I have a amplifier with 2 tube 7537, the equivalent is 572B ??? TNX and 73 de IZ2AAJ Oscar -- FAQ on WWW: http://www.contesting.com/ampfaq.html Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: owner-amps@contesting.com Search: http://www.contesting.com/km9p/search.htm