This is a valuable collection of significant professional and HiFi equipment archived for posterity.
The PMC Museum of Audio is an exceptional compendium of professional recording and HiFi equipment that has been carefully curated over many years by PMC’s founder Peter Thomas.
This unique collection of over 500 items illustrates the technical advances and achievements made by so many audio companies over the last 120 years. By bringing these products together into one collection, PMC aims to preserve examples of the best and rarest audio technology so that they can be studied and enjoyed by future generations of enthusiasts and audio engineers.
.
As a designer of world-renowned loudspeakers, it is no surprise that loudspeakers formed the genesis of Thomas’ collection. But over the years he has added examples of many different audio products, from professional tape machines and microphones to amplifiers, turntables and record players. The oldest item in the PMC Museum of Audio dates to the early 1900s, while the strangest must surely be a portable, ‘over the shoulder’ record player from the 1950s that allowed cool kids of the time to play 45 singles while on the move.
“There is a great deal we can learn from history, and this collection highlights many technologies that were never exploited properly when they were first introduced because they were so far ahead of their time,” Peter Thomas says. “The PMC Museum acts as an archive of all that we have learned about audio over the years, and we hope it will continue to inspire and intrigue enthusiasts for many years to come.”
The LS5/5, which was launched in 1967, is a large, three-way passive monitor powered by Quad amps and featuring a dispersion slot – a design that was revolutionary in its day but is now highly unusual and completely out of fashion. The dispersion slot in the front panel, which covers the bass and mid-range drivers, controls the off-axis response of these drivers so that, in a typical listening environment, you get a smoother crossover off-axis. The BBC, who instigated the design of these speakers, used them for drama and music recording because they delivered great sound quality and were very popular with BBC engineers. They have a place in our museum because they are unusual – and because there is always the possibility of learning from the past. Who knows? Maybe there is still a future for dispersion slot technology. It is certainly something PMC hasn’t ruled out!
Introduced in 1983, the KM1 high-end active monitor was created by KEF for BBC Radio. This unique piece of engineering was designed to deliver high volume without compromising sound quality. At the time the BBC was struggling to record live sessions for Radio 1 and Radio 2 rock and pop stations with in-house BBC speaker designs because its monitors couldn’t manage the required volume levels. Equipping the Maida Vale and Golders Green studios with re-purposed PA speakers wasn’t an option because they couldn’t meet the BBC’s sound quality requirements. The solution was the KMI - effectively a very loud HiFi speaker with built in Quad amplification. It was, however, not sufficiently robust for the BBC’s requirements and this eventually led to its demise. Only 72 pairs of KM1s were made, each selling for a reported £20,000 (approx. £75,000 today). Very few survive, which makes our pair even more special.
IMF was one of the first manufacturers to introduce commercial loudspeakers based on transmission line principles. Initial models were launched in 1969 and aimed at the Hi-Fi market, but also became popular with professional mastering engineers because they delivered exception sound quality. IMF’s four-way design included a racetrack bass unit positioned next to three other drivers optimising dispersion because the drive units in each pair were mirror imaged to ensure a deep and precise stereo image. PMC’s founder Peter Thomas bought these monitors in 1973 and needed a bank loan to fund them (they cost £750 - £19,000 in today’s money – but he paid half price). Despite some negativity towards transmission line technology, Thomas and his partner Adrian Loader were so impressed by the IMF MkIII that they developed their own Advanced Transmission Line system. This fixed the negative issues and became the foundation for PMC’s own monitoring products.
Launched in 1991, the PMC LB1 was the result of an R&D challenge to see just how small you could go with a transmission line loudspeaker. PMC had already launched the BB5 (installed in BBC Maida Vale Studios), but the LB1 was the company’s first foray into domestic loudspeakers. PMC believes there shouldn’t be a distinction between a loudspeaker designed for studio use and one for domestic use –it is either reproducing the music correctly or it isn’t. With the LB1, we showed that using Advanced Transmission Line, or ATL™, bass loading technology across pro and consumer products delivered ultra-high-resolution loudspeakers that could be used throughout the entire recording and playback process. The LB1 was phased out in 2006 and replaced by models designed for a more modern aesthetic. But it has a museum place because it encapsulates our philosophy of bringing studio quality audio reproduction into the home environment.
Introduced in 1973, the Studer B67 tape machine was very popular throughout the 1970s and early 1980s because it was small and compact. Designed for professional applications, this machine was a development of the Revox A700 consumer tape machine and it packed a lot of punch for its price. It offered three speed settings – 15, 7½ and 3¾ - and excellent access to the tape, making it easy for recording engineers to carry out razorblade edits and splices. This particular tape machine, which was acquired from a BBC engineer in the early 1980s, has earned a place in our museum because it is such a classic of its time.
