Audio/ Stereo on eBay Australia, TANDY, EMI, harman/kardon.

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Left GLL IC130i are an improved bass version of the British I.C.T. speaker and with the 1970s harman/kardon A402 left, the original 30Hz bass note was awesome at 90dB for 1 watt but tones with polypropylene cones improved with 1990s harman/kard on amplifiers.  The A 402 (same power meter as the Citation 19) has Frequency Response or F.R. around 4Hz - 190KHz.  No speaker can reproduce that range but it was about better bass and treble in audible frequencies.  On internet forums somebody bought Realistic Mach One and found their KM4 right were way better.  Well ... the question is ... "Way better with what?"  Klipsch KM4 (believe it or not) was the last line made by the company for U.S. armed forces distribution worldwide.  It's a 2-way ported bass reflex, real similar to a KG3.5 and both are a tour de force.  A thin gauge stamped steel basket woofer in a black vinyl wrap MDF box, gives 94dB at 1 watt, 1 meter with 36-20 and is 8 ohms, the horn compression driver is plastic.  That beats the British GLL IC130 with 30-20 at 6 ohms and 90dB for 1 watt, its compression driver is aluminum and eliminates the need for a treble x-over, but the bass units use a nasty ferrous bar inductive x-over.  In the British market, speakers are made to waste power in urban areas, they sound loud in your house but won't disturb your neighbors.  The Mach One has an aluminum compression driver for middle range and audible tonal differences of constituent parts, need different amplifiers to sound their best.  eBay Mach One need run-in with a late 1970s vintage receiver of some capability as Realistic were seriously engineered to outperform units costing twice as much.  The Realistic Mach One isn't however just one speaker, but a whole load of versions, made in different places for different model year output transistors and to cut a long story short, getting good sound means you've made a good effort or just got lucky.
If we're used to a particular sound, it could be it'll score higher than what we aren't used to.  Newer amplifiers and inputs, furtherm ore a system bought to run together - could mean something added in from eBay will lose in the short run.  But speakers like the Mach One not only need run-in with a classic receiver of the same vintage but the Mach One and X-100 also needed warme d up, that's why Radio Shack left them playing quietly all day.  D own page the Optimus X-200 speaker did 18Hz - 28KHz, one of the deepest ever bass woofers, only the EMI 901 19 by 14 inch did better at 15Hz as a professional Studio Monitor but was of the highest possible quality.  Few sub- woofers are able to voice a tiger's roar that that will make us sit up.  Below a Realistic STA-2290 in a rare photo managing to show its vast, difficult to accommodate dimensions.  It's suited for the Liquid-Cooled Mach One with edge-wound former and recommended as a matching receiver.  Try it ... then claim Mach One sound bad if you like.  The double small diameter woofers attempt to improve bass clarity over large diameter woofers but are more about not disturbing neighbors.  The steel basket KM4 travels much better than a mica filled basket GLL Imagio.  American speakers like the also now defunct Soliloquy from North Carolina used fragile mica-filled plastic baskets.
Left the KEF 104/2 is another British speaker, mostly used in Australia's farming areas with the Carver TFM-25, part of a once envied American rack system.  The rare shot inside below shows us just how awful build quality of Carver usually was, with only 20-20 by way of a Frequency Response but with very high power to get the best from tall narrow black KEF speakers without resorting to the more extreme GLL IC130i attempt at better power efficiency.  The STA-2290 a bove could run as a control amplifier with the TFM-25 with ts output to pass a line level signal back to the receiver controller, using its own amplifier with Liquid Cooled Mach Ones.  Two different speaker systems running simultaneously can however degrade sound quality of both, even with one pair driven by a separate amplifier.

A load of people hated the Liquid Cooled Mach One left because they thought here was just another clunker.  But it was a high-End design, edge-wound former speaker with the STA-2290 specially tone tailored for the often controversial sound quality of these expensive and reliable bass speakers.  Because the STA-2290 has three versions we have to match the best vintage - the first two are 100 watt with two 12000MFD smoothing cans and plywood sides, the very first issue has a fake wood top panel, then there's the final 90 watt per channel with two 10000MFD smoothing cans and vinyl covered chipboard sides, the vinyl cheeks still deliver the 'tuned chassis' sound quality absent from most all steel cases.  People who saw the small magnet on the Liquid Cooled Mach One also concluded that it was a sign of a clunker, but the edge wound former design has a smaller magnet.  The most important thing with these is matching with the right vintage of STA-2290, running them in for a while.  If your country has all the STA-2290 versions, try different models to find the best match.  Remember the STA-2290 is tone colored for an edge-wound Mach One and that with Realistic receivers not engineered for the Liquid Cooled Mach One, results are sure to disappoint.  Remember to buy only the 4029 model horns and x-over for the edge-wound woofer.
REALISTIC X-200, X-100 and T-200

SELLERS BEWARE don't plug unknown Classic Valve amplifiers or Radiograms in to the mains, in the worst case they'll explode and in the best case you may cause some damage.  Be very wary of metal chassis valve amplifiers, the current in electrolytic cans often hides in such a way that you can touch any part of a chassis one minute and the next you'll get such an electric shock you'll think you're already dead!

