VUTRAX Bridges the Analogue CAD Design Gap for Marshall Amplification

Marshall Amplification plc is probably the leading manufacturer of guitar amplifiers in the world, its products having been used by rock legends from the Rolling Stones to Jimi Hendrix, as well as today's rising stars. Since 1986 the company has used VUTRAX CAD software from Computamation for all its electronic design and, in recent years, a proportion of its mechanical drafting. According to Director and Chief Designer, Steve Grindrod, a major reason for the company's reliance on VUTRAX is its high level of analogue design functionality.

"Our design requirements are fairly unique, even within the audio industry", he explains. "Marshall amplifiers are an extension of a musical instrument - as much about the creation of music as the guitar, and because the best sounds are still analogue based, so is our electronic design."

"At the moment about 99% of our work is analogue, with digital electronics only found in the microprocessors that control the amplifiers' parameters. Ours is a relatively small industry though, and most of the electronic CAD systems we have seen are geared towards the much larger digital design market. VUTRAX is a very flexible system and caters for heavy analogue work, while also being a good digital board package."

Marshall Amplification has its design, research & development and manufacturing facilities under one roof at Bletchley near Milton Keynes. The company employs 350 people and has maintained an annual growth rate of 40% since 1981. Between 85% and 90% of all production is exported and the company received its second Queen's Award for Export Achievement in 1992.

The company has an extensive product range, with around 70 models being actively marketed, including 15 new introductions this year alone. Steve Grindrod says the company designs its amplifiers to have a long market life, so that most models are only updated after three or four years.

The company is even re-issuing many of its early models, and has been licensed to re-issue the Vox AC30 that was so popular in the British Beat boom of the early 1960s. The basic circuitry is the same, except it is laid out on printed circuit boards, while the amps have also been updated to meet 1993 safety requirements. This exercise has required that Marshall Amplification dig deep into its design archives to transfer designs onto CAD.

According to Steve Grindrod, transferring these old designs would have been significantly easier had the designers of the 1960s enjoyed the levels of documentation control now available with CAD. He believes that better documentation, described as a side effect of CAD, has been one of the most important general benefits of VUTRAX since its introduction.

The other major effect of CAD has been to improve design quality. Although the impact on quality cannot be quantified, VUTRAX has freed designers from tedious and time consuming tasks and allowed them to experiment, while making better use of componentry. Leadtimes have also been reduced. Most savings however, including any financial gains, have been redirected into better design.

VUTRAX is currently running on eight Olivetti 386 workstations, shared between nine users in a combined R&D and design department at Bletchley. All workstations are networked to a 486 file server. Work is assigned on a project basis, with teams created to contain representatives from all the major production stages, including manufacturing. Whether electronic design precedes or follows mechanical design depends on the product involved and the preferences of each particular project team.

While electronic design is performed exclusively on VUTRAX, the Computamation software also contains a mechanical drafting facility which is used by Marshall Amplification. Separate mechanical CAD software is also used at the company, but Steve Grindrod, Chief Designer, says "I personally prefer to work purely in VUTRAX, using circuit design and drafting to produce the complete set of drawings. In my experience there is nothing on the mechanical side that VUTRAX is unable to do."

He adds that the system is particularly easy to use. "VUTRAX drafting is very much like using a drawing board, and for designers brought up on drawing boards, that makes it extremely user friendly. The software has also shown a high level of continuity over the years, despite a number of upgrades. This means we can go back to designs that were made in previous versions of VUTRAX and re-work them in the latest version without difficulty."

With a wide range of models updated after relatively lengthy periods, this is an important point. Indeed, the re-launch of the Vox AC30, together with other classic Marshall amplifiers from the 1960s, demonstrates the longevity of the company's designs, and the need for them to be readily accessible.

Marshall Amplification plc continues to set the standards of quality for guitar amplifiers, yet the specialist nature of its design work means there are very few electronic CAD systems that can meet its demands. The company believes that VUTRAX is the most cost-effective means of acquiring the high levels of analogue design functionality needed. As such, the Computamation software bridges a gap in the electronic CAD market.