Siemens/RFT El34/6CA7 pair plus a spare backup (3 tubes). Manufactured during the 1970s by RFT. These tubes were Siemens answer to the Mullard EL34s and all have a distinctive “dimple” on the top of each tube. Some were labeled with the Siemens name but many were made for other tube companies. These tubes are branded International SERVICEMASTER. In the pair, one has excellent lettering and one is very good. The lettering on the spare is faint. All have full chrome tops.The pair measures 6900 gm and 6400 gm. The spare tube measures 5000 gm. Their sound is very similar to the classic Mullard vintage sound. The pair test NOS or close to NOS and very strong. The spare tests strong. All three probably had some use. Testing is done on a Weston 981 type 3 for gas, leaks, shorts and transconductance. NOS EL34/6CA7 tubes measure 6500 and above on my tester. I have established this range by testing a number of NOS Mullard and current production EL34/6CA7 tubes. The REJECT reading on my tester is 1430 gm and below. $150 for all 3 tubes. Price includes US PayPal fees and USPS Priority shipping within the continental US. Questions are welcome. R
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