Valve amplifiers are popular with certain audio collectors but suffer from a number of problems.  Although the Hi-Fi Pye 5/8 has variable Loudness many valve amplifiers lack bass.  It's because unlike the Hi-Fi Leak TL50 left, they lack power compared to Solid State amplifiers with good bass around 100 watts RMS.  The EARTH is crucial on METAL CHASSIS amplifiers, there's usually an earth socket on radiograms and you have to use it if there's no Earth in the 3-way mains flex.  If you don't Earth radiograms and then go and touch the metal record player, you'll feel a velvety sensation, if you touch a ground water copper pipe with your other hand, the current will cross your heart and the story goes you'll be thrown across the room.  D.C. power in only 16 microfarad 300 volt electrolytic cans is a serious risk even when the mains is disconnected by the plug!  So any metal parts must NEVER be touched, wear gloves!  Some owners wonder why they've to carry their Radford STA-25 with gloves!  Classic Valve amplifiers suffer from critical radio conditions meaning the domestic user cannot connect them like modern Solid State, they need to be adapted for the equipment they're to be used with or the sound would be disappointing.  Although we need a specialist to help us with Classic Valve amplifiers, modern sets are much easier as standards in audio are more alike today.  The Proton D1200 and 1100 are Australia's workhorse for modern 4 ohm speakers that make modern amplifiers heat up too much.  Impedance below 8 ohm gives amplifiers a problem, Denon made their Home Theater receivers in a 6 ohm minimum.  Below 8 ohms and due to heating, fidelity suffers, unless the amplifiers are designed to cope.  The Proton is described as rare in Australia.  Many German speakers are 4 ohm but the vintage ones are aimed at different electronics from modern amplifiers.  Vintage 4 ohm are aimed at tubes and if AlNiCo, must not be used beyond their power rating or the magnet will lose its charge.  When klutzes lay a hold of the Seas vintage speakers, their reviews suggest they're using powerful modern amplifiers and not the vintage ones meant for high sensitivity vintage speakers.  An eBay listing implying a vintage speaker rivals some disco type sound means it has probably been damaged.  The vintage AlNiCo speaker is meant to get the most out of real low power amplifiers, not provide short lived disco sounds.  But in the late 1970s Sansui and Pioneer made a series of amplifiers meant to give disco sounds, not only with surplus AlNiCo stocks and with a view to getting rid of them but also with large diameter woofers that had tiny, ceramic magnets and small voice coils meant for short lived party use.  The Sansui AU-4900 was a prestige item in working class areas, it spent its normal life playing quietly with AlNiCo speakers left over from a previous stereo record player and was intended for similarly sensitive loudspeakers of large size.  These are real special sets of rock music culture but used up some old expensive to make components like the Dynaco ST70 style irons>>>.  These gloss black transformers found in late 1970s Japanese amplifiers were surplus from the 1950s and 1960s and the claim that the industry lost the secret of making them is a subtle way of saying that Africa got its independence and quality metals became scarce.  But when these irons are seen inside amplifiers, it suggests the sound quality is more tube-like than modern irons.  The Sansui AU-D7 uses a potted toroidal and that to the uninitiated is a round iron, but the AU-D7 cannot deliver below an 8 ohm impedance without serious overheating.  Many owners don't know this and that makes the AU-D7 - despite its superb appearance and punchy rock sound, a risky buy because if neglected and allowed to heat up, it becomes unreliable.  Perhaps such amplifiers need a You Tube video that shows them starting up and running, so we know the speaker protection relay circuits aren't misfiring and the amplifiers are still giving a healthy speaker output into 8 ohms or above.  A look inside the <<<Sansui AU-4900 is going to reveal the NEC output stage and all important gloss black iron that these vintage amplifiers were actually made to clean out surplus iron storage facilities, until in the early 1980s they couldn't be found but McIntosh lay a hold of some for their Mac 4200 and at the time it was considered an incredible feat of discovery.  The MAC4200 has a white circuit board to justify the vintage quality of iron where today on eBay, we can easily find these irons again in vintage equipment listings.  In those days before eBay it was virtually impossible to get our vintage equipment of choice.  However today we're seeing a supply coming from estate sales and the last of these remaining examples will disappear again as time begins to cover later generations of buyer.  On eBay the stock of affordable, original and best early 1960s tube equipment is fast drying up.  The AU-D7>>> is rather better made and sought after than the NAD 7020 down page because it's a powerful amplifier with extremely good looks and sound quality, the light blue display is contrasted with dancing red LEDs, making it a great rock system amplifier.  The NAD 7020 is low powered, only 20 watts with claimed power near 50 but nowhere near a 'newer' harman kardon PM 650 in delivery.  Whilst 1980s harman kardon suffer badly from degrading lead solder that made them much better sounding new, the 1990s harman kardon suffer from degrading solder and plastic that makes rebuilding them impossible.  Lead solder is a problem for many restorers, but structural plastic that cracks and breaks at the slightest attempt to restore it, is simply a warning not to restore.  So we see many 1970s sets restored instead, they suit only their own vintage speakers and modern so-called 'upgrade components' may prove inferior.  The claim that 'these are better than new' is often made but on eBay we ought to seek original items that have been run regularly and still work well, then compare them with any rebuilt example.  The 'twist grip speaker connector' of Sansui and Technics has a tiny, real copper contact point that is fine and less so if barely connected.  These prevent thick wires because back in the day there wasn't a need for any.  Lengths of vintage speaker wire sold on eBay are recommended.  QED 79 strand was the 1970s standard, it has only a brown sleeve but was widely counterfeited.

Why Valve Amplifiers used to be better:-  Lower Noise in the early 1970s gave valves a good name, the QUAD 22/ II valve amplifier was -70dB noise, Frequency Response 20Hz-20KHz, Distortion only 0.02% T.H.D., simple circuit design compared to Solid State gives realism, 15 or 16 ohm loudspeaker impedance means lower loudspeaker distortion - an aspect often escaping attention, that speakers distort the final signal, S.E. 'Class A' output devices.  Valve solder betters the old age dry solder of Solid State.  Warmer valve radio sound is continued in the 1981 year Realistic STA-100, back in the day near the price of a NAD 7020 - not affordable to most buyers but a real special receiver with the screw speaker connectors of tube receivers.  The STA-100 was a 1960s 'tuned chassis' design that fitted into a beautifully crafted far eastern origin, real oiled veneer plywood glove.  The NAD 7020 has a gimmicky tuning aid with light emitting diodes but it just doesn't measure up on build or sound quality.
For anybody with space for a NAD 7020, it's seriously recommended to buy the Realistic STA-100 left instead, its rich, mellow tones, for American Country & Western music, the vibrant vocals and a huge bass punch on the matching, compact Realistic MC-1401 speakers, sporting a genuine, proven U.S. know how, Philips 'ring radiator' tweeter.  The NAD 7020 was a 'British Japanese' style receiver based on the 20 watt 3020, unsuited to Country & Western, they're lightweight sounding, shrill and were about a basic match for some 'other make' speakers that the British had made a 'rip-off' profit on selling, back in the day.  The more recent NAD 319 is (powerful) very competitive with Rotel controller/power amplifiers (2 box) and beat big SONY integrated but the NAD 319 is still a working class two-dimensional market offering - Australia has a lot of elite shoppers!  Right the 1970s Sansui AU-D7 power meter was for sensitive speakers from the 1960s when watts were much more expensive.

Why Solid State Amplifiers could be better:-  By the 1980s the NAD 3020 was getting close to the QUAD II in paper specified abilities but the old valve one had a sound quality advantage from fewer components if used with ancient Goodmans speakers.  Hum and noise by the 1990s was less than 100dB, there was very wide Frequency Response, distortion was below 0.02%, a more powerful sound, often a 'Class A' design, surround sound multi-channel.  Safer voltages and more living-space efficiency.  The claimed new freedom from radio station drift involved systems often less than perfect.  The best valve tuners do drift, if only they didn't but in the age of digital cables and decoder technology, high tech tweeters and sub-woofers, multi-channel sub/sat speakers in matched sets, offer a different kind of sound quality.  When more modern valve amplifiers are badly matched, out of use and first heard, well ... the point is they need run-in with suitable equipment, they may not impress in a secondhand demonstration of mismatched sets.

