Siemens ECC83 RSD EL34 AEG EL34 Philips ECG National 6922 Gold Aero 6922 Philips ECG AEG ECC83 Pair Orion EL34 6CA7 Valvo ECC83 Electron EL-34 General 6DJ8 tube pair Telefunken EL84 EAT 300B tube Philips Siemens ECC82 Valvo PCC88 Siemens EL84 Valvo ECC81 Svetlana 6H13C RSD EL84 Valvo AZ1 Philips E88CC Electro Edicron EL84 Siemens RS 1029 Audio Research GE 6550 A General Philips ECG Telefunken Sovtek 6550 WA Philips 6CG7 Ultron ECC82 Hoges EL12 375 National 6922 ECC82 Tube E88CC Tubes RFT EL34 Welter EL34-S Electro KR Audio KT88 Telefunken Fullmusic 300B Orion EL34 6CA7