Jurassic (S)park! Dynatron LS1428

Vintage 1970s veneers

[Dynatron LS1428 loudspeakers]

Downgrading stories: Loudspeakers

Product: LS1428 loudspeakers
Manufacturer: Dynatron - UK
Price: From £20 in flea markets and fleabay; as usual YMMV due to supply & demand fluctuation
Author: Mark Wheeler - TNT UK
Reviewed: Spring - Autumn 2021

Dynatron Downgrading, anachronism or anarchism?

Circumstances change throughout life. This reviewer's day job is often about helping people live with their current circumstances rather than continuing to do what they have always done in past situations. Our esteemed editor Lucio Caddedu has already introduced the concept of strategic downgrading. A house move has resulted in room volume reduction from 100m3 to 40m3 for your Old Scribe.

The monstrous TQWP/transmission line hybrid, Hammer Dynamics derived, high sensitivity (97dB/2.83V) passive monsters would overwhelm this room and be too close to listeners to integrate and time-align. The 3-way active Focal Audiom missiles would have the same problem and their high current electronics would not be optimum without a dedicated audio power supply. So, inspired by Lucio's experiences, your Old Scribe dug out his old Dynatron LS1428, unused for many years.

“What on earth are those?” moan Plebs Chorus, “Weren't Dynatron that British company that just made music centres and televisions to look like antiques?”

Dynatron History

Like Linn many years after Dynatron, this venerable British radio and Hi-Fi institution, Dynatron, embraced the lure of department store sales and adapted the image of their products to that culture. Unlike Linn, Dynatron failed to preserve their reputation for audio excellence in the era of aspirational separates and mainstream domination of consumer electronics by Japanese brands.

Dynatron was founded by the Hacker brothers in 1927, who eventually sold Dynatron to Ekco (famous for their Art Deco Bakelite radio). Ekco merged with Pye in December 1960 and in turn Philips took over Pye in swinging 1967. This was a typical series of mergers and acquisitions of the oldest British audio brands, resulting in uninspiring management and balance sheet marketing.

Away from the vision of their founders, Dynatron, alongside brands like Pye and Leak were sliding down the off-ramp of credibility. Philips, exceptionally among the entertainment and domestic electrical orientated groups of the day, identified good audio as a priority. Absorbed into vast electronics and entertainment corporations, many of those other former great audio pioneer companies became mere minor distractions. This is so often the case for audio and music in the 21st century too, as financial conglomerates whose focus is on casinos, bingo halls and occasionally movies do not identify high quality audio as significant contributors to annual shareholder dividend and so neglect R&D until the brands fade away. In front of your Old Scribe today are a pair of completely unrestored nearly half-century old Dynatron LS1428 making involving music with some obvious and easliy surmountable shortcomings.

Voyage of Discovery

A newly teenage scribe wandered around the various audio and electronics emporia of his provincial town of 250,000 inhabitants, admiring the wares, quizzing the staff and whenever possible auditioning equipment. Life savings of £150 were due to be invested in that first step of 1970s manly aspirational acquisition, a hi-fi system. The numerous audio, TV and record shops enabled opportunities to audition a wide range of products from many manufacturers. Pioneer, Sony, Onkyo, Sanyo, Marantz, Bang & Olufsen, Quad, Thorens, Transcriptors, Sugden, SME, Garrard, Trio (Kenwood UK brand), National Panasonic & Technics, Goodmans, Wharfedale and many others were there to be viewed and heard. How times have changed!

Music Centres were what families aspired to, one step up from a console radiogram, which combined turntable, tuner, cassette deck and amplifier under their wide perspex lids. Typically the pair of loudspeakers supplied with music centres were designed to be as inconspicuous as possible and destined to live in locations behind the sofa and on a bookshelf. These were not to be taken seriously.

In particular, the local department store, Beatties, was not to be taken seriously because it sold audio equipment made to look like antiques. Elizabethan loudspeakers, Regency turntable plinths and Victorian tuner-amplifier (receiver) housings stretched anachronism beyond all credibility. However, Beatties also had the Sony TA88 vertical styled electronics on display as well as assorted wares from National Panasonic, their more serious sibling Technics, Leak and Phillips.

Your young scribe often entered the TV & Radio department of this old department store because they sold music singles and LP's at the most competitive price in town. Wandering over to the shelves of equipment, as the only customer on a wet weekday afternoon, your old scribe spotted one of the new Direct Drive turntables that were just appearing on these shores. While trying to lift the platter to see how it worked, your adolescent Old Scribe was inevitably challenged by an otherwise underemployed salesman. On discovering the level of enthusiasm for audio displayed by this young future potential customer, the salesman devoted the remainder of the afternoon to playing hifi.