ALWAYS be sure Classic valve equipment is in perfect working order before applying the mains and that your specialist dealer has adapted the inputs and outputs to equipment you intend to connect.  These appliances are nice when working and reliable in operation but lethal, make sure all equipment is EARTHED the way the specialist has specified, they're scary things!

EMI 450 'wide dispersion' left are for a lower price type of valve/ tube amplifier known as Lo-Fi with a treble response to 13KHz and the photo here looks surprisingly posh.  It's a double box with a lower middle range speaker in its own heavy cabinet and at the top the EMI 450 adds some bass and treble. In this box the two speaker baskets are connected together in what's called 'doubled' - there's no network or divider to split the middle range from the EMI 450.

Left the heavier Realistic STA-100 iron and lightweight tone of the NAD 7020 in the video above right.

The 11 KHz top EMI 150 chassis sold at 46$ on eBay Oz and look curious with their 'whizzer con es' catering for older ceramic type record player cartridges with top at 10KHz, the whizzer isn't damaged like tweeters by high frequency scratches, tape and FM radio hiss.  People familiar with the HMV '8+8' stereo record player with 50Hz-20KHz amplifier will know its speakers are Australian made, red magnet Magnavox, dual cone, ported reflex speakers of 6 ins. dia. and with a very large whizzer, with an old pleated surround.  The HMV '8+8' record arm's cartridge is a ceramic, of the popular BSR 3-speed auto-changer type with only 40Hz-10KHz.  The '8+8' has two jack inputs and a DIN input for connecting something for its 20KHz amplifier support.
About Lo-Fi.  The basic cassette players like the Technics M-17 (15KHz, -20dB) or M-22 (16KHz, -20dB) aren't really above 13KHz at +3dB, the normal record level and these are the machines to use with the EMI 92390FY.  However the FY has a ceramic magnet system, these are suited to valve/ tube amplifiers of the Lo-Fi type, designed for ceramic magnets.   Most people will be impressed by the sound of the 92390FY suitably partnered with a cassette deck and suitable Lo-Fi amplifier, easier said than done, an entirely separate class of audio system not professional or used in a radio broadcast studio but found in domestic use.
NEVER plug a valve amplifier into the mains with no speaker connected, all the power will be shorted across the primary winding of the output transformer!  Same goes for 1960s output transformer Solid State amplifiers, don't try it, put the correct impedance speaker on both sides!
In Melbourne, Australia, TV reports were made on portable battery, operated EMI tape recorders like this one.  These reel to reel recorders were phased out in portables by the audio Compact Cassette.
Note rusting of the soft iron stampings of the Output Transformers should be treated, the whole unit serviced with replacement of coupling electrolytics and attention to high value resistors etc.

In 1958 university student Alex Encel conducted Australia's first stereophonic demonstration.  The interest created and subsequent requests for custom built systems led to the formation of his company, Encel Electronics, Australia's first specialist stereo dealer, based in Richmond Victoria.  Legendary amplifier has adjustable control M.F.B., 'motional feedback' developed by Philips of Holland, greatly reducing bass distortion in woofers, it sports 9-valves, 4 x EL 84 (6BQ5) in push pull for approx. 12 watts RMS per channel at 0.3% THD, 4 ohms, 10 watts RMS, 0.1% THD at 16 ohms with an 8 ohm tap, each on 3 thin Bakelite, fiddly speaker screw tag strip boards.  Folks dislike for the metal case and side by side speaker shorting risks.  Only one of these strips is connected at a time, they're taps from the Output transformers wired together for stereo speakers.
Left Interdyn Dorset with 10 watt SEAS speaker for the Encel valve amplifiers and sold at their store.  The ten inch, 10 watt, 25 TV-ED with 25Hz-15KHz.  Bass Res:  35-43Hz.  4 ohm (suited to 'Class B' amplifiers), 10000 guass, v.c. dia. 39MM.  The 15KHz top is MiD-Fi, essentially the tape reel speed of 3.75 (9.5cm.p.s.) i.p.s.  The 12 inch 30TV-Coax at 20KHz was Hi-Fi, meaning the reel to reel tape high speed, 7.5 i.p.s. (19.4 cm.p.s.).  Good acoustically transparent weave grille cloth is seen with the letter 'D' in Encel's own brand badge made to look like a loudspeaker.  The rather cheesy brand name 'Interdyn' came from the American best selling tube amplifier, the Dynaco ST70 available as ready built and tested or mailed as a kit in the box shown right.  It was 'Class AB', (suited to 8 ohm) 35/80 watt per channel, had EL34 output tubes and was often referred to as 'the poor man's McIntosh', another American tube amplifier.  Australia had gotten involved with U.S. hardware during the Vietnam war from 1962 with the ST70 introduced in 1959 and recommended as a good way to spend valuable time.  Although Dynaudio speakers have a following on eBay Australia, the brand Interdyn had less to do with Danes, though dating in the region to the Australian gold rushes, their population was never high.  Seas speakers were often quoted as suiting Dynaco, the Japanese Sansui suitable too.  The Dynaco ST35 left is the EL84 version and shows the Encel CSM 40 below as not real well laid out.  The Output and Mains irons ought to be placed at right angles to each other but the wrong layout between horizontal and vertical mounted irons can be hard for some to assess.  Australians often use step down transformers with imported American amplifiers, the country is slightly more makeshift than the U.S. or U.K. where their own market typed equipment dominates.
The 15-ins. Altec 604 has 104dB for 1 watt input but is Hi-Fi. The E.M.I, 13 x 8 ins. EMI 450 wide dispersion 92390FY had somewhat less S.P.L., an 11 watts at 8 ohm amplifier.  The 450 was mounted in a double box cabinet shown right and was Lo-Fi, a type of valve/ tube amplifier.  As the 150 lacks a concentric middle range cone, a speaker very good at middle range was added in its own box below.  The two speakers are covered in white acoustic wadding as seen here.  In the photo left the Encel CSM 40 has a fair quality fully shrouded black output transformer and a single fully shrouded Mains transformer, possible choke smoothing power supply is seen as the 'third' transformer and would make hum virtually absent, improving on the Encel X1212's 'hum bucker'.  (X1212 is like 'times 12 12' or stereo').  '1960s state of the art' metal rectifier is not so attractive to valve amplifier collectors, a tube rectifier said to protect from 'switch on thump'.  QUAD 22/ II amplifiers certainly thump in being turned off, even though the tube rectifier is meant to slowly decrease the voltage cooling down.  'Volume control click switches' usually get very noisy after a few years use.  Metal rectifiers mounted in valve holders or bolted to the chassis didn't wear out like valves.
