Mercury, a discrete current amplifier

Hello you all,
I'm working at the project of the pictures. It's a current amplifier with no feedback able to provide 1W to 600 Ohm load with 0,04% of distortion. It can provide till 3W with 0,08%, so it can be used also for high impedance speaker like the famous Philips 9710.
The circuit is based on two part:
  1. V-I converter
  2. 6 time current multiplier
In other words, the amplification is due a mirroring of the the original signal and this allow to the circuit a very low distortion without feedback.

Comments and advice are welcome
 

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Hello a few update:
1) As suggested by Mark added a capacitor across R7
2) replace the mosfet to IRFP9240 because it has less thermal resistance
3) increased R16 for better performance on distorsion, now estimated at 0,007%
 

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