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The Western Electric 300B and Single-Ended Audio

The Western Electric 300A and 300B filamentary power triode is the only American manufactured power output tube engineered to be used as a state of the art audio frequency amplifier. It was developed in the 1920s as the mainstay of the rapidly growing cinema industry. It was used in the Western Electric #91A single-ended and the #86 push-pull cinema amplifiers. Thousands of these amplifiers were installed in theaters worldwide. We grew up watching movies with soundtracks reproduced by low powered directly-heated triode amplifiers! More than likely, we experienced 2001, The Good, The Bad and The Ugly, Clockwork Orange, etc. through WE 300B amplifiers. Imagine a whole theater powered by 8 to 30 watts! And I keep hearing people saying there are no speakers for these low powered serious!

If today's speakers seem too inefficient for low powered amps it is simply because speaker manufacturers are too cheap to spend the money on quality magnets, precision voice coils and low loss filter components! Similar to the situation with transformers, manufacturers have started the rumor that, "transformers color the sound"...what they neglect to tell you, is that transformers can cost up to 100 times as much as a gain stage. Whenever a manufacturer tells you something is bad, ask him if it costs more than what he is using.

Due to its low (700 Ohms) plate impedance, low mu, low input capacitance and internal (natural) degeneration the 300B tube has given us the opportunity to build amplifiers that are extremely simple and reliable. Audio Note 300B amplifiers have only 3 gain stages (compared to probably 24 in your average transistor power amplifier and typically one-tenth as many components as their solid state counterparts.

Up until about 1970, almost all professional and home hi-fi loudspeakers were happy with 20 watts or less. Thirty watts was considered very high power in those days. The sealed enclosure Acoustic Research and Advent loudspeakers changed all this. These companies' sealed box alignments allowed deep bass from much smaller boxes than the horn and bass reflex enclosures popular in the 50's and 60's. Unfortunately, there is an enormous trade off in efficiency. The sealed box speaker was typically 10 dB less sensitive than the ported, bass-reflex enclosures it replaced, and as much as 25 dB less sensitive than their horn counterparts. Distortion was also raised in sealed box alignments - because of the increased excursion requirements and loss of efficiency. Crossovers became more difficult to design because of the increased back EMF that comes naturally with inefficient, long excursion drivers and complex crossovers. Long excursion drivers also tax the limits of voice coil and suspension technology.

Suddenly, the whole amp speaker interface became a new problem. These new, less efficient speaker designs required higher power, higher current sourcing ability and higher damping factors than even the big McIntosh, Harman Kardon, Fisher and Marantz amps of the time could provide. The introduction of the sealed-box speaker was the beginning of the decline of the tube amplifier.

About 1964, solid state (bi-polar) amplifiers began to appear in the hi-fi marketplace. These amps promised high power, small size, light weight, cool operation, and low price. Time has shown us that to drive the demon loads of the speakers of the 80's and early 90's, we really needed big solid state amps that are heavy, hot running, unreliable and expensive. Also, just as digital has not improved upon the sound quality of analogue - these big, expensive solid state amps have never exceeded the sound quality of even the average vintage tube amp.

Just think about it. Sealed box enclosures came about and they were smaller but harder to drive and did not improve sonically on the speakers they replaced. Then solid state amps came about that were initially smaller, cooler, and cheaper than the tube amps they replaced. These were cost/convenience based engineering decisions that compromised the sound quality. Then speakers and amps got bigger and bigger trying to restore their sonic performance. The designers needed to bring sound quality back to where it was in 1960. The promise of small, cool and cheap with better sound turned out to be false. Now we have big and hot and expensive! It is as well, questionable whether even the biggest, most expensive solid state amps and modern speakers have improved on the modest, simple tube gear and speakers they replaced. It is interesting that despite thirty five years of intense audio engineering development it is doubtful that we have come any closer to musical reality than we were in 1960, and the sad fact is that in the recording studio the decline has been just a severe, which is why old RCA, DECCA (London), Mercury's etc. are so highly priced today and are the subject of many re-releases, with modern digital LP's being completely worthless and CD's not fairing much better. Likewise ten to fifteen year old transistor amplifiers are mostly worthless today, whereas 25 - 30 year old tube amplifiers are increasing in value at an astonishing rate. Early single-ended amplifiers, like the Western Electric 91A, are worth nearly 100 times their original value! What does this say about our technological advances and our competitors claims to have perfection within their grasp? It appears that the promise of solid state amplifiers is similar to the promise of digital - "we will make you throw out your old gear and buy new stuff that is less musically rewarding".

The solid state roads and the push-pull roads have proven to be dead ends.

Because Audio Note recognizes this we are able to move forward and explore new areas and make dramatic gains with musically relevant results.

In the past fifty years, the first REAL step forward in the quest for a higher quality music reproduction came with the introduction of the Single-Ended 300B amplifier.

In Japan where technological development and time are not seen as straight unbroken lines (like they are here in the US) the Japanese audiophile always preferred the 300B triode amplifier but the triode movement in Japan really started in 1960. During the 60's and 70's, at least 50,000 Japanese music lovers were busy building triode amps and horn speakers. In 1988 the movement began in Europe and America. Jean Hiraga and Peter Qvortrup started the movement in Europe. Both were espousing the benefits of single-ended triodes as early as 1982. Audio Note in Japan introduced the ONGAKU, Single-Ended 211/VT-4C amplifier in 1988. In America, in that same year, Herbert Reichert (Eddy Electric) introduced the first single-ended 300B amp to the American public. Also in 1988, Nobu Shishido was building transformer coupled triode amps on the west coast while Joe Roberts was building all kinds of weird triode amps in Texas. Dennis Had (Cary) and Gordon Rankin (Wavelength) began in the nineties'. The re-invention of audio that started with the use of 300B amplifiers began in the basement shops of 'Dark Lantern' inventors and music lovers. This is a true grass roots movement. It started with people who wanted their music to sound less mechanical and less emotionally sterile. These early visionaries felt that high end hi-fi had lost touch with the most important aspects of music reproduction.

These early engineering efforts were fueled by the desire to be touched and drawn into the music again.


The 300B triode, operated single-ended, with no negative feedback has given us the opportunity to stop thinking about high end hi-fi and start liking music again.

This page was updated on: 06 Aug 1998
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