[Midgetguy]

  got'em! 
 
i haven't had my 598 for over a year so i'll do my best to compare.
 
plugged into my receiver; yamaha htr 5550 headphone out (it's all i got for now) i have to say i was let down - which i expected, given that it's a headphone out.
 
so far it sounds like a 598 with better detail retrieval overall, solid mids, better bass quantity/quality and a MUCH smaller soundstage.  there are a couple electronic songs i enjoyed on the 598 that give me a surreal "out of head" experience.  i didn't get that with the 600.  there's some instrument separation, but i don't feel it's worth mentioning above any other average headphone.  one thing that was nice, however, was that i found a lot more texture in electronic music i had not previously heard.
 
one thing that immediately became apparent is that my description of "lush vocals" for the 598 really should have been "forward vocals at the expense of everything else".  the 600, while sounding perfectly average in stage/imaging, sounded better on all fronts except maybe the vocals.  they still sound very good.
 
sorry i can't be more specific; don't have that critical of an ear yet - but it's natural, it's laid back.  all parts are present.  i have a feeling a decent amp is gonna bring this way up and blow the 598 out of the water.
 
if i had to choose right now?  i'd prefer a 598 unamped over the 600 unamped, despite the improvements.  the soundstage and imaging are the reasons why.  when i wore the 598 i could forget i was wearing headphones - i felt like i had instruments playing all around me, like i was on the stage behind the band/people/whatever, not like i was in a concert hall.  thankfully i'm not going to be keeping these unamped.    
 
i've decided to start small and simply use the 150$ amazon gift card to get a starting point - a couple reviews pointed me to the asgard 2 as a good place to start despite not being a tube amp.  would this open up the stage and imaging while keeping the largely neutral/natural characteristic of the hd600?  many reviews seem to indicate such.  i'm thinking later on i'd spring for the mjolnir 2 as my "endgame" amp after i've saved and learned to enjoy a basic amp and dac.

This is one of the noted strong suits of the HD600s in my opinion. While it may not necessarily blow you away (the wow factor some people look for when expecting an upgrade), it really doesn't do anything wrong. That's what has made it such a legendary headphone. Pure performance, no gimmicks.
 
You could very well be correct about the issue with the issue of amping; The HD600s are 300ohm headphones after all, while the HD598s are only 50ohms, making them much easier to drive.

 

[DavidA]

  got'em! 
 
i haven't had my 598 for over a year so i'll do my best to compare.
 
plugged into my receiver; yamaha htr 5550 headphone out (it's all i got for now) i have to say i was let down - which i expected, given that it's a headphone out.
 
so far it sounds like a 598 with better detail retrieval overall, solid mids, better bass quantity/quality and a MUCH smaller soundstage.  there are a couple electronic songs i enjoyed on the 598 that give me a surreal "out of head" experience.  i didn't get that with the 600.  there's some instrument separation, but i don't feel it's worth mentioning above any other average headphone.  one thing that was nice, however, was that i found a lot more texture in electronic music i had not previously heard.
 
one thing that immediately became apparent is that my description of "lush vocals" for the 598 really should have been "forward vocals at the expense of everything else".  the 600, while sounding perfectly average in stage/imaging, sounded better on all fronts except maybe the vocals.  they still sound very good.
 
sorry i can't be more specific; don't have that critical of an ear yet - but it's natural, it's laid back.  all parts are present.  i have a feeling a decent amp is gonna bring this way up and blow the 598 out of the water.
 
if i had to choose right now?  i'd prefer a 598 unamped over the 600 unamped, despite the improvements.  the soundstage and imaging are the reasons why.  when i wore the 598 i could forget i was wearing headphones - i felt like i had instruments playing all around me, like i was on the stage behind the band/people/whatever, not like i was in a concert hall.  thankfully i'm not going to be keeping these unamped.    
 
i've decided to start small and simply use the 150$ amazon gift card to get a starting point - a couple reviews pointed me to the asgard 2 as a good place to start despite not being a tube amp.  would this open up the stage and imaging while keeping the largely neutral/natural characteristic of the hd600?  many reviews seem to indicate such.  i'm thinking later on i'd spring for the mjolnir 2 as my "endgame" amp after i've saved and learned to enjoy a basic amp and dac.

The HD-600 and most higher impedance headphones really benefit from being amped properly.  When I say properly it doesn't just mean high voltage/current/watts etc, it means something with good synergy that pairs well.  I'm going to say sorry to your wallet at this point and I hope you find an amp and possibly a DAC down the line that does justice to the HD-600 as they are truly great headphones in their price range.

