advertisement


LEAK TROUGHLINE TUNER- UPGRADES

eguth

eguth

pfm Member
MEMOIRS OF A DIY HI FI NUT- Part XII

LEAK TROUGHLINE TUNER -UPGRADES
By eguth & toaster​

PREFACE
We worked on this project jointly. We spent well in excess of 100 hours- not including experiment, listening and correspondence. This was spread over 14 months during 1992-7. We would have liked to thank all who helped. Unfortunately, in the case of Ralph Williams, this is not possible. His tragic death at an early age was a loss to valve hi fi. Ralph held a degree in Electrical Engineering from University College, London. Thanks go to Glen Nicolas, Denys Trickett, Peter Watson, Peter Lewis (the designer of the Mullard decoder), and David Heaton. None of these are in any way responsible for any errors or omissions.

We emphasize that many of the parts specified or used are no longer available. The coil was never available. If you decide to try any of the mods we cannot advise you on any step or procedure. Nor can we advise on parts substitutes or how to wind the coil.

This article is posted as it may be of historical interest. We both still use our modified Troughline tuners and they sound excellent.

Now I can start. I’ll do anything for a laugh- if only I had a sense of humour- so when I learned that my friend toaster had just purchased a Leak Troughline MONO tuner I thought to myself “…why don’t we both ATTEMPT to convert our tuners to stereo together? This could turn out to be Very Funny. I had heard about (but not heard) stereo. Some thought it may be better than mono. After all, most of us do have 2 ears.

Toaster liked the idea of stereo. He agreed that it would be a Good Thing to do our conversions together. “Two heads are better than one”, said he. So he whipped out his RS catalogue and we proceeded to burn up the pages with out joint order. I managed to dig up a couple of old Quad 22 steel cases for the outboard decoder and its power supply. They turned out to be not a quarter of an inch too large for what eventually was put into them. It would have been absolutely impossible to do the conversion to the high standard we set within the Leak tuner case: out of the question.

I
Renovating the Tuner​
The following link shows photos and schematics referred to in this thread.

http://redirect.viglink.com/?format...ww.flickr.com/photos/3451470...7612748160694/



1. The Knobs. Nothing on earth would shift the 30 years of ingrained dirt from the white Bakelite. I finally hit upon my tooth brush and the damp scouring powder that I brush my teeth with. That shifted it.

2. The Valveholders. Remove each valve and clean the valves and sockets. The best thing I have found is Deoxit. It comes with a brush to get down into the sockets. Getting it out afterwards calls for some ingenuity. Be sure not to enlarge the socket holes when you do this. Replace V5 valveholder with the type that takes a screening can and fit a can.

3. Sensitivity Switch. Remove the two wires from local/distant sensitivity switch. Clean wires with emery cloth. Solder these together, first slipping a piece of insulated sleeving over one lead to cover the finished joint. The switch is now bypassed. Temporary; only until the entire tuner is rewired.

4. Turn the tuner upside down and remove the bottom cover. Bypass the volume control potentiometer. To do this you remove the wires, clean and solder them together. This mod brings a noticeable reduction in distortion. I installed a new, modern on/off switch in place.

5. Clean MPX phono socket with switch cleaner. Remove flying phono output lead from MONO audio output and install a quality nickel plated phono socket.

