EML 300B

Guarantee

The first owner can register the tube at the Emission Labs website, to participate in the 5 years guarantee program.

With this tube we have taken the legendary 300B in production. All critical parts, like grids and plates are constructed of hard metal for higher reliability and reproducible quality. This tube is a direct replacement for the WE300B, and features a center tapped filament as well. (See Note6)

Sound Character of the 300B tube

For the sound character of the EML 300B, we mainly refer to the original NOS 300B, as made until 1988 by Western Electric. We regard this tube the reference. Generally speaking, the 300B has not such extreme high requirements to the speaker system as for instance tubes like the 45 will have. This makes the 300B sound more predictable, and harmonic distortion is the most important parameter. The original WE Data sheet (full version) gives several pages with distortion tables, which speak clearer language than the text here. The result is though, in practical situations, a 300B tube will produce small but noticeable distortion depending on amplifier design and load conditions. Due to the lack of odd harmonics, this distortion is often experienced as sharpness, less transparency and imprecise bass. Also there is no amplifier in the world that can combine highest output power with lowest distortion. So the compromise is either on distortion or on output power. So far this is general for all brands 300B. At EML we have contributed to the best 300B sound, by extremely low hum and distortion of our tubes. This was done by a new filament construction. They are featuring a real, physical filament center tap, positioned far outside of the plates, but inside the glass bulb. The result is, we reduce the hum level of our tubes, even below that of many NOS tubes. The gold grid we use, is giving most stabile bias also under harder conditions, and good matching between two tubes of a pair is guaranteed like this over time.

In speaker systems where lower power is needed, you will see the EML300B has a great ability to play gently at low volume as well, at lowest noise and hum level, award the low power use with a clean and dry bass, and highest transparency. The glass bulb size has been reduced, to minimize acoustic feedback. The tube base is attached with soft rubber compound, minimizing mechanical chassis noise coming inside the tube.

Example of good transformer:

LL1623-90mA (Wire secondary for ALT B, C, D for : 4, 8, 16 Ohms in this order)

Features

• Gold plated Grid. (Note 8)Center tapped filamentSoft rubber suspended tube base4 circular cooling plates Hard metal Construction (Note 1) 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.)

• Note 1) 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.Note 2) 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 TagNote 3) Plate Curves: Made with the Sofia Digital Curve tracer. Plate curves with courtesy of AMRNote 4) We are recommending the same values as Western Electric in their 1950 Data sheet.Note 5) 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.Note 6. Some of our competitors claims to be the only one with a center tapped filament, but this is not true. At EML we build since many years all triodes center tapped, not just the 300B.
  Note 7) 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.
  Note 8) Gold plated grids have a few advantages, such as increased bias stability, some protection against accidental overload, and better linearity of tube curves.
• Note 9) The curves for the 300B are plotted, with AC heating. This is in accordance with the historical WE data sheet.