Favourite Hi Fi System Radio Unit?

[Synchrodyne]

In respect of the Leak Troughline, I wonder whether its good reputation was founded on the original version of 1955, or the later versions starting with the Troughline II circa 1959-60. In RF terms, there was a difference that might have manifested itself in less favourable reception conditions. The original Troughline had a two-gang front-end (commonplace in British valve-era FM practice) and a pentode RF amplifier. The Troughline II moved up to a three-gang front end with a cascode RF amplifier.

An unusual feature of the Troughline was its 12.5 MHz IF, rather than the 10.7 MHz standard number. This was chosen to ensure that the local oscillator frequency was never in-band, nor were any IF harmonics. But it was true only for the 87.5 MHz to 100 MHz tuning range of the original model. With the Troughline II, the tuning range was expanded to 88 to 108 MHz. The IF remained at 12.5 MHz, and the same non-interference claims were made. Oops! (To maintain the claims with the 88 to 108 MHz tuning range, the IF would have to have been not less than 20 MHz, also meeting the conditions that nIF was not greater than 88 MHz and (n+1)IF was not less than 108 MHz. 21.6 MHz would seem to be the lowest number meeting those criteria.)

The original Troughline also had an unusual implementation of a magic eye tuning indicator, looking somewhat like the NBS null indicator (see Radio News 1948 May p.176) modified to provide also a signal strength indication. Leak claimed that it could indicate centre-channel within 2 to 5 kHz. But that circuit was not maintained for the Troughline II, which had a more conventional magic eye circuit, albeit fed with bias from both limiters. At a guess, I’d say that the incidence of IFT (over)coupling was arranged so that the two bias feeds combined to produce a peak at centre-channel, without causing the same (deleterious) effect in the main IF channel as measured at the discriminator input.

Given that the Troughline mono units had a generous AF output from a cathode-follower, variable up to 1V at 100% modulation, the low output of the Troughline stereo, 150 mV at 100% modulation (45 mV at 30% modulation) was certainly anomalous, and noticeably below UK industry practice at the time, in which 100 mV at 30% modulation, for use with amplifier inputs of sensitivity say 70 to 100 mV at 100K could be taken as being general. Leak could do this though, as its then current and recent control units (most of them anyway) catered for both normal and low-output tuners. This may have been a consequence of their being configured for use with Leak’s earlier VS AM tuner, whose nominal output was 50 mV at 30% modulation.

An interesting change for the Troughline Stereo was the RF cascode valve, from an ECC84 (remote cutoff in-situ, although not naturally so) to the frame-grid sharp cutoff ECC88. I think that there were some changes in the standing bias and agc bias arrangements as a result.


Cheers,

[Synchrodyne]

There are some tuners from the valve era about whose performance one hears very little, but which on paper at least had the capability to be quite good.

One such was the Pye HFT111 (FM/AM), using what was more-or-less the same circuit as the RF part of the FenMan II radio receiver. It had a three-gang, permeability tuned front end, which right away put it above the majority of c.1955 offerings. That front end also used two valves (EF80 and ECF80), which one infers that Pye considered better than the ECC85 single-valve approach that it used for the lower-priced FenMan I radio receiver. It also had a three-stage IF strip with a Foster-Seeley discriminator in an era when two stages and a ratio detector were the norm. (At any given bandwidth, the Foster-Seeley has lower distortion than the ratio detector. But the ratio detector may be configured with much wider bandwidths than the Foster-Seeley, and so lower distortion. This was not done so much in the valve era because wide band ratio detectors lose their AM rejection properties and so require extra limiting (meaning extra valve(s) in the IF strip), thus defeating a major rationale for their use. Also, their consequent lower outputs were not helpful when it came to the provision of afc, either. In the solid-state era, symmetrical hard limiting over a large range of input signa stengths was easy to obtain with integrated differential amplifiers (that was an RCA mantra of the late 1960s), so wideband ratio detectors were used for a while until the quadrature type took over. Also in the solid-state domain, extra DC gain for afc and post-detector AF gain were easy to obtain.)

