Fender Amplifiers

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Fender amp "tailed" logo
Fender amp "tailless" logo

Fender Amplifiers have a long history. Leo Fender began building guitar amps before he started manufacturing guitars. The first of these amps were the K&F models, which were produced between 1945 and 1946. The original Fender amps were tube-powered and the company also started producing solid-state models in the late 1960s.

Early amplifiers: K&F and Woodie[edit]

The K&F amplifiers were the first "Fender" amps made. They were made by the K&F Manufacturing Corporation, which was run by Leo Fender and Doc Kauffman.[1] Most of the amps were finished in a "gray crinkle" finish. The finishes were baked in the Kauffman family oven. They were made in three different sizes, 1x8" (one 8" speaker), 1x10", and 1x15". They are all very rare today and few have survived.

The first amplifiers made in-house by Fender is the Woodie series, built in 1946 and 1947.

Tweed amplifiers[edit]

1953 Fender Champ in tweed covering, wide-panel cabinet

Fender amplifiers began making a name for themselves with the Tweed series, so called because of their cloth covering, which is actually varnished cotton twill (tweed is a coarse woollen fabric, commonly used for jackets, coats and caps; it is often woven in a twill pattern, which is likely the reason for the confusion over naming.) They were produced for more than a decade and are now eminently collectible and praised for their sound quality. The twill was first used in 1946 on the Dual Professional a twin 10" 6L6 powered model of which only 400 were made before being renamed "the Super Amp" in 1948. These early models are commonly referred to a "V-Fronts" due to the shape of the cabinet when viewed from above. The Dual Pro was the first twin speaker amp and also the first amp to employ a finger-jointed pine cabinet and the first amp with a top facing control panel. The construction of the amplifiers was changed as well: the chassis are mounted to the back with the tubes pointed down, as opposed to having the chassis mounted on the top of the cabinet. This has the benefit of providing ease of access to the inside while providing a strong top.

Fender stopped using the twill covering in 1960, though the Champ was still covered in twill until 1964. The first kind used was an off-white fabric, followed by a horizontal-stripe two-tone pattern, and finally a two-tone twill.

At the beginning of the "tweed" era, Fender constructed its cabinets in "wide panel", where the top and bottom panel is wider than the side. Fender later on constructed them with "narrow panel", in which all the panels have more or less the same width. Toward the end, despite keeping such construction, Fender utilized tolex to cover its amps.

Blonde[edit]

Blonde twin, 1963

The Blonde amplifiers were produced between 1960 and 1964. The blonde amps included all of the piggyback Fender amps (the Tremolux, Bassman, Showman, and Bandmaster) and a few of the combo amps, including the Twin amp. Two different colors of grillclothes were featured on the blondes, oxblood and wheat. There are several experimental Fender Tweed amps in blonde.

While the majority of the piggybacks were produced in blonde tolex, there are a few examples of the brown tolex Bassman amplifiers.

Brownface[edit]

The Brownface series was introduced in 1959 and discontinued in 1963. This period marked the beginning of Fender's use of Tolex to cover amp cabinets. Most of the brownface amps featured a "wheat" grillcloth. Some of them also came with a dark maroon or "oxblood" grillcloth.

There were many notable accomplishments for the company's amplifier division during these years. Namely, the introduction of the stand-alone spring reverb unit in 1961, followed by the subsequent incorporation of the reverb circuit within a combo-amp design with the 1963 Vibroverb. Other notable accomplishments of this period include the shift of the top-of-the-line model from the traditional Twin-Amp to include other models, like the Vibrasonic Amp in early 1960, as well as the blonde Showman Amp in 1961. Fender began using silicon rectifiers to reduce heat caused by tube rectifiers, and tweaked the vibrato circuit.

