Hiwatt

Hiwatt (stylized in all caps) is a British company that manufactures amplifiers for electric guitars and electric basses. Starting in the late 1960s, together with Marshall and Vox, Hiwatt contributed to the sonic image popularly termed "British sound".

Origins
British audio engineer David Reeves attended technical school in the late 1950s and did apprenticeships at Marconi Company and Mullard. Beginning in 1964, he began working evenings repairing hi-fi equipment and televisions in a small room over Plato Music on Crown Passage in Morden. It was during this time that Reeves first conceived the idea to start his own company and invented the Hiwatt name.

First amplifiers
Reeves' first amplifier designs from 1964 used ultralinear taps for the screen grids. Since Reeves was intimately familiar with Partridge transformers and Mullard valves from working at Mullard, they were components of his Hiwatt designs from the start. The 50-watt amps were a split-chassis design with the control panel mounted on the top of the cabinet and a black and gold nameplate with a lower-case script "hi-watt" logo. Unlike the classic British guitar amp look that Hiwatt later embodied, these earliest models more closely resembled their Vox and Selmer counterparts of the day. Reeves soon starting building amplifiers that more closely resembled the modern-day Hiwatt.

Hylight and Sound City
Reeves started the Hylight company (the name came from an early 1960s band named "The Hylights" that a friend belonged to), registering the name in September 1966. To help finance the start of his company, Reeves contracted with Ivor Arbiter's Sound City music store to manufacture Sound City-branded guitar amplifiers. These amps (the so-called "Mark I") were Reeves' current amplifier design re-badged with the Sound City name. With as much power but a cleaner sound than their Marshall counterparts, Sound City amplifiers were adopted by The Who's John Entwistle and Pete Townshend in 1967. After Jimi Hendrix and his manager Chas Chandler approached Townshend for his opinion on amplification, the Jimi Hendrix Experience began using Sound City amplifiers in addition to their Marshall amps.

Once Reeves fulfilled his contract with Sound City, he focused on building Hiwatt-branded amps. Arbiter later filed a lawsuit against Reeves, claiming that Sound City owned the amplifier design and that Hylight was using it without permission. During the proceedings, Reeves pointed to the unused holes in the amp chassis and asked the Arbiter engineers what they were for. The engineers, who had simply been producing copies of Reeves original chassis design, didn't have an answer, and the case was decided in Reeves favour shortly thereafter.

In late 1968 The Who approached Arbiter with a request for Sound City amplifiers with slight modifications. Arbiter declined the request, but Reeves agreed, creating customised Sound City L100 amplifiers. This model was named the Hiwatt DR103, which would be modified in 1970 into the CP103 "Super Who 100" model which Townshend used almost exclusively for over a decade. In 1973 the updated DR103W model was created, which has been the central piece of equipment around which Townshend's various rigs were built for the next thirty years.

Hylight Electronics also manufactured amplifiers under the Sola Sound brand for the large UK musical instrument distributor Macari Ltd.. This arrangement only lasted for a short while as the popularity of the Hiwatt amps increased.

Establishing Hiwatt
Hylight Electronics originally sold direct to the musicians so that they could reinvest the profits that would have gone to distributors and music stores back into growing the Hiwatt brand. One of the earliest famous Hiwatt users was Jethro Tull bassist Glenn Cornick. It was at Cornick's urging that the first 200-watt (and later 400-watt) Hiwatt amps were produced. Pete Townshend, who worked with Reeves on the Sound City amps, also became a Hiwatt endorser.

Hiwatt hired former band road manager Peter Webber, who demonstrated, promoted, and sold the company's amplifiers as quickly as they were built. In 1971, Hiwatt was struggling to keep up with production, so Reeves approached amp designer Harry Joyce to wire chassis for Hylight.

In Kingston upon Thames, Reeves found a site for Hiwatt's new home, a converted bakery complex in an old building that was located in a small industrial section of town known as ParkWorks.

