THD 0.00045% and 15 Watt

I built this last year for my SX3700.
2 changes are 47k resistors instead of constant current and IRF240 and IRF9140 biased at 6v. I also added 1n4148 on vas to fix clipping . Sounds great good to know distortion is this low. I am using 9.1k// 1k feedback ratio gain of 10.1 .
 
Seems I just have some parts for 'Hitachi', but some of these can be fake ones.
 

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