6. Spray AFC switch with switch cleaner and work to and fro.

7. Clean the fuse and fuseholder.

8. Oil the bearings at both ends of the tuning capacitor.

http://farm4.static.flickr.com/3494/3208766743_c52953f121_s.jpg

9. Cut a hole in the rear of the case to take an IEC mains socket (the shuttered type, FEMALE with no pins [no, I am not sexist]). A good place for this socket is at the top of the rear panel just left of the voltage selector plug. LIVE is wired from the terminal at the top of the fuseholder. The terminal hole should be drilled out slightly larger to take both wires. NEUTRAL is wired from the voltage selector terminal, which already has a large hold (see Fig. 1). (See below for mains wiring UPGRADE/SCREENING inside tuner).
10. Carefully pull out the voltage selector plug. Clean pins. Reinsert in CORRECT position a few times to clean, using switch cleaner. Double check that the final position indicates the correct voltage.
11. Aerial Connexions. There is a terminal strip at the rear of tuner. If you use balanced twin feeder this should be connected to both outside terminals and not to the centre terminal. If you use normal unbalanced coaxial cable usual in U.K. installations, you have two alternatives- neither of which is very satisfactory. Either remove the plug and connect the coax direct to the CENTRE terminal and the inner wire to EITHER of the outside terminals or, alternatively, you can run a short length of balanced twin feeder to a balun (expensive) and connect the coax to the balun. Using this second method you will lose some of your previous signal from the aerial. To avoid these problems, purchase a chassis- mounting 70-80 ohm (unbalanced) females socket [I am not sexist]. Cut a hole in the rear of the case above the terminal aerial strip. The outer contact is soldered to the centre terminal and inner to EITHER outer terminal. Plug the coaxial cable plug into the new aerial socket.
12. Feet. The original tuner had four rubber feet which were necessary to protect the Perspex front panel lip from damage. Four rubber doorstops glued to the underside of the case do a better job, because they lift the unit clear of lip destroyers. The original feet don’t.
13. Trim. The lip on my front panel was chipped in places with paint missing. Using matching pain on the REAR surface did work well; this makes it impossible for light to shine through to the front and the panel then looks undamaged.

Decoder. An inexpensive good one may be a problem to find. We were lucky to get Mullard LP1401 stereo phase- locked modules (1975 vintage) new (see Figs. 2,3,4). This decoder is more advanced than the one used in the Leak Troughline Stereo tuner and, in our upgraded form, quite superb. You can build an upgraded LP1401 from scratch using this article and diagram.



At this point some of you eagle- eyed listeners will ask “What happened to MEMOIRS OF A DIY HI FI NUT- Part XI?” You already have it in Pink Fish Media- see my Passive Switched Attenuator Thread This should be renamed MEMOIRS OF A DIY HI FI NUT-Part XI

http://www.pinkfishmedia.net/forum/showthread.php?t=29612
 
MEMOIRS OF A DIY HI FI NUT- Part XII

LEAK TROUGHLINE TUNER-UPGRADES
By eguth & toaster

APOLOGY

Sorry for the small photos you see after following the above links. I hope that my 2nd post (above) will result in large enough sizes to be useful. I am still trying to get full sized photos into the links, without the apparent need to subscribe to Yahoo- this did not seem necessary yesterday!

CENTER]
II

Conversion To Stereo​

To convert the Troughline II to STEREO with a view to making major improvements in the sound in the way we did you will need the following. N.B.: the suppliers below may no longer stock the items.

FROM AUDIO SYNTHESIS; Holco resistors as required
FROM RS:

1 X 0.1 uF polypropelyne (p/p) 100v capacitor
1.x..22uF p/p 1000v
1 x 680pF p/p precision polystyrene
1 x pack ultrafast diodes UF5408
1 x 1n precision polystyrene
1 x 100pF precision polystyrene
1 x BC 548 transistors
1 x 3300uF 63V computer grade electrolytic

Resistors
1.x. 1K
1 x 8.2K
1 x 16K7
1 x 82K5
1 x 2.2R w/w
1 x 15K w/w aluminium housed
1 x 47K
1 x 5K62
1 x 4K

Cermet trimmers
1 x 500K
2 x 10K
2 x 1K

Misc.
1 x copper shielding foil
1 x red LED
1 x green LED
2 x LED fixing clips
1 x IEC shuttered outlet socked (reversed configuration1 x IEC MALE cable plug (shrouded)
1 x phono plug
2 x black and 1 x red professional grade nickel plated chassis- mounting phono sockets
1 x miniature professional switch (gold contact)
1 pack ultrafast recovery diodes 1000V 3A
2 x 10uF polycarbonate caps 63V axial
1 x 4uF solen p/p
1 x 15V positive voltage regulator
1 x 0.01uF 50V disc cap
1 x 47R w/w
1 x ‘2141’ PCB pins
1 x VE regulator PSU PCB (Altai)
1 x 50VA torroidal transformer (12V)
1 x 315mA fuse & PCB fuseholder
1 x 100uF electrolytic cap.

