Vacuum tube amplified headphones...

We can concur on that...let them 'rub off the rough edges', prior to letting us 'beta' their product with our whines 'n times spent looking askance at their product in hand....

"They're almost perfect....But..." *L*

"If they'd Only..."

Ad absurdum...

The schemes of mice, men, and related critters... ;)

I still think an amt 'phone could fly, but they'd have to get the weight down; open-backed, as they're an omni at their best.  And, imho, look into whether that amount of magnetic field would affect ones' head over time....

All the iron in ones' blood being pulled into ones' ears....(I'm only kidding, But..) *L*🤪 

Anyway....off into my day, perchance to dream 'n scheme...

They sound interesting.  I’m not gonna read through all this and a HUGE pet peeve of mine is when I have to search for how much a damn product costs.  Please advise.  ARGH!!!

@soix .... 

Re the board & chip in the K/S 'phones...

Korg is a big concern in Asia....some have issues 'bout that but, it's a competitive world these days....and there seems a lot of new 'phile activity going on there....

Here in the West, the market is kinda....'flat', to borrow a musical term... ;)

As for the AKG and the ESS 422s'....eBay maybe....used, hopefully not abused....

Hope that helps... J

A Japanese Audio Designer known as Dr Kaneta, who is also responsible for making the Kaneta Technics SP10 MkII a realised design, of which quite a few have now copied on other TT's, is also an advocate of the Korg Nutube.

Nelson Pass is using the device as well, and a search will discover other Audio Devices have it in use in a Circuit.

When the Harmonic Ring is brought under control this little box of delights can really hit a home run.

In use the Nutube, is a Substitute for another Valve Type, that when used for certain roles would detach the Bass Driver from its chassis due to the distortion produced. The Nutube moves that distortion quite higher up the frequency, hence avoiding the impact on the Drivers. 

The Nutube Harmonic Ring is successfully being brought under control and inaudible, there are methods reported through users that clearly explain the methods used.

The Nutube is reported by the Manufacturer to have a 30000 Hour working life.

I would assume it would be a proportion of this working life, is the optimum working life, and it is not known to me if there is a fall of in sonic qualities after a certain amount of usage hours. This is a much improved working life when compared to typical Vacuum Tubes.