RFT EL34 Top "O" Getter Amplitrex Tested Matched within 8% Pair

Description: These are New Old Stock tubes purchased back in the mid 1990s they are RTF and one is branded Dynaco and one is unbranded both are in a white box, they are identical mechanical Construction with the exception of the silk screen. They have been matched within 8% and were fully tested on an Amplitrex AT-1000 tube tester at operational in circuit voltages. These are very hard to find these days and in order to facilitate tight matching sometimes different branded tubes will need to be combined together in sets to achieve that goal. RFT - East GermanyPrecision matched using an Amplitrex AT-1000 to the following specifications: Standard EL-34 Test Fixed Test Conditions: Plate Volts eP1 = 265VScreen Grid eG2 = 250VBias = Auto Results: RTF - Dynaco Branded Tube Ia/ma = 104.0Gm/umhos = 11,150 RFT - Unbranded Tube Ia/ma = 101.4Gm/umhos = 10,300 (I am including the above measurements as they may be easier to correlate to other listings as opposed to the high voltages test shown below, however it does show that they maintain their close tolerances even at high plate voltages and with a fixed bias applied) High Plate Voltage EL-34-450 Test Test Condtions: Plate Volts eP1 = 450VScreen Volts eG2 = 360VFixed Bias Voltage = -30V Results: RTF - Dynaco Branded Tube Ia/ma = 49.8Gm/umhos = 6,380 RFT - Unbranded Tube Ia/ma = 48.2Gm/umhos = 5,900 How to understand the labels on the top of the boxes:Emissions in percent / Transconductance in percent (100 being to specification)Transconductance shown in milliamperes - per - volt (Multiply by 1000 to convert mA/V into uMHOs)Plate current in milliamperesAs you can see all the numbers for transconductance and plate current are matched to within 8% between the tubes indicating an excellent match even during the high voltage test.These were tested on my calibrated tube tester and are for the actual tubes that you are purchasing, however the values you might measure using your tester and or under other conditions may not match those shown in the listing and are for reference only. Tube sockets shown are simply for holding tubes for photography and the branded boxes are just for display purposes and are not included in the listing, tubes ship in white unbranded boxes.

Price: 189.95 USD

Location: Mason, Tennessee

End Time: 2024-10-18T00:26:37.000Z

Shipping Cost: 12 USD