Free Essay

Vox Amplification

In: Other Topics

Submitted By ajrios87
Words 1033
Pages 5
Anthony Rios
Composition 1

Vox Amplification: A History
The Vox Amplifier Company are makers of guitar amplifiers that boast a history in rock and roll music, and with the invention of the electric guitar musicians were not only amplifying there guitar but exploring new frontiers.
The Vox Empire and JMI (Jennings Musical Instruments) started with just two men by the names of Thomas Jennings and Dick Denney. Thomas Jennings was always interested radios and electronics as well as an amateur accordion player from there he took his interests and joined the British Army, where he was a part of the Royal Electrical and Mechanical Engineers. Sometime in 1942 he received a medical discharge and took a job at a munitions plant in Dartford Kent, England. While working at the plant he met a big band guitarist and fellow musician Dick Denny. Denney, who was also interested in electronics and radio technology, would befriend Jennings and the two would on occasion play together during air raids to keep the morale up.
With the war still waging on in 1944 Jennings and Denney would go their separate ways and Jennings would start a small part time business selling second hand instruments and doing repairs. Around this time his business was growing fast and so was he needs to find a bigger commercial venue. It was 1946, the year after the war ended, is where he would open his first commercial premise mainly importing accordions and other musical instruments but also inventing new products. Jennings first successful production was the Univox Electric organ. This invention would serve as a launch pad for one of the most successful instrument manufacturers.
It was the mid 1950s and a new type of music was making its way across the Atlantic from the United States just simply called rock and roll. With the popular growth of rock and roll and the influence it was having over England’s youth that JMI would take notice and start designing guitar amplifiers. These amps would all be built in-house and were marketed but enjoyed very little success. All the while Denney was designing and experimenting with amplifying the guitar and developed a 15 watt amplifier that would feature a 12 inch speaker. In 1957 Jennings was looking outside the company for amplifier designs and he had heard of Dick’s amp and invited him to factory. Denney brings along the prototypes he designed, Jennings liking what he hears and offers Denney a job at JMI. Denney accepts the job and joins the JMI team as an amp designer and JMI would now become Jennings Musical Industries.
VOX AMPS in the 60s
The first amp that was branded with the VOX name was the AC/2 practice amp that came out in 1958 but it would soon be named the AC/4 for its actual power output in 1961. Cosmetically the AC/4 was designed with the “TV front” look as well as covered with fawn vinyl and the classic brown diamond grill cloth. Electronically its circuitry contained 4 tubes: one EZ80 rectifier, one EL84 power tube, one ECC81 (aka 12AX7) and one EF86. This amp would be one of many to join a complete amplifier line.
The AC-15 was the amp that really started it all. It came in two different models, the first in 1958 featuring the TV front design and then in 1961 featuring the Fender style cabinet. First designed by Dick Denney in 1957 and then produced in 1958. It had the same cosmetic features as the AC 4 but it was electronically how it was different. The tone produced by the AC-15 was the sonic blueprint for all JMI tube amps. Denney’s design held three key ingredients for the VOX tone. The power section of the amp consisted of two EL-84 power tubes to make the first component in the VOX tone along with the EF-86 preamp tube. However, the EL-84 tube had a downside. The tube had a tendency to distort when driving the amp too hard because of reduced headroom. Denney also had this covered he incorporated the negative feedback circuit to clean up the distortion but when introducing this circuit it also took some of the harmonics out of the tubes. After some tests Denney decided he liked the way the amp sounded without the negative feedback circuit. The second ingredient of the VOX tone would be to remove the negative feedback circuit from the power section in all JMI tube amps. The final ingredient involved how to bias the output tubes. Denney realized that the AC 15 would be a better sounding amplifier by abandoning manually biasing the tubes but favoring self-biasing.
AC-30: The Crown Jewel
The AC 30 is one of the most coveted amps on the market today and over the years it has been produced in several models. The first was the AC-30/4 to be designed for British bands endorsed by VOX in 1960. Rock and roll was becoming more and more popular in Britain and the need for a more powerful amp was evident. The power amp section contained a quartet of EL-84 power tubes, but in the preamp section was the EF-86 tube. The EF-86 is a high gain tube that would the drive the AC-30/4 into a harmonically rich distortion when pushed. However, due to the vibrations of the amp when being played loud the EF-86 would fail and have to be replaced all the time. Over time the cost of the tube would to be too high and the engineers at VOX would soon design a new amp without the EF-86.
The AC-30/6 would be born into the VOX line. This amp was influenced by the introduction of the Fender Twin 60-watt amp to the UK. VOX decided to resolve this by developing the AC-30/6 which would feature an additional speaker and doubling of the output power tubes. With the AC-30/4 it also included the EF-86 tube but VOX replaced this tube with a battery of ECC83 (12AX7) tubes.

