300-B Vacuum Tube

The Legendary Western Electric 300-B Returns

Specifications | Reviews | FAQ

What becomes a legend? Time and tide have been generous to the Western Electric 300-B. This low-distortion class-A triode enjoys a legendary reputation for luxurious sound in both single-ended and push-pull configurations. When the last Western Electric® 300-B was manufactured in 1988, music lovers here and abroad frantically purchased them until none remained. Other manufacturers produced 300-Bs but they didn’t embody the sound quality of our fabled WE 300-B.

Balanced, Powerful and Refined

The WE 300-B’s sound is balanced, powerful and refined with quality bass from the lowest frequencies through the upper bass. The midrange above is a thing of beauty; dulcet tones, seductive vocals, instruments of all types dimensional and present, all heightening the participatory elements of music.

Burnished and Beautifully Seductive

High frequencies are at once transparent, lovely, sweet, burnished and beautifully seductive. The air and space between performers is extraordinary, performers appear on a quiet and focused soundstage whose width and depth are masterfully rendered. You don’t have to search to find the sweet spot with a WE 300-B amplifier, it’s all around you.

Western Electric will have details for the long-awaited return of the WE 300B triode soon; look for new tubes to be rolling off the line in the new year.

Find out what tube aficionados all over the globe know, the WE 300-B is the most natural, elegant and emotive triode anywhere in the known universe.


Moderate power, filamentary triodes for class-A service.

Audio-frequency amplifier in positions where power outputs of approximately ten watts or less are required at relatively low plate voltages.

Dimensions, outline diagrams of the tubes and bases, and the arrangement of electrode connections to the base terminals are shown in Figures 1 and 2.

These vacuum tubes employ medium, four-pin thrust type bases suitable for use in Western Electric 143B or similar sockets. The 300-B tube has the bayonet pin so located that it may also be mounted in a Western Electric 100M, 115B or similar socket.

The tubes may be mounted in either a vertical or horizontal position. If mounted In a horizontal position, the plane of the filament, which is indicated In Figure 2, should be vertical.

Grid to plate 15 µµf.
Grid to filament 9 µµf.
Plate to filament 4.3 µµf.

Filament voltage 5.0 volts, a.c. or d.c.
Nominal filament current 1.2 amperes

The filaments of these tubes are designed to operate on a voltage basis and should be operated at as near the rated voltage as possible. When alternating current is used for heating the filament, the grid and plate returns should be connected to a center tap on the secondary of the filament transformer.

Technical Specs

Available early 2018.


Questions? Call 404-352-2000.


(Ef = 5.0 volts, a.c., Eb = 300 volts and Ec = -61 volts)
Plate current 60 milliamperes
Amplification factor 3.85
Plate resistance 700 ohms
Grid to plate transconductance 5500 micromhos

(Not simultaneous ratings)
Maximum plate voltage: 450 volts
Maximum plate dissipation: 40 watts
Maximum plate current of average tube for fixed grid bias: 70 milliamperes
Maximum plate current for manually adjusted grid bias or self-biasing circuit: 100 milliamperes

Recommended and maximum conditions for alternating-current filament supply are given in the table. Recommended conditions or others of no greater severity should be selected in preference to maximum conditions wherever possible. The life of the tube at maximum operating conditions will be shorter than at the recommended conditions.

Where it is necessary to operate the tube at or near the maximum plate current of 100 milliamperes, provision should be made for adjusting the grid bias of each tube independently, so that the maximum safe plate current will not be exceeded in any tube. Alternatively, a self-biasing circuit may be used, in which the grid bias for the tube is obtained from the voltage drop produced by the plate current of that tube flowing through a resistance.

Where it is necessary to use a fixed grid bias, the plate current of the average tube should be limited to a maximum value of 70 milliamperes, so that tubes having plate currents higher than the average will not exceed the maximum safe plate current.


Performance data including power output, second and third harmonic levels for a number of operating conditions are given in the table.

The variation of power output and harmonic levels with load resistance for several values of operating plate current are shown in Figures 7, 8 and 9, for a plate voltage of 350 volts.

