MILESAGO - Industry - Sound Systems

Three major firms made amplifiers in New Zealand in the Sixties and beyond (Holden and Gunn being the other two) but Jansen is probably the oldest and most successful manufacturer of musical equipment. Their range of amps and instruments will be well-known to any Kiwi musician who plied his/her trade between 1960 and 1999. They were probably the New Zealand equivalent of Fender, producing the whole range of essential rock gear including guitars, basses, organs, bass and guitar amplifiers and PA systems and their equipment is still highly regarded today.

The company began in 1959 when Bruce Eady and Jack Collins set up a business in Upper Queen Street, Auckland, repairing pianos and assembling amplifiers with the help of four other technicians. By this time the local industry was growing rapidly, and noticing that another popular brand of NZ amplifier, the Concord was then in short supply, it encouraged Eady and Collins to start a small production line on the first floor of the Methodist Central Mission building, opposite the Town Hall. Bruce Eady then had a factory built in Pollen Street, Grey Lynn and ventured into building guitars and organs. The organs had to be built from entirely from scratch as no pre-assembled keyboards were available. From there Jansen moved into premises near the Heard’s sweet factory in Parnell. The Ruskin Street factory turned out many of Jansen's now famous guitars.

Around 1965 the semi-acoustic International guitar was produced. This innovative instrument featured active pickups and tone selecting circuitry. Many of the guitars produced in those days have since become collector&'s items. Guitar Player magazine featured an article showing a Jansen solid body Beatmaster displayed in New York's Hard Rock Café. Solid Body and semi-acoustic models were all hand-made by Jansen until 1971.

In the fifties, valve amplifiers were the only form of amplification available. A bass rig of one hundred watts, fed through a set of four Rola or Philips twelve-inch speakers, was the envy of any musician who played in the venues of the day. In the days before the introduction of affordable portable PAs, many bands used Jansen's classic Bassman 50 amp as their entire sound system, with the microphones plugged into channel one and instruments into channel two.

Jansen's valve amplifiers are still prized today for their warmth and clarity of tone. Julian Reid, of Auckland indie band Stayfree Carefree uses both Jansen guitars and amps and you can read positive reviews of a Jansen Bass 75 amp on the Harmony Central wesbite.

Around 1965 the first metal-cased power transistors became available to amplifier manufacturers. Taking advantage of this new technology Jansen produced the well known PA 80 and PA 150 solid-state public address amplifiers, as well as a line of Lead and Bass Combo amplifiers. Later, in 1979, the very popular PA 5-100 joined the production line and became an industry standard, with demand ensuring production for over eleven years. They proved to be smaller, more efficient, more powerful, more reliable and were only a fraction of the cost of their earlier valve counterparts.

One satisfied group of Jansen customers in the late '60s was Sydney band The Dave Miller Set. Dave, who began his career in New Zealand, was well aware of Jansen and had dealt with them during his time in Auckland with his previous band Dave Miller & The Byrds. DMS made a tour of the South Pacific over Xmas 1967, which included a stop in New Zealand, but during the tour it became glaringly obvious that their makeshift rig had to be replaced. Luckily, Dave was able to approach Jansen and he arrange a deal with them, and with a loan from his father he was able to purchase a complete Jansen rig including powerful new guitar amps for guitarist John Robinson and a new Jansen bass and an amp rig for bassist Bob Thompson. As both Dave and John have attested, the powerful new Jansen gear gave them an edge over most of the other groups of the time, who were still using much less powerful gear (John's previous amp was a Vox AC-30, less than half as powerful as his Jansen rig) and this was a crucial factor in helping them become of the first Australian groups to successfully pursue the new "heavy rock" directions pioneered by bands like Cream and The Jimi Hendrix Experience.

It was not until the late seventies that the now well known MOSFET (Metal Oxide Silicon Field Effect Transistor) was developed by Hitachi of Japan and subsequently designed into the circuits of new Jansen products. First to appear in the Jansen catalogue was a range of keyboard, lead and bass amplifiers. Next to be developed were the MOSFET series powered amplifiers. For over a decade they won a strong reputation as being powerful, reliable and efficient comparing well with all other competitive brands.

By the the nineties, however, as the rock music boom began to slow, Jansen found it increasingly difficult to keep its products competitive against the plethora of brands being mass-produced and imported from Asia. Sadly, at the end of 1999 the proud forty-year tradition of manufacturing of “Jansen” branded products came to an end.