Encel CSM 40 M.F.B.  $437AU, 28 bids located at Caulfield.  Valve Line-Up:-  4 x EL 84 (6BQ5), 4 x 12AX7 (ECC83 pre-amplifier stages including valve RIAA phono stage ).  1 x 12AU7 (ECC82).  No tube rectifier!  Solid State rectifier gave a tighter bass sound.  RCA phono plugs on 4 tag boards make stereo inputs, a DIN socket on rear, a 1/4 ins. jack for microphone, someone put a guitar in to test with, screw fuse holder and power receptacle on rear, metal valve chassis and 9Kg wt.  Website 'NNseek' says a C.R.O. scan for Frequency Response gave the Encel M.F.B. 10Hz-90KHz.  Phono RIAA is claimed well over 20KHz.  Valves are no brand mark, made in Italy and Japan, two 12AX7 were the less known 18AX7A high gain guitar equivalents!  Silver front panel, f.s.d. pin meter, 3 pilot lamps for Channel A, B and Stereo, 9 cast silver knobs, 7 black slide switches (similar to styling of 1965 year American REALISTIC AX100 'Americana' range Solid State amplifier), black slot-ventilated cover and 'bench amplifier' style.  Rogers III Mk 3 Cadet has similar valve chassis detail.
Encel Cosmos left, amplifier, fake wood trim on front panel, 5 knob, 2 slide switch, 6BMB Russian valves.
The sweet sounding early Solid State amplifiers with output transformers and few more transistors than tube sets, are another match for EMI 150.  Modern receivers with too many transistors to count, best suit other speakers.  EMI 150 make a big impressive sound with just a few watts input, but they're dull speakers with the wrong amplifiers!  Look out for the old, very low power Solid State stereo amplifiers from the late 1960s and connect EMI 150.  1950s radio dealers sold radiograms on the number of tubes they had, the idea continued with the number of transistors, listed on the exterior panels of early Solid State radiograms ideal for EMI 150.  One example is the Heathkit AA-14 amplifier and AJ-14 tuner from 1967.  10 watts RMS, 20-15000Hz @ -3dB (very good), less than 1% THD, transistor sets based on tube theory demonstrating the cutting edge of the new know how, a set more suited to the Interdyn Dorset, a speaker made by Encel.  In Australia the EMI 150 is particularly aimed at the P.E. HSV 20 amplifier with the Lorenz output tube ECLL800, Valvo ECC808 and Solid State choke power supply, it has 7 watts per channel suited to only ceramic cartridges (11KHz maximum).  Lo-Fi Bass and Treble Cut knobs are set at 2 o'clock bass and 10 o'clock treble for a flat F.R.
Australians get the name of being Anti-British since 1987 but an Australian worked for EMI Australia and contributed a significant amount to modern speaker box design.
Encel X1212 STEREOPHONIC AMPLIFIER, $169.16 AUS, 14 bids Melbourne VIC.  Claimed first issue 1958 Encel amplifier, 3 x 12AX7, 2 metal cover screened, 4 x 6GW8/6BM8 output tubes with wire clips, 12 watt RMS x 2, hum bucker switch for heater induced hum, similar in valve chassis looks to the 'Stereo Phonic' amplifier above but with high current GZ34/5AR4 rectifier valve.  5 knobs, bass/treble/volume dual pots with balance sliders, SELECTION knob for AUX, TUNER, PHONO, MODE knob for LEFT, RIGHT, STEREO, REVERSE .  3 switches, Rumble filter, Phase norm/reverse, Speakers/phones.  1/4 ins. phones jack.  Black push button for 'power on', typical 'bench equipment' looks.  Sansui 'look' transformers, possibly whole amp made by Sansui for Encel.  Push/pull configuration. Tubes look original vintage items. 5 pairs of RCA phono plugs, 3 shielded from output transformer at LHS.  Screw type mains fuse holder, brown mains flex, red power on pilot lamp lens, mains output receptacle.  Slider Switch between two fiddly 'screw type' speaker outputs.
Above left, Encel mains transformer directly behind volume and bass knobs spells trouble for hum spread by the metal front panel.  See in the later C.S.M. 40 chassis the mains transformer is re-located well back from the front panel and hum sensitive knobs, but still not ideal like the British Dynatron LF11 above right with two valve holders empty at the back, to supply separate radio and control amplifier power.  The huge tube is an EMItron rectifier, not the later miniature EZ 80 and EZ 81 seen with EL 84, probably used for best sound quality at a bargain price.  Note how the Dynatron Output Transformer is turned around 90 degrees, as from the X1212 to the later CSM 40, also cheating hum.  Left Encel's Norwegian SEAS coaxial 12 inch may explain the absence of the Hi-Fi EMI 13 x 8 in Australia.  Optimum cabinet size is Height 673MM on a 2 inch hardwood plinth, Width 455MM and Depth 287MM.  The SEAS company was an offshoot of Norway's Tandberg electronics making Australia's early reel to reel tape recorders, compact stereo sets like the 1241 4-track.  The separate record players were covered by the German Perpetuum Ebner (PE 2020, 33T, 34T) at the lower end, and Thorens (many models) in the upper price range.  British and other makes whilst seen in combined equipment are less represented as Australian separates, Garrard certainly sounded good but Japanese equipment after 1970 is most popular on eBay.  Linn Sondek is just a British copy of the 1960s American A.R. XA phonograph turntable.
The IREE Neville Thiele Award is a prestigious award named in honor of A.N. (Neville) Thiele OAM, an outstanding Australian Electronics Engineer, former President of the IREE and a world-renowned expert on audio engineering standards and the design of loudspeakers.
Realistic Americana F.R. 25Hz - 20KHz, 45 watts peak, (22.5 watts RMS), 'heavy magnet structure for really powerful bass' say TANDY in 1974.  566g Ceramic Magnet, Stove enamel finish, cloth roll cone edge, internal dust seal for extra long life, screw binding post terminals, x-over network has cone tweeter level knob.  Encel had looked at the Seas 9 HF-TV tweeter and found it to be a 3.5" of 11500 gauss, 3KHz - 20KHz with a 13MM voice coil former.  As such it was 1500 gauss stronger than the EMI 319 tweeter allowing the x.over point to be 1KHz lower.  The 10,000 guass Seas mid/bass unit is less impressive than the 13000 gauss 319, although its voice coil is bigger at 39MM and power is less at 12 watts continuous, 8 ohm with bass resonance poorer between 35 and 45Hz, this is however acceptable because the 30TV-Coax is an EL 84 output tube AlNiCo speaker.  EL84 wouldn't usually have enough power to voice lower notes, has a claimed 20Hz lowest note but its Hi-Fi EMI speaker is the 630 with 30Hz-20KHz because EL84 lacks the power of the bigger EL34 and KT66 for the 319.