These two way HiFi speakers with 8 inch bass drivers deserves a place in the PMC museum because they delivered fantastic audio quality at an incredibly low price. Their performance matched speakers costing at least five times more than the £100 they retailed for when first launched in 1984. Whoever designed these speakers was a magician. They maximised what must have been the tiniest of design budgets to create exceptional results. Long since discontinued, the pair in the PMC museum are still in working order and were acquired in the 1980s. Back in the day they were also the recommended speaker for use by BBC staff in their offices chosen because of their neutral sound quality.
This is another small two way speaker that wins a place in the museum because its quality far outstrips its price tag. At the time of launch (1965) this tiny 10-inch tall speaker with a four-inch bass unit was one of the smallest, true HiFi speaker you could buy. It was popular not only because of its performance level but also because it was inexpensive. In the 1960’s, it was harder to make a small speaker sound great - technology wasn’t what it is today. Manufacturing costs were also higher, which makes the quality versus price equation even more remarkable. The product of an excellent design team, as the end result is so much greater than the sum of the parts. Being small and easily disposable means that not many of these have survived.
During the 1960s there was an explosion in the design and manufacture of small, cost effective loudspeakers for the HiFi market. These two way Ditton 15 speakers, launched in 1966, are a good example of that trend. They are interesting as museum pieces because they use an Auxiliary Bass Radiator (ABR) with a polystyrene diaphragm that works like a reflex speaker. The ABR vibrates with the air in the cabinet to produce much lower bass than one would normally achieve from a cabinet of this size. It is a technique that has fallen out of favour, mainly because it is less expensive to produce a reflex speaker which uses a simple tube to create a similar effect. There were also some early transmission lines with ABRs terminating the line which were successful. Performance wise, the Ditton 15 produces exceptional bass from such a small cabinet.
Launched in 1972, these 1.4 meters high speakers benefited from an advertising campaign with a great strap line: ‘The Illusion of Reality’. In terms of design, they were a complex four way drive unit design and were one of the earlier adopters of transmission line technology. They were also expensive, an equivalent today would cost around £15,000, and were aimed at the top end of the audiophile market. Being so tall and thin, they looked different from other products on the market where the fashion was for shorter and wider designs at this level, plus the front grille is unusual because it comprises of vertical strips of plastic. This didn’t work well from an audio point of view, so most people removed the grilles. However, their performance was excellent if a little dry and the form factor has stood the test of time because they wouldn’t look out of place in a modern living room.
Launched in 1972, these stand-mounted three-way speakers were hugely expensive and totally unique. Styled by Jon Bannenberg, who went on to design luxury yachts, they are stunning to look at and it’s no surprise they won a CES design and engineering award in 1978. Their landscape layout and masses of chrome set them apart from any other speaker on the market. They also sound amazing as they achieve an accuracy and performance level that is quite remarkable from a sealed-box cabinet of this size. Employing two small woofers, this 3 way design unusually featured midrange and tweeter controls on the rear panel. At launch, some were disparaging about their audio quality because they felt nothing that looked this good could also sound good. But they were wrong – these are one of the best sounding infinite baffle speakers ever made, offering an electrostatic quality midrange that could perform at very high levels.
The KEF 104 speakers are one of the first UK loudspeakers to be designed and tested using computerised measurements. Although now commonplace, back in 1973 when these were launched it was completely revolutionary. This significantly speeded up the design process and allowed many new innovations to be tried and tested, which led to significant improvements in loudspeaker design and performance. The KEF 104 is a development of the KEF Cadenza design and similarly employs an Auxilliary Bass Radiator (ABR), which provides them an extended bass from a relatively small enclosure. The front baffle offered a user adjustment of the balance of the speaker to suit a variety of rooms.
Launched in 1973, these four-way loudspeakers designed by Spencer Hughes stood out because they delivered such a neutral sound, like the smaller BC1. This made them highly coveted by audiophiles, although few could afford them because they carried a hefty price tag. Back in the early 1970s there was little consistency when it came to the sound of loudspeakers so the similarity of balance to the acclaimed BC1 was significant. It is worth noting that many large loudspeakers at the time were criticised because they often sounded rather ponderous and unexciting. However, that was more to do with amplifier technology and the limitation of power output. Amplifiers did catch up eventually, thanks to advances in transistor technology and by the mid-1970s were delivering in excess of 100 watts of high quality power. Coupling these speakers with a modern amplifier reveals their remarkable performance.
Transmission Line technology has played a key part in the development of PMC’s own loudspeaker range. The improvement it makes to the accuracy of sound reproduction, particularly the bass, has been inspiring PMC’s founder Peter Thomas since the early 1970s when loudspeakers such as the IMF TLS50 began appearing on the scene. This pair have been in his collection since 1973 and are included in the museum because they were the first transmission line loudspeakers he heard and then owned. At just under a meter tall, they were the most popular model for nearly 10 years because they delivered a huge sound and didn’t take up too much space in the home. The noticeably wider and deeper stereo image impressed Peter because it made him feel closer to the music. In today’s world, that experience can be equated to hearing immersive audio for the first time. No wonder, then, that PMC is also a leader in that field.