Similar Documents

Free Essay

[Building a Battery Powered Guitar Amplifier]

...decided that this would be the easiest choice to make it able to operate off a battery. If you will notice in photo C this power amp is the perfect fit in our combo amp. C. D. (J. Chappell, Nov. 2010) (J. Chappell, Nov. 2010) Now that the power has been converted to D.C. how will we be able to control volume, effects, and mix the sound of the amp? We do this by using a preamp, like a digital effects pedal that has everything we need in one board. You could use any digital effect pedal board, or stomp box with a preamp for this part. In this description we are using a “ VOX tone lab LE ” shown above in photo D. This gives us portability and functionality just by hooking the preamps output into the power amps input. This will cut down the expenses of having to buy printed circuit boards that are over priced, and sometimes very confusing to install. So you are done with the simple part of the build, now comes the difficult part. We have our cabinet, our speaker, our power amp, and our preamp. But none of this will function if we don’t have a way to power everything. So since our amplifier is going to operate on D.C. power this gives us the opportunity to move into the next step of our build. We need to choose the battery that will let our amplifier function the longest, allow us to recharge after......

Words: 2291 - Pages: 10

Premium Essay

Isolation of Rare Circulating Tumour Cells in Cancer Patients

...20/27 December 2007 LETTERS specificity (100%) of the CTC-chip across all five cancers. Finally, we evaluated the reproducibility of CTC capture using split samples and showed high experimental reproducibility (r2 5 0.98; Supplementary Fig. 4f). To determine whether captured cells are suitable for subsequent molecular analyses, we tested expression of two tumour-specific markers: prostate-specific antigen (PSA; also known as KLK3) in prostate cancer and thyroid transcription factor-1 (TTF-1; also known as NKX2-1) in lung adenocarcinoma. Specific expression of these markers was evident by immunostaining (Fig. 4a, b, d, e), and confirmed by direct lysis of captured CTCs on the microchip and PCR with reverse transcription (RT–PCR) amplification of the individual transcripts (Fig. 4c, f). Considering the ,50% purity of captured viable CTCs (two orders of magnitude higher than currently available technologies)26, the CTC-chip provides a powerful opportunity for CTC-based molecular analyses. To demonstrate the unique clinical potential of our approach, we evaluated the ability of changes in CTC burden to predict changes in tumour volume in cancer patients undergoing anti-cancer treatments. Patients with advanced epithelial-based malignancies that were commencing a first or second line systemic treatment regimen were eligible. Blood samples were collected at baseline and during subsequent clinic visits; the exact follow-up schedule varied between patients. Computed tomograms......

Words: 7750 - Pages: 31

Free Essay

The Art of Digital Recording

...speakers back into the recordings and to prevent feedback. This requires quite a bit of switching back and forth between headphone listening (to record) and speaker listening (to get a better sense of the sound of the recording), but it can be a workable situation. It is important to reference your recordings on your 15 THE ART OF DIGITAL AUDIO RECORDING speakers, and not to make sonic judgments based solely on monitoring with headphones. Powered studio monitors 16 There has been a growing tendency for studio monitors to come in powered versions—that is, the power amp is built right into the speakers (some manufacturers only make powered speakers). The motivation for this is simple: powered speakers ensure that the amplification for the speaker is properly matched to the speaker design and capabilities. In general, this is a very good development; the only real drawbacks are that it makes the speakers more expensive (though they do have to be powered one way or another, anyway), and it makes them heavier (which can be a bit unfortunate if you are traveling between studios and like bringing your speakers with you). I recommend getting powered studio monitors, if possible. Near-field monitor setup Positioning of near-field monitors is an important part of getting an accurate representation of the recorded sound. The basic rule is that the speakers should be the same distance from you as they are from each other, creating an equilateral triangle. This......