The later Pye Mozart HFT108, FM-only, dropped back to a two-gang front end, albeit still with two valves, but retained the three-stage IF strip. It lasted until c.1964, latterly as the HFT109. The HFT111 disappeared c.1960-61, apparently replaced by the Mozart HFT113 FM-AM unit, although detailed information on the latter is virtually non-existent.

Another possible “sleeper” was the Jason AM/FM2 of late 1957. Its FM side was better-specified than any of the Jason FM-only tuners, of which the FMT3 and FMT4 had the highest performance. It had a cascode RF amplifier, probably as part of a three-gang front end, although I haven’t been able to confirm that. It had a three-stage IF strip. And its AM side, albeit MF-only seemed to have been much better than average, heading towards the standard set by the later Quad AMII.



The AM/FM2 evidently inherited some of its features from the earlier (c.1956) AM/FM model, but little information is available about the latter. (Which shared the same faceplate and perhaps chassis dimensions with the otherwise quite different Jasonkit Argonaut.)



Then the Beam Echo Avantic 612 was very similarly specified to the Jason AM/FM2, to the extent where one could believe that Beam Echo had adopted the Jason circuit. I’d guess though that if they were essentially the same, that the Beam Echo version would be more highly prized today.




Cheers,

[wd40addict]

I wonder if what the Jason gains on the front end it my lose in the switchable IF? I have the Heathkit AFM-1 in addition to the FM-4u but no amount of careful setup will bring the performance of the former up to the latter. My thoughts are that the extra capacitance / inductance of all the band switching is spoiling the IF performance. Both have ECC85 front end.

[Synchrodyne]

I suspect that the Jason AM/FM2 may have had separate AM and FM IF strips. I don’t have confirmation, but the valve count of 11 total does support that notion.

The Jason AM/FMS2 was a contemporary of the AM/FM2. The AM/FMS2 had a switch-tuned FM section, an MF-only, single-selectivity, variably tuned AM section, and a combined IF strip. It had 7 valves (plus a metal rectifier), as follows:

EF80 FM RF amplifier
ECF80 FM self-oscillating mixer and AFC reactance valve
EF89 AM RF amplifier
ECH81 AM mixer-oscillator and FM 1st IF amplifier
EBF89 AM IF amplifier, FM 2nd IF amplifier and AM demodulator and AGC rectifier
ECF80 FM limiter and AF cathode follower
2 x crystal diodes FM discriminator
EM81 Tuning indicator

Thus, a possible valve line-up, with separate IF strips, for the AM/FM2 might have been:

EF89 AM RF amplifier
ECH81 AM mixer-oscillator
EBF89 AM IF amplifier, AM demodulator and AGC rectifier
EM81 Tuning indicator (also used for FM)

ECC84 FM RF amplifier
?? FM mixer, oscillator and AFC reactance valve (one or two valves)
EF80 FM 1st IF amplifier
EF80 FM 2nd IF amplifier/limiter
ECF80 FM limiter and cathode follower (the latter also used on AM)
2 x crystal diodes FM discriminator
ECC8n Twin neon tuning indicator driver

Reading back from the 1958 FMT3 suggests an EF80 mixer and an ECC81 oscillator and AFC reactance valve, which would make for a total count of 11 valve envelopes, assuming a metal rectifier in the power supply. It seems not unlikely that the front end of the FMT3 was derived from that of the AM/FM2. Possibly the AFC bias was derived from the twin neon driver, as Quad did for its FM, B-series, but I think that that approach provided but a narrow AFC range (±120 kHz in the Quad case). The variable AFC used on the AM/FM2 (and also on the FMT3) suggests that it had quite a wide range when set at maximum.

