I was persuaded by John after telephone call that he could improve the sound of my A-100, via an upgrade. I was just looking for a service plus a few minor repairs. I was persuaded reluctantly to go down the upgrade route, despite the cost. However, the results have been quite startling. The amp has retained its very fluid natural sound that in was renowned for, but as running in there has been as huge improvement in the the bass, being more taunt than before with much more punch. Added to this, and I did not think this was possible the amp is even more open and transparent. John certainly knows his stuff!

Neale Cockwell