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Mystery Leak Troughline III with internal stereo decoder

Well there’s not much love for the poor old Troughline here is there! I’d posted this hoping for a little help in identifying what I thought was a fun little curiosity, but thanks for reminding me that this hobby isn’t meant to be fun. Foolishly, in my time away from all things audiophile, I’d forgotten that the real purpose of this interest is to quash any positivity or enthusiasm, while simultaneously demonstrating how much more you know about an individual’s personal possessions than they do. Silly me, my memory really isn’t what it used to be y’know.
 
Well the old mono Troughline is producing a wonderful concert of the Bach Brandenburg Concertos on Radio Three. It's the interval now!
Oooh, was that the early music festival? I forgot about that - was it good, should I catch up with it?
 
Very fine concert. Well played and very enjoyable. York Early Music Festival [recorded on Wednesday], and certainly worth listening to on BBC Sounds.

Best wishes from George
 
TBH I'm far from sure they were the best British tuner thoughout their lifetime in production. Leak was a pretty good salesman/marketingbod. Knew how to promote by 'selling' some technical detail. (Ducks and runs... 8-] )
The description would fit a certain gentleman from south Glasgow...
 
Two units were fully restored back in the mid-1990s, one for HiFi World and one for HiFi News and both were done for review purposes. HiFi World used this Leak tuner to compare against every other tuner thereafter in their reviews. HiFi World were also very supportive of our work on vintage tuners as we also did the QUAD FM1 tuner and Chapman tuners as well as some McIntosh models from the USA, typically the MR65 and MR71.
Both Troughlines were completely stripped down to the bare chassis, then fully cleaned, then fully rebuilt with all new components including new valves. Then they were fully realigned and a specially developed stereo decoder was fitted. All of this work is why they sounded so good. We did hundreds of Troughines like this over the years but stopped about 2005 as demand diminished mostly due to the Beeb's intent on switching off the FM transmitters.
 
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Well, I am beginning to think that the experts are suggesting my radio is rubbish - a 1957 Trouhgline used daily.

Yesm it would be an odd suggestion as a sweeping assertion. But a tuner always doesn't have to be the 'best available' to deliver good results. Nor are the requirements for mono the same as for stereo. So this isn't a simple best/rubbish binary.
 
Two units were fully restored back in the mid-1990s, one for HiFi World and one for HiFi News and both were done for review purposes. HiFi World used this Leak tuner to compare against every other tuner thereafter in their reviews. HiFi World were also very supportive of our work on vintage tuners as we also did the QUAD FM1 tuner and Chapman tuners as well as some McIntosh models from the USA, typically the MR65 and MR71.
Both Troughlines were completely stripped down to the bare chassis, then fully cleaned, then fully rebuilt with all new components including new valves. Then they were fully realigned and a specially developed stereo decoder was fitted. All of this work is why they sounded so good. We did hundreds of Troughines like this over the years but stopped about 2005 as demand diminished mostly due to the Beeb's intent on switching off the FM transmitters.

It is perhaps a shame that Hi Fi magazines have rarely bothered to re-review equipment when it has been in production for some years. In at least some cases, the designs were modified and improved *without* any external sign or change being visible.

I can cite some specific examples from personal knowledge - the Armstrong 600 range - and say that in their last year or two they were somewhat better than when first released. But I think much the same could be said of other models that went though development which often passed unnoticed by magazines and most buyers.

Sometimes this is detailed in 'official' documents - e,g, the service manuals for QUAD kit. But some examples like the changes to the 600 range FM tuner and decoder never appeared in the released circuit diagrams, etc. Yet they had a distinct effect on aspects of performance.

That said, I doubt most people would have noticed because the differences might only show up in 'difficult' circumstances.
 
Yesm it would be an odd suggestion as a sweeping assertion. But a tuner always doesn't have to be the 'best available' to deliver good results. Nor are the requirements for mono the same as for stereo. So this isn't a simple best/rubbish binary.

Dear Jim,

I would agree that the last word in technical perfection does not always equate to an enjoyable listening experience.

When a youngster, I bought an HMV Model 102 portable gramophone [£4 from a junk shop in 1972], and it was so far from hifi that you could wonder about it! But it gave me years of pleasure playing hundreds of 78s that I found. There seemed a sort of directness in connecting to the live four or five minute takes engraved directly into wax. I never noticed the surface noise, the occasional thump as the spring unwound itself, or the need to change the record perhaps 10 times for a whole Beethoven Symphony! In reality it worked better on 78s than most electrical record players designed for LPs.

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Not my one.