The Heathkit FM-4U and AFM-1 are an interesting pair. In respect of the AFM-1 strip, as well as losses attributable to the AM-FM switching and perhaps the series-connected IFTs, its different valve line-up may also have contributed to its lesser overall performance than that of the FM-4U. The latter had a neutralized EF89 1st IF amplifier, a neutralized EF89 2nd IF amplifier/limiter, followed by an EF80 limiter. On the other hand, the AFM-1 FM IF strip started with an ECH81 heptode section 1st IF amplifier. As an amplifier, this was proximate to an EF41, so not as good as an EF89. The second stage was an EF89 switched to operate as an amplifier/limiter on FM. Neither of these stages appeared to be neutralized, so probably operated at lower relative gain than those of the FM-4U. The third stage was an EF89 switched to operate as a limiter. The conventional wisdom is that sharp cutoff valves such as the EF80 make better limiters than remote cutoff valves like the EF89. One imagines that Heathkit chose the (2-gang, no RF, 2 x IF) form for the AM side in order to minimize valve count by maximizing overlap with the FM side, whereas the (3-gang, 1 x RF, 1 x IF) form was I think regarded as being a better disposition of two amplifying stages, the more so where SW is involved.

The FM-AM combined IF strip disadvantage might also have applied to the Pye HFT111 as compared with the Pye Mozart HFT108, although Pye did use a dedicated EF8 FM limiter in the HFT111. The AM side of the HFT111 was fairly basic, (2-gang, no RF, 1 x IF), although it did at least have delayed AGC.


Cheers,

[wd40addict]

Thank you for the detailed explanation!

I can imagine back in the day someone being disappointed that they could only afford the FM-4U and not the apparently better specified AFM-1. But the reality was they had the better unit

[Synchrodyne]

Another vintage FM tuner in the “sleeper” category was the Dynatron switch-tuned model series, FM1 and FM2. Their main claim to fame is their use by the BBC.

The BBC HR/17 and HR/18 monitoring receivers were based upon the Dynatron FM1, with the HR/17A and HR/18A being based upon the FM2.

The BBC RC/5-1A and RC/5-1B were rebroadcast receivers based upon the Dynatron FM2, modified for single-frequency crystal-controlled operation.

As best I can determine, the FM1 was Dynatron’s first venture into FM tuners, and was announced in Wireless World 1954 September, p.487. In part, it was designed to work with the then-new “Ether Marshal” radio-gramophone system which had been announced in 1954 September. The Ether Marshal electronics comprised the T139 AM tuner-control unit combination and the LF613 amplifier and power supply. The T139 was equipped with an additional input for the FM1 output, and also equipped to supply LT and HT to it. A separate power supply unit, the P1, was also available.

The FM1 had a three-valve front end, with Z719 (EF80) RF amplifier, Z719 mixer and B719 (ECC81) oscillator and AFC reactance valve. The aerial input was broadband, the interstage being switch-tuned, so effectively it was two-gang. It allowed for three pre-tuned stations in the 88 to 95 MHz band, and the oscillator was on the low side of the signal. The IF strip was based upon three Z719s, amplifier, amplifier/limiter and limiter, followed by a Z77 (EB91) as Foster-Seeley discriminator.

The FM2 was listed in Hi-Fi Year Book (HFYB) 1957, so it was probably released either late 1956 or early 1957 as the successor to the FM1. It allowed for four pre-tuned stations over the 87 to 100 MHz band and had its oscillator on the high side of the signal frequency.

Oscillator-high was I think more common than oscillator-low in British FM tuner practice, perhaps because such was also the norm in the export market. On the other hand, BREMA eventually recommended the 10.7 MHz IF with oscillator-low (see WW 1958 January p.44). The BBC RC5-1A and RC5-1B respectively had oscillator-low and oscillator-high, so that the better option could be chosen situationally.

