General 6550 Röhren JJ Electronic JJ Electronic Philips ECG Audio Research RCA 2A3 JJ Electronic Electron EL-34 Svetlana KT88 McIntosh KT88 Sovtek 6550 WA GE 6550 A JJ Electronic Valvo PL36 Sovtek 6550 WE V.A.L. 300B RSD EL34 Valvo EL34 Golden Dragon KT88 Röhre Ruby Tubes KT88 Hoges EL84 Siemens EL84 Audio Research Hoges EL12 375 Shuguang 300B S 6CA7 EL34 Hoges EL12 375 The Fisher 7189 Telefunken EL41 6550 Röhre Röhren 6n3C-E Svetlana 6H13C 6550 Röhre Sovtek 6550 WE Sovtek KT88 Orion EL34 6CA7 Shuguang 300B Mullard EL34 AEG EL34 Fullmusic 300B Welter EL34-S Tube Audio Bonn EL34 Röhre Valvo E84L