Remembering Tim de Paravicini
A Special Year 2006
Behind the scenes, Guido Tent and Emile Sprenger of the organizing committee wanted to invite somebody significant, somebody of importance. What about a name that would be known and recognized by everybody attending? Because this was to be a celebration of the 100th anniversary of the invention of the first real tube, the Triode.
A Special Year 1906
The patent was applied for on January 10th, 1907, but the invention took place during 1906 by Lee de Forest and the patent was accepted in 1908. Marconi initially contested it, but then admitted that the addition of the Grid was significant enough for a patent and they came to a license agreement for Marconi to manufacture it, which later became known as the Triode.
So who would you invite to celebrate such an event? What would have been your choice?
The choice was to prove inspired. Tim de Paravicini was invited to give a lecture and he graciously accepted. This of course would be the highlight of a series of other great lectures and presentations and we had a great event in store. The video I hour and 45 minutes presentation is now available for viewing on YouTube (embedded near the bottom of this aticle).
Now for some background on ETF06 and how this video came about.
Beukenhof's former monastery in Biezenmortel, Netherlands.
The location within The Netherlands.
The ETF06 organizing committee then got more creative. As the annual European Triode Festival was as usual limited to 100 participants, then 100 T-Shirts were made and we were all to be given one each. So it was a 100th anniversary, 100 attendees and 100 t-shirts. These would have the EFT06 Logo on the front and Lee de Forest's original patent application printed on the back. I still have mine and have never worn it. So I decided to photograph both the front and back. The latter is available in large enough resolution so that the patent can be read by zooming in. Here is the first opening declaration and note that it was invented for amplifying signals and hence this is a historical declaration of the first amplifier:
"Be it known that I, Lee de Forest, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented a new and useful Improvement in Devices, for Amplifying Feeble Electric Currents, of which the following is a specification."
The Amplifier was now born!
Another lecture was by Bruno Putzeys on DAC measurements, this too has been posted on YouTube. Morgan Jones likewise did his lecture on oscillations, about circuits that go unstable, and did so with his usual British wit. Another highlight was Guido Tent and with the help of colleagues at Philips, had made an actual Triode a la 1906 technology and turned it into an actual working amplifier. I wonder how long it would work for as I was told by somebody that the tube, a globe actually, would not stay non-leaky for long. But I can testify that it did work.
Saturday: The Tim de Paravicini Lecture
Allen had spoken to Max Townshend about Tim, that it was sometimes difficult to get him started in conversation and Max had told Allen that general aviation (small planes) and vintage cars, especially vintage motors, those subjects would get him started and then go onto audio from there. Once in full flight, you had a treat on your hands, as the video makes clear. I also gather that he flew his own plane across the English Channel to be with us.
We had the video equipment set up; a Sony HDV Camera and matching Bluetooth microphone (you can see that small silver thing) and Emile did the introduction.
Three of us preparing to start, Emile the Intro, I behind the camera, Tim is ready.
Many have not met Tim de Paravicini and / or seen him 'in action'. Watching this 1hr 45min video from 2006 you get a much better sense of the man in his prime. His way of speaking, his body language, and so on. Lots of little stories ahead, especially about his time in Japan and how that is a different kind of world to ours and some unusual business practices. But all told in a way that is his story and his insight.
Sit back for the duration of the video and enjoy, even if you don't get the finer points of the discussion, because some of it is very technical and aimed at geeks like us.
The topics started with power supplies, and soon proceeded to single-ended and push-pull tube topologies. The good versus bad transformers, what is commercial to do, and what is not was also discussed. Tim warned up to his task admirably and he had our rapt attention, as you can hear from the audience off screen. In the video, most of the schematics drawn are fairly clear and it is the explanations that clarify what he is doing with his black marker. I was particularly struck by how his mind worked, note how he had all these rules and ratios in his head; why do calculations that you had already done when you understood what lies beneath them and have the practical experience to do it right every time?
My favorite quote from the lecture, slightly shortened, was this:
"An output transformer... if fed from a zero source impedance, will have zero distortion."
While this may go over the heads of many, it has the quality of a thought experiment behind it and is pure gold. The point? Even if you cannot do it, aim for it! This is why a Triode amplifier should be better than a Pentode amplifier. But this does not mean abandoning Pentodes as they can be forced into getting that low impedance into the output transformer as well. Personally, I believe that is what his circuit does and he called it "Balanced Bridge."
Tim and his "Balanced Bridge" push-pull amplifier.
My-Fi Or Hi-Fi?
"It is MyFi sound, not HiFi sound."
For a classic tube sound, people can go somewhere else. But even he was aware of the commercial pressure that manufacturers can put on designers do produce some of that tube sound and gave one curious example. Like having to add a small 6dB of feedback to make an amplifier sound more commercial? I bet you, if he was listening to his personal pair (they were mono-blocks), he would have disconnected the feedback; very simple, just cut two wires. That is what I would have done.
In the end, we must make note of Tim's work with Mastering recorded music and, at some time or other, we have all listened to recordings that were mastered with equipment that he designed or re-designed, as well as his famous Recording Heads used in Tape Recorders and Microphones.
Take a good look at the next two photos of something you won't see every day. It is a special piece of gear that has been used in projects that I have personally been involved in using my microphone preamps designs, fed into this beast.
Studer C37 1/4" track converted to full 1" track by Tim de Paravicini.
This monster conversion by Tim, also fitted with his Recording Heads and Custom EQ, was rebuilt for Phil Punch of Electric Avenue Studios, here in Sydney. Phil kindly sent me these photos.
Tim de Paravicini 1" half-track recording and playback heads.
Please look up other pictures of the standard Studer C37 on Google Images. None will look like this one; they are all measly quarter-inch tape. This was rebuilt and uses tape that is four times wider at a full one inch and is stereo two-track, 15 inches per second. It took Phil about a year to get it back fully converted.
Phil also told me it was sent to the US for some time and got used in New York by Barry Wolfson and others at Sterling Sound Mastering. It is now back in Australia and is tentatively up for sale. Is anybody interested? I believe there are only two of these in the entire world? You would be buying history!
ETF06 – The Audience
ETF06 - The Ending
Finally, may I mention that the push-pull circuit that Tim was discussing, that Allen was independently working on an amplifier design that had features that overlapped in some ways Tim's "Balanced Bridge" – it did not strike me until fourteen years later, a few days ago watching the video again. But they were still very different designs, but with very similar aim – low impedance into the output transformer equals low distortion and a modern Triode sound. For me, it put into context some of Allen Wright's reactions during the lecture. So that is something I took away from seeing the video again.
On December 17th, 2020
Please enjoy this rare treat.