Having had my MF A3 Dual Mono Pre amplifier upgraded in 2019 by John the difference in sound quality was immediately noticeable and improved even more over time. In the search of sound perfection John had also suggested at the time of upgrading my MF A3 power amp to increase the quality even more. The word “spectacular” was sown and stuck with me… move on and 2 years later… I bit the bullet and went for the stage 2 upgrade. Coupled with Monitor Audio Gold reference speakers I just cannot believe the depth of sound, the bass and tone across all the ranges is incredible, I have purposely waited three months before writing and again over time the sound just continues to improve, and is way beyond my expectations. .JS Audio truly have delivered “Spectacular” in every way. Thank you so much.