Klipsch Quartet 12 ins bass, 100w R.M.S., 38Hz-20KHz and the bigger Forte II are best known for their high efficiency, the Quartet with SPL of 97.5dB at 1w/1m, the Forte II, 99dB at 1w and 1m.  Taking a closer look at these speakers shows a network x.o. similar to the REALISTIC Mach Two with an iron core inductor, not best thought of in the audio high end despite some claims the large 'iron core' is as good as an 'air core'!  Both the main driver and passive radiator have stamped steel baskets, another surprising aspect of these more expensive speakers that bears compare to REALISTIC.  Often claimed as push/pull by eBay sellers these are not M&K type 'push pull' designs at all!  What they are, is rear firing  ABR drone speakers.  'Push pull' is a real special M&K sub-woofer concept where two identical drivers, one turned around so the magnet faces out of the cabinet, offer a cancellation of cone distortions with both sub-woofer cones electrically driven.  Push pull sub-woofers are usually mounted on a baffle hidden in the box so you don't see any drivers on view.  It is not recommended to believe all claims made by sellers, the Forte II does only 32Hz and the Quartet only 38Hz.  Another valued speaker in Australia is the Wharfedale 12/R.S./D.D. and it has an AlNiCo red magnet.  The later ceramic magnet version is the SUPER 12/R.S./D.D.  These speakers work with Rogers amplifiers.  The AlNiCo version works with the Rogers Cadet II and the SUPER version works with the Rogers Cadet III.  When the Klipsch Quartet 12 ins is compared to Home Theater with double ten inch M&K 'push pull' drive, the bass is much deeper, cleaner and faster in the sub-woofer.  The Quartet drone and REALISTIC Americana driver have a cloth edge like the Wharfedale R.S./D.D., the Klipsch main driver has a rubber edge.  Drone designs fell out of favor as having a slight reverb effect, fuzzing bass images.  Amplifiers that sound good in Australia with Klipsch Quartet 12 are the rare Proton D1200 and the commonplace  Dynaco ST70.  We can't connect any amplifier to any 'great sounding' speaker and expect it will be as good, it has to be a known performer.
The presence of EMI speakers in Australia stems from British elite communities present in New South Wales, the Australian vintage stereo scene as a whole is split four ways between German, Japanese, British and American imports with scant sign of quality home made competition.  DRS Industries, Silcron speakers look like junk.  Choices aren't wide as compared to eBay U.K. but narrow as if a few sole importers have chosen what they know will sell.  The Hi-Fi EMI speakers aren't seen at all on eBay Australia, only the Lo-Fi type and are rare at that.  On balance TANDY is reckoned to have been No.1 with Australians but from appearance of REALISTIC sets on eBay, it appears that nobody is selling.  The Australian eBay stereo market seems starkly divided between super-rich owners and junk.  Above right the stereo control amplifier for the Rogers Cadet II AlNiCo magnet version Wharfedale 12/R.S./D.D.  The Cadet II power amplifier left has push pull ECL 86, without doubt the best miniature tube for audio.  These Rogers amplifiers belonged to the Australian and British 'Old Boy' network, former 'Old School Boys', for example from the King's School in Parramatta.  This lends to them a particular fascination from certain elite audio collectors although they undoubtedly sound wonderful to anyone lucky enough to have heard them.  Looking at the under chassis of the Cadet Mk II power amplifier from Littlehampton, South Australia, we see the superior sound quality rigid tag and solid wire construction that came before printed circuit boards.  Restorers must resist the temptation to replace the parts, due to the little known vintage 'Euphonic Distortion' where sound quality of the copper wire in old composite resistors etc is superior to the modern wire in metal film and whilst the latter offer far lower distortion, may not improve overall sound.  Whether they do would need a rebuilt set to be carefully compared with an original at every step of replacement, noting the exact changes.  The professional standard QUAD II is seen in Australia and usually worked in England with a speaker called the E.S.L. 57, that isn't seen because they were large cumbersome electrostatic radiators, that became unreliable and were likely discarded or simply too large to ship to Australia.  QUAD II are seen instead powering the 12 inch Wharfedale Dovedale or 10 inch Glendale, that's surprising but Australians even after eBay, probably still have a much harder time getting a decent amplifier and pair of speakers than in the U.K. or USA.  The large tubes seen are a very old design called the KT66, the amplifier dates from the year 1952 until 1967 and would be run in Australia with the Goodmans 100c 12 inch Triaxial or Axiom-80 that contrary to biased claims don't outperform the American Electro Voice EV+ or Altec Lansing because the American speakers have their own dedicated amplifiers and listeners.  If someone selling Goodmans on eBay tries to claim they outperform another hi-End speaker, they're being silly.  Each speaker needs its own ideal amplifier and inputs.  Another amplifier using ECL 86 is the Armstrong 226 found in Victoria rather than N.S.W. and so note its rough wooden baseboard so we know it really is from Victoria.  We know the 226 is okay because it's recommended by the 'Old Boy Network' of Australia, a type of person seeming to radiate absolute bliss and not merely content on the happiness scale.  But these 12 watt per channel tube amplifiers also came in mono 'M' versions, because in places like Queensland, mono was enough for cricket.  It's necessary to double check on eBay if the unit is stereo.  The 226 has a magnetic cartridge input of 3 m.v., so we know it's good for modern cartridges and has a rumble filter on the back panel that's less about 'cheap' record players as able to use anything.  Left Richard Allan speakers from the year 1975 with the CG 12 inch bass unit.  The rectangular port drone has no pipe, it's not a bass reflex design but one like the Spendor B.C.1.  Australia has a great deal of Richard Allan speakers.  Why?  -Like TANDY they were rated highly on value for money since 1968 when their A21 'Class A' amplifier was half the price of the Sugden Si 402 it was based upon.  Question of some Australians will be:  are Richard Allan 'Old Boy network' approved?  To answer this question we must know that unlike TANDY, Richard Allan were unremarkable in the F.R. extremes, they were around 50Hz-20KHz but their plotted curves were smooth, meaning they would give very detailed reproduction when suitably quality inputs were connected.  But we need to look carefully at the 'old boy network' Spendor B.C.1 and compare the Richard Allan.  The early B.C.1, pictured was probably finished by E.M.I. but the later all black baffle, Australian model is seen priced at $1050AUS, viewed at 1 per hour, with 54 watching whilst the Richard Allan C.G. 12 had no interest at all.  The trick with the B.C.1 is that it's AlNiCo magnet, so needs partnered with an amplifier meant for AlNiCo speakers, a tube amplifier conceived up to the year 1962, known to sound good with AlNiCo magnet speakers.  Richard Allan CG12 is ceramic magnet so needs an amplifier suited to the colder sound.  The B.C.1 has the same tweeter provision as the B.B.C. Hi-Fi EMI speakers, like the B&W D.M.1 - not seen in Australia.  