I have the energy sink principle to thank for getting me on the right path to my first dose of convincing sound, 30 years ago. What happened was that I become more and more focused on stabilising physically the very ordinary B&W bookshelf speakers I was using, until I got pretty close to having them effectively locked onto the concrete foundation of the house. This gave me very impressive, tight bass behaviour - but made every deficiency, and slight variation in electronics behaviour stand out in intense relief. So, became highly motivated to work out what was giving me the "messy" changeability in this area, and persevered until one day "correct" sound suddenly popped out ... and I fell off my chair,
...So, I knew from then on what I had to do ...
....and.....?.......and persevered until one day "correct" sound suddenly popped out ... and I fell off my chair,
So, I knew from then on what I had to do ...
Dan
Be careful, I once carried something much smaller than that up a spiral staircase, which was so narrow and steep that I could not stand up straight and my torso was slightly twisted. After that I had terrible spasms in my back for about ten years. Doctors couldn't find anything, but sometimes they would drop me to my knees, all it took was a slight movement the wrong way. It finally, slowly, got better.
Achieve complete control over, and understanding of that, obviously desirable, behaviour. I fluked the first instance, and it rapidly faded away because the electronics equilibrium was continually altering - I had to learn how to grab onto the optimum state and maintain it, and that is something I'm still working on. And there are still issues I scratch my head over - they obviously matter, I know I need to do various things to fine tune them - but I don't understand them in the "scientific" sense; the cause and effect linkage is obviously there, but I haven't a "sensible", convincing explanation ...
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Hah !...been there done that also, + dishwasher, dining table (in pieces), beds, futon couch (in pieces) etc etc without assistance/assistants.
On move out I got smart and removed verandah railings and handed down said items to helpers on the ground.
What is the '' Aristotélēs book'' you mention ?.
Dan.
So what did you use? Dolly? Sling? Pure muscles and leverage? I've done stuff like that and always thought afterwards I was chancing it a bit too much.
Hi,
Knowledge helps and shortens the trial and error time no end.
The key is to get the basic engineering points right.
No audio manufacturer to my knowledge applies these basic principles to the full but they are key.
These can easily change a rather mediocre product into a rather nice performer.
I urge you to read the book, Frank. It's nothing new but it helps you to understand what you found empirically.
Just to tease the Pi guys; Uneven numbers are king.
Cheers
Knowledge helps and shortens the trial and error time no end.
The key is to get the basic engineering points right.
No audio manufacturer to my knowledge applies these basic principles to the full but they are key.
These can easily change a rather mediocre product into a rather nice performer.
I urge you to read the book, Frank. It's nothing new but it helps you to understand what you found empirically.
Just to tease the Pi guys; Uneven numbers are king.
Cheers
Tie down straps and lack of cerebral activity.
(birthday boy initially asked for a 20'' wide table-height fridge, due to the staircase)
And which book might that be,
?Looking back, there were factors, "confounders" in the situation 30 years ago that I was completely oblivious of at the time, and there would have been nothing in the literature that would have helped me ...
The analogy is just plain wrong, as stated here again. It shows a woeful lack of understanding of physics. Energy transfer by impedance matching has absolutely nothing to do with rectification. "I realize it's not your field but it's real." be careful about patronizing me, this stuff has been wrong for a long time. I first heard it from Tom Miiller reviewer for TAS in reference to his review of the SOTA turntable.
The dozens of books, please list a few.
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So what are you guys actually talking about?
https://www.google.com/search?hl=en...mages&tbs=&as_filetype=&as_rights=&gws_rd=ssl
https://www.google.com/search?hl=en...mages&tbs=&as_filetype=&as_rights=&gws_rd=ssl
Two different concepts floating around: impedance matching, and the mechanics of vibration. Impedance matching only relates to the electrical, sound, optics fields, and mechanics in the sense of bodies colliding; what's being talked about in the thread is the mechanics of vibration, and there appear to be a couple of books around, by Bishop, Hansen, Rao, etc, which cover that ...
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Am I misunderstanding that statement? The Rega Planar 3 was introduced in 1977. The Thorens TD160 was introduced in 1972. Are you saying that Thorens responded to the challenge of the Rega Planar 3 by developing a time machine so they could introduce their response five years earlier???
Or are you just referring to sales strategy in an English shop? It is not clear who was attempting what in that sentence, perhaps I am not understanding you.
you might read the links yourself - contemplate why it gets the gee wiz science discovery treatment for papers this decade
may mean it is not established Mech E practice used in 1970's turntables, isn't what those oh so advanced audiophile nose bleed leading edge designers were missing credit for inventing back then
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The staircase part was heroic. Driving the refr over, a good Samarian action. Buying it, hmm...is there something more than a simple acquaintance? I smell blood relationship.
