FOR SALE;ONE USED TUNG-SOL JAN-CTL 6188/6SU7 TUBE. THIS TUBE HAS BLACK PLATES, EXTRA SUPPORT RODS, 3 MICA AND D GETTER. THIS TUBE WAS TESTED ON MY TV-7 D/U TESTER THAT WAS CALIBRATED BY DAN NELSON.THE TV-7/DU MINIMUM RECOMMENDED VALUE FOR THIS TUBE IS 30/30 @ 750/750 micromhos. THIS TUBE TESTED 39/44 @ 975/1100 micromhos. DOMESTICBUYERS/INTERNATIONAL BUYERS, IF YOU WANT YOUR PACKAGE INSURED PLEASE ADVISE AND WAIT FOR AN INVOICE. I USUALLY SHIP 1 to 2 BUSINESS DAYS AFTER PAYMENT. Read my feedback! I pack and ship to you, the way I would want you to pack and ship to me. I strive to ensure your entire buying experience rates 5 stars.Questions?? Please contact me BEFORE bidding! *The pictures are a major part of the description. *Payment to be received within 2 days of the auction.*All tube test results are guaranteed to be accurate however no warranty is expressed or implied as to how tubes will perform in any audio application. PLEASE CONTACT ME BEFORE LEAVING ANYTHING BUT GOOD FEEDBACK.

GM Measurement: 1700/1700 micromhos 106%/106%

4 NIB NOS Sylvania 6188 chrome dome tubes Made in the U.S. and of vintage 1980 production. The 6188 tube is a high-tolerance military version of the 6SU7/6SL7. Very good testing and great sounding tubes! Appear and test to have never seen use. Free from gas or shorts. Listened in circuit: All are quiet with no noise or microphonics. All four have the same date codes: 8026 AAX. Packed in May, 1980. Round plates. 3 holes per plate. Clean pins and glass. Top, disc getters. Excellent gettering. Tight bases with no cracks. Center keyways intact. Dual-tested on a calibrated TV-7D and at real operating voltages on an Amplitrex AT1000 in fixed-bias mode. Tubes ran-in 10 min ea. before tests to ensure stability. TV-7D test results: Tube 1- Gm: 60/58. Tube 2- Gm: 53/59. Tube 3- Gm: 50/54. Tube 4- Gm: 54/48. Minimum is 30. AT1000 test results: Tube 1- Gm: 1700/1600 µmohs. Ip: 2.1/2.0 mA. Tube 2- Gm: 1500/1700 µmohs. Ip: 1.9/2.2 mA. Tube 3- Gm: 1400/1600 µmohs. Ip: 1.7/1.9 mA. Tube 4- Gm: 1500/1400 µmohs. Ip: 2.0/2.0 mA. Minimum good 6188 tube per section- 1040 µmohs, 1.4mA. Nominal, new 6188 range, per section- Gm: 1500-1600 µmohs. Ip: 2.0-2.3 mA. Test parameters- 250v plate, -2.0v grid bias. In conclusion-? 4 NOS NIB & quiet Sylvania 6188 tubes. An excellent addition to anyones collection! Full refund of the returned tubes if you are not satisfied. All items are 100% guaranteed to arrive as represented for 30 days upon arrival. I offer a full refund if you are not satisfied. Weve been selling vintage electronics since 1999 with perfect ebay feedback and many happy, satisfied customers. All items professionally packed to arrive safely with no extra handling costs. Our mission is to offer quality-tested tubes to make you happy with your purchase. Terms & Conditions: Payment must be received within 3 days of sale date. Items described to the best of my ability. Shipped by U.S. Priority Mail. If you have questions, please contact us BEFORE purchasing. Thank you!

Electrically and physically matched pair of 2 vintage NOS/NIB JAN Philips ECG 6188/6SU7GT vacuum tubes made in USA. Electrically tested using a calibrated Sencore MU150 Continental II Vacuum Tube tester. These tubes test AS-NEW and have never been used. Due to the nature of vintage vacuum tube electronics, these tubes are being sold for parts AS-IS and will be properly packed for shipping. Please check my extensive feedback rating for confidence.