The MESA EL34 STR 447 is our very best overall EL34. It is a premium grade, NOS (New Old Stock) equivalent and our tube of choice in the production of all new Mesa EL34 powered models. It has a traditional EL34 tone & feel that is very urgent and aggressive and is an excellent choice for all styles of gain, especially classic rock, alternative rock & metal. This tube is true to the crown with focused low end, crushing mid range crunch and crystal-like highs. This is one of our favorites for authentic British tone. Excellent structural quality provides exceptional consistency and reliability.
We test and match our tubes while under the stress of actual operating conditions, to the tightest, most demanding specifications in the industry with our proprietary aerospace-designed tube analysis system called Robotube. Only the absolute FINEST tubes are excepted. And then, as evidence, are backed with the best warranty in the business for a minimum of six months! Testing and Matching capacity is where confidence and true value come in. In the case of any MESA tube, you can install with complete confidence of guaranteed premium performance from the world’s leading designer of custom, hand-wired amplifiers.
Please note: It isn't uncommon for a grid leakage indication to appear when testing EL34s in certain tube testers. This does not indicate a failed condition for a guitar amplifier. Not all tube testers test for parameters relevant to a tube guitar amplifier.