A History of SQN       Part Two - Further Developments

In 1980, BBC outside broadcast were considering covering the upcoming football World Cup in Spain using the first Sony Betacam VCRs and therefore required a professional mixer for recording location sound. After seeing a Type M at Photokina and taking one for appraisal they put forward a list of thirteen detailed modifications they wished to see. The most important of these was the incorporation of a monitoring amplifier. No monitoring amplifier had been included at this stage since it had been assumed that anyone using the Type M would monitor off tape on the Nagra. Even though the Betacam had no off-tape monitoring facility, the BBC argued that they would at least like to be able to bring back a return signal to check that the sound was reaching the camera. This seemed to make sense and so in September 1981 the Series 2000 version of the SQN-3 came into being.

The SQN-3M mixer transcended in miniaturisation, endurance and performance all that had gone before and set new standards that other companies worldwide struggled to emulate.

All mixers produced up to September 1981 and all Type C mixers regardless of age are of the original Series 1000 pattern and carry a serial number 1 - - - (four digits only). The Type C continued in production until September 1988 but only about 100 were delivered. The National Film Board of Canada equipped all its 16mm film units with the Type C, but most other producers at this time were turning to videotape.

The SQN-3M Series 2000 was to continue in production virtually unchanged for exactly ten years. Only a few improvements were felt necessary when the Series 3000 version (serial numbers 3M-31000 on) was introduced in 1991, most notably the addition of an XLR-3M output connector and provision for Mic channel 3 to be switched to line level. In 1993 the six rotary baseplate switches, which originally were screwdriver operated, were fitted with shafts and control knobs.

No sooner had development of the SQN-3 Series 2000 been resolved than improvements to the Betacam by provision of a stereo sound input led SQN's broadcast customers to demand a stereo mixer of similar size and performance to the SQN-3M. Development of the SQN-4S 4:2 mixer began. Those customers insisted that this mixer should feature twin Peak Programme Meters in accordance with standard British broadcasting practice. The challenge was duly met and the first prototypes of the SQN-4S were exhibited at IBC, Brighton, in 1984.

SQN-4S Series 1

Volume production in Port St. Mary began in June 1985. Once more SQN had produced a unique innovative product and demand was so great that in April 1987 it was necessary to move to a much larger factory at Ballasalla. The SQN-4S soon supplanted the SQN-3M as the ‘industry standard’ portable audio mixer in Britain, though due to differing practices in various countries demand for the mono mixer was to remain steady for many years to come.

The meters selected for the SQN-4S were manufactured by Ernest Turner Instruments who unfortunately ceased production in 1987. When the SQN-4S was in development the smallest Ernest Turner meter had been the only one suitable for the minature design. In the meantime, however, Sifam had produced an alternative with a similar size scale, but occupying more space behind the panel. It became necessary to redesign the mixer internally and so the Series II came into existence.

The original 4S, known now as the Series I, has serial numbers from 4000 to 4399. Serial numbers for the Series II commenced with 4400, reaching 5 digits eventually. The SQN-4S Series II appeared in February 1988 and featured a decoding matrix in its headphone monitoring circuit enabling the recordist to listen to the output of a Mid Side microphone in X-Y stereo, although at that time no purpose built MS microphone had reached the market. In February 1993 the Series III version of the SQN-4S was introduced (serial numbers 43000 onwards). Essentially a development of the Series II, it added an MS decoding matrix in the audio path on Channels 1 and 2 and a phase inversion switch for channel 2.

In June 1993 further changes were made in a redesign of the Panpot panel and change in function at the Channel 2 fader. This version known as the Series IIIA (serial numbers 4S-43100 onwards) remained in production until the end of 1996.

Although the SQN-4S was the chosen mixer of the European Parliament, the company felt that the strictest compliance with the requirements of the EMC Regulations, which came into force on 1st January 1997, would require some redesign to improve screening against r.f. interference. In practise fair warning was given of the introduction of these regulations (if not of their precise meaning) so that a complete redesign of the SQN-4S was planned with the intention of also improving its performance, facilities and ergonomics even further. The SQN-4S Series IV (serial numbers 4S-50000 on) was first exhibited at AES Munich in March 1997 shortly after production had commenced.