A series of auditions used up the remainder of the afternoon for both scribe and salesman. Several return visits resulted in a growing knowledge. This was interspersed with auditions at the numerous other local Hifi emporia that graced every medium sized British market town in the early 1970s. One day that Beatties salesman suggested substituting Dynatron loudspeakers, from the furniture audio end of the department, for the similarly sized Sony and Wharfedale pairs already auditioned that afternoon.

Immediately this scribe was impressed by the much bigger scale the sound created. The term soundstage was yet to be coined, but that is indeed what this was. Holst's planets were clearly in a much larger Solar system than that orbiting in the Wharfedale Lintons.

The loudspeakers creating this sense of space were Dynatron LS1428. How could this be? Dynatron equipment was never mentioned in 1970s Hi-Fi magazines. The little Wharfedale Lintons were a budget favourite in the HiFi dealer ads and the Hifimarkets press. The Lintons had impressed far more than the equivalent entry level Celestions, which at the time seemed to lack both treble and bass (a boy's audio priority during puberty) and here were a much better pair of loudspeakers from what seemed to be a furniture maker.

Your adolescent Old Scribe also noticed that these Dynatron LS1428 loudspeakers really rocked, when we borrowed the latest Mott The Hoople from the adjacent records department. At that time the term PRaT had yet to be coined. Whether loudspeakers could affect it was as yet undebated, but your Old Scribe clearly heard rhythm bounding along more accurately from these Q≈0.7 sealed boxes compared with the lumpy Q reflex rivals.

That venerable department store Beatties soon had a sale on and those Dynatron LS1428 were duly purchased at half price.

Fast forward to the present day

Resurrected from their attic abode, very little work was needed before reconnecting and auditioning. These poor old things had been subjected to a variety of indignities as a young scribe tried to improve their sound quality. This had included trying different tweeters, different stuffing and (temporarily) changing the loading to port loading (the Peerless Thiele Small driver specifications were provided by request from a local supplier). All the experiments had been reversed afterwards, but integrity of each connection and fixing tightness had to be checked after so much time.

Sound Quality

Fearful of the terrible disappointment of cherished memories, exacerbated by deteriorated driver suspensions and ancient electrolytic crossover capacitors, your Old Scribe began listening with the free disc from this month's copy of Uncut magazine. Initially tested in the old listening room to ensure that the Dynatron LS1428 will work when relocated, the first play was on the end of modified Shanling CDT100C, Audio Research Corporation Reference 3, Breeze Audio clone of a Nelson Pass single ended solid state power amplifier. With removals imminently due, there was time only for a couple of discs and the turntables had already been packed.

Suffused with anxiety that these might not work, or work very poorly, the system was powered up and that free sampler disc from Uncut magazine was loaded and play was pressed.

Hmmm. Not bad at all. Perched atop Target sand filled LS3/5a stands and a sheet of vibration control polymer, bass is articulate, although midrange was slightly recessed and slightly distorted. Treble dispersion accurately matches the bass-mid driver but treble distortion is obvious, while no worse than any vintage mid priced soft-dome tweeter via the dried out electrolytic capacitors of a half-century old series crossover. That bass articulation and pitch accuracy from the second-order loaded 200mm paper cone Peerless driver is refreshingly different from the dominant modern reflex loaded small driver flavour.

Back in the day Pink Floyd's Dark Side of The Moon was probably pumped through this pair of Dynatron loudspeakers for more hours than many other albums. Only Jimi Hendrix's Electric Ladyland got more hours, so the MFSL DSOTM CD gets a spin. These little speakers had never sounded so good, apart from the age related treble problems. Indeed, with that caveat about treble, on the end of a system featuring products from Shanling and ARC Reference these unrestored Dynatron LS1428 did not seem out of place.

The bass is the most impressive surprise from these 28 litre sealed cabinets. Without any undue emphasis from high Q alignments or a port squeezing some extra extension, these are more bass articulate than the similarly sized vented market leading stand-mount (then known as bookshelf) loudspeaker of a decade later. Good bass timing and articulation might be expected of a lean sealed box alignment, at the expense of extension. However, these Dynatron LS1428 sound fairly close to Q=0.7. Also known as maximally flat or critically damped, Q=0.707 is the optimum trade-off of low frequency extension vs flat frequency response with minimum ripple.

Any Colour You Like on DSOTM surprises with its rhythm, dynamics and even cymbal work well preserved. The latter is of particular note as these are old cone tweeters, a technology thought old hat (even old high-hat) the year this pair were in the shop. Your Old Scribe did try contemporary alternative Kef T27 mylar dome and Peerless fabric domes (the two types as fitted to contemporary IMF and Infinity systems in the 70s). It helps that there are still folders of notes to consult. Although the alternatives increased top end clarity it was at the expense of a very narrow sweet spot in the listening room due to the sudden change in dispersion at the crossover point.

