The iESL is about as good as an srd7mk2 from what ive been told, but much more feature rich and can be bought new. It also has an advantage with normal-bias cans due to the way the bias circuit works which makes some cans that would otherwise have an imbalance, not have an imbalance since it charges the diaphragms evenly even if the coating on one is worn off, or something.Good info!.
I checked, in Japan is quite cheap the SRD7
I flight from time to time there, so I'll have present your recommendation.
The ifi eESL model looks good. Is a clear step over the Stax offers?.
Sometimes I'm tempted to sell my SR-007MkII/SRM-727 and go for some great non-electrostatic headphone. At least, it would be very cheap to get a great amp for it. But the detail... the Stax sound is so .... god.
BTW I made (well, paid for) the Spritzer mod in the SRM-727, and definitively was better after it.
For that price range I'd rather go for a unit that uses beefier transformers, tho you typically have to have those custom built and it's not as simple as clicking buy on an order page or auction.
And yeah, I don't think there's anything that beats Stax on detail.