I think you need very high percentage of silver to get the sonic effect. Apparently soft annealing and some kind of crystal formatoin is also important
Order from Audionotekits Canada, the kit price is USD$1599, shipping fee around USD$175
Just go to their web site for price details
www.audionotekits.com
I also ordered some upgarde parts, such as copper covers for the output transformers, some matached tubes, tantalum resistors, ROE resistors and Jensen silver wire.
The upgarde parts cost around $5000 ~ $6000