You must, of course, obtain a Mullard LP1401 decoder. Or you could build the decoder from scratch (upgraded) as per Fig.9 & 10 .

And you must get a substantial case, at least 10 1/4” wide by 5” deep by 4” high.

The Decoder Chassis
The Quad 22 case we used has channels welded along the middle of the case sides, internally. Toaster made a shelf to fit out of aluminium sheet.

eguth forgot to mention that he carefully filed down the front panel so that it ended up undersized [but I expertly bashed the case in afterwards so that it lies flush-eguth]. The panel is secured to the Quad case via ‘L’ brackets and self- tapping screws. We sprayed the panel with three coats of Humbrol Gold. Then mounted a plastic ‘LEAK’ decal- that eguth fabricated- securing the decal in place with Marvin Medium, a useful glue which dries as clear plastic (see Fig.6). [eguth has spare decals if anyone is interested: if so send PM to eguth].

Wine- coloured Humbrol car enamel was painted on the case to match the tuner. This paint really toughens up after a few months.

All components are mounted on the shelf except the transformer, input and output sockets. The front panel carried the two LEDs and the ‘stereo inhibit’ toggle switch to reduce noise on weak transmissions. When switched on the green LED lights. A voltage divider provides about 3-5V to trigger the stereo inhibit, and in fact reverts to MONO. This connects to Pad 3 via the stereo inhibit switch (see Fig.7).

The Power Supply
The thing about toaster that I like so much is that he does not follow the crowd. He goes his own way. The massive 50V torroid transformer- the equivalent of powering the decoder with Battersea Power Station- is bolted to the left- hand wall of the case so that it sits vertically. Bicycle inner tube was glued to both roof and floor of case above and below and to the wall side (see Fig.8). Michelin gives a good, puncture- free ride.

The completed PCB is mounted on standoffs. Power enters from the IEC plug which draws its supply via the IEC socket on the tuner. The mains lead we used is two- core, grounded via the phono plug MPX. For safety reasons the cable is secured to the shelf with a strong “P” clip before soldering it to terminals bolted to the shelf and fully covered with heat- shrink sleeving in addition to a second complete shroud of thick insulation. Be sure to sleeve and completely insulate all mains connexions. The positive connexion from the other side of the mains terminals should go through a 300mA fuse before connexion to the decoder. The ordinary bridge rectifier is replaced with 4 x 1000V 3A ultrafast recovery diodes. A separate external earth terminal on the rear of the power supply case is fitted so that an extra safety earth can be connected but easily removed in case of hum problems. In practice, there was no increase in hum using it and it is always connected.

The Decoder Board
We fitted this with an edge connector and fixed the connector to the shelf with ‘L’ brackets. The MPX input is made via a flying lead from the PS/decoder case. The quality of this lead is crucial, as is its length. We used RS ‘The Blue’ (78ohm data cable) and site the PS/decoder case on top of the tuner, allowing a very short lead to be used. This lead should be as short as possible.

The audio output is taken from pads 5&6 with a shared earth connected to pad 7. We used ‘The Blue’ again, with its two conductors and a shield. It might be better to use separate earth returns.

The outputs are attached to the board via 10uF polycarbonate decoupling caps. If you omit these the output floats on a DC offset of 6V; do don’t leave them out.

The shelf is fixed to the case with two self- tapping screws, one on the bottom and one on the side, so that it is very secure (see Fig.8).​
 
Markus S

Thanks for pointing this out. I have now changed the setting so that anyone- I hope- can see the photos. I would appreciate it, Markus, if you would confirm that you have now succeded in viewing them. VERY sorry (again) about the inconvenience.
 
III
Upgrading The Components​
THE MONO TUNER

First remove C50 (100p de-emphasis capacitor).