The early E.M.I. cabinets with the sprayed varnished wood baffles look just awesome, albeit pommy.  Pommy or not, such British speakers have an immense following on eBay Australia along with other, actually Royal Navy officer choices like the elderly Tannoy Dual Concentric, although strictly speaking, not the usual retired Royal Navy officer's small, ten inch Tannoy Dover with cork baffle!  At $15,999.99AUS, eBay offered a Tannoy Autograph box, reproduced in Japan for ease of shipping and fitted with a 12 inch Tannoy Red, ten eBay traders were watching and 3 viewed per hour, located in Essendon, Victoria.  So Spendor B.C.1 are suited to BBC amplifiers but to which ones?  The safest match to try with B.C.1 is going to be QUAD 50D or E, followed by a 1960s 303 if that doesn't please.  There are two main versions of 1960s QUAD 303, the first lower powered KT 66 sound version and the later higher powered simulated EL 34 sound version, of which just how many versions there were by the time the B.C.1 was offered to the public, is going to be like looking for a needle in a haystack.  However the E.M.I. cabinet of the B.C.1 pictured, reminds us it was a BBC speaker and workhorse long before it was offered to the public.  The Australian market B.B.C. Leak TL 25+ left is a bass/treble/volume version of the American market E.M.I. STD.373 using KT 77 or in lesser fussiness the Leak, EL 34.  STD.373 is rated above the Leak in original working condition but is so sophisticated that careless restoration ruins its abilities.  It must be remembered that modern reissues of the Radford STA-15 cannot match the original because the quality of parts today 'at a price' is no longer available.  For example if the quality of copper wire is inferior and its heating effect greater it's like a poorer quality camera lens with poorer resolution and distortion qualities to capture an image.  The Australian will inevitably ask after the QUAD II, but it's difficult to get a good stereo pair, especially in Australia.  QUAD II are available with a solid state rectifier, their main problem is cost-engineered power irons, worn out with control units and tuners, the best QUAD II on eBay weren't part of the QUAD tube tuner set that's been used a great deal.  Restored QUAD II and increased power versions aren't recommended, best to use more sensitive speakers and not higher power.  We now leave the British 'Old Boy' stereo scene and move onto Australia's very hard to follow American audio components.  We're going to Brisbane in Queensland to look at a McIntosh MC2155 power amplifier with 0.02% T.H.D. and around 60 watts of power.  So why do we find McIntosh in Brisbane?  They're both Scottish names, Sir Thomas Brisbane gave his name to the city's river, a keen astronomer who built Australia's first observatory.  Rather confusingly Brisbane had been governor of New South Wales, recommended (1821 - 25) by the Duke of Wellington he'd seen military service with.  In the great audio age of 1959 - 85, McIntosh equipment was top of the affluent American suburban sector in regionally envied states like South Carolina.  The amplifiers are quite simply awesome, the safe choice of America's professional class.  So how about the American RtR 'Total Capability' Series II speaker, seen in Australia?  Well they're a sensitive American speaker that owners feel they wouldn't ever part with.  It puts one in mind of fourex, a beer brewed in Milton, Brisbane by Queensland Brewers, Castlemaine Perkins, now Japanese owned.  The small city of Castlemaine is also confusingly based in the state of Victoria and not Queensland.  In the U.K the brewery ran an advert with the slogan, ' Australians wouldn't give a Castlemaine XXXX for anything else.'  The American RtR is similarly appreciated but especially in Australia.  Note the baffle drone port like the Rogers B.C. 1 up page.  Next notice this is a 3-way design and the upper frequency drivers are cone speakers, therefore suited to tubes and amplifiers needing sensitive speakers for low down volume quality.   The foam covering most of the squawker is very interesting, it brings the middle range forward and increases the clarity of vocal sounds, it's a feature of some American speakers.  The diamond placement of the tweeter lets it be closer to the squawker.  The woofer has a large concave speech dome that reduces the frequencies carried by the woofer.  The most important thing about these RtR is that they're American tonal balance and like TANDY or Richard Allan, offer value for money.  American tone is real different from British tone.  The RtR isn't going to sound anything like a Spendor B.C. 1, nor suit a similar owner.  So will we really find McIntosh running RtR?  In Australia yes.  But let's look at the JBL L250 tower with B460 18 inch sub-woofer that runs with amplifiers rated at 50 watts per channel via a passive BX63 dividing network.  They're in Victoria, Australia and were one of the first hi-End speakers to have a Super Tweeter.  Both the B460 and L250 ($18,300AUS, secondhand) need huge rooms, no use buying them for a small house.  Right the Audio research VS 55 looks a bit like a Manley Snapper but uses KT 88 instead of EL 34.  The Manley Snapper is more pricey and used with the Tannoy Dual Concentric Cantebury, ($22,000AUS).  They're much more expensive than the Cheviot, Arden or Berkeley type speakers.  The slight difference in price allows the VS-55 to power speakers like the JBL L250/ B460.  The sound of these sets is obviously in the hi-End category.
'Let the shot deer go and weep
and the surviving hart enjoy its play
For some must watch while some must sleep
So runs the world away'.
Left Hartley speakers, once sold by Encel in Australia, are thought to be American but came from London, the 220MSG following the American Altec 420A bi-flex type cone, similar to the London-based Baker's triple cone of the 1950s.  These were first at trying to be rid of the loudspeaker back wave, sound coming from the back of a speaker.  The 215 full range driver and its cabinet were called the 'Boffle', a mixture of the words box and baffle.  Not much is known about the strange and extinct speakers in the elite times 1927-1950s.  Even EMI would be little known about were it not for internet coverage.  The speakers date to 1927, the designer H.A. Hartley coining the phrase 'High Fidelity'.  The large white cone AlNiCo speaker reputed to be 24 inches in diameter, the Hartley-224S goes down to 16Hz, found in Levinson speaker boxes as part of their HQD System including QUAD ESL-57, DECCA Kelly DK-30R ribbon tweeters and Madrigal Audio Laboratories Inc HF10c.
In 1949 Robert Schmetterer owned and operated a U.S. installation facility in New York, assisted by Piers Powell a writer for 'The London Times'.  H.A. Hartley sold rights to the company with which he maintained a working relationship and in 1953 formed the U.S. company to make only speakers, it was the first distributor of mono Ferrograph tape recorders in the USA.  The company's Dr Harold Luth in the 1960s got patents for the first synthetic cone material, a unique control system, "magnetic suspension" and one of the first true coaxial speakers.  In the 1960s only three speakers a day were turned out as needing fifty hand operations before going to the cabinetry.  Like EMI, Hartley were sold only through recommendation by scientists, engineers, recording technicians and musicians, making the claim to be 'the best anywhere in the world at any price' and are still being used by recording mixing studios.
