Interview with Peter Thomson, founder of Plinius

September 2009

By Michael Jones

Peter Thomson founded the iconic New Zealand hi-fi brand Plinius in 1980. Now living back in his native Australia, AudioEnz took the opportunity to quiz Peter on the early days of Plinius

Q. Until the move to Christchurch this year, Plinius has always been based in and around Palmerston North. So how did a Tasmanian end up in Palmerston North?

My family and I arrived in New Zealand in 1976 to start an aluminium ladder fabrication factory for a Christchurch based family business. They had a factory in Christchurch and Auckland and wanted to be able to service the lower half of the North Island from a central location.

We wanted to live in New Zealand at the time, were passing through Palmerston North and I saw the position advertised in the local paper. It sounded interesting, suited my engineering background and so I applied for the job. The company owner flew up to Palmerston North to interview me and I went back to our motel after the interview with a new job plus a chook that he had won that night at the Commercial Travellers club. He didn’t want to take it back to Christchurch.

Q. New Zealand was very different back then. What was the hi-fi scene like in New Zealand at the time?

Most equipment in those days was either smuggled in from the outside world or built by enthusiastic amateurs of whom I became one. There was some commercial equipment available but nothing that was anywhere near sanely priced.

Q. A traditional path for a hi-fi business is a guy in a garage building an amp or speaker for himself, with friends hearing it and wanting one. Is this how you started?

My first real project was a head amplifier for a moving coil (MC) cartridge and after I had built it had a bit of a problem, as I didn’t actually own a MC then. So I contacted a local music lover, he had one and we tried it out in his system. It was pretty amazing for those days. He had a Yamaha receiver, Linn turntable, KEF105 Speakers and soon one of my head amps. I then built my first pre/power combination and he had the second one.

Peter Thomson (left) discussing amplifier design with Jerry O'Dowling, an electrical engineer at Massey University
and Robert Johnson of Audio Associates

Q. It's a big jump from building the odd amp in your spare time to trying to make a living from it. When did you make the jump? What was behind the decision?

Naivety and stupidity and not necessarily in that order. I think that I had no fear in those days and figured that with a bit of backing I could make a go of it. I had about $1.80 but a friend, David Lane, had a business he wanted me to run for him and so I jumped ship from the ladder factory, started with David and began serious electronic development using some of the profit from the existing business. It was amazing; I took my first amplifier and preamplifier to the PSIS Investment store in Wellington [then a major hi-fi outlet – Editor]. They had everything there but no amplifiers that would successfully drive the newly available Acoustat electrostatic loudspeakers that they were selling. My amp seemed to cope and they gave me an order for 24 of them. I couldn’t believe it.

Q. Where did the name Plinius come from and how did you choose it?

My wife Vonnie actually chose the name. We were stumped for a sensible name and I asked her to get a map of the moon as there are some great sounding crater names. She went to the library and found Plinius. It sounded pretty good and Plini seemed a good guy in all that he did so there it was.

Q. I know there was a model 2 preamp and a model 3 power amp. What was the Plinius model 1?

There was no Model 1. We started with 2 as it looked as though we had been around for a while!

Q. When I was at Massey University in Palmerston North in the early 1980s I asked a local dealer about Plinius amplifiers. His response was that they didn't stock the brand as the store could go down the road and get one if a customer asked for a Plinius. How difficult did you find it to get hi-fi retailers to stock your amplifiers?

Well like all things local the grass is greener on the other side of the fence. It’s also more difficult to mow but most people don’t think of that.

As I said I had good support from the Wellington region but that was really about it for a while. Frank Denson from Soundline in Christchurch arrived in Palmerston North at one stage and saw and heard a Plinius 2 and 3 at Manawatu TV and Sound. He liked what he heard and George Anderson from MTV sent him around to see me. That started a very long relationship, which saw Frank selling Plinius in Christchurch for the next 27 years.

The local retailers gradually began to give us some shelf space and then we started to have some success in Auckland. There was a lot of NZ manufactured competition in those days but, save for Perreaux, they all fell by the wayside.

The best thing that ever happened to Plinius was the meeting and eventual friendship that Gary Morrison and I started. We were together for 20 years and it was a really rewarding relationship. Unfortunately Gary’s own brand Craft did eventually die and it was probably our fault that this happened. We decided when we merged that we would manufacture Craft in the same factory as Plinius but sadly it was not successful. I think that we tried to combine the two identities and use some common manufacturing methods. If the two had have been kept separated Craft would have continued. It would be interesting to see the result had this happened.

Gary Morrison and Peter Thomson with a range of Plinius product, 1999

Q. The first Plinius models were the 2 preamp and 3 power amplifier, released in 1980. Were these units largely your own designs, or a variation on an existing circuit?

The original 2 and 3 were a mix of circuit designs, some of my own, some generated by an old (now deceased) friend at Massey University and some ideas from other sources. The important thing was that they were solid and had a real ability to convey the emotion of music unlike many other amplifiers around at that time. It was a time of real experiment with transistor designs and of course a time when it was becoming quite obvious that measurement had no relationship with what was heard.

Q. Sometimes known as the "Plint", the combination of the Plinius preamp combined with a smaller power amp was very popular in New Zealand. How did the Plint come about? And how did it develop over the years?

