[414353]

Well, I think I'm narrowing down the field. From all I've read it looks like my choice for my next headphone will be staying in the Sennheiser family between the HD598, HD600 and HD650.
I have the HD518s and looking to upgrade.
I'm not sure which if any if these I will be able to demo. I demoed the HD600s at CanJam,but I think it was either a bad amp or miss-matched amp, something wrong with the particular cans themselves or bad source. So I have not really heard them yet in that case.
My dilemma is the fact that if I choose the HD600 or 650 I will have to get an amp. If I go with the HD598, no amp required which saves lots of money. Sure I can pick up a new Schiit amp on the cheap, but I've plugged my 518s into the Magni with the Modi2 and the 518s sounded like crap while plugging them into a receiver or what have you they sound far better. I don't know if the less expensive Schiit amps would work well with the HD600 or 650. I know the Oppo HA-1 probably would because it even made my 518s sound pretty nice, but that is quite an investment at $1200! Too much for me.
 
So I'm leaning more towards the HD598s right now ,but I wonder how they compare to the 518s? I know they use the same drivers, but I understand the vents are different and somehow effect the sound.
PS: I'll never know how they compare to the AKG K7xx though. 

 

[PurpleAngel]

AKG K7XX, good bang for buck headphones, like them better then my modified HD558.
http://www.head-fi.org/t/763088/akg-7xx
 
Get a Modi 2 and Vali, $220 + tax/shipping.
 
ODAC/O2 (used), $150
http://www.head-fi.org/t/763026/o2-and-odac-with-triad-power-supply

 

[414353]

  AKG K7XX, good bang for buck headphones, like them better then my modified HD558.
http://www.head-fi.org/t/763088/akg-7xx
 
Get a Modi 2 and Vali, $220 + tax/shipping.
 
ODAC/O2 (used), $150
http://www.head-fi.org/t/763026/o2-and-odac-with-triad-power-supply

Yes from the one minute of the K7xx I heard, I liked them, but clearly that is not enough time and the music was not familiar to me. If I could have maybe 5 to 10 minutes with them, that would be enough to make a final judgement. However, the K7xx is unobtainium and will be offered no more so that makes them rare now and price will soon denote that. Besides, for headphones I would rather go new instead of used.
 
Yes, Schiit is good value for dollar. I plugged my HD518s into a Magni with a Modi 2 and the 518s sounded horrible. Makes me wonder if the HD600 or 650 would sound good with those amps. Explain to me if I'm wrong, but could it be the reason my 518s sounded so bad with the Magni is because the 518s are very efficient and driving them with an amp does something to make them sound far away and dirty? I don't know off hand what the ohms rating on the 518 is. 

 

[414353]

Well, it's looking like I can't do any better than my current HD518s. I'm hoping to get a chance to try the HD598s if they don't need an amp, but other than that I have decided to avoid bothering with an amp. 
So it looks like upgrading my headphones is a dumb idea as in I don't need to do so.

 

[PurpleAngel]

  Yes from the one minute of the K7xx I heard, I liked them, but clearly that is not enough time and the music was not familiar to me. If I could have maybe 5 to 10 minutes with them, that would be enough to make a final judgement. However, the K7xx is unobtainium and will be offered no more so that makes them rare now and price will soon denote that. Besides, for headphones I would rather go new instead of used.
 
Yes, Schiit is good value for dollar. I plugged my HD518s into a Magni with a Modi 2 and the 518s sounded horrible. Makes me wonder if the HD600 or 650 would sound good with those amps. Explain to me if I'm wrong, but could it be the reason my 518s sounded so bad with the Magni is because the 518s are very efficient and driving them with an amp does something to make them sound far away and dirty? I don't know off hand what the ohms rating on the 518 is. 

 
Your HD518 should have sounded about the best it can, plugged into a Schiit stack, why it sounded horrible I'm not sure why?
Maybe the Schiit hardware was defective?
Or there was an issue with whatever source the Schiit stack was plugged into?
Maybe even defective cables?
 
