If such amps have negative reviews, then i´d like to see schematics and circuit working points, to understand why
I see several choke benefits.
1) DCR is low (DC voltage lost on it is low - low heat. Can´t say that about resistors of mosfets).
2) For example 400H choke has only ~2k DCR; at 1kHz has reactance 2,5 Megohms.
Resistor represents same value at any freq, DC.
3) MOSFET gyrators can replace choke, but you need to use 2x anode voltage.
Amp consumption.. (choke has EMF, gyrator does not)
4) DHT or any good triode, working into
ultra high impedance, will have low THD and maximum gain (very close to µ)
(choke or gyrator are excellent)
5) Transistors like to explode - release smoke when near limits (high power peaks). Choke survives.
Example with
ideal triode stage: with choke 400H 2kDCR 15mA, you will need just 300Vsupply.
Output swing would be almost 0..600V peak (minus a little voltage lost on DCR)
To match that with MOSFET gyrator, you´ll need
600V supply, and heat lost on mosfet will be 10x of choke (~4,5W)
Supply power consumption will be 2x.
With high current-voltage stages, consumption and heat lost, will make mosfet unattractive
Choke/transformer has 2 problems, $$ and size.
Makes more sense to me, spend 250€ on chokes, than $$$ for gold usb cable