But the company continues, still a family concern, with Bruce Eady's son(?) Brent as co-director. Jansen Limited (formerly Jansen Sound Limited) combined with Jansen Agencies Limited in early 1999, and the company now imports a complete range of musical equipment from around the globe.

from John Robinson's Blackfeather Music Productions website:

"(At Xmas 1967) both Bob and I invested in new Jansen stacks 100-watt RMS heads with two quad boxes each. These were Kiwi amps modelled on the Marshall design. The tone was not as nice as the Vox but they were LOUD! ... The higher power and coverage of the Jansen Amps was giving us the edge over other Sydney groups. "

from New Zealand Musician magazine, Vol. 8, No. 3 June/July, 1999

Matt's Speaker Facts

By Matt Hennessey

"Old Kiwi Valve Guitar Amplifiers"

The genesis of this article was a coincidence of events. I received several email messages and phone calls from readers after my column on valves (tubes) in the December/January issue asking for information about designs and restorability of old Kiwi-made valve (tube) amps.

By old, I mean amps made in the '60s and '70s which include Jansen, Fountain, Fender (which were New Zealand assembled), Gunn and Holden. Around the same time I was asked to repair several of them. As I repaired these amps I noted my impressions of their performance, the quality of construction, their ongoing serviceability and their ability to be upgraded. (I must also admit here to having an uncommonly extensive stash of valves just in case I get around to building my design for a 1000 watt room-heating amp I've had knocking around my brain for the past decade.)

Unfortunately I did not repair or test any Holden amplifiers for this article but I have repaired them in the past and know they are reliable amplifiers with good tone.

Fountain only made one guitar amplifier, the Thunderbird. It was two channel with tremolo and rated at about 35 watts. This is my least favourite of the old Kiwi amps. The use of non-guitar-amp-standard EF86 preamp tubes and a two-plane hand-wired component layout make service difficult. Although I was only able to visually inspect one of these amps, I suspect their tone would be 'unique'.

I tested each amp for frequency response, paying particular attention to the useable clean low frequency and high frequency performance, maximum clean power at onset of distortion over the useable frequency range, and maximum power output capability driven into severe distortion. I should note here that valve guitar amplifier manufacturers typically save money by using simple output transformer winding techniques that handle power but limit the treble performance to all that is required for a guitar.

Hum and hiss noise were measured peak-to-peak (P-P) on an oscilloscope with the master and tone controls on full, one channel at about half and input shorted. I also had a guitar player friend do a non-comprehensive listening test using a 2 x12" Celestion cabinet and '70s Fender Stratocaster. Results were as follows:

Jansen Bassman 50
This is by far the most common of all the Jansen valve amps, followed by the Bassman 75. Bassman 35s, 100s and 150s are rarer. Guitar amplifiers include the 620, 630, 640 Twin, 645 etc. All the Bassmans use the same basic circuit which is a Jansen original. The power amp driver is almost hi-fi with a pair of ECC82 (12AU7) valves in a slightly more complex three stage circuit than your average Fender or Marshall. Each of the two input channels use the usual single ECC83 (12AX7) valve. The tone control circuits are rather weird with a special 350K ohm tapped potentiometer for the treble control. However, all of the tone components are hand wired point-to-point off the main board and can be easily modified. The amps were 100% hand wired before 1968. After this circuit boards were used for the preamp/driver valves. Some also have the output valves sockets mounted on the board while others have the output tube valve sockets mounted on the amp chassis, a more preferable arrangement. Serviceability is generally easy. Something I like about Jansens is they copied the Fender Bassman chassis layout. So, the amp heads are easily converted into combo amps by making a vertically stretched cabinet that holds speakers as well as the amp. Two 10" or single 15" speakers fit nicely.

The Bassman 50 that I serviced was well maintained. The chassis was sturdy and component quality generally good. The transformers were larger than 50 watt Fender Bassmans.

I replaced the output tubes with Sovtek 5881s. Cheaper Sovtek 6L6GCs could not handle the plate voltage although they would be a good choice for the Bassman 35. I also repaired some wiring faults and modified the power amp feedback circuit per Jansen's instructions. All preamp/driver tubes were fairly new and tested.

Listening tests revealed a grainy, dull tone which showed up as poor treble response in bench tests. Jansen used a variety of transformer manufacturers, so all Bassman 50s may not sound this way. Bass response was good.
Jansen Sound recently reorganised to Jansen Ltd. Although they have stopped manufacturing, they still service and have ample spares for valve amps. See the end of the article for contact info.

Gunn 100
The amp I tested used 3 x ECC83, 1x ECC82, and 4 x EL34 output valves. The power amp circuit is similar to some 200 watt Marshall types. The two channel amp had simple tone controls on channel one and Marshall type tone controls with a simple foot switchable gain boost on channel two. Gunn made a variety of 50 and 100 watt amplifiers, some in combos.


References / Links

Jansen Professional Audio & Lighting

New Zealand Musician

John Robinson's Blackfeather Music Productions

Harmony Central