The FM2 was available with “low” AF output, as the FM2LV, or with a “high” AF output, from an additional amplifying stage, as the FM2HV. The FM2 was used as the tuner section of the Dynatron Ether Minstrel FM-only console radio receiver, which I think was Dynatron’s last model of that cabinet form. (I am not sure if the FM1 was also used in the RV12.) The final version of the earlier Merlin console receiver, the R1712ME, had used the Ether Marshal electronics, so it may have been possible to retrofit it with the FM1 (or FM2) – I don’t know. Thereafter seems to have come the decline of Dynatron. I think that its next (non-portable) radio receiver (as distinct from radiogramophone) offering was the Pathfinder TVR14 AM-FM table model of 1960, with a less elaborate front end. One might say that Hacker, with its FM-only Mayflower RV14 table model of 1961, with its claimed tuner-quality RF section, was more the heir to the Dynatron tradition. (Its RV14 designation was in the Dynatron series.)

That these Dynatron FM tuners were used as the basis for BBC monitoring and rebroadcast purposes does I think point to their being at the top level (of the time) in terms of overall performance.

The BBC information is available thus:

http://www.bbceng.info/ti/eqpt/HR_18.pdf

http://www.bbceng.info/ti/eqpt/RC5_1.pdf

http://downloads.bbc.co.uk/rd/pubs/reports/1955-26.pdf

Dynatron was quite early in offering switch-tuned FM tuners in the UK. Others who did so subsequently included Chapman, GEC, Jason and Rogers. But it wasn’t quite the first. Apparently at Radiolympia 1949, Kolster Brandes showed both a switched FM receiver and a corresponding adaptor (i.e. tuner) using the same RF section. (Reported in WW 1949 November pp.434,435.)

Dynatron also offered a more conventional tuner, the AM-FM Ether Pathfinder T10, from later 1955; it was mentioned in WW 1955 September p.417. This signalled several changes in the Dynatron pattern. The T10 was a “true” tuner, lacking any audio control facilities. Previous Dynatron “tuners” in the “T” series, such as the T139 and T99, had been tuner-control unit combinations, used in conjunction with amplifier/power supply units. The T10 was intended to be used with the TC10 separate control unit and the LF10 amplifier/power supply unit. The latter had an ultralinear output (possibly it was similar to the Osram 912), whereas previously Dynatron had used triodes or triode-strapped tetrodes/pentodes. There was also a new numerical part of designation system, starting from “10”, perhaps because the LF10 amplifier was nominally of 10 watts output.

The T10 followed the common pattern of having a combined AM and FM IF strip. The FM front-end was of the single-valve (B719 (ECC85)) type. The AM section was three-gang, with an EF89 RF amplifier and an X719 mixer-oscillator, the heptode section of the latter also serving as the FM 1st IF stage. Then followed a pair of EF89 IF stages, with separate D77 demodulators for AM and FM, the latter being a ratio detector. There was an EM80 tuning indicator. On the AM side it retained some elements of the preceding T139 and T99 models, with one RF and two IF stages, and four-position variable selectivity, although I am not sure that the whistle filter was retained. But SW coverage went only to 23 MHz, rather than to the 30 MHz off the T139, T99 and T69 before it. The FM section I suspect would not have been as good overall as the FM1. So, some “watering-down” was apparent.

The T10 was replaced by the T10A, first listed in HFYB 1958. Here the FM tuning range was expanded to 88 to 108 MHz, whereas the T10 had been 87 to 100 MHz. The photographic evidence also shows that the T10A had a two-valve FM front end, although no details are known. Perhaps Dynatron was after better performance, or perhaps it was using proprietary front ends, and that is simply the way the wider tuning range unit came. On paper, one might judge the T10A to have had very good, although not quite top shelf FM performance, and better-than-most AM facilities. If the Pye HFT111 was a “sleeper”, then so was the T10A.

In 1958 the Dynatron T11 arrived, first listed in HFYB 1959. This represented a reversion to the tuner-control unit combination. As best I can work out, it was mostly intended as a replacement for earlier AM-only tuner-control units to allow upgrading of the radiograms in which the latter were fitted. To a first approximation, the T11 RF section appears to have been a “short” version of T10A, with one less IF stage on both AM and FM, SW coverage to 20 rather than 23 MHz, and with an EM84 tuning indicator. One might say that the T11 (RF section) bore the same relationship to the T10A as had the T57 to the T99. But the T57 had been positioned as a lesser model. With the T11, one wonders whether the deletion of an IF stage (one valve and two IFTs) was done to allow enough room on the chassis to accommodate the extra valves required for the audio control function. Curiously, with the TVR14, Dynatron did go back to the 3-stage FM/2-stage AM IF strip.


