This tube is a direct replacement for the Western Electric E300B as build until 1988. Glass height and diameter are the same.
Guarantee program for first owner.
At EML we have the normal guarantee. In addition to that, the first owner can register the tube within 4 weeks after receival, at the Emission Labs website, to participate in the 5 years guarantee program.
- Gold plated Grid (Note8)
- Soft rubber suspended tube base
- Hard metal Construction (Note1)
- Two extra large getters
- Hand blown Glass bulb
- Anti-microphonic plate- and grid suspension
- These tubes are shipped in a high quality dual box
- Tube printing with real gold (metal),red color is glass burned into the glass
- Machined, solid tube base pins for highest contact precision. YAMAMOTO tube sockets highly recommended.
- Gold plated pins,black ceramic socket.(White bottom.)
Sound Character of the EML 300B
It is the most asked question, and for this we refer to the one and only genuine 300B, as made until 1988 by Western Electric in the Hawthorne plant in Cicero, Illinois, USA. (So definitely not the later USA made replicas under WE brand, from 1997 onwards).
The 300B tube has less interaction with the speaker system as smaller tubes like the 45 will have. This makes the sound character less dependant on the speakers, and for that reason quite dependant on the tubes itself. We see 300B often used with medium efficiency loudspeakers. Meaning, the tube often needs to work relatively hard, which is indeed what it is designed for.
However, a Single Ended, no-feedback amplifier can not combine highest output power with lowest distortion. The user often comes into a situation where relatively high output power, still requires relatively low distortion. Moreover, distortion should increase as little as possible, during the aging process, and lifetime should be high by itself, even though this tube is loaded often quite hard by the amplifier. All in all, these are not the easiest specifications for a tube in general.
At EML we have contributed to this, by extremely low hum and low distortion of our 300B tubes, over the major part of the lifetime. This is done by our unique filament and grid construction, featuring a real, physical filament center tap, positioned outside of the grid, but inside the glass bulb. We use not only gold grid wire, but we completely gold plate the grid, after it is made. The clean, gold plated surface increases bias stability, and good matching between two tubes of a pair stays constant like this over the full lifetime of a pair.
We have two versions for the heater: Normal heater, or Center Tapped heater.
EML 300B Filament Ratings
Filament Voltage = 5 Volt (AC or DC) Tolerance on filament voltage 4% Filament Current ~ 1.3 Ampere
EML 300B Maximum Conditions Plate Voltage 350Volt Plate Current 70mA Plate Dissipation Continuous 17Watt
Highest possible Grid to ground resistor, Single Ended.
Highest possible Grid to ground resistor, Push-Pull.
EML 300B Factory Test conditions Plate Voltage 300V Plate Dissipation 17Watt Plate Current 56mA Grid Voltage -58Volt DC Plate Impedance 700 Ohm Amplification Factor 3,9 Transconductance 5.6 mA/V Grid Voltage matched Transconductance matched
300B Recommended Single Ended operating points. Other choices are possible.
Plate Current (ma) Plate Rp (Ohm)
350 -74 60 720 2000 21 10.2 21 350 -74 60 720 3000 21 8.3 26 350 -74 60 720 4000 21 7.0 30 350 -71 80 640 2200 28 9.6 26 400 -74 60 720 3500 24 10.5 26 400 -74 80 720 2500 32 12.5 25 450 -100 60 780 4000 27 12.5 26 450 -100 60 780 5500 27 10.0 30 450 -98 73 720 2000 33 16.2 21 450 -98 73 720 3000 33 13.2 25 450 -98 73 720 4500 33 10.5 30 450 -97 80 700 2000 36* 17.8 21 450 -97 80 700 3000 36* 14.6 26 450 -97 80 700 4500 36* 11.5 31
* Lifetime gets less at 36 Watt dissipation, regardless of the tube brand. For best lifetime, it is recommended to stay below 33 Watt. For highest output power and no compromise with lifetime or distortion, it recommended to choose the 300B-XLS.
Choice of output transformer impedance: For each working point, a wide range of primary impedance is possible. When using a transformer of another value, you can estimate the output power and distortion by averaging between two rows of this table. Example: 450V, 60mA. Use of Lundahl LL1679-70mA (4k5 type). This will give you appr. 11.5 Watt @ 27dB 2nd harmonics. (28dB distance of signal to 2nd harmonics.
EML 300B tube curves. See Note 3
Some recommended Lundahl transformers
Auto Bias Cathode resistor
Plate Current Plate Voltage to ground LL1623-090mA
3000Ω Alt.B = 4Ω
Alt.C = 8Ω
Alt.D = 16
750 Ohms 80mA 435V
3000Ω 8Ω 750 Ohms 80mA 435V
EML 300B Mechanical Data
Size including Socket
(but excluding pins)
148 x 65 mm
Pin 1: Heater1
Pin 4: Heater2
Pin3: Anode (Plate)
Weight of one tube:
Shipment weight for pair in gift box:
Note1) Hard-metals can be used in electron tubes, though these are more difficult to use, and more costly than the classical nickel. Hard metal plates have a more precise plate distance, and do not change shape when heated, or at mechanical shock. This ensures reproducible tube parameters, and long term stability. Wolfram grids allow the most precise grid wire distance, because wolfram is an extreme hard metal. Best grid geometry ensures uniformity and linearity of the tube curves.
Note2) Individual Test data, such as: Matching Data, Grid Current, Vacuum, Filament Current, etc., are on the Certificate that is on the outside of the tube box. Each tube is numbered from the inside, with a metal Tag
Note5) The Western Electric 1950 Data sheet. says 36 Watt maximum dissipation. Later data sheets say 40 Watt. Though 40 Watt is possible, this is a peak value only, and no normal working point. When you intent to get the "maximum" out of a 300B, and operate this tube at the limits of safe operation, it is a better idea to use the 300B-XLS in such a case.
Note7) Don't experiment with lower filament voltage, to expect better lifetime. If it was that easy, we would make them like this ourselves. The specified filament voltage is the one for best lifetime.