While the additional arrangements required an increase in dimensions of the casework, there was no increase in the weight compared to the series IIIA model (2.2kg.) This was a side effect of the change to transformerless microphone inputs, which were introduced to improve the trade-off between overload margin and noise at low frequencies. Multi-layer circuit boards were introduced at this stage.

Although almost 1000 units were sold in the period following its launch, it became clear from user feedback that the new design offered rather more facilities than were strictly necessary, and that the 'modal' format of the controls appeared unintuitive to those brought up on the earlier designs. In consequence, the mixer appeared to be complicated to operate, although there were a few recordists who did indeed use all of the facilities offered.

A  decision was therefore taken to return to a simpler format which users of earlier models would find more familiar.

The series IVe (for evolution) was introduced in November 1999 (serial numbers 4S-51000 onwards) and greatly pleased those who had been critical of the now superseded series IV. The second M-S decoder, on Channels 3 and 4, was omitted and switching of the 4 Channel output was made a function of the connector rather than a front panel switch. A new limiter circuit took account of the fact that many users appeared to treat this device more as a compressor. Low current LEDs were installed for meter illumination in lieu of the earlier Betalites. Numerous other detailed improvements were incorporated.

Despite the continuing success of the SQN-4S in the market place, there had always been a pent up demand for an even smaller stereo mixer. The logical size for SQN to use would be the same as the ever popular SQN-3M, but just how useful could such a small mixer be, considering the limited space for controls?

In such a small case it would not be realistic to include all the facilities of the SQN-4S if the controls were to be accessible in professional recording work. After reviewing carefully the actual use that most recordists made of the SQN-4S, we concluded that by taking advantage of our considerable design experience, it would indeed be possible to provide what most people really needed in this small enclosure.

And so in June 2002, the first SQN-2S 4:2 mixer was produced (Serial Nos. 2S-60001 onward). It features the same Peak Programme Meters (or VU-meters if preferred) as its parent SQN-4S and the same limiter circuits. It also has the same Mic amplifiers and facilities for Channels 1 and 2, but Channels 3 and 4, intended primarily for radio mic. inputs have reduced facilities. Its weight, 1.1kg is exactly half that of the SQN-4S and 0.2kg lighter than the SQN-3.

Having satisfied those users who particularly the needed smallest possible size, the question naturally arose as to what further use could be made of the extra degree of miniaturisation represented by the SQN-2S. The logical outcome was the addition of an extra 5th channel to the SQN-4S and the replacement of the heavy output transformers with the electronically balanced output stage that had proved so successful in the SQN-2S. The result was the SQN-5S, introduced in January 2005. Particular efforts were made to keep the power consumption down by reorganising the way in which certain internal functions were carried out. This was so successful that the power consumption of the 5 channel mixer was marginally less than that of the 4 channel. The new mixer, at 2.1kg, also weighed 100g less than the SQN-4S.

The new 5S had continued in its original form for just 12 months when it became clear that the new circuitry had left enough space inside to allow its usefulness to be extended even further. Accordingly, a second pair of output stages and a second monitoring return output were added so that the mixer would be capable of working with two cameras or recorders. At the same time, the output connector block was reorganised to provide more unbalanced outputs. This new version was simply named SQN-5S Series II.

The 5S had always had post-fader access to the individual channels. With the rise of multi-channel disc recorders, this facility was used more often and also pre-fader output was required. From November 2006, the scope of the direct outputs from the 5S was increased to include both pre- and post- fader outputs, together with a line-up tone to provide easy calibration of the recorder inputs relative to the most convenient setting of the mixer controls.

The 2S also underwent a transformation. In December 2006 it became the SQN-4S_mini. Bass cuts were added to channels 3 and 4. These channels were also provided with redesigned control knobs which were easier to use and better matched the appearance of the large fader knobs. The replacement of the old 4S by the 5S facilitated the renaming, which was intended to make clearer the 4 channel nature of the small mixer.

In July 2010 the SQN-4S_mini mk II (with Serial Nos. from 4SM-62000) appeared. The facility for powering the long obsolete D.I.N. (AB) T-power microphones on Channels 1 & 2 was dropped in favour of a line input (-40dB), so that all 4 channels could be fed with line level signals. The Cannon XLR-5M connector was substituted by an XLR-7M which allows for feeding out not just the stereo mix and Line-Up tone, as before, but also 4 individual channels at pre-fade level to drive multi-channel recorders.