The transients of Nightmares on Wax Gambia Via Vagator Beach are so top to bottom linear and in ya face that the track gets repeated at higher level. The cheap little Pass clone 10W single ended solid state power amplifier is sufficiently up to the task. Indeed the grille cloth of the left loudspeaker drops out, loosened by the vibration of bass thwacks. The treble immediately opens up. Covers off is the order of the day.

On moving to the new listening room, a vintage Accuphase E-202 amplifier was chosen to power this resurrection. This magnificent Japanese integrated amplifier stood head and shoulders above even the rarified competition from Sony and Pioneer of the day, when your Old Scribe auditioned them. Your Old Scribe spent far too much time loitering in records shops and audio stores which probably explains his dismal exam results. The Accuphase E-202 has bypass switching to avoid the circuit complexity of the various tone control and filter circuits. It has two moving magnet cartridge turntable inputs, one with a level control to match when comparing. It even has a variable damping factor control (i.e, variable output impedance) for loudspeaker matching. The Accuphase E-202 would admittedly be from a very different market segment, several strata above the Dynatron LS1428 but neither of them have been recapped or otherwise serviced so this audition is representative of what you might buy now on the used market.

Trawling through the music that would have graced the Old Scribe turntable when these were new, it might be expected that they would disappoint. The Dynatron LS1428 merely continue to surprise by their capabilities. Many listeners prefer paper cone bass-mid units to more high-tech ostensibly low-colouration cone materials and the Peerless bass units make a good case for that opinion. Particular strengths include male vocals and the timbre of instruments in cello range. Despite a relatively tiny magnet for a 200mm bass-mid driver, the low mass cone and choice of sealed box alignment combine to deliver punchy bass.

The cone tweeters closely match the bass-mid driver for dispersion around the octave each side of the crossover point, helping produce a balanced sound in acoustically untreated rooms. The cone tweeters are no less resonance prone than dome tweeters increasingly fashionable in the 1970s. In that respect the Peerless HFC200 tweeters occasionally draw attention to themselves irritatingly. The contemporary Peerless HF10MRC was a favourite in high-end monitors of the day. Your Old Scribe tried those tweeters on top of these boxes crossed over externally, at the time and concluded that Peerless and Dynatron had made the correct choice.

Technology

Dynatron had previously used Goodmans drive units in their 1960s loudspeaker range. Like most British audio manufacturers of the pre-VAT days, they were subject to the dreaded purchase tax on all goods for domestic use. The reason certain driver sizes proliferate in British loudspeakers of that era was that they could avoid purchase tax if deemed for “professional/commercial” use, like the ubiquitous EMI 13x9 driver. By the 1970s taxation on domestic electrical goods were converging with other household electrical goods, allowing designers more freedom.

The Danish driver manufacturer Peerless was offering kits of its drive units, offering ready permutations for box stuffers. Peerless was founded in Denmark in 1926, a similar vintage to Dynatron. Peerless drivers apparently get stuffed into Acoustic-Energy, Castle Acoustics, Eltax, Harbeth, Heybrook, Jamo, JPW, Mission, Monitor Audio, Paradigm, TDL etc.

1970s Context

A friend brought round their newly purchased class leading, well reviewed, loudspeakers sold as monitor quality, even described in one regurgitated press release (aka review) as “studio monitors”. These 4-way monsters contained twice as many drivers and nearly twice as much air as the little Dynatrons. They were reputed to be the last word in low distortion, low cabinet colouration, high power reproducers with extended bass. They sounded flat and lifeless beside the LS1428s.

The friend suggested that the Dynatron LS1428 enjoyed some kind of synergy with the Phillips derived Dynatron amplifier in use (a pair of Phillips modules with a surprisingly large power supply) so we substituted a Trio (UK edition of Kenwood) with the same results. All four loudspeakers were schlepped to the friend's place and hooked up to their Quad 33/303 pre-power combination. The outcome was the same. My friend posited the hypothesis that the “liveliness” was entirely due to the colouration of the smaller cheaper speakers adding “artificial excitement”.

In retrospect the extremely complicated response shaping, high order (steeper sloped) 4-way passive crossover of the big monitors was probably to blame. The 3 transitions between drivers probably screwed up the phase response and the high component count probably caused higher losses than the simple series crossover of the 2-way Dynatron LS1428. The reflex loading of the 4-way monitors will also result in considerably more group delay than the Dynatron/Peerless maximally flat Q of 0.7. A decade later the trend in cutting edge UK loudspeakers was towards simplified gentle slope crossovers. The Dynatron LS1428 was simultaneously ahead of and behind its time.

Many similar sized loudspeakers were tried in our various systems and the Kef Chorale impressed with good bass and much lower colouration, Jensen 3 with similar excitement and cone colouration, Acoustic Research AR14 for bass speed and size-performance ratio. The Kef and AR now sell for much more money (your Old Scribe has seen damaged examples of the latter for over £500 on Fleabay) than the still bargain Dynatron LS1428.