One of the advantages of a separate ‘plug-in’ box for the decoder is that it is easy to hear the effect the decoder has on the sound. With the decoder plugged in this tuner sounded like a CHEAP transistor design; signal strength seemed way down, background noise up, separation not good and there was a severe loss of bass. Moreover, the treble sounded harsh. In short, it was far better on mono through the LEAK only- but not up to eguth’s Sugden R50 transistor tuner in any way save that midrange was more realistic. The LEAK mono sounded distorted compared to the Sugden stereo.

So we decided to have a go at upgrading the old carbon resistors though we were not hopeful of great improvements. Were we wrong! We also thought about replacing all the capacitors (now some 30 years of age) but were warned that doing so would throw the tuner out of alignment. Servicemen willing and able to realign this tuner for a modest fee are few and far between.

Before starting on the component upgrades we replaced all the ancient hookup wire on both the Under Chassis and the Top Chassis with RS 78 ohm data cable “The Blue”- itself an audible MAJOR upgrade. Enlarge mono audio output hole and install a nickel- plated phono socket if you haven’t already done so. You can use this output as an alternative to the MPX outlet, giving you an additional buffer stage and cathode follower to the decoder. Some seem to prefer the smoother ‘valvey’ sound using this output -but I prefer the MPX and find it more revealing. Bass is stronger and deeper via the audio output, but the MPX outlet sounds slightly less distorted.

We did end up replacing some caps but steered clear of the RF section. The three-in-one can 40uF power supply electrolytic was upgraded and replaced. I should have listed the upgrade on the parts list above. This 30 year old electrolytic was replaced with three separate 47uF 385V very high grade, high temperature, low ESR Phillips caps kept in place with three strong plastic- coated clips and bypassed with .1uF 1000V p/p. There is no room for the bypass caps next to the new electrolytics, so we mounted the bypasses on the Under Chassis. We replaced C56 4uF with a Solen p/p. RS 1000V p/p were used to replace C47 and C33.

Neither any of these capacitor replacements nor any of the resistor replacements had the slightest effect upon the tuner’s alignment- if clarity of sound is to be the test. Caps were replace ‘one at a time’ with listening in between because we were nervous about possible alignment problems.

We restricted resistor replacement to the Under Chassis only where all resistors are accessible and not sealed in cans (See Fig.5B). [Except R31, 1K w/w which we upgraded to 15W aluminium clad].

We found that it is best to start replacing the resistors surrounding V1 and then worked our way round the other valves. Most resistors were upgraded to 1/4W 0.5% 50ppm Holcos, but some higher wattage and some lower ppm Holcos were used. A few very high values not available in metal films were replaced with carbon film low noise high stability.

We listened at intervals. After replacing the resistors around VI there was an increase in clarity and the unit sounded less distorted. After V2 it sounded yet better; pretty good, in fact. At the end of V3 replacement the bass improved. Small further benefits resulted from the remaining replacements. The end result was that the tuner sounded quite good compared to before. Eguth was not sure that he did not prefer it in mono to the Sugden in stereo; gone was some of the mellow ‘valvey’ sound which had previously smothered everything in pleasant glow of ‘sameness’. A good improvement; more than we had expected.

All valves were replaced with new ones and some upgraded to better types including military valves. These make an audible different given the upgrades so far (see Fig.11 for suggested valve upgrades). Removing just one upgraded valve and replacing it with a good quality ordinary one made a quite audible downgrade.

However, when the decoder was plugged in the stereo was much the same as before. Completely unacceptable. Something had to be done. Apart from anything else, this decoder is unsuitable for use direct into a passive preamp. It needs a buffer stage.
 
IV​

The Decoder​

We used ordinary solder inside the tuner but switched to silver solder for the decoder.

1) All resistors were replaced with Holcos. Then all capacitors with upgrades. Good job we decided upon a largel, separate case for the decoder and its power supply; not even the large, new caps would have fitted inside the tuner. As it is they stick out inches either side of the decoder PCB- let alone that there is no room for everything else inside the tuner.