The HD518, HD558, HD598 all use the same 50-Ohm driver.
I believe the implementation of the driver in the HD518 is to give it more bass, I'm guessing at the sacrifice of mids and treble.
Where as the HD598 may not have as much bass as the HD518, but everything else should sound better (mids, treble, surround sound, etc).

 

[414353]

   
Your HD518 should have sounded about the best it can, plugged into a Schiit stack, why it sounded horrible I'm not sure why?
Maybe the Schiit hardware was defective?
Or there was an issue with whatever source the Schiit stack was plugged into?
Maybe even defective cables?
 
The HD518, HD558, HD598 all use the same 50-Ohm driver.
I believe the implementation of the driver in the HD518 is to give it more bass, I'm guessing at the sacrifice of mids and treble.
Where as the HD598 may not have as much bass as the HD518, but everything else should sound better (mids, treble, surround sound, etc).

Yes, I thought my 518s would at least sound the same as always plugged into the Schiit stack, but they sounded awful. You may be right though in thinking it might have been the source. It was this tablet I could not work and it was stuck on Pearl Jam and I am assuming MP3. The hardware was not defective because I plugged a different set of cans in and it sounded fine. I know my cable is fine too, so it was not that.
 
The mid-highs is where I feel my 518s are lacking a little, but I am a little concerned about giving up bass. It will make it hard to listen to Rush and such.

 

[essasin]

I was in the same boat. I found out they are different headphones for different purposes.
 
HD600 - They are still pretty good unamped but I would prefer the HD 598 if you never intend to use an OTL amp. I auditioned them with a bottlehead crack. Very neutral and analytical from top to bottom. 
 
HD650 - They have a warmer, darker tone than the HD600 with more sub bass presence. 
 
HD598 - Excellent right out of the box. Excellent sound stage with everything else being just a notch below the HD600 + OTL amp. It is not a knock against the 598s because one could purchase (4) HD598s for the total cost of the HD 600/650 + bottlehead crack. The most striking aspect for me was the comfort of the 598s. They are seriously one of the most comfortable pair of cans I have ever put on. 
 
I hear great things about the AKG 7xx. I personally went with the fidelio x2 as they checked more boxes for my taste.

 

[414353]

  I was in the same boat. I found out they are different headphones for different purposes.
 
HD600 - They are still pretty good unamped but I would prefer the HD 598 if you never intend to use an OTL amp. I auditioned them with a bottlehead crack. Very neutral and analytical from top to bottom. 
 
HD650 - They have a warmer, darker tone than the HD600 with more sub bass presence. 
 
HD598 - Excellent right out of the box. Excellent sound stage with everything else being just a notch below the HD600 + OTL amp. It is not a knock against the 598s because one could purchase (4) HD598s for the total cost of the HD 600/650 + bottlehead crack. The most striking aspect for me was the comfort of the 598s. They are seriously one of the most comfortable pair of cans I have ever put on. 
 
I hear great things about the AKG 7xx. I personally went with the fidelio x2 as they checked more boxes for my taste.

I'm hoping to hear at least the 598s by May sometime. I'm told I'll lose bass with them. I'm not a bass head, but I want bass where it should be and how it should be in my music. (Think enjoying Geddy Lee's playing, etc.)
I don't use headphones for anything other than music so I'm not concerned with real sub level bass for movies and such.
I don't know what an OTL amp is, but I kind of want to avoid worrying about amps because I would be using the phones on different systems which means I'd have to always be moving the amp around, not something I want to be doing. I'm also not interested in those battery powered portable jobs, besides they are meant for cell phones and such, not big home systems.
 
I'm also interested in the AKG 7xx, but I don't think we will be seeing those again anytime in future. 
I tried the fidelio x2 as well and found it was pretty good, but the bass sounded loose to me and kind of added rather than natural, but still a good headphone in my opinion.
 
