advertisement


Amazing Troughline, first variant.

Dear marshamp,

I have been using mono for about five years from digital via firstly a Naim DAC V1 and for the last three years with an Audiolab MDAC.

The digital source for the MDAC is a Mac mini running iTunes [uncompressed AIFF files from CDs] and the MAC offers a satisfactory method of combining the two channels of stereo to mono [Accessibility preferences -> Audio -> Play stereo audio as mono] at the digital stage prior to conversion to analogue. Obviously the mono emerges at the MDAC as dual mono [ie. both output RCA sockets are the same mono signal], and what I do is feed one of these to the Quad II Forty and the other to the input of a headphone amp, so as to give a dummy load to the the MDAC on the redundant channel.

The issue of mono compatibility [in a stereo recording] is important to consider. Most classical recordings - being recordings of natural un-amplified instruments actually recorded in ensemble in a real hall - are mono compatible. The point is about phase coherence between the two stereo channels. For non-compatible recordings the conversion process can produce a comb-filter effect that really is odd. However for the tiny number that I have which don't convert to mono well, I can listen to the left channel alone of the stereo ... This works well enough, albeit that the information in the right channel is lost and the right side of the orchestra will be further back in the balance ... Not ideal, but fortunately for me most of these non-compatible [with mono summing] recordings were made in the 1970s [in the short lived era of ultra multichannel recordings and a huge number of spot microphones] at a time when none of my favourite musicians were active in the studios.

Obviously the Troughline being a completely mono tuner, it is a question of a single channel source feeding a single channel amplifier and speaker. Very simple approach.

A sidelight on stereo recording in the 1950s and 1960s is that the recordings were most often issued in mono pressings as well as stereo. More recent recordings from the 1980s onward tend to be true compatible stereo as the fashion for a simple microphone array came back into favour.

I hope that helps a little.

With best wishes, George

PS: I don't use any further digital signal processing. Just AIFF and combined at the digital stage to dual mono - most classical recording is well enough done to work well without the need for manipulation of the EQ beyond what is issued on the CD.
 
Last edited:
Progress is good, especially when it is steady enough to get things just right!

A few of the valves - now at least sixty years old - have tested weak so getting good replacements is underway. Waiting also for some unusual [nowadays] resistors that have gone off, all to add to a complete re-cap! In spite of its fine condition and very clean cosmetics, it seems to have had a great deal of use. That is good in my book. It must have already given a good deal of pleasure to its previous owners.

But I am really pleased that it is now in pieces on the bench!!!

ATB from George
 
George J said:
Dear marshamp,

I have been using mono for about five years from digital via firstly a Naim DAC V1 and for the last three years with an Audiolab MDAC...
Click to expand...
Thank you for such a comprehensive response, George - plenty of food for thought there. Omnidirectional speakers, rather than mono, have been my answer of late, but you never know.

I hope that the Troughline rebuild goes well.

Nick M
not far away, in Shropshire
 
Progress.

The Troughline now has a full compliment of good valves, resistors and capacitors.

Tuning Alignment next week!

Oh! The anticipation!
 
The radio is done.

The trouble is that amongst other health issues, my right knee gave out this week, and I would not attempt to drive to the other side of Reading from Herefordshire. I visited my GP this morning on very short notice, and the next step is an urgent X-ray in Hereford ...

Problems, problems.

It will the balm for the rest of my time. Only Radio Three, but that is alright!

I'll report next week when I get it.

With best wishes from George
 
George J said:
Today I collected a Troughline of the first version [ie. prior to the Troughline II, III etc].

Here is a link to my Flickr page. Hope that works:

https://www.flickr.com/photos/146183770@N06/with/46578917072/

More in a follow up post.

ATB from George
Click to expand...

Dear Friends,

The story is completed. I have uploaded five pictures, with a picture of the Ercol table that is the support for the Troughline, sitting on three half wine bottle corks. Three photos of the venerable old radio itself, and one of my Little Dot Three. I am using Sennheiser HD 600s, but I don't suppose anyone needs a photo of those.

I am not going to attempt a high flown report on how it works. I shall keep it to, "I am utterly delighted."

With the new capacitors and more or less a set of NOS Mullards, it is safe to use, though I'd never leave vintage valve equipment turned on if I were not there, even to make a cup of tea ...

I think it is still an interestingly close to original piece that shows just how right those early Troughlines were! Is it perfect? I doubt it, but it more than good enough!

Please visit the Flickr link [in the quote in this post from the opening post of the thread] for the pictures before and after.

This is my last expenditure on replay, except for repairs.

Happy Easter and best wishes from George
 
Hard to avoid some comment on the quality and presentation.

Listening to Berg's Violin Concerto in what must be an excellent recording in the first place, I was struck just how natural and fine is the tonal balance. For anyone who might assume it has a valve-like sound, then they would jump a mile! It is nothing like those lovely old huge cabinet kitchen radios, found in many homes forty years ago. I think the description of them might be: Inoffensive, softly balanced, and very pleasant - Steam age Radio!