Australia rated highly the American REALISTIC brand because they were sold in local stores and designed to be heard on audition.  Many similar looking sets of oriental origin weren't designed to be listened to but to look their best in a catalog.  Remember that appearance has to be paid for and late 1970s Technics were the most expensive of similar, mail order list receivers.  REALISTIC were real critically appraised by U.S. audio publications and found out if inferior to a Levinson.  Carver had complained against the publication 'Stereophile' for describing its efforts as 'junk'.  In Great Britain the audio press is lenient on home made equipment.  REALISTIC were made of obsolete spare parts based on oriental sets a few years older and so continued to offer vintage quality when other brands had lost it.  Many people thought REALISTIC overpriced back in the day because it wasn't known then they were cobbled together from quality spares.   TANDY stores were unfriendly places with arrogant staff complaining of being underpaid for their qualifications, these salesmen weren't as a rule interested in what they were selling and appeared very busy and overworked.  Owners of REALISTIC were impressed but didn't put the word around.  The REALISTIC sets are built of fairly standard stuff, Bakelite boards and round metal body carbon track pots, interestingly similar in appearance to the highly respected American Hafler equipment left.  The Leak Trough Line 3 is the best of tuners for stereo but in Australia, a problem with metal roofs and rain gutters means an attic antennae won't work and must be mounted at least ten feet above it to avoid reflections.  If the coaxial lines follow steel rain gutters there's increased noise unless a superior coaxial cable is used.  In Australia back in the day, an indoor 300-ohm folded dipole was made from scrap JETDS RG-59 coaxial 75-ohm cable, hung inside or out, across a double window with as short a 75-ohm cable run as was possible to avoid any signal loss.  This indoor aerial is one that radio engineers like Leak would have preferred and is still as good a way of getting hiss free reception with superb stereo effects.  Cables used by antennae services today are mostly the more profitable 50-ohm, sold for transmitters and everything else.  93-ohm is better for long receiver runs but scarce.  An FM aerial and high quality 75-ohm cable run are a prerequisite of Realistic STA-2000 or Leak Trough Line FM sound quality.  Quartz Lock Receivers from Sansui, Technics etc were engineered to offer less stereo FM hiss with a low quality FM cable but at the sacrifice of audio quality deemed acceptable under the circumstances.  These include 1990s Radio Data Service equipped FM receivers with in the best of sets, nearer to two-dimensional stereo sound, not the three-dimensional sought after in 1960s equipment played through EMI 319 speakers.  Getting that magazine rave-reviewed 'Trough Line sound' is not going to be easy with 'metal roof' mounted antennae but if it is possible in your location, improves on the already superb sounding 300-ohm folded dipole, that is however unsightly and best made to assess your local signal quality, if disappointed with your 75-ohm roof mounted installation.  The folded dipole, right sounds as good on the 75-ohm tap as the 300-ohm and far better than the roof mounted antennae, they oscillate between inner and outer lengths, note the faraway bare copper alloy wire end.  In the 1960s the British elite used a curious 300-ohm dipole shaped like a large 'Vee' that affects the two critical lengths, it was hung high on a large wall, after a real comical fashion where the horizontal square dowel type are made with inner hoops to hang another folded dipole, tuned to a different ideal frequency, underneath,  these being copper antennae able to be switched for best station fidelity.  A roof antennae doesn't have any of the more expensive copper elements and outside weathers so rapidly that dowel dipoles are seen painted in flat black enamel.  Although we think of a 75-ohm antennae as best in being the usual roof mount value, elite engineers claimed 300-ohm as better, the details of antennae construction were for many years kept secret in cities, to avoid interference from illegal transmissions.  The Pioneer TX-520 is an affordable tuner, highly regarded in Australia and now offers an eBay alternative to the once as plentiful Sansui T-80 Quartz Lock tuner, the TX-520 considered to outperform the Realistic STA-2290 tuner section when used with the STA-2290 amplifier section and so worthy of a listen.   Left an Australian STA-2290 working as new has few tuners able to compete on sound, clarity, station pulling power or anything.  The TX-520 has likely been deployed for a 2290 out of use for years, some capacitors then known to degrade, improving by running the set daily.  The 2290 has a 'keeper' presence but is too big for even its best friends, pictures always manage to make it look compact, the volume knob is large, copying the tuning knob on earlier receivers and often preferred to the button search or presets.  A Carver MXR-150 is of similar size but not nearly as well made.  Best for American sized rooms. 
Right this Mach One, the 40-4024 is what we call the black foam surround model.  There's a bit of damage in the foam at 5 o'clock.  Before the Liquid-Cooled 4029 model for the SA-2290 above became available, there was a later grey foam surround version that ran with the Realistic STA-2080 receiver, these heavy foam surround models don't rot away to dust but are claimed to harden.  The earliest Mach One has a chrome Realistic badge and is seen in Canada, it has a grey rubber edge but each of these models is carefully tone matched to certain production run receivers and contrary to simplistic advice, we're not out to get the rubber surround woofer to run with all receivers and amplifiers, the rubber woofer edge model is only best with some early receivers.  The black foam Mach One runs with the Realistic STA-2100 receiver, fitted with the round transformer.  It's no use trying to get some other receiver to do what the STA-2100 was carefully engineered to do.  It might make you happy to write on some internet forum that Mach One sounded so bad - that your Klipsch KM4 blew them away but if Mach One sound bad it's your fault.  A Realistic STA-2100 won't make your Klipsch KM4 sound any better because it's meant for the black foam edge Mach One.  This 1970s foam surround Mach One is in good shape, this version often crumbles at the tweeter horn panel corners.  When you get a STA-2100 or whatever receiver best matches your model of Mach One, you've had it serviced and its giving a decent sound, only then will you be in a po sition to write on an internet forum that your Klipsch KM4 blew them away.  But one thing is for sure, the amplifier that sounds best with the Klipsch KM4, won't sound best with any Mach One.  In the days of eBay, we'll find black foam woofers with a 4024A speaker connector, telling us the original rubber edge woofer or speaker connector have been replaced.
Left the Marantz L.S.17A woofer basket showing similarity to that of the Liquid Cooled Realistic Mach One and probably made in the same factory.  It has a very small magnet as many of these home disco speakers had but suggests the similarity in appearances between the Marantz L.S.10 and Mach One, stem from this company Radio Shack used, putting only 'Japan' on the magnet, so that any of the 1982 to 1983 year quality Radio Shack speakers are going to sound almost as good as a Marantz L.S.17A, it's main advantage is a claimed 99dB for 1 watt.  Just to let you know - that is certainly as loud as a Disco speaker.  However Marantz themselves hadn't made these Home Disco speaker models, they've been done by a custom manufacturer.