My old Troughline [working as noted in mono, which I prefer anyway] has similar qualities of directness on live relays, but without the surface noise, or side changes, and if you listened just to the ESL without sight of the electronics, most people I am sure, would not guess that the radio is actually from the 1950s.

Now I have not put it side by side with a more modern tuner. Why would I? I am not that curious, but over the years I have owned three solid state tuners, and each gave me huge pleasure. Now the Troughline is doing the same. It is the most solid on station of any of them once warmed up, and after ten or twenty minutes requires no tweaking of the tuning control, thought is terribly sensitive to being marginally off. Much more so than the solid state ones, but on station it is grand. Now I don't know how it would measure beside newer ones, but I do know it does the business for me, and those who have heard it here have been in each case surprised just how well it works. Almost like they find it hard to believe anything could be that good six decades ago.

The specific reason I tracked down an original first variant was because I knew that no provision for a stereo decoder was incorporated. Thus most people avoid them and a good one [cosmetically] will be much cheaper as well. For most people mono is curio at best and technically inferior by definition. Also the original Troughline had a sold copper actual Troughline compared to copper plated mild steel in the later variants, which [copper trough] is actually better at stability on station. I had a Tr III [a pair in fact] and these required the use of the [switchable] AFC to retain stability.

So in my case at least I have the ideal radio for my application. Evening concerts are an almost daily thing with it, and the Proms start on Friday!

What is a little sad is when the discussion about these things becomes too binary. Of course a discussion of technical quality is not only interesting, but useful. it is not a question of the oldies being rubbish as such or useless, or whatever, but rather whether they do what they were made for and give pleasure playing music, or a good play ...

For me I get a huge kick out of something old but good, such as my classic Carlton bike, which is quick, responsive and stable, but is it competitive with a modern road bike? Of course not, just like an E-type is not competitive with a modern sports car!

Best wishes from George
 
Foolishly, in my time away from all things audiophile, I’d forgotten that the real purpose of this interest is to quash any positivity or enthusiasm, while simultaneously demonstrating how much more you know about an individual’s personal possessions than they do. Silly me, my memory really isn’t what it used to be y’know.

Ignore know-it-all trolls, who (one can only assume) take some perverse enjoyment on raining on others parades. Some people sometimes act as if this was their personal blog and can’t graciously take a back step, hold their tongue, and allow those who clearly want to enjoy certain vintage gear to do so without said gear - and enthusiasm for it - being criticised. I for one enjoyed reading your original post and the photos. I have a late grey Troughline Stereo waiting in the wings here to be restored, along with a Stereo 20 and Varislope, which all belonged to my Great Uncle. I’ll be starting work on the Stereo 20 first, health issues/energy allowing. Love seeing this gear restored and being used & enjoyed still. In today’s disposable ‘culture’ it’s even more heartening, and important I think.
 
Dear Jim,

I would agree that the last word in technical perfection does not always equate to an enjoyable listening experience.

I agree. Might be worth my saying that:

1) Although I have, and have used, a CT7000 FM tuner, on a daily basis I prefer an Armstrong 626 and a QUAD FM4. Neither can come close to the RF performance of the Yamaha, but they deliver good sound given a reasonable RF feed. The CT7000 scores when reception conditions are particularly difficult.

2) I do also have a 'Decca 60' wind up gramophone. It even has one of my old 'climbing and walking' socks in the horn as a volume/tone adjustment. 8-]

My point was that a *general assumption* that the TroughLine is the 'best' tuner with no qualifications at all isn't one I'd go along with. Partly a matter of personal choice, partly down to *reception circumstances*. Even in mono, some people may find an unmodified TroughLine useless, but a CT7000 worked well.

Of course, if a tuner is heavily modified, then the performance may alter, However we're then talking about a unit differs from the original even if in the same chassis with the same fascia.
 
Dear Jim,

Such a nice reply - thanks.

I would not call my Troughline better than more recent tuners. It is quite forward in presentation, and too close a microphone technique is not well done. Radio One gets an unbearable quality. Later Troughlines have a slightly softer characteristic in my experience, but not one I would prefer. Of course, when modified all bets are off. Mine is not modified from original but rather serviced in the original style, so probably not wildly different from what it was when freshly bought new.

Just like my old Carlton cycle it has its good points, and I would have no doubt that better has been done since in the true stereo era! But on a good day it brings sublime pleasure. Cannot be all bad if it can do that.

I had a Rotel RT 850-AL, which was really nice, but not so correct as to instrumental timbre. It was much easier as to antenna set-up. A piece of damp string would get something reasonable, but the TR gets something else - the sense of good timbre, bright as a button on bright music, and svelte as svelte on muted violins. Plus something inexplicable in a visceral sense like the old HMV 102 portable gramophone. Something quite undefinable and direct. [Addition - edit. I have so often found that mono replay of some respectable quality has this directness that evaporates when the same music is replayed in stereo].

