The V-12/V112, V1121/V1122 and V1123 Buckingham Head
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Thomas Organ introduced three generations of the Buckingham head in the two year period between 1965 and 1967.
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V-12 or V112 Buckingham Heads - Introduced in early 1966, the first generation V-12 and V112 Buckingham circuits were electronically identical and documented on a single schematic from Thomas Organ. The amp head was rated 35 watts RMS, 70 watts peak into a 8 ohm load.
The three channel amplifier featured tremolo in the "Normal"
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channel, reverb that was selectable to either the "Normal" or "Brilliant" channel and MRB or "Mid Resonant Boost" in the "Brilliant" channel. The "Normal" channel included a "Top Boost" rocker switch while the "Bass" channel featured a sweepable frequency tone control called "Tone-X."
The amplifier was housed in a trapezoidally shaped cabinet reminiscent of the JMI Vox AC-30SRT amp head. The
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A "round top" Amphenol three pin XLR jack was mounted to the rear panel of the V-12, V112, and earlier V1121/22 amplifiers for speaker connection. While using what would normally be considered to be a microphone jack in this application might seem a bit unusual, Thomas Organ was simply following the Jennings (UK) Vox tradition of providing locking XLR speaker cables with heads and cabs. Jennings used these locking speaker cables for an important reason. Many JMI Vox tube amp heads were prone to electronic damage if the speaker cord accidentally pulled out of the amplifier during performance. |
Two separate foot switches were provided with the amp. A two button foot switch with a 1/4" TRS (stereo) plug controlled the reverb and tremolo. A second single button "egg" shaped foot switch remotely controlled the MRB feature via an electro-magnetic relay located inside the amp. When the MRB button was depressed on the foot switch, you could actually hear the clicking sound of the relay from inside the amplifier.
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V-12 & V112 Reverb/Tremolo Pedal
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MRB Pedal
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Foot Switch Jacks
on Rear Control Panel
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V1121 and V1122 Buckingham Heads - Introduced in mid 1966, the second generation V1121 and V1122 Buckingham heads expanded and refined the design of the previous V-12 and V112 models. The new amp retained the same three channel design and features as the earlier model. The amp was rated 35 watts RMS, 70 watts peak into a 8 ohm load.
The V1122 Buckingham included the same features found in the
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V112 amp (reverb, tremolo, MRB, Top Boost and Tone X) but the effects were controlled by a new three button foot switch that consolidated the previous two foot switches into one.
The V1121 Buckingham head added a feature Vox called a Distortion Booster, or "fuzz tone," to the amplifier. There was no control panel switch for the distortion effect, it was activated by a new four button foot switch. This foot switch included a red indicator lamp to indicate that the fuzz tone was engaged.
Circuit Design and Layout - The V1121 modular preamp section was originally designed for the Viscount/Buckingham series amps by Thomas Organ/Vox engineer Sava Jacobson. The entire V1121/V1122 preamp section was interchangeable with those used in V1151 Viscount, the V1131/V1132 Royal Guardsman and the V1141/V1142 Super Beatle amps. The preamp section was sealed inside an rectangular aluminum enclosure that also included the control panel.
The preamp circuitry was designed on three printed circuit boards. One of these three boards included the Distortion Booster circuitry, another was dedicated to the reverb circuit. The third and largest circuit board included individual preamp and tone control circuits for all three channels, along with the components for the Top Boost and MRB switches plus tremolo and Tone X.
The foot switches controlling the V1121 "Fuzz" and "MRB" circuits actuated electro-magnetic relays located inside the preamp chassis that enabled the effects. When the "D" or "M" button was depressed on the four button foot switch, you could actually hear the clicking sound of the relay from inside the amplifier.
On the basis of amps I have recently inspected, I am led to believe that the fuzz tone circuitry was actually present in the V1122 chassis, despite the fact that fuzz tone was not included in the list of features for the V1122 amp. It appears that the only real difference between the V1121 and V1122 Buckingham amp heads was the foot switch included with the amp. When I connected a Vox four button foot switch (Reverb, Tremolo, MRB and Distortion) into a V1122 amp head and actuated the distortion button, the V1122 proved to have fuzz tone.
The V1122 Buckingham head did not have a serial number plate specifically produced for the model. Rather, Thomas Organ put a sticker with the number "2" that covered the last "1" on the V1121 serial plate. I believe that this simple method of changing the model number facilitated the rapid creation of the V1122 on the V1121 production line. Exchanging the four button foot switch normally equipped with a V1121 to the three button version completed the V1122 conversion.
The Further Evolution of the V1121 and V1122 Buckingham Heads
Thomas Vox Buckingham amp heads were still in a period of evolution. Not only had the V-12 and V112 been replaced within months of their introduction with the improved V1121 and V1122 models, even more revisions were in the works in future months for the second generation V1121 and V1122 Buckingham heads.