Cheers,

[stevehertz]

Originally Posted by Jonster

My favourite consumer model would be the Sony ST-SB920 it has all the bells and whistles, a very sensitive front end and superb audio quality. A lot found their way into professional environments too as they are easy to fit to a 2U 19" rack tray.

Mine too. I spent a lot of time choosing it and it has variable bandwidth, selectable antenna attenuation, lots of presets and a great overall performance and sound. When you store a station you can include the selected bandwidth, antenna, stereo/mono setting etc etc, so when you subsequently select that station it's already 'programmed' with your customised settings for it, brilliant. If only Sony - or whoever - did a similar tuner that also had DAB..

[Nickthedentist]

Originally Posted by Jonster

My favourite consumer model would be the Sony ST-SB920 it has all the bells and whistles, a very sensitive front end and superb audio quality.

Just picked one up for under a tenner on eBay. Very pleased

[Focus Diode]

The quality of VHF sound broadcasting on the 1970s Alba 8006D radiogram was superb. I still have many recordings made from it which sound outstanding. I deeply regret scrapping it about 20 years ago.

For stereo VHF a conventional light bulb lit up under an orange square. The stereo killer, not unlike a colour TV CK was over sensitive however so I fitted an over-riding switch to allow stereo from weaker signals.

The whole Alba unit could hardly be considered "Hi Fi" owing to the use of a conventional BSR auto changer with ST15 stylus but on radio alone it was a damn sight better than many Hi Fi units.

And how about a 1959 HMV 1131 that could often receive LBC on 97.3Mhz with an indoor wire aerial some 100 miles from the transmitter? A "Hi Fi" tuner couldn't achieve that when fed by a 6-element outdoor aerial? To be fair it was in the wrong direction!

[Synchrodyne]

Originally Posted by G6Tanuki

Must be said though, I've always been more of a DXer than anything - I want to 'hear' a station not actually listen to it, so I rate receivers on sensitivity, selectivity, resistance to cross-modulation rather than the quality of the recovered audio. You don't worry about stereo separation when you can barely hear the signal above the noise.

Would not a VHF communications receiver be better for that purpose, i.e. “hearing” rather than “listening”? Thus the ICOM R7000 comes to mind as a DX’ing candidate. Its sound quality, when used to feed a hi-fi amplifier via its tape output, was acceptable reasonably acceptable but a little “coloured” as compared with that from a hi-fi tuner. Of course, it was mono, not stereo, but with very weak “DX” signals that probably didn’t matter. I recall from the 1970s or 1980s that one of the hi-fi magazine commentators – it might have been Angus McKenzie – used an Eddystone 990R VHF communications receiver to check for FM DX openings before trying his main FM receiving equipment.


Cheers,

[Synchrodyne]

A related and “vintage” issue is who was the first UK maker to offer an FM tuner?

The earliest reference that I can find is to a Kolster-Brandes (K-B) model mentioned briefly in Wireless World (WW) 1949 November, described thus:

“The set shown by Kolster Brandes relies on crystal control for frequency stability with switching to the appropriate station in the range 90-94 Mc/s. An adaptor for use with existing sets is also available; the circuit is the same except that there are no a.f. stages.”



So, the K-B adaptor variant was effectively an FM tuner. Whether many or even any were produced beyond the prototype is unknown.

The next I can find is the prototype Quad FM tuner, briefly mentioned in WW 1952 July, page 257. This though did not go into production at the time. The somewhat revised production version was mentioned in WW 1955 July, page 313.

Possible the first that actually went into production was a Lowther model that was mentioned in WW 1953 July, page 302, and was advertised in WW from at least as early as 1953 July.



This unit covered VHF-AM as well as VHF-FM. The succeeding FM-only Lowther Mk II model was advertised in WW from at least 1955 November. I am not sure, but the original model may have been FM-only in later production.

