FAQ

Q. I am seeing a blue glow inside my WE300-B. Is this bad or a feature?

A. A blue glow may appear in the dome of the WE300-B just below the upper mica and the top edge of the plate. The space between the plate and glass is small at this point (less than 1/8 in.) and appears to be the only area of the tube where this phenomenon takes place. The glow is caused by the electrons striking the plate, volatizing the surface, and dislodging atoms of nickel. High speed barium-strontium electrons from the filament collide with the atom, tearing off electrons, ionizing them and causing a deep blue color even in a well evacuated tube. The glow is a function of the plate voltage and the number of gas molecules in the envelope. In a good vacuum there are still billions of molecules. The electrons do not cause trouble because they all return to the positively charged plate. The size of the glow also varies with plate voltage and is not the same for each tube: it can vary from not discernable to very obvious even in daylight. It does not affect tube performance as can be shown by observing the characteristic curves during tube operation.

However, dangerous levels of gas can ionize throughout the entire bulb from a high voltage spark. In this case, the gas will be pink in color and will cause variations in plate current. Air in the tube will ionize in a similar manner i.e. throughout the entire bulb, but will be more blue than pink. It will oxidize the filament and cause the emission to drop dramatically.

Q.The WE300-B has a center tapped filament that your competitors do not have. Why use the center tapped filament?

A. To prevent electrolysis and to provide an equipotential balance across the cathode in the case of direct current excitation.

Q.Is the WE300-B 100% American made?

A. The WE300-B is manufactured in Rossville, GA and is manufactured with 100% American made materials and components.

Q.What is the useful life expectancy of the WE300-B?

A. The WE300-B is rated for an average life expectancy of 40,000 hours when operated within published specifications. As far as we know, no other 300-B tube available comes close to this life expectancy.

Q.What, if any, are the differences between the newly manufactured WE300-B and the new old stock WE300-B manufactured many years ago?

A. The WE300-B tubes manufactured today are able to take advantage of materials that are of a higher quality and processes that are more advanced than were available in the past. The current tube enjoys a vacuum that is at least two decades lower (2×10**-6) Torr than previous runs due to the employment of turbomolecular vacuum pumps, resulting in longer life. Although the tube is newly produced, the filamentary cathode core material is from the original WE inventory derived from a 1963 melt from the Western Electric Hawthorne Works in Chicago. The tooling used in the manufacture of WE 300-Bs is original equipment, some going back as far as 1943.

Q.What is the warranty on the WE300-B?

A. End Users receive a standard 90-day warranty on each tube. Fill out the warranty card and send it within 10 days of original purchase for an extended 5-year limited warranty.