The shift from the tweed design to tolex occurred in limited production in 1960. The tolex on the earliest versions in this era was pinkish brown and rough textured. There were only six amplifiers covered in tolex originally, and they were called the Professional Series: Bandmaster-Amp, Concert-Amp, Pro-Amp, Super-Amp, the Twin-Amp (production halted Feb-May 1960, resumed as the blonde Twin) and the Vibrasonic-Amp. These were considered a step above the student models (Champ, Harvard, Princeton) which remained tweed-covered in 1960. Grillclothes were initially the same as those used in the previous tweed era (i.e.: maroon with gold stripe). Beginning in mid to late 1961, Fender introduced another color combination: a smoother but still light brown tolex with a dark maroon or "oxblood" grillcloth. By mid-1961, after this short-lived look, Fender was using the darker brown tolex which was a mainstay for many of the mid-1961 to 1963 amps. Between 1961 and 1963, there were three different grillcloth colors: wheat, brown, and maroon and many tolex-grille color combinations are found suggesting that Leo Fender and Co. was not hesitant to use up whatever stocks of materials were on hand. This mode of operation would seem to extend to the electrical components as well given that it is not uncommon to find actual production amps that vary from the published schematics.

The Deluxe made the transition in 1961. The circuit was also changed to include a tremolo effect, and the output was increased.

As the brown-era wore on, the plight of the smaller amps was varied. They all remained in name at least except for the 1x10" Harvard which was not continued through 1961. The 1x8" Champ-Amp remained a tweed-covered through 1963 and into 64 when it made the change to black tolex. The 1x10" Vibrolux amp remained a tweed amp until it was upgraded in 1961 to a single 12" speaker powered by a duet of 6L6 power tubes and a larger output transformer. Also upgraded from tweed was the Princeton-Amp which acquired its brown tolex in 1962 along with a larger speaker array: 1x10".

Blackface[edit]

Blackface Deluxe Reverb
Blackface Princeton Reverb

The Blackface amplifiers were produced between 1964 and 1967. The first piggyback blackface amps (as well as the Princeton) had white knobs. After 1964 the amps had skirted black knobs. The blackface cosmetics were discontinued in late 1967; they returned for a brief period in 1981 before their discontinuation the following year.

Blackfaced cosmetics do not necessarily mean "pre-CBS" since the CBS company takeover took place in 1965 and amps with blackfaced cosmetics were produced up to 1967. After the buyout the front panels were changed from "Fender Electric Instrument Co." to "Fender Musical Instruments". No real changes were made to the amps until the silverfaced amps of 1968 where certain circuit changes made them less desirable than the blackfaced amps. This affected some models more than others. For example, the Twin Reverb and Super Reverb combos, along with the Dual Showman Reverb and Bandmaster Reverb "piggyback" heads were equipped with a master volume control while other models such as the Deluxe Reverb were not altered in any way except for the change in cosmetics.

Silverface cosmetics do not necessarily denote silverface circuitry, however. Leo Fender was notorious for tweaking his designs.[2] During the transitional period from late 1967 to mid-1968, the circuit designs of the Twin Reverb and Super Reverb were altered to eliminate an uncommon but serious oscillation in the signal chain. These changes took some months to finalize, as Leo worked through some designs, and happened after the cosmetic changes. Furthermore, the schematic and tube charts that shipped with these models did not always reflect the actual circuitry. Fender had many leftover AB763 (blackface) tube charts left over well into 1969 and shipped these charts with silverface models.

Save for a few series (such as HotRod series), a majority of modern Fender amplifiers sports blackface cosmetics.

Silverface[edit]

Silverface Twin Reverb, 1973
Silverface Princeton

Fender Silverface amplifiers were built between 1967 and 1981. They are often referred to as Silverface (or Chromeface) because of their brushed aluminum face plate.

The first Silverface amps, manufactured between 1967 and 1969, had an aluminum frame (trim, known as a "drip edge") around the grillcloth, mid-1960s "tailed" amp logo and the AB763 blackface circuit. An even rarer feature were the vertical, narrow black lines, which separated knob groups in the control panel. This cosmetic detail (later referred to as "blackline") was abandoned pretty quickly, though. All of the Silverface amps generally had blue labels on the face plate, but in some rare exceptions (such as the Bronco) the colour was red instead. Some transitional models produced before the "tailless" period in 1973 featured the AC568 circuit, still retaining the tailed Fender amp decal introduced in 1964.