The peak value of the sinusoidal input voltage, Egm, which gives the indicated power output, Pm and harmonic levels, F2m and F3m for each point in both the curves and the table, is numerically equal to the grid biasing voltage at that point. For a smaller input voltage Eg, the approximate levels may be computed from the following relations.

F2=F2m+20 log10(Eg/Egm)
F3=F3m+40 log10(Eg/Egm)
200 -42 30 2000 3.0 20 31
200 -39 40 2500 2.6 26 38
200 -37 50 2500 2.5 30 45
250 -55 30 2000 4.9 18 27
250 -55 30 4500 3.2 27 40
250 -52 40 3000 4.0 26 36
250 -50 50 2500 4.4 26 39
250 -48 60 2000 4.7 26 38
250 -48 60 2700 4.1 30 45
250 -45 80 1500 5.0 26 41
300 -65 40 2500 6.7 20 30
300 -63 50 2000 7.2 21 29
300 -63 50 3000 6.1 26 37
300 -61 60 2400 6.6 26 37
300 -61 60 3400 5.6 30 44
300 -58 80 1700 7.5 26 37
350 -76 50 3600 7.8 26 38
350 -76 50 5000 6.2 30 45
350 -74 60 2000 10.2 21 30
350 -74 60 3000 8.3 26 38
350 -74 60 4000 7.0 30 44
350 -71 80 2200 9.6 26 39
400 -91 40 5000 8.4 26 37
400 -89 50 3000 11.5 21 31
400 -89 50 4000 9.4 25 38
400 -87 60 3500 10.5 26 38
400 -87 60 5000 8.3 30 46
400 -84 80 2500 12.5 25 37
450 -104 40 6000 9.5 26 38
450 -102 50 5000 10.7 27 39
450 -102 50 6500 9.0 30 45
450 -100 60 4000 12.5 26 38
450 -100 60 5500 10.1 30 44
450 -97 80 2000 17.8 21 30
450 -97 80 3000 14.6 26 37
450 -97 80 4500 11.5 31 45


Plate-current characteristics for a typical tube are shown in Figure 3 as functions of grid bias, for alternating-current filament supply. The corresponding amplification-factor, plate-resistance, and transconductance characteristics are given in Figures 4, 5 and 6, respectively. When direct-current filament supply is used, and the grid and plate returns are connected to the negative end of the filament, the same characteristics are applicable if 3.5 is subtracted from the numerical value of each grid bias.

"Generally speaking, amps that use the 300-B tube are marvelous musical instraments that transcend hi-fi. They sound so immediate and alive that certain editors, accustomed to churning out reviews of "proper hi-fi products," have said they "hate it" when they hear sound like this — so immediate, so alive [and so damned musical—-Ed]."

Sam Telling
SAM'S SPACE Vol.20 No.12
sterophile - January 1997

"All in all, however, the buyer is concerned with the tube's performance. These new Western Electric 300-Bs will probably prove to be just as good, maybe even better from a fabrication point of view, as a treasured "original.""

Don Jenkins
Test Bench
V&T News - January 1997

"The reissue 300-B by Westrex sounded very close to the vintage WE 300-B. Again it was lush sounding. We heard slightly more volume from the reissue 300-Bs, but that may be because my old 300-Bs are a little tuckered out from many years of use. The mid-range in the reissue tube, which has always been what single-ended triode amps using".

Howard Stone
The 300-B Tube Lives Again!
Antique Radio Classified - January 1998

"Amplifiers you and I may have judged poorly could have gotten a minor bum rap because we didn't hear them with WEs. Without shortchanging the magic part, the WE tightens up the loose ends."

Srajan Ebaen
Western Electric 300-B Redux
Sixmoons.com Audio Reviews - June 2006

"The 300B is still one of the most important triodes in audio history. Reviving the 300B with understandable pride is one thing, but perhaps even more Important is the renewed spirit of Western Electric manufacturing."

Luca Chiomenti
Costruire HIFI - 1999

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 (2x10**-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.