What would happen if you drove a car that was 60-70 years old and not had anything done to it. What do you think it would drive like? That is similar to these old tuners. Like anything that is that old it will need a complete restoration. The Leak Troughline if properly restored and realigned can sound superb. The original stereo model had a very poor stereo decoder which outputs a very low signal. Replacing this decoder with a modern one can yield better stereo performance and near line level output at full quietning. Some of the early mono Troughlines didn't have the bandwidth for proper stereo operation so it could be an expensive exercise converting it to stereo for minimal gains. Correctly aligned Troughlines it possible to get 26dB of channel separation. Check out some of my articles and reviews in HiFi World, HFN & HiFi Choice from back in the 1990s. Done properly the Troughline is hard to beat, even against some of the more expensive and complicated American tuners of the day.
Leak TL which decoder?
- Thread starter Linnovice
- Start date
What would happen if you drove a car that was 60-70 years old and not had anything done to it. What do you think it would drive like? That is similar to these old tuners. Like anything that is that old it will need a complete restoration. The Leak Troughline if properly restored and realigned can sound superb. The original stereo model had a very poor stereo decoder which outputs a very low signal. Replacing this decoder with a modern one can yield better stereo performance and near line level output at full quietning. Some of the early mono Troughlines didn't have the bandwidth for proper stereo operation so it could be an expensive exercise converting it to stereo for minimal gains. Correctly aligned Troughlines it possible to get 26dB of channel separation. Check out some of my articles and reviews in HiFi World, HFN & HiFi Choice from back in the 1990s. Done properly the Troughline is hard to beat, even against some of the more expensive and complicated American tuners of the day.
When my TL was refurbed it was stripped down to the chassis and rebuilt up. I know some of the component values were not available but my pal was able to rebuild them and the final measurements matched or exceeded the original specs. I don’t want to wax too lyrical but I have absolute faith in his judgement, experience and skill. He also has a workbench that looks like the control bank at NASA! When (before lockdown) I visited him in his man cave we would sit and natter as you do. Within two minutes the conversation when right over my head. The last time he had the front end of a fifties radar unit in pieces in the process of a rebuild. Why? Because he can. Prior to retirement he was employed by Raethon, Hartman Karden, Teac and I think Phillips. I think he’s 78 but his memory is encyclopaedic when it comes to electronics. So, in answer to the question ‘was it aligned properly’ the answer is yes.
Moving swiftly on.
I did say originally that I was bored. I spent yesterday swapping out my AV5103 pre amp for a Technics SU3500 I rebuilt last year (with some instruction and advice from you know who). I’m only using the front end to drive the LK100’s and Kabers but I’m really impressed with it. The combination of the Technics and Leak Stereofetic work really well (ok, I suppose I’ll have to give the TL a second chance). Could it be the technology matches better?
I’m not saying the AV5103 isn’t good, it is, but it’s a much more clinical open sound. I’m compromising by running the pc/dat/MD through my DAC and they also sound really good. I can’t play my 2M Bronze through the phono inputs either so I still use the outboard phono pre.
Overall I’m finding it a smoother and slightly mellow sound (but not like granny’s radiogram ).
I did say originally that I was bored. I spent yesterday swapping out my AV5103 pre amp for a Technics SU3500 I rebuilt last year (with some instruction and advice from you know who). I’m only using the front end to drive the LK100’s and Kabers but I’m really impressed with it. The combination of the Technics and Leak Stereofetic work really well (ok, I suppose I’ll have to give the TL a second chance). Could it be the technology matches better?
I’m not saying the AV5103 isn’t good, it is, but it’s a much more clinical open sound. I’m compromising by running the pc/dat/MD through my DAC and they also sound really good. I can’t play my 2M Bronze through the phono inputs either so I still use the outboard phono pre.
Overall I’m finding it a smoother and slightly mellow sound (but not like granny’s radiogram ).
G T, this may seen a niave question. Where can I get a ‘modern’ decoder from. I could try, as has been advised earlier, to buy the components and build it myself but without the knowledge or experience, if it didn’t work I wouldn’t know where to start looking. (I can’t ask my pal. He’s struggling with COVID at present.)
There doesn’t seem to be any off the shelf ones available. That I can find any way.
Another question. When I turn on my TL there is a Mono stop on the control. Does that buy pass the decoder?
There doesn’t seem to be any off the shelf ones available. That I can find any way.
