An Interview with the PM Series Development Team

The year 2003 marks the 30th anniversary of the birth of Yamaha PM-series consoles. Since the release of the PM200, the first mass-produced professional console, the PM-series has virtually led the field of sound reinforcement. It is fair to say that Yamaha PM consoles have defined the evolution of sound reinforcement consoles.

Tetsuo "Ted" Wakamatsu

Joined Yamaha in 1967 and immediately began working on sound reinforcement products.
A chief engineer who produced many legendary mixers, and has been part of PM history since the PM200.

Kenji Ikeya

Joined Yamaha in 1981. Mostly involved in large console development. Also took part in the development of the DMR8 digital mixer/recorder. A future-looking engineer putting his deep digital knowledge into PM5000.

Koji Aoyama

Joined Yamaha in 1975. An electronics engineer who took part in development of the PM180 and PM170, as well as the P2002 and other power amplifiers. A "craftsman" engineer who has mostly been involved with analog mixer development.

When was the first PM-series console released?

Wakamatsu: The first console was the PM200. I think it was released in November, 1972, more than 30 years ago.

Tell us what led to the development of the PM200.

Wakamatsu: Yamaha was organizing a large number of music events here in Japan at the time.
There was the NEMU - Jazz Inn, the Popular Music Contest, the World Popular Song Festival, and others. The history of Yamaha PA production began with the development of original equipment for those events. As the events grew in scale, new equipment had to be designed to handle the changing requirements. Before the PM consoles there were the EM-series (EM = Ensemble Mixer) powered mixers.

These were designed to allow a wide range of instruments to be easily mixed, and featured guitar inputs and built-in rhythm machines for this purpose. We sold systems complete with speakers - the Yamaha Ensemble Systems - that were popular for their ease of use. But as the needs of our users changed the output power and feature complement had to be increased.

Returning to the PM200, it was at this stage that we separated the mixer and power amplifier for PA applications, and concentrated on boosting performance.

The PM200 had unbalanced inputs and outputs and a mono output bus, but balanced inputs and outputs and a stereo bus were provided on its successor, the PM400. That was a time when PAs were evolving from small, simple systems to much larger systems.

What consoles were the big-name artists from overseas using in the early 70's?

Wakamatsu: Most were using name-brand recording consoles modified for sound-reinforcement use. When domestic gear was used it was mostly high-priced custom consoles of the type that were used in broadcast studios.

Whenever artists came from overseas we would always go to the concerts to see what gear was being used, and how it was being used.

The PM1000 was released in 1974. How was it possible to provide such high performance and advanced features at such a groundbreaking price?

Wakamatsu: We designed all parts and circuitry ourselves to achieve the highest possible reliability, while mass production allowed us to reduce the overall cost.

For example, we were using faders made by another manufacturer during the prototyping process, but eventually designed and produced our own. Unlike modern linear designs, we used a unique friction-driven rotarycontrol system in the early faders. To ensure that high performance and reliability we used a volume pod that employed carbon chips for the contacts and duralumin for the control shaft. By creating our own high-performance parts, we were able to reduce production cost.

The same can be said about transformers. Highperformance audio circuitry was advancing rapidly in the early 70's, as was the design of audio transformers, and we applied these advances to our PA equipment. We had custom transformers wound to our precise specifications in order to achieve the desired performance.

Why was the PM1000 so widely accepted?

Wakamatsu: Because it answered the needs of the times. It was, for example, the first model to incorporate our matrix mix system. The matrix system was developed to solve a channel-capacity situation we encountered at our own music events. We had to use one PM200 just for drums, a second for guitar, bass and other instruments, and a third to combine the outputs of those two mixers with vocals. It was clear that what we really needed was a mixer that somehow provided several mixers in one. Apparently many of our users felt the same way.

We have continued to implement new ideas and features in every new model in the PM series: the matrix system in the PM1000, hard chassis construction in the PM2000, VCA faders and mute groups in the PM3000, and so on.

How was the response from overseas?

Wakamatsu: In overseas markets, especially the U.S.A, the reputation of Yamaha consoles grew rapidly. One of the biggest west-coast bands of the era used the PM2000 on their national tour.

Why do you think leading professional around the world adopted the PM2000?