After May, I am giving up upgrading my phones because I have found a thread running through everything I read. That is that no one headphone is good at reproducing all genres of music. Most tend to do either only one genre well or some do maybe 2 or 3 well. I can't afford to pursue things that do not exist or get caught up in a marry go round of endless headphone looking. It isn't worth it to me just as it is not worth chasing after non-existant perfection in audio as so many audiophiles and high-end types do. For one thing it leaves no time for music.

 

[SimonPac]

I have and enjoy the HD518 and have tried the HD600. In my setup, with a Cambridge DACMagic 100 and a DIY hybrid headphone amp, I find the 518 a little shrill at times on average quality CD material when driven from a low impedance source. I suspect the driver was designed with high mechanical damping to accommodate high impedance sources, which will also impart a warmer tonal balance. To me they sound better over the longer term with a 30-plus ohm output impedance. This can be added intentionally to a solid state design, and is inherent in most valve designs.
 
Regardless of source impedance, the HD600 is unquestionably a more neutral headphone in balance than the 5_8 series. It really sounds natural, and superb on vocals. Beats the HD700 here from memory. Perhaps the 518 adds a little drama to some rock material with its mid range dip and mild bass lift. But the 600 is clearly the more even in frequency response and actually has the greater resolution in reality, assuming the source signal is right.   

 

[LEntless]

I know this is an old post, but this thread was bumped apparently..
 
Right now, my main headphones are the 598's, which I've been using since the $115 Amazon Canada lightning deal around Christmas. Prior to these, I had 555's (not unlike the 558's), for a few years; the headband crack issue finished them off. The 598's shouldn't have this issue, as it was reportedly solved early in production, years ago. I have always had an ASRock Extreme 4 (z77), with Realtek ALC898 on-board audio. The ALC898 is praised well, as far as on-board audio is concerned.
 
I listen to rock and progressive metal: Rush, Yes, Dream Theater, Paul Gilbert, to give you an idea. I will listen to classical music and extreme metal rather seldom. I never listen to pop and rap.
 
I'll mostly focus on the 598's.
 
The main thing I notice is the 598's have better soundstage, so there is more room to listen to individual instruments. These headphones are great for Rush. They are not in your face, and won't rip your face off with sub-bass, but the added soundstage allows you to nearly isolate/stem tracks pretty well, compared to the 555's. The tone of instruments are left intact and don't blend with each other.
 
The 598's also have more bass guitar definition; the 555's might have more sub bass, but the trade-off for instrument bass is much more important to me. Mids and highs are better overall on the 598's.
 
About the bass- I can listen to any Rush song on the 598's and auto fixate on Geddy, whereas I couldn't on the 555's. You can clearly hear everything he plays. I much prefer that to having sub-bass.
 
The only issue I have with these headphones is with playing fast music- they are decent, not great. Listening to fast music at a slightly lower volume helps, but these headphones are not primarily designed for fast music. No surprises here. Get grado's or similar. However, I'd imagine you'd lose some qualities that these headphones excel at.
 
The 598's are a good upgrade from the 555's. It is not completely night and day, but I cannot go back to them after using these, especially with the overall clarity boost, especially in the lower mids.
 
I also tried AD700's. They have less of a "filter", but as a result make some music sound slightly grainy. They are more in your face, and handle faster music well. Interestingly, I found that they didn't represent lower mids as well as the 598's for slower music (Rush), but faster music was better. The 598's are easier to listen to for longer periods of time. 

 

[LEntless]

Also, I wouldn't get the 598's until you see a good flash sale. That $99 USD Amazon sale was epic. If you could get them under $130 and sell the 518's, it would be a pretty solid upgrade.
 
(kind of an edit)
 
They are $150 on Amazon.com, and $113 used w free shipping on the amazon warehouse. I would snag them for $113 if there were no strings attached.