Another question. When I turn on my TL there is a Mono stop on the control. Does that buy pass the decoder?
Arkless Electronics
Trade: Amp design and repairs.
I totally disagree! Quite the opposite. They are really poor no matter what you do with them. All the reviews back then saying they were a super tuner were bollox designed to sell the 10 TL's every hifi dealer had in use as door stops and book ends.
A Stereofetic will wipe the floor with a TL.
Arkless Electronics
Trade: Amp design and repairs.
There was a company called "One thing" that did a decoder for them. It was crap. other than that.... there was a unit from EAR I believe but rare as hen's teeth.
If I can't put you off the idea then I can build you one.... I probably even have some from the past lying around.
Radfordman
pfm Member
Big John
pfm Member
I have One Thing Audio Quad 57s I do not believe they make the decoder any more I have a Troughline Stereo that came with the original leak decoder, Len Gregory persuaded Tim de Paravicini to make me one of his stereo decoders and fit it to the Troughline this was years after he stopped making/selling them. I was and still am very happy with it, I also have a Meridian 104 tuner which unlike the leak will get a signal from a piece of wet string. There are also some modifications within the case I remember looking and seeing new resistors and capacitors & neatly secured wiring. If fed a good signal the Leak TL trounces the very good Meridian 104 but it is not as it left Leaks Acton factory.
Radfordman
pfm Member
I believe that it's the early decoders that were usually not up to much and often destroyed the tuners output quality.
Arkless Electronics
Trade: Amp design and repairs.
I have about 10-12 TL's and have built maybe 6 decoders of various designs over the years. I've converted many mono spec TL's to stereo spec (all the changes other than the decoder). I use Hitachi, Denon and Tandberg tuners for my own radio listening
(and have a few Stereofetic's and Delta FM's as standby)
(and have a few Stereofetic's and Delta FM's as standby)
Arkless Electronics
Trade: Amp design and repairs.
If you like it then fine. IMO even a budget Japanese tuner of any make will trounce any TL no matter how modified it is.
There is a
Leak Troughline Stereo Valve FM (Hi-Fi World/E.A.R) Decoder by Tim de Paravicini
on ebay at present. The chap is asking £250 for it (which seems a touch excessive considering you can pick TL up for about £50 and it wouldn't cost that much to refurb it). It has an input for an mpx lead from the TL which mine hasn't got (its a TL Stereo).
Leak Troughline Stereo Valve FM (Hi-Fi World/E.A.R) Decoder by Tim de Paravicini
on ebay at present. The chap is asking £250 for it (which seems a touch excessive considering you can pick TL up for about £50 and it wouldn't cost that much to refurb it). It has an input for an mpx lead from the TL which mine hasn't got (its a TL Stereo).
Radfordman
pfm Member
Decades ago I bought both new, Quad FM3 and a cheap Rotel RT222, there was not much to choose between them. Both still work OK.
Both bought from Planet Hi Fi Edgware, long gone now.
Arkless Electronics
Trade: Amp design and repairs.
It looks very good and excellent VFM. Yes it would need alignment. The usual is to set the oscillator frequency. It can be done near enough by just setting it to the centre of the range of the trimmer where the stereo light comes on.
Have you read the Noel Keywood review (HiFi World) on our "G T Audio Restored" Troughline? It was their reference tuner for many many years and as far as I know it is still mentioned in their magazine. During the 1990s and early 2000s we got hundreds of these tuners in to restore update and fit stereo decoders too. My records show we restored at least 600 and owners were extremely pleased with them. We even used to get HiFi shops asking us to restore them too. I compared our version of the Troughline to all the top American tuners from the 1960s/70s, i.e. from Marantz, Fisher, McIntosh and Scott (I owned all of their top models as well as the CT7000 from Yamaha) and the Troughline was not quite as good as the US made tuners but it was significantly more simple and not that far behind in the sound quality stakes. We even developed a special stereo decoder for the Troughline using a modern Philips decoder chip which fitted inside the chassis and that worked very well. Even Tim de Paravicini must have thought the Troughlines was good otherwise he wouldn't have bothered developing a special stereo decoder for it either...
The best sounding Leak tuners are the mono Troughlines with the variable gain on the front panel, i.e. pre stereo. The audio from the mono tuner doesn't have to go through a stereo decoder so the fidelity is better, you just don't get stereo. Not sure that is much of an issue these days...