Building the team
Mike Allen and Danny Edwardson were brought on board to improve upon the current crop of speaker cabinets that were currently being produced in the U.K. The first step was to use a more robust and acoustically sound material for the cabinets construction. This came in the form of 14-ply Baltic Birch, a much heavier and denser wood product than most of the other amplifier manufacturers of the day were using. Next, the cabinets were internally braced at no less than 9 points, and the construction was finished using tongue- and-groove joints. The cabinets were finished off with the most resilient and "classic-style" vinyl covering Reeves could find (made by Brymor Ltd.) and the "tough as nails" black, white & grey fret cloth (speaker cloth) covering that was distinctively HIWATT.

To put the cabinets into a small production stage, Reeves enlisted the services of Henry Glass and Co., known as BEESKIT, one of the U.K.'s premier cabinet builders. Henry's meticulous production techniques were a perfect complement to Hiwatt's already legendary road-worthiness, and Reeves fanatical approach to building nothing less than the ultimate guitar amplifier.

Another integral member that was added to the team at Hylight Electronics was Phil Dudderidge, whose specialty was the design and manufacture of public address systems. Phil's knowledge and extensive expertise in working with most of the major acts in Europe at the time, made an ideal choice to expand the Hiwatt name into the realm of sound reinforcement.

The design of the amplifiers changed bit by bit through the 1970s, reflecting changing tastes within the industry. Some odd designs briefly surfaced during this period, including the "SAP" model with footswitch and the mysterious DR118. The use of printed circuit boards was started at the end of the 1970s.

Also during this time, some custom amplifiers were produced by Hiwatt for their most famous clients, including Pete Townshend's CP103 and David Gilmour's linked-input models.

The company changes hands
In early 1981, Dave Reeves died after falling down a flight of steps. Control of the company fell into the hands of solicitors, although Reeves' stated intention had been for his three children to inherit the business. Mary Clifford, the admin for the company at the time, along with other existing employees formed Biacrown Ltd., and continued making Hiwatt amplifiers. There were some minor innovations to the circuitry produced during this time, including the "OL" (overload) model which had an extra gain stage added. Some were labelled "OL", while many were not. Some had an additional gain control added to the front panel labeled "overdrive". Biacrown closed in 1984, and the Hiwatt name was sold to Richard Harrison and his U.K. company Music Ground.

Classic Hiwatt circuits
Input stage variations:

Phase Inverter (PI) Variations:
 * The early input circuit version (Input 1) used a traditional resistive mixer to combine the two input channels. Half of V2 went unused.
 * The later input circuit (Input 2), used both halves of V2 to do the input channel mixing.
 * The OL and LEAD input circuits (Input 3) went back to the resistive mixer, and used the second half of V2 as an additional gain stage. These can be easily recognized by the "flying" components on the V2 socket.


 * The earlier circuit (PI 1) used a cathode-follower directly connected to the PI circuit to both set the DC level and buffer the signal.
 * The middle and later units (PI 2) capacitively coupled the last preamp stage to the PI. The former cathode follower section now has its input connected to a DC voltage divider, and is used strictly as a low impedance voltage reference.

Combination I: The earliest DRs with 4-inputs used Input 1 and PI 1.

Combination II: At some point, the circuit was changed to use Input 1 and PI 2 (this version is represented by the Audio Bros and Hiwatt.com schematics). Some 4-inputs may have been made this way.

Combination III: Finally, the circuit was changed to use Input 2 and PI 2. This change was definitely in all the 2-input heads, and is represented by the widely circulated freehand-drawn schematics in Pittman and elsewhere.

The OL Model (early 1980s): Biacrown's "high gain" model moved back to the Input 1 circuit (still keeping PI 2), but used the "extra" half triode as an additional gain stage.

The LEAD Model (early 1980s): This was basically the same as the OL model, but with an extra level control after the extra gain stage, which was marked "Overdrive" on the front panel.