One of the most important things about TANDY in Australia is the rural agricultural influence as in this Holden Ute left.  This is Radio Shack styling, silver, dark grey, nice wood trim, black leatherette look.  In the USA it was usual to find only Radio Shack in rural communities and they delivered the goods and satisfied customers better than anybody else could.  Mining people bought Realistic or Interdyn because they were the best, because they offered a real good sound at a price and basically that's where they differ with 1970s harman/kardon, Realistic sound wonderful but the build quality of more expensive brands better withstood the test of time.  It's possible to get parts for Realistic but harman/kardon are boasting ability to supply all parts for their vintage receivers!  Also with the JBL Century L100, we can have the Alnico V magnet system woofer recharged.  Back in the day TANDY were making similar claims to harman/kardon, that 'for a price you could not spend better than with them'.  But it's unlikely harman/kardon outperform Realistic on sound or stereo effects, they're just not engineered to the same demands on extreme 'bang for the buck'.
Damping Factor affects those who think the cone of a long excursion bass unit is meant to flop about at high volume.  A video on You Tube had a Kenwood KA-8100 with a Damping Factor of 50, showing just how badly it controlled the bass cones, but the person who'd made the video, thought the wild cone behavior was a good thing.  50 isn't a great amplifier figure for long excursion cones, it's better than a SONY V-FET with 35, but such amplifiers weren't made for long excursion cones, even though sold with them!  The 'wagging' bass cones weren't making the best bass in town, they just looked like they might be, once the system was bought and set up at home.  But it all depends on the family of speakers your amplifier is made for.  It's not about good or bad but just a mismatch of a speaker and amplifier.  The Technics SU-V9 had a Damping Factor of 80 meaning it's twice as good as one with 40, at getting useful sound from a long excursion woofer.  But nobody on internet forums is saying what the SU-V9 sounds good with, all they say is that it sounds good, or some amplifier sounds good, nothing about with what.  On these internet forums like Audiokarma, there's people that want the thread to go a particular way, that we all hear different and what impresses on paper, often doesn't in sound quality.  The Marantz LS-17A is a type of Home Disco speaker meant to run with vintage amplifiers that have Mic-Mixing jack.  Another Marantz Home Disco speaker, the L.S.10 looks like a Realistic Mach One but is louder.  Back in the day and even now ... some people still want a huge amplifier called the Leak 3900A.  The amplifier was made by Rotel and in electrical content, real similar to a Realistic STA-2000,
similar in power but half the distortion thanks to an ALPS volume pot.  Although everybody seems to think these are awesome, they didn't have any figure for Damping Factor, neither did the Radio Shack receiver.  Just what the 3900A sounds best with, we don't know for all the internet forums that have been around to date, but it probably suits a Realistic Mach One.  The power meters in speakers seen left in the Marantz LS 17 A, don't help sound quality but protect the sensitive speaker system from abuse.  The power meters aren't much use with shrill amplifiers of British style, because they're meant to be connected to Japanese amplifiers with a very good deep bass ability at lower power.  A restored 40 watt per channel harman/kardon A 402 may deliver a suitable sound with a Damping Factor of 50, but a power overload lamp suggests the speaker overloads at 300 watts.  This tells us that the Marantz LS17A is pulling at 35 watts but has a higher reserve nearer 300 watts per channel.  So what's needed is a very expensive 300 watt amplifier that pulls well at 35 watts.  Another problem of such big bass diameter speaker systems is the system resonance, not published for the Marantz, but Radio Shack offer 50Hz for the old Mach One and 65Hz for the Liquid Cooled version.  This means these speakers are suited to an amplifier that offers 20Hz but we're only going to 'feel it', not hear it.  We're not going to hear anything below around 50Hz, so the lower quality doesn't need to be so great as in studio equipment that gives an audible 20Hz.  A powerful 300 watt Home Theater receiver will probably give a good 50Hz note provided it's not adjusted to drive a separate sub woofer.  The separate sub-woofers also add unwanted distortion and it's not going to be easy to get the best sound from any of these old speakers.  The big problem with the Marantz LS17A is the squawke r quality, that is the main driver and getting an amplifier to flatter it, needs you to find an amplifier originally sold for a similar middle range.
In 1985 when the Marantz LS17A were launched so were the PM94, that we see here is copper clad and has two separate 'mirror' power amplifiers inside.  So the PM94 were really meant for squawkers with aluminum 'chrome' speech domes, despite the journalist's view of the amplifier as some kind of dream.  The PM94 don't suit Wharefdale E series, nor do the Rank own brand Leak 3900A but the PM94 is the price of amplifier they had in mind for the Marantz L.S.17A and we now know that it suits a steel case amplifier, albeit a copper clad one.  The PM94 was also a MOSFET with 'Class A' at 35 watts,
so we now know that the L.S.17A power meter's 35 watts is very high quality.  In England Marantz PM 94 were actually partnered with Tannoy Super Red but the L.S.17A may well be a better match, the L.S.17A had been banned by then for noise pollution and the home market made Tannoy Super Red weren't, they're not lightweight portable disco speakers.  Seeking another amplifier for Marantz PM94 sound, we need a MOSFET with 'Class A' 35 watts and a round transformer with a mirror power output circuit but a Damping Factor of at least 200 is essential, to rival the PM94.  Basically do we need a pair of Marantz L.S.17A?  There will be other systems that sound just as good at lower power.
The McIntosh 240 is mentioned in a guide with Lo-Fi amplifiers because as the top amplifier of its day, it sported a Damping Factor of 10.  This means it's no use for modern speakers with which it may be seen on You Tube.  It suggests that lesser Hi-Fi valve amplifiers may well have a damping factor of 1.  What does this mean?  It's the sort of bass sound these amplifiers give with long excursion bass speakers.  These vintage amplifiers need matched with vintage loudspeakers made for low Damping Factor figures, generating a lot of sound with amplifiers that have both low continuous operating power and low power headroom.  The Marantz PM94 is a 35/300 watt amplifier and if the Mac240 is operated at 80 watts, its maximum operating power is likely around 8 watts, if at 40 watts then only 4 watts.  But 8 watts into a speaker with a stiff pleated edge, not the surround seen on the Marantz LS17A with a matching amplifier Damping Factor of 200.
Left the Stentorian available in Australia, offer the right surround for low Damping Factor, low power valve amplifiers.  A system of taps matches them to 4, 8 or 16 ohm amplifiers, they're mounted in a small shallow box and the magnet is screened alnico but a rusted example may have weakened.  Sellers ought never to store alnico speakers in cold or damp air.  These speakers have a horn for Hi-Fi use, mostly available on the U.K. eBay.  Often people look only at speaker sensitivity in matching valve amplifiers to speakers but a consideration of all specifications is best.  People will ask in forums, how suitable are Realistic Mach Ones for valve amplifiers?  Well it depends a lot on the vintage of valve amplifier under consideration.  The Mach One will suit same vintage American Audio Research or McIntosh designs but not much older sets.
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