 

[madwolfa]

 
i've decided to start small and simply use the 150$ amazon gift card to get a starting point - a couple reviews pointed me to the asgard 2 as a good place to start despite not being a tube amp.  would this open up the stage and imaging while keeping the largely neutral/natural characteristic of the hd600?  many reviews seem to indicate such.  i'm thinking later on i'd spring for the mjolnir 2 as my "endgame" amp after i've saved and learned to enjoy a basic amp and dac.

 
Asgard 2 is awesome and I have one, but I think Vali 2 would be great for HD600 at a lower price point.

 

[yangian]

  got'em! 
 
i haven't had my 598 for over a year so i'll do my best to compare.
 
plugged into my receiver; yamaha htr 5550 headphone out (it's all i got for now) i have to say i was let down - which i expected, given that it's a headphone out.
 
so far it sounds like a 598 with better detail retrieval overall, solid mids, better bass quantity/quality and a MUCH smaller soundstage.  there are a couple electronic songs i enjoyed on the 598 that give me a surreal "out of head" experience.  i didn't get that with the 600.  there's some instrument separation, but i don't feel it's worth mentioning above any other average headphone.  one thing that was nice, however, was that i found a lot more texture in electronic music i had not previously heard.
 
one thing that immediately became apparent is that my description of "lush vocals" for the 598 really should have been "forward vocals at the expense of everything else".  the 600, while sounding perfectly average in stage/imaging, sounded better on all fronts except maybe the vocals.  they still sound very good.
 
sorry i can't be more specific; don't have that critical of an ear yet - but it's natural, it's laid back.  all parts are present.  i have a feeling a decent amp is gonna bring this way up and blow the 598 out of the water.
 
if i had to choose right now?  i'd prefer a 598 unamped over the 600 unamped, despite the improvements.  the soundstage and imaging are the reasons why.  when i wore the 598 i could forget i was wearing headphones - i felt like i had instruments playing all around me, like i was on the stage behind the band/people/whatever, not like i was in a concert hall.  thankfully i'm not going to be keeping these unamped.    
 
i've decided to start small and simply use the 150$ amazon gift card to get a starting point - a couple reviews pointed me to the asgard 2 as a good place to start despite not being a tube amp.  would this open up the stage and imaging while keeping the largely neutral/natural characteristic of the hd600?  many reviews seem to indicate such.  i'm thinking later on i'd spring for the mjolnir 2 as my "endgame" amp after i've saved and learned to enjoy a basic amp and dac.

If you have $150 Amazon GC, I would recommend this for 600: http://www.amazon.com/Nobsound%C2%AE-Headphone-Amplifier-Preamplifier-Aluminum/dp/B00WSFMZD0/ref=sr_1_1?ie=UTF8&qid=1460065320&sr=8-1&keywords=little+bear+p8+amplifier 

 

[madwolfa]

Day 2: "How could I sell them??"

 

[Kodachrome2000]

Lmao, not quite. I'm really enjoying listening to them. Screwed around with the foam mod, liked it, but back on stock for now. It opened up the soundstage a bit and brought the treble forward, made it more engaging, but some songs were too sibilant.

Had a spooky moment earlier on the keyboard - played a few notes just to see how it sounded and i thought something was wrong...i could hear my fingers hitting the notes and the keys moving...and the notes themselves...i actually had to take the headphones off and play the notes again because i thought FOR SURE there was something wrong with the headphones; there's no reason i should be hearing the piano when i clearly had the headphones plugged in...turns out it was through the headphones the whole time, and i just busted out laughing. It was eerie.

I don't think these are veiled, but i do feel like there's *something* between me and the music. I just find myself wanting a bit more energy, which i got by removing the foam and that little extra treble. I imagine an amp and dac plus a little eq will go a long way to accomplishing exactly what i want since these seem like such a jack of all trades.

 

[ColtMrFire]

  got'em! 
 
i haven't had my 598 for over a year so i'll do my best to compare.
 
plugged into my receiver; yamaha htr 5550 headphone out (it's all i got for now) i have to say i was let down - which i expected, given that it's a headphone out.
 
so far it sounds like a 598 with better detail retrieval overall, solid mids, better bass quantity/quality and a MUCH smaller soundstage.  there are a couple electronic songs i enjoyed on the 598 that give me a surreal "out of head" experience.  i didn't get that with the 600.  there's some instrument separation, but i don't feel it's worth mentioning above any other average headphone.  one thing that was nice, however, was that i found a lot more texture in electronic music i had not previously heard.
 
one thing that immediately became apparent is that my description of "lush vocals" for the 598 really should have been "forward vocals at the expense of everything else".  the 600, while sounding perfectly average in stage/imaging, sounded better on all fronts except maybe the vocals.  they still sound very good.
 
sorry i can't be more specific; don't have that critical of an ear yet - but it's natural, it's laid back.  all parts are present.  i have a feeling a decent amp is gonna bring this way up and blow the 598 out of the water.
 
