The Sennheiser HD620s are dynamic-driver closed-back headphones retailing for 349€ in the EU. They are available in black color only.

The Unboxing experience is very basic, they come in a simple cardboard box, included accessories are a protective bag,
a one-sided single ended cable of decent size ending in 3.5mm and an adaptor to 6.35mm is also onboard and that's it.
For those how like to have a balanced cable, it can be purchased separately from the same brand at around 60€.

The built quality of the headphones themselves is ok, the most part is made out of plastic as it is typical for a Sennheiser
headphone but nonetheless they should last for a very long time. The earpads are made out of pleader and can lead to sweaty years
during the summer. Right out of the box the headphones can get quiet uncomfortable for medium to larger heads as the clamping force
is very high but it will get better over time at least in my experience. Overall the fit is not to bad after giving them some time
to settle in.

On the technical side the drivers used inside the 620s are dynamic drivers, having an impedance of 150Ω with 110dB/mW Sensitivity
they can be easily driven. From a simple Apple Dongle to a powerful desktop amplifier no issues driving them to loud listening levels however
these headphones can scale in performance when fed by higher-end amplifiers.

Sound Signature & Performance: The 620s have a mostly balanced and precise tuning with a slight hint of warmth, the bass is more
about quality than quantity, it is there, it is noticeable but far away from exaggerated. The mids & highs are were these headphones
shine the reproduction of instruments is right on point, vocals are quiet enjoyable too like with most other Sennheiser offerings.
In terms of soundstage & imaging the 620s are also performing surprisingly well for a closed back headphone.

Pairing: The 620s performed very nicely with all of my amps with both portable and desktop gear. But as already mentioned before
the better the source gear the better the performance will be. The high impedance makes it a perfect partner for an
OTL tube amp like Feliks Echo Mk2 and i found this pairing was really amazing it opened up the soundstage even further and added
airiness to the overall presentation.

Comparisons: Closed back headphones are getting considerably better lately, where a few years ago in the price range below
1k there was really not much to choose from now it is getting crowdy at around 500€ there is the Focal Azurys a very good
headphone, but to my likening i would prefer the 620s in almost every category except for the bass and the looks. Both headphones
are great for portable use with the 620s also outperforming the Azurys when it comes to Passive Noise Isolation, in fact
the isolation on the 620s is one of the very best i have ever witnessed in any wired headphone regardless of price.
Another comparison with the new "GOAT" of budget closed back headphones the Fiio FT1 retailing at around 170€, this one has
a more fun presentation and the bass is the star of the show. Both are very close in performance but also very different
so that both could coexist in a headphone collection, but if i would have to choose one of them it would be the FT1 while
for me the Fiio would exclusively be used in a desktop setup rather than a portable use.

Final Verdict: The Sennheiser HD620s is a great closed back headphone, for both desktop & on the go. There could be some
issues with fit and comfort for some, but overall it should be on the shortlist for everyone looking for a closed back
at a reasonable price.