Don't fall for it, Jan.
I understand pursuit of excellence, but there are limits, and if you cross them, it starts to become art for art's sake. If people spent more time just listening, we'd have a much better educated audiophile gang.
Or we can resort to the esoterica. Try passing the loose, middle end of your power cable through a pot of cold water, that might cool it down.
Well one buddy of mine makes money by selling AC motor upgrades. One upgrade is tuning the phase shift capacitor value to get exactly 90 degrees between the two motor phases as that minimizes the vibrations. I've seen some convincing spectrum analyzer shots but I want to check it out myself.
Jan
This is a synchronous type used as an alternator. This shows how it is futile to go too mad on sine wave quality of the PSU . The Lingo was more about being 66 V rather than class A ( 90 V start up . 90 is also typical of Valhalla ). If a series resistor is added to a near perfect PSU this distortion results on the scope. Thus phase and voltage are the key questions.
In fact when used at the higher turntable voltages the wave elongates and looks to be >10% THD. Again two motors might help at 70% maximum .
A question I have never been able to answer is what happens where the PSU has almost 0R output impedance. By holding the motor I would say no different. The problem is to measure these things it is usually necessary to have a small resistance. I did the above with and without a load. I had it producing 1 watt ( 0.5/0.5 ). It made very little difference. I had considered a negative output impedance. Never got around to it.
I am not disputing tweaking, it does work when applied properly. There isn't a thing made that you couldn't improve upon, but there's always the question of the cost/benefit results.
Like you Nigel, I have known Ivor T. for about 40 years, and I got my first LP12 (with a Grace arm) from a hi fi store in Bristol, back in 1974.
I did my 'pilgramage' to see Ivor's factory in 1976. We are still good colleagues, though we don't see each other much, anymore. I think that the Linn is an EXCEPTIONAL turntable and that belt drive and syncronous (sp) motors are pretty darn good, better than a velocity servo, that was first used to replace it. Position servos are OK, and comparable, but belt drive still has its advantages.
I did my 'pilgramage' to see Ivor's factory in 1976. We are still good colleagues, though we don't see each other much, anymore. I think that the Linn is an EXCEPTIONAL turntable and that belt drive and syncronous (sp) motors are pretty darn good, better than a velocity servo, that was first used to replace it. Position servos are OK, and comparable, but belt drive still has its advantages.
Fortunately with audio the game is quite different, because the ear/brain is a key component. Cost, mainly in terms of efforts and focus, can be expended with little apparent true benefit - all that seems to be happening is getting more of same, swish "hifi" sound, - until the "magic" barrier is broken through, and convincing sound pops into existence - the benefit "measure" has just gone through the roof, courtesy of the hearing system now doing a lot of the work, unassisted. This is now a plateau of excellent cost/benefit behaviour - a little bit more "cost" adds even more quite significant cream of "benefit", and the limits of this area of improving seem almost boundless ...
“Take this brother, may serve you well…Number nine?!”
Hiten, such calculations are trivial for Jacco. But he is a special case.
I spent two hours for to get the numbers you see below: D
George
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Indeed it does John, but they also have their problems. Mostly in terms of the drive belt - stretching, wearout, slipping, etc. In my view, their greatest shoprtcoming (most of them, but not all) is the lack of ability to correct rotation speed. So, when it starts to deviate, that's it, the pitch stars to change along with it.
Philips used to offer speed control even with their TTs. My old 2N4504 open reel tape deck had belt drive for the capstan, mounted on a 3 kg flywheel, the inside of which had a LED and a photocell, measuring pulses.
How Linn Sondek got almost legendary status is amazing. It started as a direct copy of Thorens suspended subschassis turntables. It is said to have unique spindle construction , but so far I have not found any detailed information about it. It had and has incurable illness-spring are randomly positioned without taking in account suspended centre of mass, distance to armboard, platter etc.That is the reason why Linn spring adjustment is an art, and it is taking hours. My Pink Triangle PT-TOO has perfect spring position and mass distribution. And much more neutral sound , acrylic platter has also a influence here. Linn Sondek is realy overpriced, British audio magazines made a legend of it. But, unlike former Pink Triangle company, Linn is well a organized company with outstanding marketing department and customer support.
I even had a problem to get PT-TOO instalation manual!
I even had a problem to get PT-TOO instalation manual!
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1210 crudity?
I always thought the problem with the Technics decks was the arm, designed more for stable DJ cueing than ultimate sound quality.The DDS type psu allows the waveform to be pre-distorted. They are programmed with a sine table, but this can easily be modified for smoother torque
This is a synchronous type used as an alternator. This shows how it is futile to go too mad on sine wave quality of the PSU . The Lingo was more about being 66 V rather than class A ( 90 V start up . 90 is also typical of Valhalla ). If a series resistor is added to a near perfect PSU this distortion results on the scope. Thus phase and voltage are the key questions.