Words: 111233 - Pages: 445

Free Essay

Brave New World - Aldous Huxley

...spell that would restore the dead past to life. But the spell was ineffective. Obstinately the beautiful memories refused to rise; there was only a hateful resurrection of jealousies and uglinesses and miseries. Popé with the blood trickling down from his cut shoulder; and Linda hideously asleep, and the flies buzzing round the spilt mescal on the floor beside the bed; and the boys calling those names as she passed. ... Ah, no, no! He shut his eyes, he shook his head in strenuous denial of these memories. "A, B, C, vitamin D ..." He tried to think of those times when he sat on her knees and she put her arms about him and sang, over and over again, rocking him, rocking him to sleep. "A, B, C, vitamin D, vitamin D, vitamin D ..." The Super-Vox-Wurlitzeriana had risen to a sobbing crescendo; and suddenly the verbena gave place, in the scent-circulating system, to an intense patchouli. Linda stirred, woke up, stared for a few seconds bewilderly at the Semi-finalists, then, lifting her face, sniffed once or twice at the newly perfumed air and suddenly smiled–a smile of childish ecstasy. "Popé!" she murmured, and closed her eyes. "Oh, I do so like it, I do ..." She sighed and let herself sink back into the pillows. "But, Linda!" The Savage spoke imploringly, "Don't you know me?" He had tried so hard, had done his very best; why wouldn't she allow him to forget? He squeezed her limp hand almost with violence, as though he would force her to come back from this dream of ignoble......

Words: 64884 - Pages: 260

Free Essay


...and tendency. A free Synonyms and Antonyms, by James Champlin Fernald people must be jealous of their liberties if they would retain them. One is suspicious of another from unfavorable indications or from a knowledge of wrong in his previous conduct, or even without reason. Compare DOUBT. Antonyms: contented, friendly, kindly, satisfied, trustful, well-disposed. Prepositions: 132 Envious of (formerly at or against) a person; envious of his wealth or power; envious of him for, because of, on account of his wealth or power. ***** EQUIVOCAL. Synonyms: ambiguous, enigmatical, indistinct, questionable, doubtful, indefinite, obscure, suspicious, dubious, indeterminate, perplexing, uncertain. enigmatic, Equivocal (L. equus, equal, and vox, voice, word) denotes that which may equally well be understood in either of two or more ways. Ambiguous (L. ambi, around, and ago, drive, lead) signifies lacking in distinctness or certainty, obscure or doubtful through indefiniteness of expression. Ambiguous is applied only to spoken or written statements; equivocal has other applications. A statement is ambiguous when it leaves the mind of the reader or hearer to fluctuate between two meanings, which would fit the language equally well; it is equivocal when it would naturally be understood in one way, but is capable of a different interpretation; an equivocal expression is, as a rule, intentionally deceptive, while an ambiguous utterance may be simply the result of a want either of......

Words: 206737 - Pages: 827

Free Essay


...but it is just a thought experiment (I am aware that there may be no such thing as a legislator with intellect, courage, vision, and perseverance; this is the point of the thought experiment). The legislation is not a popular measure among the airline personnel, as it complicates their lives. But it would certainly have prevented 9 / 1 1 . The person who imposed locks on cockpit doors gets no statues in public squares, not so much as a quick mention of his contribution in his obituary. "Joe Smith, who helped avoid the disaster of 9/11, died of complications of liver disease." Seeing how superfluous his measure was, and how it squandered resources, the public, with great help from airline pilots, might well boot him out of office. Vox clamantis in deserto. He will retire depressed, with a great sense of failure. He will die with the impression of having done nothing useful. I wish I could go attend his funeral, but, reader, I can't find him. And yet, recognition can be quite a pump. Believe me, even those who genuinely claim that they do not believe in recognition, and that they separate labor from the fruits of labor, actually get a serotonin kick from it. See how the silent hero is rewarded: even his own hormonal system will conspire to offer no reward. Now consider again the events of 9/11. In their aftermath, who got the recognition? Those you saw in the media, on television performing heroic acts, and those whom you saw trying to give you the impression......

