Dave Peterson from Shere Sound now offers instruction sets for his professional AC30 modifications for little money. It covers differnt models of the AC30 and offers BIAS adjustment, power select and other modifications. For details you can visit his facebook site: https://www.facebook.com/sheresound/
All the best for 2018 from Moco and me. A few month ago we had an attack on this guide and the hoster closed our account. After a long time we could restore the guide, but some already written articles and some pictures were lost.
We hope you now can use all those information here again.