2) The power supply electrolytic was bypassed with 100uF electrolytic, and RS 1000V .22uF p/p and 0.1uF.


3) We used 10uF polycarbonate 63V for decoupling.

4) Decoder PCB upgrades: 0.01 Wondercap; 100n with RS .1uF p/p; 1n with precision polystyrene.

The sound now greatly improved. Background noise was gone. Up went stereo separation; seemed to be as good (now) as the Sugden. Back came quite a bit (but not all) of the bass.

However the general stereo quality still did not match the mono. So we went further.

5) We replaced the short wire running to the MPX plug inside the tuner with OFC as well as the leads to the aerial socket and terminal.

6) The 10uF tantalum bead was replaced with a Solen p/p.

7) The carbon trimmers were removed and replaced with good cermets.

After these replacements the fidelity was better because CD on R3 was usually apparent; CD sounding inferior.

The Tuner (again)

Put a 2.2R wirewound resistor in series with the festoon lamp in the tuner. This will mellow down the light (more in keeping with the age and style of the tuner) and will extend the life of the bulb, which may become increasingly hard to replace with an exact original. Eguth got the idea from the success he had using low voltage to run 25W ‘Pickwick’ lamps in his chandelier; 18 years using these bulbs without a single failure.

Toaster began to get seriously interested in the Leak Troughline Tuner project. So he took a week off work to get his tuner and decoder out of sight. One of the charms of toaster is that his pace alternates between a slug and a gazelle. In either mode no one can keep up (or down) with him. This tuner may become redundant and useless in about 24 years when parallel FM broadcasts may be phased out, leaving only digital ones (ugh). I do hope that toaster stays in Gazelle Mode long enough to hear his tuner before FM is phased out.


The Tuner (again)-Further Work

The mains lead FROM THE LEAK MONO TUNER to its mains plug was replaced with 2.5mm cross section mains cable, fastened to the Leak chassis with a strong strain relief cable gland (see photo of rear). It had to happen.

All mains cable located WITHIN the tuner was now removed and replaced (along with the internal run to the fuse) with high quality OFC, encased within braided shield. The shield is connected to earth. After these changes the bass IN STEREO arrived back home. There was also the expected further improvement, generally.

The Decoder (Again)

9) The IC was damped with sorbethane and the transistor upgraded to BC 548.

10) The PCB pads were hard wired to the edge connector terminals with ‘jumper’ leads; a noticeable improvement. Moral: never trust a connector!

The Tuner (again)

11) All valves except the EM84 ‘magic eye’, and V5 (already in screening can) were fitted with valve dampers. Essential.

The Decoder (again)

12) At this stage we had completely rebuilt the decoder except the IC & the coil. So what next? Audio Synthesis had just come out with some new, almost 100% pure silver wire; we soldered some of this to the PCB tracks with silver solder, to turn it into a hard wired decoder. We also ran an extra star earth from the IC ground to the pad. I discovered that the tuner does sound better after being on continuously for several days.

We had more or less come to the end of the line of upgrades that we could reasonably do and do at modest cost. We had spent about just short of £225- excluding the cost of the tuner- though this included an extra set of very high quality valves for future use. Was it worth it?

A Problem

A problem that refuses to go away is this tuner’s lack of sensitivity. Good modern tuners go into full limiting with 1mV of signal. One should aim to have at least this on all main stations. The Leak Troughline, however, requires 2mV to go into full limiting. Sensitivity of the Leak could be increased by modifications, possibly with a broadband amplifier. But this would probably compromise sound quality. Even in locations of strong signal strength close to transmitters (such as eguth enjoys- being less than 10 miles and in a direct unobstructed line of sight of the transmitting mast at Beulah Hill) signals of 2mV may be hard to obtain. You could try one of the Ron Smith superb aerials mounted high up. So…. The solution appears to lie in future technology. What is needed is an ultra low noise low cost masthead amplifier that will boost the signal from the aerial very considerably with no significant deterioration. I now use only a Ron Smith Diamond 12 aerial, vertically polarised; this is far from the most elaborate array you can fit.
 