There were such special cases of people then as there are probably now.
The rarity of such exemplary figures is evident by reading their contemporary chronographers and close in time historians and geographers (a ‘by product’ from such readings is forming an (*) opinion over the progress of our social behavior, beliefs, trends)
---
Mechanical impedance=applied Force/resulting Velocity.
Gradual F/V change in one direction through gradual change of material mechanical properties isn’t like an electrical diode action.
For mid to high acoustic frequencies and above but not for low frequencies (**), guiding mechanical energy flow in the form of vibrations from one point to another, works through selecting directional matching of acoustic impedance (Z= density times speed of sound in that material) of materials in such a way as to lessen the back reflection and subsequently increase the through transition in one direction. Reflection coeff. R= [(Z2-Z1)/(Z2+Z1)]^2
With higher ultrasonic frequencies, choosing favorite mating angles to promote mode conversion and scatter attenuation is in action but not with near-acoustic ultrasonics. (***)
Abrupt F/V change through form, function (e.g. a ratchet mechanism) is like an electrical diode action.
The shape of speaker stand spike resembles a diode schematic symbol but I can’t see how it can function as a diode at such low frequencies.
George
(*) discouraging
(**) Lowering the frequency, bulk material velocity takes over and mass becomes influential.
(***)This is not new research subject. Dr. J. Krautkrämer (in Germany~1946) revamped and modernised the 50 years earlier work of S. J. Sokolov (USSR), Floyd A. Firestone (USA), D. o. Sproule (UK)
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The crazy thing is years before I met Peter Dunlop who made the later RD11 and Systemdek we had Dunlop Westair storage radiators in the shop by some weird coincidence. My link with Ariston was not through him. I remember one day we ordered 2 Systemdek 2 at a trade price of £260. Peter drove them the 400 miles to Oxford as he found couriers unreliable! How anyone could make anything like a turntable and deliver it for that price beats me. Unlike the RD11 the Stytemdeks were super competent. Peter only said he did the production for Ariston, others say he owned Ariston. Funny he didn't say if so. What you say about the RD11 suspension is true. Whatever was wrong with Linn it wasn't things like that. Ivor said he and " his partner " couldn't agree on production standards. Maybe Hamish only wanted to be nearly as good as Thorens and let hype do the rest? Linn springs would put that right. When fitting the support bolts must be vertical. I would almost guarantee they will be about 5 degrees out. Linn dealers had a special tool to set them. A piece of tight fitting tube for bending and spirit level will do just as well. The deck level to assist you. Where possible the springs central by very gently rotating them . Spit on the rubbers to aid rotation. You will not believe how the sound changes when this is right. When a vertical bounce the deck is also locked against rotation. If the bounce has gyration it isn't. If you allow gyration with greatest freedom to gyrate the sound becomes seemingly more detailed. It looses the timing quality that Linn coined as a concept. Curious it does this and logical. The LP12 specialty is preserving rotational stability and vertical modulations of music, sadly the belt and motor stop it succeeding. The vertical bit is the good stuff. If bearing movement it is the bad stuff. I once heard an LP12 with a defective bearing point ( only ever once ) . I suspect someone forgot some process or wrong steel supplied. Whilst there was no obvious rumble the sound was poor.
To my shame I have never listened to the Decca arm although had them at the workshop. People do say how good they are. I love arms made of wood, There was an ADC arm like that.
One day a student came to me having bought a real dog of a LP12. He had paid far too much and was very unhappy. I took pity and said I had many secondhand parts he could have from upgrades. I am not sure what his LP12 was. I suspect more than one LP12 was in it. It certainly was an early one as the motor mounting slots were slightly different. From early days we had a piece of cast iron gas pipe that was the LP12 bending tool. So there I was with the bending tool and hammer using the shop stone steps and plate glass window as a reference. Who should walk up but Trevor the Linn rep ( who still is ). At first it was all very friendly. Then I was told the gas pipe had to be returned to Linn. To which I said. No way I still use it on recent production. Next sentence " We use a 20 ton press " . To which I said " Too small obviously ". How it was settled is I had given my word and if it meant loosing the Linn agency I don't brake my word. Trevor gave in and said " well you know where we are if you fail ". My promise to him was I wouldn't pass this LP12 down the line without it working properly even if it cost me money. The sub-chassis was the worst I had ever seen which made it like some RD 11 I had seen. The hammer put it right and no horrible marks, surprising as it had some big hammer strikes. Off loaded some as new secondhand parts and found joy of joys it set up in 2 minutes ( because it was absolutely straight ) . Then the very big surprise. It was mostly a LP12 mk1 as I tried to keep it as something that might have been sold. The sound was exceptional. From then on all LP12 were given the plate glass test. The bearings trued with a depth gauge and the gas pipe. By doing this I saved hours getting an almost OK deck to bounce. When everything is straight it is going to be easier. My LP12 proves this. 25 years on and only a height tweak. Bounces like it did on day one. 30 seconds to rest with no sudden stop. One thing you never can get right is armboard central in the cut out. Best you can do is square. The 3 fixing screws have enough clearance to do that. If you do get it central likelihood is the bounce is wrong. Typical is 1 mm nearer the motor side.
