The Special 6 EL84 adapter reconfigures the Special 6"s 6V6 output tube socket to accept an EL84 output tube. Now Special 6 players can enjoy the earlier breakup, distinctive midrange complexity and legendary top end chime that only an EL84 can provide. The Special 6 EL84 adapter works in other 6V6 amps as well. Check with your amp tech to be sure your amp"s voltages don"t exceed the maximum ratings for an EL84.