Wakamatsu: I think reliability is the biggest factor. Expensive custom consoles and other equipment are one-of-a-kind products that cannot easily be subjected to rigorous reliability testing.

Mass production, however, allows the implementation of drop testing, extreme temperature testing, and other procedures that guarantee the durability of the final product. And since mass produced products may be used in a wide range of conditions all around the globe, we receive plenty of feedback that can be used to improve quality. Yamaha's worldwide service network is another very important factor.

At the time of the PM2000 consoles were becoming quite large and chassis rigidity was becoming an issue. One of the tests we are still using is our "flight case test". During prototyping we order a custom flight case - not even a very sturdy one - and place the console in it. The flight case is stood on end, and then tipped over in both directions and allowed to fall to the floor. If the console powers up immediately and works flawless after that ordeal, then it passes the test. This type of durability is essential to withstand the rigors of a tour that might span more than 6 months and several tens of cities.

One very popular rock group at the time sent us a message of thanks because they had actually dropped one of our consoles down a flight of stairs and it had still worked perfectly.

The PM3000 was the first to introduce VCAs in a sound reinforcement console. How was the response?

Wakamatsu: At the time VCAs were being used in a number of recording consoles, but the general attitude was that VCAs simply didn't sound good.

Aoyama: Our sales staff even asked us not to use VCAs.

And so why were VCAs eventually used?

Wakamatsu: We created original Yamaha VCAs using discreet hybrid ICs. We were absolutely confident that we could deliver the quality, and wanted to implement some new ideas.

Aoyama: In addition to sound, usability was an important determining factor. In the PM3000 all 8 VCA groups could be assigned in any combination.

Wakamatsu: However, for about a year after the console was released I didn't see anyone using the VCA faders. It took a while before they were accepted, but it was clear to us that in the future other makers would be using VCAs in their consoles as a matter of course. We were confident that we were doing the right thing.

What was new in the PM4000?

Wakamatsu: Stereo auxiliary buses, and fully-parametric EQ.

Aoyama: For the first time we marketed three versions: hall (for the domestic market only), monitor, and FOH. And it was possible to replace mono input modules with stereo modules (for a maximum of 64 input channels). People were beginning to use more stereo sources at the time, and there was a huge demand for stereo modules.

Why do you think the PM4000 became the defacto standard sound-reinforcement console?

Aoyama: The PM4000 completely solved all of the deficiencies of the PM3000. We are exceptionally lucky to have so much feedback from leading artists and engineers that gets incorporated into our knowledge base. That's another advantage of mass production: we can reach a large number of users worldwide who contribute to the development of succeeding models through their feedback. That's why we opted not to take the custom-shop route from the PM200 onward.

As a result, the PM4000 took sound quality, operation, and reliability to an unprecedented new level.

And now the PM5000. Tell us about the development concept.

Wakamatsu: We aimed for the best sound ever in the PM series. The term "sound quality" alone does not suffice to define truly great sonic performance. Signal-to-noise ratio and separation are also extremely important elements. In the digital domain S/N and separation are not an issue, but in an analog mixers all three elements must be given careful attention. The hurdle is much higher in the analog domain, and in a sense it was a challenge.

Ikeya: In terms of sound quality we achieved the desired results through circuit design, parts selection, and repeated evaluation by professional engineers. Optimum S/N and separation were achieved through circuit design, a grounding scheme that eliminates the effects of noise from the power supply and external sources, and careful redesign of the printed circuit board patterns.

What does the PM5000 offer in terms of usability?

Wakamatsu: Scene recall is an important feature. Not just a simple scene memory, but a comprehensive implementation of the digital control system that has proven to be of great value in the PM1D all-digital console, including the recall safe and fader safe functions. There are a number of other innovations, such as the new summing gain controls.

And finally, why an analog console?

Wakamatsu: To us there is really no difference between analog and digital mixers. Our goal is simply to give discriminating professional engineers the tools they want and need to do the best possible job at any time.

Aoyama: The PM series has been at the top of the field for 30 years, and it's going to stay there.

Ikeya: We are fortunate to have extensive know-how and resources in both analog and digital sound. We haven taken the best of both worlds and created the best-sounding PM console to date: the PM5000.