The student was charged £0. However I think I made much money from it as I could fast track the work and was confident my LP12's were the best. To be honest as every Linn was taken apart so was every RD80. I had to be careful with them as the bolts were spot weld on. I never took TD160's apart as they didn't need it. It wasn't because they were better made. It was because Thorens made it irreverent. Unfortunately this meant slightly less than perfect set up on all. TD 150 was like a RD 11. It did need it.
I hope all the people who write about Linn copied Ariston when they all copied AR etc might just stop to think. They have no hands on experience. The LP12 and RD11 is about commitment to quality. Linn being very crafty and getting the real work to be done by dealers. If none of it matter at least do the wise thing and buy a TD160. Although a bit of prejudice on my part no doubt the all metal TD160 patters just seem more correct. The point is the metal on the periphery is all that matters so the plastic will be OK from that point of view. The mass ratios of the original was by mass to cancel the bell resonance. Doubtless the plastic does it by a different but equally valid route.
To my shame I have never listened to the Decca arm although had them at the workshop. People do say how good they are. I love arms made of wood, There was an ADC arm like that.
One day a student came to me having bought a real dog of a LP12. He had paid far too much and was very unhappy. I took pity and said I had many secondhand parts he could have from upgrades. I am not sure what his LP12 was. I suspect more than one LP12 was in it. It certainly was an early one as the motor mounting slots were slightly different. From early days we had a piece of cast iron gas pipe that was the LP12 bending tool. So there I was with the bending tool and hammer using the shop stone steps and plate glass window as a reference. Who should walk up but Trevor the Linn rep ( who still is ). At first it was all very friendly. Then I was told the gas pipe had to be returned to Linn. To which I said. No way I still use it on recent production. Next sentence " We use a 20 ton press " . To which I said " Too small obviously ". How it was settled is I had given my word and if it meant loosing the Linn agency I don't brake my word. Trevor gave in and said " well you know where we are if you fail ". My promise to him was I wouldn't pass this LP12 down the line without it working properly even if it cost me money. The sub-chassis was the worst I had ever seen which made it like some RD 11 I had seen. The hammer put it right and no horrible marks, surprising as it had some big hammer strikes. Off loaded some as new secondhand parts and found joy of joys it set up in 2 minutes ( because it was absolutely straight ) . Then the very big surprise. It was mostly a LP12 mk1 as I tried to keep it as something that might have been sold. The sound was exceptional. From then on all LP12 were given the plate glass test. The bearings trued with a depth gauge and the gas pipe. By doing this I saved hours getting an almost OK deck to bounce. When everything is straight it is going to be easier. My LP12 proves this. 25 years on and only a height tweak. Bounces like it did on day one. 30 seconds to rest with no sudden stop. One thing you never can get right is armboard central in the cut out. Best you can do is square. The 3 fixing screws have enough clearance to do that. If you do get it central likelihood is the bounce is wrong. Typical is 1 mm nearer the motor side.
The student was charged £0. However I think I made much money from it as I could fast track the work and was confident my LP12's were the best. To be honest as every Linn was taken apart so was every RD80. I had to be careful with them as the bolts were spot weld on. I never took TD160's apart as they didn't need it. It wasn't because they were better made. It was because Thorens made it irreverent. Unfortunately this meant slightly less than perfect set up on all. TD 150 was like a RD 11. It did need it.
I hope all the people who write about Linn copied Ariston when they all copied AR etc might just stop to think. They have no hands on experience. The LP12 and RD11 is about commitment to quality. Linn being very crafty and getting the real work to be done by dealers. If none of it matter at least do the wise thing and buy a TD160. Although a bit of prejudice on my part no doubt the all metal TD160 patters just seem more correct. The point is the metal on the periphery is all that matters so the plastic will be OK from that point of view. The mass ratios of the original was by mass to cancel the bell resonance. Doubtless the plastic does it by a different but equally valid route.
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