V​

Comparisons & Evaluation​

There were times during this project when the following thought occurred:

“…this is an historic moment… we are the only persons in the entire history of audio privileged to be listening to The World’s Worst Tuner…”

However, due to perseverance, indolence, inspiration, perversity, genius, circumstances beyond our control, catastrophe, atmospheric turbulence, good guesses & a bit of luck we managed (at last) to step out of this gloomy historic atmosphere of hysterical depression into the radiant sunlight of ecstatic joy- tempered only by the sober realisation that absolute perfection still eludes all FM listeners.

I have not compared the finished conversion to other tuners except my off- the -shelf Sugden P51, purchased new in 1976. Rather than speculate, I will make only such comments as seem unexceptional.

Firstly, the upgraded LEAK is not better in every way from the sound point- of- view than the SUGDEN; it IS better in many ways- but the Sugden is more sensitive and has better selectivity: it also has a slightly tighter and deeper bass and at first sounds as if it is slightly less distorted. The LEAK has a clearly better midrange and much more dynamic range than my Sugden, though I absolutely refuse to sell the Sugden despite The Crunchiness of Credit & The Scarcity of Yorkshire Pudding.

Secondly there would be no point in comparing our upgraded Leaks to any tuners other than Hi End ones.

Thirdly, the sound of our conversion IN STEREO is much better than the sound from our modified and upgraded Leak used in MONO: this quite apart from the benefits of stereo. No conversion of a Leak mono tuner will be as good unless it sounds significantly better IN STEREO than the sound from a standard LEAK MONO tuner. This is not likely unless the Leak mono tuner is first upgraded and a huge, dedicated power supply built for the decoder. It also speaks volumes about the quality of the Mullard LP1401 decoder thanks to Peter Lewis of Mullard, who designed it all those years ago.

Fourthly, I am not aware of any commercially available upgrade and conversion which uses components overrated and of the quality we have chosen. E.g. distortion figure for the de Paravicini valve decoder is 0.2%; no better than the bog standard Mullard LP1401; but valve distortion may be less objectionable than that produced by a pure transistor design. Our modified LP1401 has a better distortion figure than the bog standard original. We have not measured it.

For an expenditure in the region of £200- for upgrades to the tuner and conversion to stereo via our separate PS and decoder- we believe we have a bargain. It’s reliable, trouble-free and a pleasure to use. It is lovely to look at with its decoder/PS sitting on top. The two exude a kind of olde-=worlde charm.


The high output impedance of the LP1401 should be followed by a buffer stage. It was designed to be used within a mono tuner before the tuner’s buffer stage. Both of us use a buffer stage after the volume controls in our passive preamps. We have found that the modified LP1401 works well into our buffered passive preamps. Neither of us has felt the need to add yet another buffer stage to the LP1401. You could add one to make the conversion useable with any setup.

I (eguth) say that I think that the virtues of this Leak tuner have sometimes been exaggerated.

I dislike the term ‘anacrophile’ and don’t want to be one. I believe in progress- in hi fi and everything else. If progress entails going back to the past then I am all for it; but going back to the past for its own sake is of limited use. If we really can’t do any better within our budget then all right; but let’s not become backward- looking by habit. Having said this I do think that some old things have never been bettered, and some never even equalled and may never be. I’m all for taking the best in hi fi from the past and improving it if possible rather than accepting some flash-in-the-pan offering that may not stand the test of time and has, at the moment, mainly novelty to recommend it.

This Leak tuner is good even in unmodified form. It is easy to listen to. It makes every broadcast sound at least reasonably good. But it suffers from a ‘valvey’ sound, masking the ‘nasties’ and covering up what should not be covered up. It is a bit wrong in the bass- a common fault in valve designs. Also, it plays its own (very acceptable but nevertheless glorified) versions of the signal. Not quite good enough for me, I’m afraid. But it will have to do until something better which I can afford to build or modify comes along.