if i had to choose right now?  i'd prefer a 598 unamped over the 600 unamped, despite the improvements.  the soundstage and imaging are the reasons why.  when i wore the 598 i could forget i was wearing headphones - i felt like i had instruments playing all around me, like i was on the stage behind the band/people/whatever, not like i was in a concert hall.  thankfully i'm not going to be keeping these unamped.    
 
i've decided to start small and simply use the 150$ amazon gift card to get a starting point - a couple reviews pointed me to the asgard 2 as a good place to start despite not being a tube amp.  would this open up the stage and imaging while keeping the largely neutral/natural characteristic of the hd600?  many reviews seem to indicate such.  i'm thinking later on i'd spring for the mjolnir 2 as my "endgame" amp after i've saved and learned to enjoy a basic amp and dac.

 
Properly amped and with EMI or signal noise/degradation eliminated, the HD600 should blow the 598s out of the water.  There is no contest, at least on my end.
 
After the few tweaks I mentioned in my earlier post (which are worth investigating since their so cheap), the soundstage became almost cavernous and detail/resolution as well as punch/impact and instrument separation jumped several notches, with crystal clean/clear highs being loud but without a hint of harshness or grain (no fatigue even after listening all day at higher volumes).  I really can't stress this enough... the HD600 needs any possible USB/DAC/AC-power noise eliminated and proper amplification to really show what they can do.  And I'm not even using a balanced connection yet.
 
As far as your receiver goes, do you turn it off when not in use?  My Denon receiver didn't sound amazing until it had been on for several hours, and now I don't even turn it off.  Of course not every receiver has good headphone outs (I think I got lucky, since it was a random purchase from craigslist), but to be sure you may want to leave it on for a day and compare.
 
What I love about this hobby is that really small, but inexpensive tweaks can make a huge difference, and the HD600 scales amazingly well with tweaks.

 

[ColtMrFire]

I'm a big believer in cables making a difference, but I'm also a big believer in snake oil.  I wanted to replace my $6 RCA cables, since the noise had been eliminated from my system, and I figured it was now only as good as the weakest link (true in anything in life)... I bought a $40 set of Audioquest Evergreen cables from Best Buy.  Made absolutely no difference... in fact, I swore it didn't sound as good, so I returned them.  Even the stock USB cable I got from my old Audioengine D1 DAC/amp sounds better than a pricey USB cable I got from a head fi seller...

 

[audiojun]

I know cables makes a big difference in turntables. Those $3-5 monoprice premium cables are good quality it has made a difference for some of my mine and my friend's set ups by just replacing some thin cables with the thicker monoprice ones. The difference between an $3-5 premium monoprice cable and one of those $100+ cables are probably very very small.

 

[Kodachrome2000]

getting a new cable is on my to-do list, for sure.  not for sound purposes - i just don't like this cable.  it feels like i'm trying to run a telephone line somewhere.

 

[TheRealMVT]

Asgard 2 is awesome and I have one, but I think Vali 2 would be great for HD600 at a lower price point.

Can confirm from my own experience that the Vali2 does a great job with the HD600.

 

[audiojun]

Can confirm from my own experience that the Vali2 does a great job with the HD600.

I second that the Vali 2/Modi 2 combo sounded fantastic in my experience at canjam.

 

[ColtMrFire]

I wish I still had my Vali so I could see how they sound with the HD600... but I sold it and my Dt880s in order to get the HD600.  I wasn't a fan of how they sounded with the 880s... but I hear the 600s like tubes.
 
I am definitely curious about the Bottlehead Crack/Speedball amp + HD600 combo, which everyone raves about.  But so far I am digging solid state.

 

[Bob A (SD)]

  I wish I still had my Vali so I could see how they sound with the HD600... but I sold it

I'm quite pleased with the synergy between the Vali and my HD600s.  And from the many reviews and comments I've seen elsewhere, I'm not alone.  

  This from a long time HD580/600 fan.

 

[ColtMrFire]

  I know cables makes a big difference in turntables. Those $3-5 monoprice premium cables are good quality it has made a difference for some of my mine and my friend's set ups by just replacing some thin cables with the thicker monoprice ones. The difference between an $3-5 premium monoprice cable and one of those $100+ cables are probably very very small.

 
I actually hear a noticeable difference between the stock HD600 cable and the 650 cable.  It's not dramatic or anything, but the 600 cable made the sound slightly "smaller" and less impactful.  And the 650 cable is like $20 bucks or something, so it's worth trying.
 
When I get a bit more disposable income, I'm going to investigate upgrade cables for the HD600 to see for myself if there's any merit to the fancier cables like Cardas, etc... opinion of it being a noticeable upgrade is strong, but I wanna try for myself.