Swiss-made and introduced in 1957, this landmark record player was the first to incorporate a belt between the motor and the idler wheel which drives the turntable platter. It might not seem like a massive innovation but by separating the idler wheel from direct contact with the motor, Thorens significantly reduced rumble and vibration, making this a very desirable turntable indeed. The fact that it was also built like a tank made it popular in professional environments such as broadcast studios. It was expensive, too, but Thorens used their research to develop less expensive models in the following years. These days few remain in original condition as there have been many third party modifications over the years, After years spent searching for a pristine example, PMC was lucky enough to locate two in the space of a few months. This is the Mk2 version, but we also have the Mk.1.
A tape boom in the middle of the 20th century gave rise to many different tape recorder manufacturers. In the 1950s alone there were over 100 of them, all producing machines that allowed you to make a recording at home, even if it was just capturing the voices of your children. UK company Ferrograph was one such company. It became the UK’s foremost brand and developed high end machines ultimately leading to this example. This tape recorder was launched in 1966 and it became popular as a semi pro machine because it was so very well engineered and reliable. It came in a cabinet with its own loudspeakers and retailed at a premium price point. We are including this machine in the PMC museum because it is an example of a classic1960s UK high end tape recorder. We also love the colour – BBC green – which is so evocative of that era.
Launched in 1970, this was one of the earliest speakers on the market to incorporate an Auxiliary Bass Radiator (ABR), which delivered extended bass from a relatively small enclosure. Only 60cm tall and 30cm deep this two way speaker was very advanced for its time and became the forerunner of the KEF 104, which is also in the PMC museum. Along with the Coda and Concerto, this range was named after descriptions of sections or movements of music beginning with the letter C. We can only assume that someone in KEF’s marketing department wanted to develop a naming theme that was easy to remember. It certainly worked and continued for many years.
Revolutionary is the best way to describe these speakers, which were launched in 1957 and became popular because of their incredible natural and accurate sound. They do look strange (more like radiators than speakers) as they employ electrostatic technology, where sound is produced by passing an electrical charge across two large metal plates that sandwich a thin mylar diaphragm. Although they offer very low distortion, they also have disadvantages. These speakers, for example, radiate sound from the rear as well as the front so room placement is more critical as they can’t be positioned too near to a wall. They are also complex to manufacture, which makes them expensive. When we started PMC, we considered electrostatic design for our own products, but we ultimately rejected it because of their limited maximum volume available.
Transmission Line technology lies at the core of PMC’s speaker design because it delivers very accurate and natural sound. For this reason, we are including many different examples of Transmission Line speakers in our museum. The Leak 2075, which was launched in 1975, fits this brief and is also a good example of 1970s aesthetics. This four-way speaker system, which represents Leak’s only foray into Transmission Line design, has a massive bass unit and a top cabinet containing a tweeter, a low mid range unit and an upper mid range unit. This top cabinet of the speaker can be rotated allowing listeners to optimise the sound to suit where they are sitting. The Leak 2075 is also very efficient, and even with a small amplifier it is possible to get high SPL’s. Considering their quality and size, these speakers were excellent value for money, in part due to Leak’s ownership at the time by the large Rank organisation and the use of mass production techniques to keep costs down.
This tape recorder was a landmark, both in terms of its technology and what it was used for. Launched in 1972, it was developed as a multitrack tape recorder for recording tour tracks simultaneously on quarter inch tape and then mix down to stereo. It became hugely popular as a semi pro machine for the home recording market. However, because its launch happened to coincide with the advent of quadraphonic sound it became the standard machine for this format. The machine we have was originally owned by the BBC and used for some of its experimental quadraphonic broadcasts on Radio 1 and Radio 2. It just goes to show that timing is everything in that Teac released this multitrack machine of this quality just when people were developing an interest in quadraphonic sound.
This Revox E36 is a great example of an early, high quality tape recorder. It is also charming because it looks like a smiley face. Launched in 1962 by Studer’s consumer brand Revox, this machine is the epitome of Swiss design. These were not inexpensive, but they were sturdy, reliable and had a built-in speaker for playing back material, which made them popular in both domestic and office settings. They also sported “BBC” green paint, a colour that is so synonymous with audio equipment of that time. Another interesting point is that this machine uses transistor pre-amps, but valves for everything else. We have no idea why Studer designed them this way, especially as later versions went back to being all valve. We can only assume that, after this brief foray into transistors, the company decided to wait until transistor technology improved.
Precise and clever engineering is the reason why this Thorens TD160 turntable was such a hit with audiophiles when it was launched in 1972. The TD160 replaced the smaller TD150 and was so successful that it remained in production until the early 1990s. With this model, Thorens has incorporated a belt-driven turntable with a floating sub-chassis suspended by three adjustable springs. As the turntable platter and arm are entirely independent of the plinth, it is quiet, stable and capable of exceptionally high quality sound because it is isolated from feedback and vibration. In addition, this beautifully constructed unit delivers on the aesthetics front as it is very attractive to look at. No wonder it is now considered a classic and remains a collector’s item.
