Try the following links:
Europe and Asia:
JAC-Music
Horber Steige 25, D-72172 Muehlheim, Germany
Tel: 0049-7454-406777 Fax: 0049-7454-406888 Mobile Cell: 0049-175-5382641
http://www.jacmusic.com
USA:
AMR, contact: Bob Ungemach, 700 Verdant Drive, Elm Grove, Wisconsin 53122 USA
Tel: 262-827-9800 or Fax: 262-827-0876
Hope this helps, great tubes by the way.
Regards, Richard