I’ve owned two MF amps , the m6i , then upgraded to the m8500s , I found the sound of the m8 to be very clean, low distortion/noise and with endless authority and I thought I would keep this amp forever, £5k is an awful lot of cash for an amp and I thought this was the best I could get within a reasonable cost. I’m always looking to upgrade my system though but I don’t like changing things for the sake, I’ve got a reference dac and streamer already and looking around I found JS audio on the net, and found his MF upgrades. Ive been toying with the upgrade idea , but Having an engineering background I didn’t like what I heard from other up graders , so decided not to do it. However talking to John it’s very clear he is an expert and has years of experience in the industry, on the back of my conversations with him I decided to have him upgrade my precious M8. I’ve had my amp back from him for two/three months now after a full stage two upgrade. The results are brilliant, the amp now seems to have virtually no noise, it has much more resolution, mid range is much better and more forward, it has savage relentless power and authority now. The upgrade wasn’t cheap but you get what you pay for and I would recommend this upgrade to anyone wanting a high end, big power amp but doesn’t want to pay £20k for it. Absolutely awesome, thanks John.