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Emission Labs EML300B-XLS Matched Pair

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Emission Labs EML300B-XLS Matched Pair

Regular price $1,052.00 USD
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Almost same standard as WE300B

Easier than standard 300B to reproduce the required loudness


This tube features the classic grid construction and tube curve of a 300B.However, the vintage 52B has a stronger anode structure and larger glass.Therefore, we have combined the best of two classic products into one tube.

Sound Characteristics of the EML 300B-XLS

The 300B-XLS is ideal for single-ended amplifiers. In other words, tubes should not be operated at their maximum electrical limits. 300B-XLS is in the right place, taking advantage of the tube's high electrical margins. 300B-XLS can reproduce the required loudness more easily than a standard 300B. The result is a more transparent sound image at low and medium volumes, and at high volumes without compromising the dynamics of the original sound.

Also, when used in a push-pull amplifier, this tube is an excellent choice because this type of amplifier is, by definition, taxing on the tube. 300B-XLS was created to address this situation, allowing the amplifier to gently reproduce at small sound levels, with the detail expected of a push-pull amplifier and accuracy expected from a push-pull amplifier.

Bias of the 300B-XLS

The 300B-XLS is biased in the same way as the original WE300B in any amplifier. The sill can be used in two ways, depending on your preference. These two methods are described here.

  1. Any 300B can be replaced with this tube; simply plug it into a 300B amplifier and the tube will be set exactly to the original 300B operating point. the EML 300B-XLS is a very powerful tube and can more easily develop output power. Especially for amplifiers where 300B tubes work very hard, the EML 300B-XLS is the right product. Amplifiers trying to get as much power as possible from a regular 300B will benefit from the 300B-XLS. The result is better sound quality and longer life.
  2. Another purpose of the EML 300B-XLS is to get more power than is possible with standard 300B tubes. This can only be done if the bias of the amplifier can be adjusted higher. If the anode current of the tube exceeds the standard 300B specification, the tube will move to the part of the curve with lower anode resistance. This is a feature of the 300B-XLS. This improves the attenuation coefficient of the loudspeaker in the low and mid frequencies, resulting in a more natural sound. Check out the Customer Feedback section of our website.
  3. Alternatively, the entire amplifier can be built around the 300B-XLS. You can then choose any operating point as shown in the table in this datasheet.

All critical components such as filaments, grids, and anodes are constructed of tungsten carbide for maximum reliability and reproducible quality.

  • Gold plated grids.Several advantages include improved bias stability, protection against accidental overloads, and improved linearity of tube curves.
  • Soft Rubber Suspended Tubing
  • Tungsten carbide construction.Hard metal anodes have a more accurate anode distance and do not change shape due to heating or mechanical shock. This ensures reproducibility and long-term stability of tubing parameters.
  • Two oversized getters
  • Hand-blown glass sphere
  • Anti-microphonic anode and grid suspension
  • These tubes are shipped in high quality dual boxes.
  • Tubes printed with real gold (metal), red is glass baked into glass
  • Gold plated pins, black ceramic sockets (white bottom)

EML 300B-XLS filament rating

Filament Voltage = 5 volts AC or DC
Filament voltage tolerance 4%
Filament current ~ 1.5 Am