Best wishes from George
 
Dear Jim,

Such a nice reply - thanks.

I would not call my Troughline better than more recent tuners. It is quite forward in presentation, and too close a microphone technique is not well done. Radio One gets an unbearable quality. Later Troughlines have a slightly softer characteristic in my experience, but not one I would prefer. Of course, when modified all bets are off. Mine is not modified from original but rather serviced in the original style, so probably not wildly different from what it was when freshly bought new.

Just like my old Carlton cycle it has its good points, and I would have no doubt that better has been done since in the true stereo era! But on a good day it brings sublime pleasure. Cannot be all bad if it can do that.

I had a Rotel RT 850-AL, which was really nice, but not so correct as to instrumental timbre. It was much easier as to antenna set-up. A piece of damp string would get something reasonable, but the TR gets something else - the sense of good timbre, bright as a button on bright music, and svelte as svelte on muted violins. Plus something inexplicable in a visceral sense like the old HMV 102 portable gramophone. Something quite undefinable and direct. [Addition - edit. I have so often found that mono replay of some respectable quality has this directness that evaporates when the same music is replayed in stereo].

Best wishes from George

A nice tuner! Also available for 3 times the price as the later version of the Musical Fidelity T1... Same innards!
 
Dear Jez,

On my say so a good friend got the Rotel for a real snip, and loves it. It is rather fine, I think.

I did not think that a valve based tuner would be quite right for my friend, though we share an interest in crazy classic English steel framed road bikes!

Best wishes from George
 
Dear Jim,

I would not call my Troughline better than more recent tuners. It is quite forward in presentation, and too close a microphone technique is not well done. Radio One gets an unbearable quality.

The is a big difference between R3 and R1. In general, R3 is modulated at relatively low levels whereas R1 is generally modulated at levels close to the maximum. This matters particularly when a tuner has a narrow IF because it tends to hike the distortion levels when the modulation is high. This is particularly the case when stereo is transmitted *even when heard in mono*.

TBH the channel bandwidth for FM stereo is only *just* adequate. This is why some 1980s 'super tuners' offer a choice between wide/narrow IF as this can help a bit for cases like R1... assuming you can still bear the music they broadcast anyway. 8-]

The early TroughLines tend to have a relatively narrow IF because they were optimised for mono. But these days even listening in mono can't escape the above problem having an effect. So its no surprise if R1 sounds lousy... even ignoring the music as such. :)

Listening to R3 via a 626 as I type this. :)
 
Dear Jez,

On my say so a good friend got the Rotel for a real snip, and loves it. It is rather fine, I think.

I did not think that a valve based tuner would be quite right for my friend, though we share an interest in crazy classic English steel framed road bikes!

Best wishes from George

I think a point needs making that in the case of many valve tuners the valves probably have little or no effect on the sound! I say probably as I don't think subjective effects at 100MHz from valves is something I've ever seen investigated or even mentioned before!

Up until the discriminator the signal is not at audio frequencies.... it enters at RF (Radio Frequency) at around 100MHz (88 -108 MHz) is filtered then amplified before going to the mixer where an internally generated RF signal (the local oscillator. The actual troughline bit is part of this) at a fixed offset from the received signal is mixed with it and the beat frequency (just like in musical instruments) between them is obtained, usually at 10.7MHz but 12.5 for later TL's. This is called the IF, Intermediate Frequency, and it is at this frequency that most of the amplification and filtering happens. At this stage the "intelligence" ie the audio modulation, is still frequency modulated (FM), it has been transposed down from 100MHz to 10.7MHz but contains the same FM modulation, ie the frequency goes up and down in time with the audio amplitude. It is only right at the end of the process where this IF goes through a circuit called a Foster Seeley Discriminator that it becomes audio.... In the case of your early TL the diodes in the Foster Seeley are in fact valves but in many, including TL 2 and 3, these are solid state germanium diodes (whether or not valve diodes have a particular sound is a moot point!). In yours it then goes via a cathode follower to the output but in a TL2 used with decoder it goes from the SS diodes to the multiplex output socket without seeing a valve at all at any time after the signal became audio once more !
 
The valves at RF/IF probably don't matter much beyond, perhaps if the LO valve isn't steady. However the details of the IF filtering do matter as that can alter the FM pattern, and hence cause distortion, etc. The demodulator can also affect this.

For the above reason, the performance might also vary with signal level if that means the source impedances of the valves alters, in turn altering the matching to the staged filters.

Devils in many details.
 


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