Vacuum tube amplified headphones...

@pindac ...I'd be at a loss of verbs, too....if I'd heard & verified my ES 'phones could be outdone, and without having to charge 2 small elements right next to ones' ears....  As an owner and fan of ESS amts', which also don't require a charged element, there was for a time a pair from them, the 422H.  It had strengths but weakness' that couldn't be overcome at the time (one being heavy, not surprising given the magnet structure the element requires)...that, and it had qualities one could eq out, but....🤷‍♂️  A newish effort ( I suppose, but...) that will take more time to iron out that others have the time to do so with their products...

Anything new has a 'gestation' period of sorts, enabling that sort of 'sort out'....*s*

We can DIY, but face the same sort of obstacles....

The Producer of the RH Design, is not just your average DIYer.

There are all aspects of HiFi devices produce by their hands.

DAC's, Head Amp's, Phonostages, Pre Amp's, Power Amp's and quite few Speaker Builds, and over the recent year+ a Tonearm is also produced.

A DAC built for approx' £200 recently A/B compared to a Denafrips Venus really caused the Venus owner to rethink their situation with DAC. It seems the recent Denafrips Firmware Updates has allowed the DAC owner a little more grace, as they feel there is improvement now on offer.

I think is fair to say the RH Design is buildable, but the fine tuning of the finished product is probably best left to those with a time served experience.    

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