The Chapman FM81 was advertised in WW from at least as early as 1953 November.



In its initial guise, this also covered VHF-AM as well as VHF-FM. But there appears to have been an FM-only second iteration, followed by the FM81 Mk II (with somewhat different circuitry) in 1956.

Sound Sales advertised its FM tuner (with VHF-AM capability) at least from the WW 1954 July issue.



And Goodsell advertised its FMT/401 from 1954 September, if not earlier. This may have been of the FM-only form.



More information, including performance commentaries on the Sound Sales and Goodsell tuners is probably unobtanium. But there is a little on the Lowther and Chapman models, to follow.


Cheers,

[Synchrodyne]

And this Berry’s advertisement from WW 1954 November suggests that Lowther, Chapman, Sound Sales and Goodsell were the main available makes of FM tuner at the time.




Cheers,

[Ted Kendall]

...which leads to the question, when exactly was there a viable FM service from Wrotham? BBC Yearbook states mid-1955, from memory, but some off-air recordings from 1954 suggest FM reception. These adverts suggest something was going on considerably earlier than that.

[Synchrodyne]

My understanding is that there were ongoing VHF trials right from the end of WWII. Initially they were low power, at 45 then 90 MHz, from Alexandra Palace, then high power from Wrotham from when it opened in 1950 until regular FM broadcasting started in mid-1955.

The early AP trials settled the FM vs. AM issue with the expected outcome, but then the matter was reopened after lobbying by BREMA (who was apparently pushed to do so by C.O. Stanley of Pye, perhaps trying to emulate Sarnoff’s anti-FM stand.) So, Wrotham was also engaged in FM vs. AM trials.

Evidently the scope of the Wrotham experimental service in terms of programme hours was enough to create sufficient public interest to spur some equipment makers into offering receivers and tuners. The 1949 crop of such were FM only, perhaps so in the belief that the modulation issue had been settled. The early 1950s models had a bet each way, covering VHF-AM and VHF-FM, although the emphasis was definitely upon FM. I understand that the original Quad FM version of 1952 also covered VHF-AM, which would explain the specific nature of its IF strip.

The first UK TV-FM receiver, the English Electric 1550 of late 1949, I think, was FM-only for the 90 MHz sound broadcasting, even though it was obviously AM for TV sound. That is also indicative of the thinking that the modulation issue had been decided, and that regular FM was not far away.

Some background is provided in the attached Wireless World items.


Cheers,

[Synchrodyne]

For the Wrotham FM vs. AM trials, the BBC had Ambassador Radio design and build a VHF “Comparator” receiver to its specifications. This was a complete domestic-type receiver with integral amplifier and speaker. The RF side was a real tour-de-force, although the AF side was quite simple. One wonders what happened to this fleet of receivers when the trials were over, and whether any survived into collections.

One of the 1949 FM receiver group, mentioned in the 1949 November WW excerpt in post #51, was the HMV 1250, which was a complete receiver. The RF section was the basis of the BBC HR/12 receiver, used as the receiving end for radio microphone units at outside broadcasts. It was probably a relatively good FM receiver for its time, and so a sound basis for a domestic FM tuner.


Cheers,

[paulsherwin]

I'm surprised there was a large enough potential audience for the pre 1955 test transmissions to make consumer products commercially viable. They would have been expensive, and there wasn't a lot of money around in postwar Britain, even in the AP and Wrotham service areas. Maybe the manufacturers were hoping to sell them to the BBC itself.

[Nickthedentist]

Or export, possibly?

[Synchrodyne]

I had also wondered whether the export market was the primary focus for the early movers in the FM tuner field. The UK hi-fi industry was generally export-oriented, and for example amongst Chapman’s range of AM tuners were some E-suffix models specifically configured for export markets. Its top-of-the-line S6BS was definitely more of an export than a domestic model, although sold domestically. And the same might have been said of Lowther’s DT/5.