In 1973 CBS changed the "tailed" Fender amp logo to the modern-looking "tailless" style (which was first introduced in 1967 on the student Bronco amp). A master volume knob and a pull-out "boost" pot were added on some amplifiers, followed by ultralinear output transformers and a "scripted tailless" amp decal (featuring a "Made in USA" script in the bottom) in 1977; the power was increased between 70 and 135 watts on certain models.

All Silverface models usually came with a sparkling silver/blue grillcloth (some later models had a non-standard sparkling silver/orange grillcloth, and a black grillcloth was even fitted to some production runs). The Silverface control face plate was discontinued in 1981 and the second series of the blackface amps designed by Paul Rivera were produced.[3] Paul Rivera went on to found Rivera Amplifiers.

Fender made a limited-edition Mini-Twin practice amplifier modeled after the mid-70s Twin Reverb models in 1996. The Silverface Edition MT-10 had the authentic look right down to the grillcloth. This 1-watt Twin featured 3 in. speakers, "skirted" style Fender knobs for Gain, Volume, Tone and Power and included a tilt-back stand.

In 2013, Fender released the silverface '68 Custom amplifiers as a part of their Vintage Modified series, modeled after the original drip-edge silverfaced amps of 1968. Models include the Twin Reverb, Deluxe Reverb and Princeton Reverb. Each amp incorporates reverb and tremolo on both channels. Other features include a Custom channel (which has a modified Bassman tone stack giving modern players greater tonal flexibility with pedals), quicker gain onset and reduced negative feedback for greater touch sensitivity.

Early solid-state models[edit]

Fender's first transistor amplifiers were introduced in 1966. At the time they were the company's "flagship" range and aimed to make the tube-based designs obsolete. The amplifiers were naturally given traditional Fender model names, earliest including 'Dual Showman', 'Twin Reverb', and 'Bassman'. Other products in the line were the 'Solid-State Reverb Unit' and the 'Solid-State Public-Address System'. 'Super Reverb', 'Pro Reverb', 'Vibrolux Reverb' and 'Deluxe Reverb' amplifiers followed in 1967.

The amplifiers were mainly designed by Robert "Bob" Rissi, Sawa Jacobson and Paul Spranger, who came up with the novel idea of making a heatsink to operate like a chimney to achieve increased and non-restricted airflow. Paul also designed the distinctive angled chassis and overall cosmetic styling. He was granted patents for both accounts.

In 1969 more transistor amplifiers were introduced, including the 'Zodiac' series and the behemoth 'Super Showman System'. Seth Lover, the legendary designer of the Gibson "P.A.F." pickup, and another former Gibson employee, Richard Chauncey Evans, were hired to help in designing the latter series, which consisted of an 'SS-1000' preamplifier head and 'XFL-1000' and 'XFL-2000' self-powered speaker cabinets. The head featured three cascadable channels, a "Dimension V" oil can delay effect, reverb, vibrato, and a fuzz. The powered cabinets could switch between normal and "tube-emulated" operation.

Zodiac-series amplifiers consisted of 'Capricorn', 'Scorpio', 'Taurus' and 'Libra' models. Aside from being covered with fake alligator skin, they were cosmetically very similar to Super Showman. However, these were smaller combo amplifiers with fewer features and aimed for the lower end of the market.

Fender's early transistor amplifiers had an extensive marketing campaign but in the end they proved to be a major disaster. Many key executives of Fender had resigned after the CBS purchase and quality control of the PCB-constructed amps was rather sloppy during the times. Reputedly many of the early solid-state amplifiers failed simply because employees didn't bother to clean up the soldering machines or attach the semiconductors properly to their heat sinks. The infancy of semiconductor technology also meant that many designs failed due to thermal runaway caused by insufficient cooling or lack of knowledge concerning "safe" power ratings of transistors. The cascaded effects from all this created a very poor reputation for the transistor products and the entire solid-state line was discontinued already in 1971. Additionally the experience also scared Fender away from solid-state amplifier technology for the next ten years.

