New Plate Current Tested Electro-Harmonix EL84 (6BQ5) Vacuum Tube Finally, an Electro-Harmonix version of the EL84 power tube. Expect them to take the heat in AC30 amps. Electro-Harmonix says this about their tube; "The EL84EH tube faithfully recreates the classic Mullard design. Tri-lam plate material and selected screen wire increase thermal dissipation. The EL84-EH tube is a remarkable reproduction of a vintage tube that is capable of maintaining its sweet and musical tone under any voltage conditions." Tubes are tested and/or matched at full operating voltage with regulated power supply on a Maxi Matcher tester for general mutual transconductance (Gm). In addition, power tubes are tested/matched by plate current (Ip) and preamp tubes are tested/matched by gain. Rectifier tubes will be tested for emissions on a calibrated military grade tube tester. Our goal is to match within 5% with an upper limit of 15% (15% is the industry limit to consider a set). They will be matched by the same parameters (Ip & Gm) but to the manufacturer's standards. Factory testing will be indicated in the item title and description.