E130L

The E130L, also marked 7534 in Philips and Siemens sheets, is a special-quality power tube with high transconductance. The makers present it as a pentode for wideband amplifiers, cathode followers, series regulators in stabilized supplies and output stages. Siemens explicitly adds push-pull amplifiers and transformerless output stages. Archived descriptions identify beam-forming plates in place of a suppressor grid; the sheets’ pentode terminology and the archive’s beam-tetrode classification thus describe different aspects of the same tube. Its glass bulb has an octal base and an anode brought out to a top cap.

The indirectly heated heater requires 6.3 V and 1.7 A with parallel AC or DC supply. Philips gives an initial range of 1.62–1.78 A; Siemens specifies 1.7 ±0.1 A. The Siemens sheet from 1960 gives approximately 110 g weight and any mounting position; the 1968 Philips sheet gives maximum bulb diameter 39.7 mm and base diameter 43.7 mm. Photographs show metal fins at the top of the system, described in our sources as control-grid heat dissipators. This is a construction detail consistent with a power tube, without by itself implying additional electrical performance.

One characteristic point uses anode 250 V, screen 150 V and control grid −15.5 V: anode current 100 mA, screen current 4 mA, transconductance 27.5 mA/V and internal resistance 10 kΩ. A separate test circuit uses a 275 V anode supply, 180 V screen supply, +15.7 V first-grid supply and 300 Ω cathode resistor. The positive figure refers to the supply, not grid–cathode voltage. In this circuit initial anode current is 85–115 mA, transconductance 22.5–32.5 mA/V and screen current no greater than 6 mA. Without an external shield the stated input capacitance is 35 pF, output 17 pF and grid–anode no greater than 2 pF.

Audio use is documented with complete examples. In class A, with anode 250 V, screen 150 V, −15.5 V bias and 2.7 kΩ load, Philips gives 11.5 W output at 10% distortion with 3.82 V RMS input. For a pair in class AB, anode 300 V, screen 150 V, −17 V bias and 1.6 kΩ anode-to-anode load, the stated output is 60 W at 5% distortion. In the latter example anode current rises from 2 ×80 mA at idle to 2 ×182 mA at full output and screen current from 2 ×2.5 to 2 ×22 mA. These powers belong to those particular regimes and are distinct from maximum dissipation of one tube.

Long life is described with explicit conditions and criteria. Philips performs 10000-hour tests on production samples in the circuit with a 300 Ω cathode resistor; end-of-life criteria include a 40% reduction in anode current or 30% reduction in transconductance. Siemens states life above 10000 hours and resistance to at least 2000 on/off cycles, one minute on and one off, tested with a 7.6 V heater and 125 V heater–cathode voltage. These are test conditions, not nominal supply. Philips documents 500 g shocks and 2.5 g vibration at 50 Hz for 32 hours in each of three positions, separate from normal use. Accurate heating remains essential to the stated life.

Philips absolute limits include 900 V operating anode voltage, 27.5 W anode dissipation, screen 250 V and 5 W, continuous cathode current 300 mA and bulb temperature 225 °C. In triode connection, with anode and second grid joined, voltage is limited to 250 V and combined dissipation remains 27.5 W. First-grid resistance is limited to 0.5 MΩ with fixed bias or 1 MΩ with self-bias; cathode–heater voltage to 200 V with the cathode positive or 100 V with it negative. Pulse regimes are separate: 1.5 A cathode current for up to 4 ms with a 150 mA maximum average, or 4.6 A for up to 1.5 µs with a 14 mA maximum average. Reading the datasheet therefore requires distinguishing continuous quantities, peaks and circuit configuration.