It is the best VHF radio I have ever come across in terms of its complete lack of hiss, or VHF nasties such as birdy sounds. After three quarters of an hour it has not drifted, and I am surprised how little heat it is generating. When I had a Troughline 3 [mono only] that got distinctly warm. I am not going to put the radio in a case. I reckon keeping the air flowing round it will keep it as cool as possible in use. That is surely a good thing.

I knew that I could expect very fine quality on the higher musical lines, but what is a bit of a surprise is the absolute clarity and quality [and correct proportionality] of the low instruments including a very fine way with the Gran Casa - orchestral bass drum.

I tried a few other stations I can get, and at the extreme top of the tuning range, it can fix Classic FM. Unfortunately the radio made a great point of showing the amount of compression that particular sender uses! Radio Three is a happy compromise in this respect. Radio Four is very pleasing because all the factors that suit music make for a good presentation of the spoken voice.

I am using about half the rotational gain on the radio volume control, and similar half rotation up on the Little Dot. It does not seem to matter if using more gain on the radio with less on the headphone amp or the other way round, so half and half seems reasonable.

Anyway it is all good!

Best wishes from George
 
Last edited:
George,
I'm delighted that your Troughline is back. I got my Troughline 3 back from a GT Audio rebuild just over a week ago. It sounds fabulous. Mine is tuned into R3 at the moment too. Happy Easter!
Charlie
 
Ah well. I crumbled. I connected up the ESL and Quad II Forty. They are probably not going to leave now. There is rightness about this combination that defies analysis. Though the Q II Forty is a juvenile compared to the radio and speaker - both made 62 years ago now - the style of it fits right in. Also the output of the radio is better suited to the amplifier's input than the Little Dot 3. A nice volume of sound comes about one third of the rotation on the control on the radio.

Are well, this is probably the nicest pure mono radio in Herefordshire if not the whole of the UK!

Best wishes from George

PS: I'll just have to be careful with music and my neighbour!
 
Dear Barry,

I am not the world's most effective photograph taker! But here are three taken a few moments ago.

https://www.flickr.com/photos/146183770@N06/with/46578917072/

Top three pictures. The radio is as bright as a button cosmetically, though not cleaned beyond a good de-dusting. It looks a bit of a jumble, but that is because I have the speaker a long way out, and the various cables have only so much length. I listen from the centre of a 17 by 17 foot room that is quite high. Sort of almost near field listening, which the ESL is rather good at.

Anyway, I suppose I am getting something of the quality that I might have had in 1957 with such a "wireless" set! Impossible of course as I was not born for another four years!

I am looking forward to the Saint John Passion tomorrow at 13:00 hours from Amsterdam! [Radio Three]. This is music I played quite a few times in bass-playing years, and I have been to three live concerts of it in the audience. I have two recordings which don't seem to live up to anything live, if its good!

That is what it is best at. Live music making.

Best wishes from George
 
It’s nice to see you come to your senses! I’m glad you did it...

Now about converting your car to steam power.....
 
To round this out, sometimes a new piece of hifi kit can lead to a certain degree of remorse after realising it is not quite as fine as hoped, and possibly not really worth the expense.

I could not be more pleased with this old radio, as it astounds and delights from moment to moment. If I regret something, it is that I did not get such a radio years ago!

Okay that it is a bit of one trick pony. Classical music on Radio Three, but that is alright. I would prefer something that does its one function nicely, over a multi-tasker that does nothing quite as well. It does make a good job of Radio Four, but I would not waste valve hours on speech radio. My little portable is as functional for the needs of the spoken word.

Best wishes, and thanks to everyone, who have made so many kind posts in the thread, from George
 
Yesterday evening I listened to Elgar's Dream of Gerontius from the Lighthouse, Bournemouth - Bornemeouth Symphony Orchestra, superb Choir and Soloists and a very able and musical conductor. The best I have ever heard Gerontius at home including the rather fine Boult [EMI] recording from the 1970s. Nothing would match the experience of being in Hereford Cathedral in the mid-1980s with Roy Massey leading the forces of the Three Choirs Festival! Unforgettable that was!!!

But I have refined my aerial, which remains a wire dipole. This has brought a useful improvement in signal strength and quietude. It is now as quiet in silence as the BBC stream on Sounds. But sibilants are much more natural with the old radio.

I'd love to be able to use a proper external aerial though. Not so much for solid signal strength as not having a flying aerial in the room!

Best wishes from George
 
Interesting, I need to read up on how FM stereo actually works as to be honest I’ve not got a clue! I’m curious as to what a mono signal is in a stereo age, i.e. is it broadcast simultaneously in mono and stereo? The vintage Leak obviously doesn’t know what stereo is; it was born before it was invented, so can’t be ‘flattening’ a stereo signal to mono. Not knowingly anyway!

The point I’m eventually getting to is maybe the mono FM signal is actually different to the BBC Sounds app commoned to mono or however you are getting both channels to appear out of your mono amp and speaker (I assume you are doing this otherwise you would have a very odd orchestral balance if just listening to either the ‘right’ or ‘left’ channel of a stereo broadcast).

I’ve never really thought about this as I’ve either listened to stuff in stereo or via the little Roberts radio in the bathroom!
 
You must log in or register to reply here.


advertisement


Back
Top