Second series blackface[edit]

The Silverface amplifiers were succeeded by a new breed of Fender designs. Fender was now competing with manufacturers who were more in tune with the market; specifically, many guitar players were interested less in "cleanish" country amp and instead wanted more versatile tone controls and, perhaps more importantly, greater amounts of distortion. This market was dominated by companies such as Marshall and Mesa Boogie—both of which had gotten started modifying Fender amps (the Bassman and the Princeton, respectively).

The Blackface cosmetics were reintroduced in the mid-1970s in a series of amplifiers designed by Ed Jahns. The first amplifiers in this new line included the infamous 180W 'Super Twin' and 'Super Twin Reverb' amplifiers which featured active tone controls and a built-in distortion circuit that blended between clean and distorted sounds. Some bass amplifiers with similar architecture were also released, namely the 'Studio Bass' and 'PS300'.

These amplifiers didn't yet render obsolete the Silverface series and manufacturing of both co-existed for years. In fact, many Silverface designs were revised to the ultra-linear architecture to step up their output power from 100 watts to 135 watts.

The new Blackfaces came in varying cosmetic styles. All of them had a black control panel and traditional knobs, but they no longer featured the Blackface-style lettering to depict the model name and the traditional control panel layout was partially redesigned. Some of these amplifiers had a silver grillcloth typical to previous BF and SF series amps, but more often the amplifiers sported a black grillcloth. Some amplifiers also had an aluminum trimming running around the grille. The styling didn't become consistent until the early 1980s, at which point all these designs were already discontinued to make way for the very similar looking "II Series".

In the late 1970s and very early 1980s the "Supers" were followed by the tube-based '30', '75 (Lead)', and '140' tube amps (with reverb and overdrive features) and two solid-state 'Harvard' amps (one with reverb), which were 15W practice amplifiers. Design-wise the tube amplifiers were quite different from their predecessors, as the active tone controls and blending distortion circuit had been removed and the latter feature replaced by a crude version of the channel switching concept. A new feature addition was a crude insert-style effects loop.

II Series & the Rivera Era[edit]

The II Series amplifiers were produced from 1982 until 1986, being the last Fender amps to be made at Fullerton. The specifications for these amplifiers, and leadership of the design team, came from Paul Rivera (then marketing director) and are known as Fender Rivera era amplifiers. Some amplifiers in the series used the II moniker such as the Deluxe Reverb II and Twin Reverb II, while others such as the Concert and Super Champ did not. Many of these amps had the normal Fender clean sound and in addition a switchable mid voiced gain channel, designed to compete with the Mesa Boogie Mark Series series amps that had gained popularity at the time. The tube amps in the series feature hand-wired eyelet board construction and are also becoming sought-after collectors items, due to the design and build quality. There were also some solid-state amplifiers using the II moniker, such as the Harvard Reverb II. Other solid-state amps produced during the Rivera era included the Yale Reverb, Studio Lead, Stage Lead, London Reverb, Montreux, and a solid-state issue of the Showman. Many of these units shared the same circuitry boards in one capacity or another.

Red Knob[edit]

The Red Knob amplifiers were produced from 1987 until 1993. These were some of the first models produced by the newly formed Fender Musical Instrument Corporation. These amplifiers, named for their bright red control knobs have a slightly similar appearance to the older Blackface cosmetics, having black control panels with white lettering and the late 1970s "scripted tailless" Fender logo. Many of these models were simply refitted with black knobs and early 1970s "unscripted tailless" Fender logos in 1996 when most Fender amplifier manufacturing moved to the Ensenada factory in Mexico. This series of amplifiers all used printed circuit board construction and the tube amps are notoriously difficult to service. The Red Knob amps, with their high-gain channels, had their own sound, not much like the older classic Blackface and Silverface designs.

Popular Fender amps[edit]

Fender amp vacuum tube

References[edit]

  1. ^ The Soul of Tone-Tom Wheeler
  2. ^ Gagliano, Greg. "Dating Fender Tube Amps". 20th Century Guitar. Retrieved 2007-09-25. 
  3. ^ Fender Amps:The First Fifty Years (Teagle and Sprung, publ.Hal Leonard)