The older I get the more intensely I believe that ‘what you know’ or ‘how much you know’, whether this be ‘know that’ or ‘know how’ (and no matter how much of it you possess) is not as important as the use to which your knowledge is put. That is a good test of its worth.

Finally a BIG thank you to toaster for staying the course, complaining at intervals, generally behaving in a toaster- like manner and always being understanding and continually telling me to “take it gently”. The GREAT THING about toaster is that he always gets to where he is going. We DID get to the end in the end, didn’t we, toaster? Yes,yes,yes,yes,yes, yes,YES!

This is…….

????????????????????????????????????????????????????????????????????????????????

_____________________________​
THE END​
 
Jonclancy
I’m glad you found the thread useful. In case you do some work on a Leak we would all benefit if you post what you did and your results- whatever they may be- on this thread. I can add that since writing the article I replaced the audio output phono socket with a gold plated high quality one. I now only use the audio output and not the mpx output. It has a better bass and I find it more listenable.

Steve67
Steve: there is already a schematic for the TL2- the model we worked on- on the thread

http://www.flickr.com/photos/3451470...7612748160694/

The second photo- the one after the photo of the tuner with separate PS on top- is the circuit diagram for the Troughline II tuner. That is the only diagram I have. You can enlarge it to useable size using the Flickr site. I do not know what difference there is between the II and III, but I suspect that there is not a great deal, save for the decoder stage.

You should not have a lot of difficulty getting a diagram of the III. You could try Google. Also, I seem to remember that there is a commercial firm that supplies (or used to supply) photocopies of all kinds of commercial equipment and they may be able to oblige. If you are in London, a trip to the Institution of Electrical Engineers (located in the Strand behind the Savoy Hotel) will get you a day pass to their library, and I am certain you will be able to unearth a copy there through their back issues of hi fi and engineering journals. (Visitors in person, only). They let you do ‘one off’ photocopies. These used to be 5p. Those were the days!
 
stevec67 said:
Nice work eguth. You don't by any chance hav a schematic do you? I've a faulty TL3 I needx to repair.
Click to expand...

I have found a link to the Troughline 3 tuner giving you the circuit diagram.

Google 'Black Widow Audio'.

Then search on the site for “LEAK Troughline 3 valve Tuner”.

Scroll down until you come to the link shown in RED “STEREO”. That takes you to the circuit diagram.
 
Thanks Eguth, that should help. It's not very legible as it's a scan but I think I can get something from it.

regards
Steve
 
stevec67 said:
Thanks Eguth, that should help. It's not very legible as it's a scan but I think I can get something from it.

regards
Steve
Click to expand...

The way round it is as follows:

1) click ONCE on the diagram. This will enlarge only part of it, and make the enlarged part completely legible.

2) highlight the enlarged portion and copy and paste this into WORD.

3) Now highlight the WORD document and print the highlighted document.

4) Repeat steps (1)-(3) for the rest of the diagram.

I hope you manage to sort out the problem. If so, and you think what you have done might be of interest to Troughline II conversions I hope you will post your result here.

Best

eguth
 
Biggus-Dickkus said:
I haven't read through all of your posts here but I couldn't see any mention of realignment...........
Click to expand...

We did not mention realighnment because it was not necessary to realign.

However, years later, when I sent the tuner and seperate PS/decoder to London Sound they realigned it. This was unnecessary (again).
 
> Cut a hole in the rear of the case to take an IEC mains socket (the shuttered type, FEMALE with no pins [no, I am not sexist]).
>
> ICE MALE Cable plug (shrouded)

Are you mad? This is LETHAL advice. The chassis socket should be male with pins, and the cable plug female with no pins. Otherwise the cable plug has exposed pins with mains voltage.
 
Wow, that's a while since this was bumped!

Hi EJP51, you are correct it would be lethal if it were the mains INPUT.
But it is not, it a mains output to the decoder so is correct as written.

s4xw5u.jpg



Alan
 
You must log in or register to reply here.


advertisement


Back
Top