way can you mess with the wiring of a twin! It has to be point to point! No way russian tubes are going to be the same...etc!)...still rendering here...