I realised that to exist in New Zealand with its small population it was not going to be enough to have just one model available. We had by this time released a mono power amp and a mono preamp to cover the upper end of the market and so it seemed logical at the time to produce a less expensive amplifier to go with our 2 preamplifier. The Plint was originally a 50 Watt per channel amplifier with a relatively small but dynamic power supply and it sounded really good. As a system it had the house sound mainly due to the preamplifier and drove most speakers very well. It was less expensive to build than the larger models and allowed an entry point to more Plinius customers.

The Plinius Plint – a combination of the 2 preamp and 7 (later 760) power amplifiers

Q. The 2 preamplifier went through four versions (2, 2b, 2c and 2.4). How did your preamp designs change throughout the life of the 2 preamp?

The 2 Preamp was in a very small box and the power supply was contained in the 3 power amp. We did make a separate power supply available at a later date during the life of the 2 and 3 and this made a huge difference to the sound of the preamp. The transformer was very large and of course there was a large storage capacity as well. The 2b was the first preamp in a slimline chassis and took what we had learned about power supplies and included these ideas in one box. The 2c was a little different and was the first with a higher gain phono stage as well as an updated line amplifier. The 2c had a larger chassis and better shielding. The 2.4 was a real change and in was introduced just prior to Gary becoming involved in the Company. In fact Gary took one look at what we had done and made a couple of very good changes to the 2.4 that certainly enhanced its sound. Consequently the 2.4mk2 was a major leap ahead.

Q. Fairly early in the life of Plinius you introduced a mono power amplifier. What can you tell me about it?

The Limited Mono was a variation of the original circuit from the 3 power amp. The differences were quite substantial in that the mono amp had an increased number of output devices and a much larger power supply. The transformer was around three times larger and the storage capacity was increased. Although only 125 Watts it had an immense ability to drive loudspeakers due to increased current delivery and the Limited Mono sold really well.

Q. The MA100 was the first class-A Plinius power amplifier produced - a path that lead to great success for Plinius. Why did you start looking at class-A amplification?

I had been messing with Class A for a while and had converted a couple of 3c power amps into mono Class A to see if I could hear what I was reading about from other parts of the world. Yes there were differences and they were significant. However there was a real issue of heat and getting rid of that efficiently was a real task. Stax at the time were using a heat pipe in one of their newer amps and so I did some research and found that we could simply fabricate a heat pipe in house. I had some help from Temperzone, the refrigeration company, and they manufactured the parts for us in Auckland.

Q. The amplifier that put Plinius on the map internationally was the mighty SA100 power amplifier. Was this the culmination of the design work for Plinius amplifiers, or a new direction? Why was it that the SA range in general and this model in particular, launched Plinius internationally?

The SA100, while not unique, certainly was a major change for Plinius. The large external heatsinks were very distinctive and the concept of having all that performance in a relatively small footprint opened plenty of doors. The SA100 sounded wonderful and was probably the first Plinius product that was accepted as being internationally competitive. It was the first Plinius product on show at the CES and attracted our first US Distributor. In fact it was David Chesky who heard the SA100 on the last day of the show and made a lot of noise about how it was the first time he had heard his recordings outside of a studio reproduced correctly.

The mighty Plinius SA-100 power amplifier

Q. Today, integrated amplifiers are mainstream at even higher price points. But back when Plinius introduced the 2100i, any serious audiophile “knew” that a pre-power combination was necessary for great sound. So why did Plinius introduce their first integrated amplifier? And was it simply a preamp and power amp shoved into the one box?

The primary idea of an integrated was to provide a new entry point to Plinius. The pre/power combinations were increasing in cost for a variety of reasons and we wanted to keep the door open at the less expensive part of the market. The 2100i was our second attempt at an integrated. We tried one previously but it didn't see the light of day. The 2100i was a major rethink on Gary's part and started a very successful segment of Plinius's business.

Q. I still own an 8150 integrated amp, which was another important model for Plinius internationally. What made this amplifier special?

The 8150 was a progression from the 2100i. After the 2100i had been in the market for a while it was decided to go further upmarket and increase power and add a phono stage worthy of a pre/power combination. We achieved this and of course as market demands were identified, changed the power level and a few features to establish the 8200 and then the chassis change to the current rounded look demanded an model change with the 9200. For many customers the 8150/9200 concept is all that they will ever want in an amplifier and it sure does fit into a domestic environment far more easily than some of our other efforts. It’s not easy to hide an SA250 in a 'stereo' cabinet!

Q. You've always been a big vinyl fan, even carting your own turntable to hi-fi shows and talks to audio groups. So it was a big event for Plinius to bring out a CD player, the CD-101. What was behind this event?

The release of the CD-101 allowed our customers who had already invested heavily in the new Plinius products to finally be able to have a product that not only raised the performance bar but also physically matched the other equipment. We also needed to honour that Plinius was a music company and that people derived their musical pleasure from many different sources. Digital is as valid as analogue as are all types of music and it would be foolish not to acknowledge that there are many ways of skinning a cat.

Peter Thomson is currently enjoying semi-retirement, travelling around Australia with his wife Vonnie in a caravan he built himself.