In fact when used at the higher turntable voltages the wave elongates and looks to be >10% THD. Again two motors might help at 70% maximum .
Remember that ac motor torque is a function of current, not voltage and that the coil inductance could be saturating
Answered your own question.
I had one for a short time- all in all, I preferred my re-armed AR, though the Linn was an excellent table. Sold the Linn table when I had a chance to get an experimental VPI at a good price; I kept the Ittok LVII.Jan brought along his TT analysis system- if American Airlines ever finds his luggage, we'll do some testing. That VPI is now over 30 years old, so I won't be surprised if it's not running "as-new."
When I went in 1976 to Castlemilk I was talking to Ivor and Charlie Brennan. Ivor asked me what I thought the most important thing in business is ? I said honesty. Ivor said " There is no place for honesty in business ". There was a very long silence and then " Of course you are absolutely right " said Ivor. I asked Ivor how he thought up the LP12. I have almost the same as a photographic memory. This extends to things said. I will quote as I remember.
Ivor " My dad sent me to be a brain surgeon. I failed him by becoming a decorated war hero ( shortened ). On returning I bought a direct drive turntable and hated it. On a hunch I went to buy what I had before , a TD150. The replacement TD160 wasn't as good. I asked my dad to make me a TD150. He refused and said 50 turntables or nothing. With a friend we sold them. My dad said the TD150 bearing wasn't optimum. The partner lost enthusiasm and would not sell the next 100 . He wanted the cheaper TD 150 style bearing. He went on to make Ariston. And that's as near the truth as I will ever tell anyone. If you want the real truth bribe one of my staff."
All of the Formula One cars are the same except some win. Can you imagine how frustrating that is. Little things matter. Obsession matters. What didn't help Thorens is the Swiss and German sides split. A year or two back the designer of Thorens and I went as guests of Renault to FI test day. Kurt told Renault why Red Bull was faster. They didn't take any notice. He was 100 % right. It became known as blown diffuser. Little details. I was heart broken for Kurt as we turntable designers could always do with some pocket money. I live 4 miles from the now Lotus so know one of them.
I wrote to the ex parts manager of Thorens last night as the arm mass of the TP16 is quote as 7.5 or 16.5 g!!! It would help to know. I have bought a D110 yesterday to put in the LP12 Ekos. I must get the resonance right . This should be a dream come true. The family can use the LP12 if the DL110. The Lyra is too fragile. Wouldn't it be crazy is the TD145 was almost as good. I doubt it. All I will say is like the Golf GTi things can be so good that the Lamborghini is not so important.
Remember in 1976 I was 19 or 20. Ivor was a very grown up, grown up.
What you might see is I am someone prepared to spend any amount on a turntable ( not the idiot ones ). When amplifiers it only needs to be OK ( that is technically perfect in the old school of hearing tests perfect, 20 db less than other peoples perfect ). The thing is the source of sound can never be replaced by a better amp. If you ever hear a great microphone into lets say a NAD 3020 and OK speakers most hi fi seems a joke. We were never the real customers of the recording industry. Hi fi allows us to take the ordinary and find the good in it. The good that escaped to recording session. Audio Fidelity's recording of Louis Armstrong is the exception. Satchmo Plays King Oliver. Playing as I type.
Ivor " My dad sent me to be a brain surgeon. I failed him by becoming a decorated war hero ( shortened ). On returning I bought a direct drive turntable and hated it. On a hunch I went to buy what I had before , a TD150. The replacement TD160 wasn't as good. I asked my dad to make me a TD150. He refused and said 50 turntables or nothing. With a friend we sold them. My dad said the TD150 bearing wasn't optimum. The partner lost enthusiasm and would not sell the next 100 . He wanted the cheaper TD 150 style bearing. He went on to make Ariston. And that's as near the truth as I will ever tell anyone. If you want the real truth bribe one of my staff."
All of the Formula One cars are the same except some win. Can you imagine how frustrating that is. Little things matter. Obsession matters. What didn't help Thorens is the Swiss and German sides split. A year or two back the designer of Thorens and I went as guests of Renault to FI test day. Kurt told Renault why Red Bull was faster. They didn't take any notice. He was 100 % right. It became known as blown diffuser. Little details. I was heart broken for Kurt as we turntable designers could always do with some pocket money. I live 4 miles from the now Lotus so know one of them.
I wrote to the ex parts manager of Thorens last night as the arm mass of the TP16 is quote as 7.5 or 16.5 g!!! It would help to know. I have bought a D110 yesterday to put in the LP12 Ekos. I must get the resonance right . This should be a dream come true. The family can use the LP12 if the DL110. The Lyra is too fragile. Wouldn't it be crazy is the TD145 was almost as good. I doubt it. All I will say is like the Golf GTi things can be so good that the Lamborghini is not so important.
Remember in 1976 I was 19 or 20. Ivor was a very grown up, grown up.
