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Siemens 12At7/Ecc81 Matched Pair Tested With Roetest V10 New/Nib Long Plate!

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Seller: valtek_2005 ✉️ (16,124) 100%, Location: Bucuresti, default, RO, Ships to: WORLDWIDE, Item: 255525865208 SIEMENS 12AT7/ECC81 MATCHED PAIR TESTED WITH ROETEST V10 NEW/NIB LONG PLATE!. SIEMENS TUBE 12AT7/ECC81 MATCHED PAIR  BY CURVES  TESTED WITH ROETEST V10  NOS/NIB    LONG PLATE!     
Tested with Roetest V10, "the Rolls Royce of tube testers" [emissionlab quote], a wonderful german professional system for testing tubes, it shows everything about a tube.          You are looking at a matched pair of NOS ECC81  , best selected by curves using Roetest V10 professional tube testing system, the best tube tester that exists now, a wonderful device.

If you have experience in the field of tubes you can find in the photos and in the details below the testing / sorting procedure and all the results, and if you do not have the necessary experience to understand what is explained you can trust that we deliver only very good tubes.

The best method of selecting tubes in pairs is to overlap the G1/Ia curves, the superimposed curves show us that the tubes have the same plate current and the same transconductance in the whole operating range. One point matching method used with analog tube testers is a pretty good compromise solution, but identical tubes at one point can have big differences at higher or lower currents, testing in 20÷50 points with these devices and drawing curves take hours for each tube.  Roetest does this quickly and with great precision.

 This is the best way to select pairs, based on overlapping curves. The tubes meet datasheet specifications, first the quality tests – filament test, shorts test, gassy test (Ig1, vacuum factor, Ia variation with 1M2 grid series resistor), kathode isolation (leakage to filament), then quantity tests – value of current for plate, kathod, G1, value for transconductance, gain, G1 curve, Ia curve etc., all results for these tests can be seen on te datasheet delivered for each tube.   

Please allow for the following shipping times:

EU countries: 5-8 business days, on rare occasions a few days more USA: 10-15 business days, on rare occasions more South East Asia (Japan, Singapore, S. Korea, Hong Kong, Taiwan etc) 10 business days, on rare occasions more India, China, Russia, Kazakhstan, Pakistan, Indonesia, Malaysia, Thailand, Australia, South Africa etc: at least 15 business days, but frequently around 25 business days   Please note that shipping cost is calculated at average. If you have any objections please contact me for a specific quotation.
  • Condition: New
  • Brand: Siemens
  • Type: NOS Tube
  • Tube Type: Vacuum Tubes
  • Product Type: Tubes
  • Model: 12AT7/ECC81 MATCHED PAIR

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  •  Popularity - 8 watchers, 0.0 new watchers per day, 710 days for sale on eBay. Super high amount watching. 4 sold, 3 available.
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  •  Seller - 16,124+ items sold. 0% negative feedback. Great seller with very good positive feedback and over 50 ratings.

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