The V-12, V112 and early V1121/22 Buckingham heads were equipped with "frosted" red and green pilot indicator lenses (see photo, near upper right). These were changed to translucent, or clear lenses in the later production of the V1121/22 amp models (see photo, near lower right).
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Red and Green "Frosted" Pilot Lamp Assemblies
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Red and Green "Clear" Pilot Lamp Assemblies
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An "E Tuner" circuit was also added to later production runs of the V1121 and V1122 heads. This circuit provided a reference "E" pitch that would assist in tuning a guitar. This circuit dipped into the Thomas home organ parts bin, using a tunable inductor coil and a transistor in a basic organ oscillator circuit. The "E Tuner" was connected to the volume control of the Bass channel. When initially added to the amps, a rear panel rotary switch activated the reference tone. Later models utilized a slide switch.
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Some of the changes introduced by Thomas Organ to the V1121/22 models were aimed at reducing production costs. The solid aluminum escutcheon at the rear of the control panel of the V-12, V112 and early V1121/22 amps was replaced with a thin aluminum stamping in the later production of the V1121/22. While nearly identical in outward appearance, the stamped part was susceptible to damage when removing the chassis from the cabinet for service. The photo at left shows both the solid and stamped escutcheon and the damage that could occur to the stamped part.
Thomas Organ dropped the use of plywood in their cabinets as a further cost savings measure during the production of the second generation Buckingham heads. The new cabinets were made of particle board, a cheaper, heavier and less durable material.
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Thomas Organ also replaced the "Super Reverb Twin" badge that had been mounted to the lower right corner of the grill on the V12, V112, and early versions of the V1121/22 heads with a new "Solid State" logo.
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The "round top" Amphenol three pin speaker output jack installed on the rear panel of the V-12, V112 and early production of the V1121 and V1122 Buckingham head was replaced with a similar "flat top" panel mounted jack from Switchcraft (see photo at left).
By mid 1967, the V1123 Buckingham amp head replaced the V1121 and V1122 models, completing the two year evolution of the Buckingham head.
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V1122 Pedal
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V1121 Pedal
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Foot Switch Jack
on Rear Control Panel
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V1123 Buckingham Head - Introduced in 1967, the third generation V1123 Buckingham head again expanded and refined the abilities of the previous Buckingham models. The new amp retained the same three channel design and retained all the features of the V1121. The amp was rated 35 watts RMS, 70 watts peak into a 8 ohm load.
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A new, one piece, and in a sense, "universal" preamp circuit board was designed by Thomas Vox lead engineer Stan Cutler to replace the two or three board preamp circuit board arrangement used in the V-12, V112, V1121 and V1122 amps. This new board was designed to incorporate all of the eight individual preamp and effects circuits found in the Viscount, Buckingham, Royal Guardsman, Beatle, Sovereign and Westminster amps. The individual circuits included on this board were the first, second and third channel preamps, tremolo, reverb drive and receive, repeat percussion, mixer and "Watchdog" compressor/limiter.
Thomas Organ would install electronic components only into the sectors of the preamp board that would be consistent with the features included in a particular amp model. No electronic components would be installed in circuit board sectors where the channel or effect was not included with the given model. As an example, the extensive list of features included in a V1143 Beatle head required a completely populated preamp circuit board. In contrast, the Westminster bass head preamp board would omit the electronic components to support the tremolo, reverb, and Repeat Percussion effects plus the second, or "Brilliant" channel.
As the Buckingham was a three channel amp with reverb and tremolo, it would utilize a nearly completely populated preamp circuit board. Only the Repeat Percussion sector was unused as this feature was unique to the V1143 Beatle amp.
While the V1123 retained the features as the V1121 Buckingham, it has always been my opinion that the fuzz circuit sounds smoother and less buzzy in the earlier V1121 Buckingham amp head than in the V1123 model.
The V1123 used FET signal transistors in the preamp to minimize noise and hiss. New, modern FET switching transistors in the Distortion Booster and MRB circuits replaced the electro-magnetic relays used in the prior Super Beatle models.
The "E-Tuner" circuit that had been introduced in the later production of the V1121 and V1122 heads continued in the V1123.
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V1123 Pedal
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Foot Switch Jack
on Rear Control Panel
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What Year Was My Buckingham Head Built?
After looking at hundreds of Thomas amplifier serial numbers, I have come to the conclusion that the first digits appear to provide a clue to the year the amplifier was produced. Serials starting with "9" were from the first full year of production, 1966. Those starting with "I0" or "10" were produced in 1967 while those starting with "I1" or "11" were built in 1968. Following this same pattern, a serial starting "I2" or "12" indicates 1969.
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North Coast Music manufactures many replacement and restoration
parts for the Buckingham under license from Vox. These parts are
available exclusively at North Coast Music. Some are shown below.
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Photos and editorial content courtesy Gary Hahlbeck, North Coast Music
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