[Dynatron LS1428]

Conclusion

The Dynatron LS1428 is a little known vintage bargain. To be had for as little as £20 on fleabay for those willing to collect them in person. The constant refrain online and in the comics is that “speakers have come a long way” in 50 years. However, “ye cannae change the laws of physics, Captain”. Loudspeaker manufacturers buy a lot of advertising space in the magazines and there ain't no opinion expressed as strongly as a vested interest masquerading as an independent opinion.

These little Dynatron boxes are a similar size to the mid-treble modules of the 3-way Focal driver active system that was usually resident at the transducer end of the system in the Old Scribe TNT-audio.com mountaintop lair. Yet there, the Dynatron LS1428 rocked the room and created a better soundstage than could ever be expected from a system without flush drivers or rounded cabinets. The solid chipboard cabinets with real wood veneers produce very little cabinet colouration. The Peerless drive units may seem dated but they deliver the musical goods.

These 47 year old Dynatron LS1428 will be worth the investment in new crossover capacitors and fresh wire and resistors. If there are half-timbered mock Tudor or Regency versions for sale, these are likely to be at least as good, having much heavier 7.5kg veneered chipboard cabinets. Those would certainly surprise visiting audiophool snobs!

In place on the end of a vintage 1970s audio system, whether classic British brands like Leak or Quad or period Japanese, mainland European or American electronics, the Dynatron LS1428 will surprise listeners with a lively dynamic sound missing from many modern budget contenders.

Music enjoyed while writing this review

Reference system

  • Various Artists: Uncut selection CD
  • Pink Floyd: Dark Side of the Moon MFSL CD
  • Nightmares On Wax: Still Smokin CD
  • Jimi Hendrix: Electric Ladyland CD
  • Alice Cooper: Love it to Death CD
  • Bob Marley: Exodus MFSL LP
  • Charles Mingus: Mingus-ah-um MFSL 2LP 45rpm
  • Frank Zappa Teenage Rockin Combo: Dumb All Over, 1981 concert recording
  • Leftfield: Leftism, triple vinyl reissue bought after seeing the live performance at Womad

Equipment used in this review:

  • Primary Turntable: Michell Orbe SE with Pedersen subchassis & suspension kit and two belts
  • Orbe armboard: Pedersen Michell Armboard isolator
  • Primary Turntable vibration isolation: Polycrystal PolyCrystal Point Discs beneath Orbe feet and Deflex plain sheet beneath Orbe motor pod
  • Pick-up arm on Orbe: Hadcock GH242 SE with all silver wiring from cartridge to silver Eichmann Bullet plugs
  • Turntable shelf frame support: Origin Live Ultra wall support, chrome plated, nylon cord replaced by chains, outriggers filled with kiln dried sand
  • Turntable shelf wall isolation: RCD Cups (larger surface area than Polycrystal Point Discs to reduce wall plaster deformation)
  • Turntable shelf frame support: Rawlbolts embedded in hard plaster
  • Turntable shelf: 10mm laminated glass
  • Turntable support 2: Wilko AV shelf frame, filled with kiln dried sand shelves replaced from selection
  • CD Player: Chevron Audio modified Shanling CDT100C
  • Other tuning includes: Yamamoto Sound Craft including Yamamoto PB9 & PB10 and BrightStar extra large IsoNodes and various vibration control products.
  • Decca London (John Wright serviced 2020); Cartridge Man Music Maker II; and a selection of classic Stanton, Ortofon and Shure moving magnet types.
  • Phono pre-amplifier 1: Canor TP306 VR+ still top phono-preamplifier, on BrightStar extra large IsoNodes
  • Line Pre-amplifier: Audio Research Corporation Reference 3 with steel top cover removed, casework damped by BrightStar Little Rock 5, tube rolled and vibration further controlled internally by silocone O-rings and Pearl valve cooler/dampers, on Something Solid end grain balsa plank, on kevlar sling supported by separate sand-filled steel frame support
  • Power amplifier: Breeze Audio Nelson Pass Zen clone
  • Integrated vintage Amplifier: Accuphase E-202
  • Passive Loudspeakers:TQWP/Transmission-line hybrid passive loudspeakers (18mm & 25mm birch-plywood cabinets; long fibre natural wool stuffing; Deflex panel lined) loading the late the late John Wyckoff's Hammer Dynamics bass-mid driver
  • Passive crossover with litz-wired inductors & couture capacitors) and B&CDT400N & B&C DE-35-8 tweeters and Fostex ring tweeters.

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Copyright © 2021 Mark Wheeler - mark@tnt-audio.com - www.tnt-audio.com