[Time Diver]

Hello, I am new to the forums & very happy to be here!

If I may ask, when were these headphones first released?

Sennheiser HD-600 & HD-650

Beyerdynamic dt880 & dt990 600ohm versions

AKG K701 & K702

Denon AH-D5000

Of these headphones I like the sound of the dt990 and the one I never liked is the K701, I wonder what should I get next? Don't worry about my budget I am open to any reasonable suggestion

 

[cel4145]

Welcome to Head-Fi. Sorry about your wallet

Sorry. I have no idea how "old" those headphones are. If you google the make/model name for each along with "press release", you might find announcements about their initial release with a date.

Have you considered headphones like the HD800 or HE-560 as your next upgrade?

 

[Time Diver]

Everyone here seems to have or had an HD-800 at one point, I still wonder if they are really that great? Perhaps I will try them at one point but I have that strange feeling that I will not be impressed. HE-560s are somewhat lacking in build quality.

I am considering the second generation of the T1 but I don't know how does it compare to my reference point dt990 and I might not like the sound signature. I would love to try the T1 in balanced mode with the new cable and see if the new contacts are durable, I had two expensive cables for HD-6xx that failed after a short time. I thought I was safe with two cables but I was wrong and now I can't use balanced mode, anyway It was fun while it lasted.

 

[KG Jag]

Hello, I am new to the forums & very happy to be here!

If I may ask, when were these headphones first released?

Sennheiser HD-600 & HD-650

Beyerdynamic dt880 & dt990 600ohm versions

AKG K701 & K702

Denon AH-D5000

Of these headphones I like the sound of the dt990 and the one I never liked is the K701, I wonder what should I get next? Don't worry about my budget I am open to any reasonable suggestion

 
The DT 990 had a strong "V" shaped sound signature.  Generally speaking cans move closer to neutral than that sound signature as they move up their line.
 
Most all of us would have to search for the initial release information for each of these cans and/or write the company who makes/made them.  That is something you can do as easily as we can.