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Here we have for sale is very nice rare set of NOS tested Mullard xf2 series EL34 6CA7 Tubes. Welded plates with the dual OO getters. Made by Mullard England and labeled for distribution by Siemens. Excellent cosmetic condition with nice intact labels and clean unused corrosion free pins. Tubes are genuine Mullard produced tubes evidenced by the B codes shown in photos. Tubes are an excellent MATCHED pair with strong even testing. Made in the famous Blackburn factory England with Date Matched codes of xf2/B3F4. 3X tested with included Amplitrex testing shown in photos. Both tubes tested with a quality/matching grade of 10 on the Divo tester again showing them as an excellent MATCHED pair. With Hickok TV-7 results shown in photos and below. Full parameter testing for Gm, Em, Gas and Shorts. Tubes will ship professionally packed in their original Siemens tube boxes and paper wrapping.
Tubes undergo dual testing procedures whenever possible. We utilize fully calibrated and modernized Hickok 539c, AVO 163 or Triplett 3444-A and Amplitrex testers. Then digitally tested and displayed on the Divo/Orange tester for its ease of interpretation by buyers. As a result, you are assured to be getting some of the finest quality, fully tested and proven vintage tubes available for sale.
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Hickok TV-7 Results
Tube 1 = 58
Tube 2 = 58
Minimum = 30
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Tubes have undergone and passed all the following testing
Heater filament test: Short circuit
Heater filament test: Open circuit
Heater filament test: Tolerance check
Heater cathode insulation: Leakage
Heater cathode insulation: Short Circuit
Tests for heater current abnormalities
Amplification factor
Voltage gain
Power gain
Screen grid test
Mutual conductance test
Dual test for double triodes
Emission
Inter electrode leakage
Inter electrode short circuit
Flash-over (arc detection, high voltage breakdown)
Gas ionisation test
*** SALE TERMS - PLEASE READ COMPLETELY ***

Please ask any questions or concerns and we will respond promptly. USA SHIPPING ONLY. Please check our other listings for more rare and hard to find tubes that are also available. All items will be very well packed and shipped the next day whenever possible. Due to the fragile and sensitive nature of vintage tubes we DO NOT ACCEPT RETURNS because of a myriad of factors including but not limited to the buyers unknown equipment condition, bias settings, misuse or mishandling etc. We will however certainly work with any buyer to address a problem that may occur such as a tube that arrives damaged in shipping. We require any buyer that encounters a problem to notify us within 72 HOURS after delivery of a pending issue. As a prospective buyer, please be aware that if you feel you can not adhere to and honor the sales terms of our listings, we kindly and respectfully ask that you DO NOT purchase tubes from us. Unless specifically stated in the listing and commonplace amongst the majority of tube sellers, we do not warranty or make any guarantees related to noise, hum or microphonics. As is commonly understood, tube testing results do not necessarily translate between different brands and models of tube testers and the different approach each manufacturer used to achieve their test results. As a result all tubes listed for sale are represented and sold on a AS-IS basis and STRICTLY off the results shown and provided by the testers used in the listings. All the testers used are some of the most respected models ever produced and are professionally calibrated regularly by top techs in the business. Calibrations are checked routinely using bogie tube sets dedicated for each tester. All the aforementioned factors ensure solid and accurate results for the tubes tested and confidence for the buyer in the vintage tubes being purchased. Therefore please let it be understood that we will not guarantee or compare the results off any other tube testers. Partial refunds or returns will NOT be granted based off claims made from unknown testers and their obviously unknown condition and accuracy. As a courtesy, every tube we sell is cleaned and treated with Deoxit to remove 50+ years of corrosion and grime.