What you might see is I am someone prepared to spend any amount on a turntable ( not the idiot ones ). When amplifiers it only needs to be OK ( that is technically perfect in the old school of hearing tests perfect, 20 db less than other peoples perfect ). The thing is the source of sound can never be replaced by a better amp. If you ever hear a great microphone into lets say a NAD 3020 and OK speakers most hi fi seems a joke. We were never the real customers of the recording industry. Hi fi allows us to take the ordinary and find the good in it. The good that escaped to recording session. Audio Fidelity's recording of Louis Armstrong is the exception. Satchmo Plays King Oliver. Playing as I type.
Thanks for reply gentlemen. gpapag as I am technically illitrate I will try to understand. If Motor is not controlled by any servo or other control mechanism. And if we consider kinetic energy of moving platter from your example. Is this energy enough to override fq. fluctuations of very short time period ? If we use heavy motor and platter and store rotational energy mechanically we would not have to worry about minor fq. changes. From here it seems frequency changes are less than 1 hz per day.
How do cutting lathe maintain exact speed ?
Regards.
How do cutting lathe maintain exact speed ?
Regards.
Though I rarely listen to Louis Armstrong. I do have one Audio Fidelity Louis Armstrong vinyl as this. On first listen I found it sounded good (though I am no expert) so have kept it in my collection. Thanks for pointers.
Regards
In my LP12 graphs they are the current waveforms at Linn voltages. Pre distortion could work.
What could be better is a hysteresis motor. The distortion seems to be about - 52 dB with them . The distortion is if you like the composite of the input waveform and the superimposed vibration. My conclusion is the simple slots in a synchronous are too simple. Mostly a stepper motor has identical construction.
This is an 11 watt Crouzet. Avid use this one with modifications.
Cutting lathes are very heavy and have very powerful motors. They just about keep rumble low.
The problem is very simple. The music is like sand paper. It is very difficult to keep a constant speed over a surface that is forever changing. The big effects like flywheel are helpful as they take away the problems that are simple to solve. If you don't solve those you might as well not bother.
The best servo turntable I heard was made by a record dealer. Loosely speaking a Pink Triangle clone. He used a Yamaha ( guess ) tape deck motor driving the belt. As he said only sensing speed inside the motor made sense. That was a touch of genius. If others have done it I doubt he read it. He said with the confidence of someone who is right. Sensing from the platter must screw up the music. That's right and the direct drives don't solve that.
When a Technics SP 10 is used as a cutting lathe motor it is fine when slow melodic music. In fact it is excellent. When Peter Gabriel So it was just wrong. Like my when sick TD 145 it sounds like everything was falling over itself. "So" has very incisive bass . The SP 10 couldn't cope, drunk was the best word. I guess the Scully motor had died ? To me it was a down grade.
1210 crudity?
The arm is OK. The structure seems better as wood. Wood is a magical material that often gives you what you want without maths coming into it. I was very surprised and would rate it above SP10. I would love to own Bob's 1210. He did have his own design of arm. Made from brass and ultra heavy. The Lyra didn't mind. Was an Argo I think?
BTW . Ivor deliberately set the springs in the " wrong " position. If you set the centre of gravity at the turntable centre it is not a great solution. Often better to have no springs ( Nottingham Analogue Dias went spring less later in time. He was criticized for dynamic wow). The LP12 " wrong " springs make the setting up very hard. What seems to happen is it makes it resit rotation. It is incredibly easy to reset the mass centre of AR TD150 LP12 RD11. An outrigger to the bearing will do it. You should find the deck sounds worse ( slightly slurred ). As far as I can tell all the LP12 suspension does is isolate the mass of the outside world from the transmission loop. It does absolutely nothing else of great note. It is totally hopeless if badly set. The TD 160 was an attempt to solve it. What Ivor maybe got wrong is the TD160 springs are too soft. When I put the LP12 springs in the TD160(145) it was right in 2 minutes. All springs on centre and job done. No way an LP12 done that quickly.
If you put a screwdriver to the arm base of a Dual turntable and the handle to the bone behind the ear you should hear a highly distorted version of the record. When an LP12 it sounds exactly as through the speakers allowing for EQ. It is curious that the Dual 505 sounds as good as it does considering that . It isn't easy to do this with an LP12 as the suspension might move. This suggests to me that the LP12 does do the things Linn suppose. Linn say the chassis must be strong and light to allow the transfer around the loop. Surprisingly wood allows for the other thing . That is it is lossey and seems to have reasonably broadband resonances of no great amplitude.
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Often tape-decks had identical motor types ( synchronous or hysteresis which is close ). The fluctuations were mostly canceled by identical errors. Problems came later when some tape-decks were quartz locked. This was a disaster as the lathe wasn't, often records got out with errors. I don't know enough about the later lathes to say what happened there. All people I know don't want the later lathes.
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