However, the available evidence points to the pre-1955 market having been more in the direction of domestic listeners who were within range of the Wrotham experimental transmissions and had the desire and means to acquire a suitable tuner, at approximately the same cost as a good wideband AM tuner of the time. These listeners were probably few in number, but enough to support manufacture by small companies who were accustomed to making some models that sold in only tens or maybe low hundreds per year. Those hi-fi makers whose typical production numbers were higher, say low thousands per year per model, may have elected not to enter the FM tuner business until the FM broadcasting moved from experimental to a regular service. Evidently Quad, who was early with a prototype tuner, then held back until this was the case.

Certainly, some of the advertising supports the notion of a domestic orientation. In respect of its first VHF FM-AM model, Lowther said: “Tunable 85-100 m.c.s. on both A.M. and F.M. for experimental transmitter from Wrotham and other sites as erected.”

For its original FM81, Chapman said: “Tunable between 87.5 Mc/s. – 100 Mc/s., the FM81 will receive the B.B.C. Frequency Modulated or Amplitude Modulated V.H.F. transmissions approximately 50 miles radius from WROTHAM.” From 1954 June, if not earlier, this advertising statement was changed slightly, to: “Tunable between 87.5 Mc/s. – 100 Mc/s., the FM81 will receive the B.B.C. Frequency Modulated V.H.F. transmissions approximately 50/60 miles radius from WROTHAM.” Thus, Chapman evidently deleted the AM facility following the TAC decision (in 1954 January), accepted by the PMG (in 1954 February) that VHF broadcasting in the UK should be FM not AM.

The inclusion of the VHF-AM facility in some of these early UK FM tuners is another indication of their domestic market orientation. UK was virtually alone in considering VHF-AM in the 1950s, although there is evidence that Belgium might also have done so. Also, in most cases the tuning range was relatively restricted, with 100 MHz as the upper limit. For the export market 88 to 108 MHz was really required. In fact, in this regard, one might say that the UK industry had a domestic market orientation even after 1955. Of the FM tuners listed in Hi Fi Yearbook 1956, only one, the Quad FM, had an” international” tuning range of 87.5 to 108 MHz. The others all stopped at 100 MHz or just above it. This gradually changed through the late 1950s and beyond, with for example Leak making the change to 88-108 MHz with its Troughline II early in 1960. Some, such as Chapman, moved to offering a choice of two FM tuning ranges.

This Lowther advertisement from 1955 November was mostly about its FM Mk II model, but also mentioned was the fact that it offered an AFC retrofit service for its earlier VHF AM/FM model. One might reasonably infer that it had sold enough of these to justify advertising the modification service.




Cheers,

[Synchrodyne]

Originally Posted by Synchrodyne

More information, including performance commentaries on the Sound Sales and Goodsell tuners is probably unobtanium. But there is a little on the Lowther and Chapman models, to follow.

By that I meant this short commentary by Arthur Wayne writing in Hi-Fi Year Book 1962. I had forgotten that this mentioned the Goodsell tuner as well as Chapman and Lowther.



Wayne gave the Lowther Mk V a high ranking. This was released in 1960, and was Lowther’s final valved model. Interesting was that it had a two-stage IF strip, whereas the better-ranked FM tuners usually had three-stage IF strips. Given the timing of the article, the Quad FM variant that Wayne tested I’d guess to be a Series B, second iteration. Later, Wayne did a review of the Leak Troughline II for Hi-Fi News magazine (1963 February), although I haven’t seen this.

The FM side of the Chapman S6BS/FM was found to be average. This model had separate FM and AM sections, and the FM part was the same as the FM91, Chapman’s top FM-only model.


Cheers,

[paulsherwin]

The whole of Europe had the restricted VHF band, not only Britain. Europe generally had a system of state or semi-state monopolies operating a small number of national or regional networks.

I wondered if some of these pre-55 tuners were targetted at the German market, where FM started much earlier. The German radio industry was on its knees in the immediate postwar period and British manufacturers might have considered it an easy market into which to sell (if so, their hopes were soon dashed).