Words: 158140 - Pages: 633

Free Essay

Spa & Wellness Industry

...Hill/Irwin, Columbus, OH. Suggested web resources: Kotler, P., Keller, K.L. (2006) Marketing Management, 12th Edition, Pearson Prentice Hall, Englewood Cliffs, NJ. Marketing, online marketing & research MediaPost Media, marketing and advertising news, expert analysis and professional resources http:/ /www.mediapost. com Internet Advertising Board& Daily Newsletter IAB Informer International community for online advertising issues, news, expert analysis and insight, resources http:/ / eMarketer E-Business and online marketing research & analysis The Wise Marketer Customer loyalty and retention marketing: news, analysis, research and resources for loyalty marketers Marketing Vox Internet marketing and e-marketing resources, research and news ● ● 276 Spa marketing Spa Industry SpaFinder Inc. Consumer and industry global spa resource, including SpaFinder Insider newsletters for spa professionals on latest industry trends and news, as well as blogs by industry experts. International Spa Association Largest professional, global organization of the spa industry (75 countries), site features education and business tools and resources Day Spa Association Primary business resource for day spa professionals, with news, resources, educational and......

Words: 153860 - Pages: 616

Premium Essay


...not to give the lie to the image I have drawn of my qualities, commonly less deformed and contradictory than consists with the malignity and infirmity of the judgments of this age. The uniformity and simplicity of my manners produce a face of easy interpretation; but because the fashion is a little new and not in use, it gives too great opportunity to slander. Yet so it is, that whoever would fairly assail me, I think I so sufficiently assist his purpose in my known and avowed imperfections, that be may that way satisfy his ill-nature, without fighting with the wind. If I myself, to anticipate accusation and discovery, confess enough to frustrate his malice, as he conceives, 'tis but reason that he make use of his right of amplification, and to wiredraw my vices as far as he can; attack has its rights beyond justice; and let him make the roots of those errors I have laid open to him, shoot up into trees: let him make his use, not only of those I am really affected with, but also of those that only threaten me; injurious vices, both in quality and number; let him cudgel me that way. I should willingly follow the example of the philosopher Bion: Antigonus being about to reproach him with the meanness of his birth, he presently cut him short with this declaration: "I am," said he, "the son of a slave, a butcher, and branded, and of a strumpet my father married in the lowest of his fortune; both of them were whipped for offenses they had committed. An orator......

Words: 179434 - Pages: 718

Free Essay

The Origins and Development of the English Language (Textbook)

...(1100–1500) 117 (compare Kenny, with revised spelling to indicate a pronunciation somewhat closer to the historical one) and Menzies (with the Scottish pronunciation [mɪŋgɪs]). The newly borrowed shape g was used to represent not only [g] in native words, but also the [ǰ] sound in French loanwords like gem and age, that being the sound represented by g before e and i of French in earlier times. The consonant sound [v] did not occur initially in Old English, which used f for the [v] that developed internally, as in drifen ‘driven,’ hæfde ‘had,’ and scofl ‘shovel.’ Except for a very few words that have entered standard English from Southern English dialects, in which initial [f] became [v]—for instance, vixen, the feminine of vox ‘fox’—no standard English words of native origin begin with [v]. Practically all our words with initial v have been taken from Latin or French. No matter how familiar such words as vulgar (Latin), vocal (Latin), very (French), and voice (French) may be to us now, they were originally foreign. The introduction of the letter v (a variant of u) to indicate the prehistoric Old English development of [f] to [v] was an innovation of Anglo-Norman scribes in Middle English times: thus the Middle English form of Old English drifen was written driven or driuen. When v, the angular form of curved u, came to be used in Middle English, scribes followed the Continental practice of using either symbol for either consonant or vowel. As a general......

Words: 164520 - Pages: 659