[Plieb]

Doesn’t mean they are a disaster with solid state amplifiers…

No but they do sound a bit subpar on those linear amps with no character. The s2 is much more forgiving on those amps. They even sound half decent on thx amps.
The 600 sounds very nice on my tube like class A Rebel amp. In comparison they lack transparency though. The s2 is more liquid. The 600 has a bit more favorable timbre. I also appreciate that the s2 has slightly reduced mids which i think gives it a bit more breathing room and sound stage vs the 600. But its definitely not V shaped.
Just my opinion

 

[marekm]

I am certainly enjoying my HD660S2 with Lake People G103 MKII

 

[frkasper]

After learning the only-start-evaluating-after-the-ears-get-adjusted-to-the-transducer trick, this hobby became way easier to me.

Having said that, the HD600 is still the easiest to recommend to newcomers. But it is the HD660S2 that gives me a better experience in the long run.

Cheers.

 

[Quadfather]

For whatever reason, Sennheiser HD660S2 is delightful on Lotoo Paw 6000. I actually think HD660S2 sounds best on it. I also own Lotoo Paw Gold Touch and I prefer P6000 with my Sennheisers.

 

[Shane D]

I was comparing 660S2's to my Grell OAE-1's and they are complimentary. Two interesting versions of a lot of jazz today. Any song I liked on one headphone, I enjoyed on the other. The OAE-1's made the S2's sound a little "thin", which they do to every other headphone I have.

A lot of great jazz today!

 

[JonM78]

Also I think the reason the pads flatten over time is because of friction with the skin, not really because of the exerted pressure. I think the friction weakens the material and over time it loses density. Then the material kinda compacts, I could be wrong though.

It's the foam that gives. That isn't making direct contact with your skin, the velour is. The foam is just like a metal spring. It's fine initially but the more you compress it over and over through time by taking the headphones off and on, the foam starts to give and maintain it's compression. That's why the only thing you can do is buy replacement pads.

 

[drummerman1]

I was comparing 660S2's to my Grell OAE-1's and they are complimentary. Two interesting versions of a lot of jazz today. Any song I liked on one headphone, I enjoyed on the other. The OAE-1's made the S2's sound a little "thin", which they do to every other headphone I have.

A lot of great jazz today!

And that perhaps is the way to look at this headphone. Different/complimentary ... an interesting alternative rather than a direct comparison?

 

[Plieb]

One of the characteristics i love about the s2 is it's superior transparency. Especially compared to the other models in the 600 series family.
To my ears it's as if you can hear through the music. Extremely lucid sounding.
Not enough people talk to that aspect about this phone
Using with singxer sa1. Great pairing.
Update...
Even better with my Rebel Amp. The lushness and detail really stand out on this combo. Was going back and fourth with sa1 but Rebel takes more advantage of s2's assets.

 

[Digital Enigma]

Giving them a second chance now I have a lot more gear to pair them with.

 

[Digital Enigma]

With the 660S2 there’s a bit of an edge in the treble somewhere around 5-8khz that I’ve found a bit harsh coming from a long time owner of the 650. With a combination of schiit vali 3 and RCA 5670 tube it has smoothed it over and added a slight warmth to the mids. At this stage I feel like I have a 650 that is clearer and has faster transient response, very happy with the synergy I have achieved with this set up.

Sennheisers new sound seems to highlight this brilliance region a bit more than in the past 600 models. 620S just has too much of this new treble bite that I’m not a fan of so I did not keep that headphone for long. With 660S2 though I was able to tame it to a point I’m content and is here to stay.

Side note - the packaging box is unacceptable for a headphone of this price, mine came crushed and dented in multiple places with no protection on the inside so I’m surprised it’s in one piece. A soft thin bag is not good enough. HD650 came in a hard black hinged box with dense foam and is lovely when used a storage case. I expect to see better packing for premium headphones in the future, no excuses.

 

[kman1211]

With the 660S2 there’s a bit of an edge in the treble somewhere around 5-8khz that I’ve found a bit harsh coming from a long time owner of the 650. With a combination of schiit vali 3 and RCA 5670 tube it has smoothed it over and added a slight warmth to the mids. At this stage I feel like I have a 650 that is clearer and has faster transient response, very happy with the synergy I have achieved with this set up.

Sennheisers new sound seems to highlight this brilliance region a bit more than in the past 600 models. 620S just has too much of this new treble bite that I’m not a fan of so I did not keep that headphone for long. With 660S2 though I was able to tame it to a point I’m content and is here to stay.

Side note - the packaging box is unacceptable for a headphone of this price, mine came crushed and dented in multiple places with no protection on the inside so I’m surprised it’s in one piece. A soft thin bag is not good enough. HD650 came in a hard black hinged box with dense foam and is lovely when used a storage case. I expect to see better packing for premium headphones in the future, no excuses.

I have noticed that about the S2 myself, but for me it was the relaxed upper mids/lower treble that bothered me the most and that made the 5-8khz region stick out a bit more. I also had problems with the HD 650 which I didn’t have with the HD 600 or the HD 6XX. I oddly found the HD 650 and HD 6XX different, moreso in presentation and subtleties rather than FR response. This could be unit variance, but I gather there is some slight rear driver foam differences between the HD 650 and Hd 6XX which may also account for the subtle sound differences. The HD 650 has a more liquid sound but also a bit hard in the upper mids to me to my ears, the HD 6XX was more akin to a warmer HD 600 and didn’t quite have that liquid syrupy sound of the HD 650 and had a slightly more crisp and dry sound like the HD 600. I feel the S2 was the best of the Hd 6xx line in the lower half of the spectrum and there are other things I really liked about the S2, but sadly it was its upper regions that caused me to let them go. The HD 6XX ended up my favorite of the line as it mixed what I liked most about the HD 600 and HD 650.

I do have the HD 620S, but it does have a slightly too strong of an edge on the treble and I found fiddling with the fit does help with this though and have been able to mostly address it by wearing it a little tighter; the upper bass is a tad lean though so it’s not quite as full sounding as the open HD 6xx line. For me I found the Azurys especially with a different cable sounds more akin to a closed-back HD 600/650 than the HD 620S as the Azurys has a tamer treble, present full mids/vocals, and the fullness of the upper bass.

 

[Gintaras]

Question for Senn 6xx lovers club: if you had the opportunity to buy brand new, sealed in the box straight from the Senn factory, HD660s2 or HD600, which would you choose?

 

[drummerman1]

Question for Senn 6xx lovers club: if you had the opportunity to buy brand new, sealed in the box straight from the Senn factory, HD660s2 or HD600, which would you choose?

58X Jubilee

 

[pietcux]

Question for Senn 6xx lovers club: if you had the opportunity to buy brand new, sealed in the box straight from the Senn factory, HD660s2 or HD600, which would you choose?

HD660S2

 

[Gintaras]

58X Jubilee

there is no offering from Senn factory for 58x