RFT EL34 Dynaco Branded Top "O" Getter Ampletrex Tested Closely Matched Quad NOS

Description: These are New Old Stock tubes purchased back in the mid 1990s they are RTF branded Dynaco in their original white boxes as I received them. Beautiful red Dynaco silk screen. They have been tightly matched 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.In this case, they are all the same! RFT - East Germany Branded Dynaco Precision 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: Tube #1 Ia/ma = 104.2Gm/umhos = 11,050 Tube#2 Ia/ma = 105.6Gm/umhos = 11,160 Tube#3Ia/ma = 103.8Gm/umhos = 10,310 Tube#4Ia/ma = 105.4Gm/umhos = 10,750 (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: Tube #1 Ia/ma = 51.3Gm/umhos = 6,490 Tube#2 Ia/ma = 53.1Gm/umhos = 6,640 Tube#3Ia/ma = 51.4Gm/umhos = 6,360 Tube#4Ia/ma = 49.6Gm/umhos = 6,200 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 milliamperes As you can see all the numbers for transconductance and plate current are very tight 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 are not included in the listing.

Price: 449.95 USD

Location: Mason, Tennessee

End Time: 2024-09-03T23:22:12.000Z

Shipping Cost: 20 USD