I would have to ask Adam who requested it, his qualifications are in design so that's his baby. I am doing the how it works bit. I am trying to make it different and better than typical designs whilst seeming 90% the same. I made a turntable a few years ago that was both wonderful and awful. I know why but could never get over the reasons. I would like to revisit the ideas as I might have a fix. Because I will be paid for this I doubt I will be able to boast about the how and the why too much. The odds of it working correctly are 25% against I feel. The wonderful was dynamics better than anything I know of. The awful was rumble worse than any. The rumble was frustrating rather than impossible. Not unlike some 78's. Having made the worlds most silent idler drive at - 79 dB I know the rumble isn't a false stimulas ( vibrato ). The Garrard 501 is very dynamic. In fact removing vibration makes it more dynamic which is logical. Vibrato whilst impressive is obviously false. Rumble is nothing like violin vibrato.
My friend Martina battled the last 10 dB out of the design. In my opinion she went too far and it has cost her a fortune ( not £2000, more like a house ). The Loricarft 501 is a better use of money and is not cheap as it cost a fortune also to get right ( mostly time taken and people having no idea how to make it even though engineers ). The 501 is a exact generic of the Swindon built 301/401. All it has is a bigger motor run at it's best point. The bearings whilst the same are very slighly better. Some people " upgrade " the 401 bearing. That is all wrong. The -79dB would be possible with the 401 bearing. A ceramic ball conversion as Loricarft predicted drilled a hole in the 401 spindle given enough use. The 301 is only 55 Rockwell hardness which is fine for the bearing type ( flat ) . The 501 uses 64 Rockwell ( I guess Linn to be that and I know SME to be that , Ariston claimed the same ) . 200 is possible and almost for fun the turntable I am working on might have that. My interest in that is just a perfected Rega clone bearing already in use. The ultra hard bearing is made by the same process as hardening crankshafts. Even so the ceramic ball might kill it given time ( months ). Most 301's of 60 years of age are still as new where it matters. The Rega bearing is 8 mm wide and about 45 mm long. I was told it comes from an aircraft wheel bearing ( an element by SKF ). It has wonderful spec whilst being cheap. I imagine Roy being at Ford meant he knew who and how to ask to get that. Although costing peanuts to make I doubt it has any great problems and might be almost as good as it gets.
It is hard to say if 301 is better than 401. I use a 401 myself ( will do when my lastest gets finished . LP12 for now ). As time goes by mid number 301's seem best to me ( 50 000 ish ). 301 is still at todays prices a bargain. The rumble is high. Seldom worse that my favotrite recordings.
I had an arguement with someone recently over motors. I built my mistake and it works great. I won't be sharing that. It has some horrible problems that I am getting to grips with. Nearly everything is not in text books or if it is you are told not to bother. One problem almost seems from the spirit world. The fix is bonkers and not easy to understand. I hate when that happens. A similar one is the shorted turn. As I had predicted to have less vibration the motor needs a load. The need is about > 1000 % greater than my wildest estimate. Where this person and I fell out is if you like he saw the engineering as the bolt on devices that transform awful into usable. I wasn't interested in that as to me that was like trying to perfect the wheel by looking at polygons. I will find an infinitely sided polygon to be best. I was interested in the magnetic structure. My conjecture was right. And yet text books take you away from that. I suspect I will find their sage advice will be true. In this world you never know if you don't try. Nothing is fact that isn't observed. It's other peoples facts. Alas, seldom do we have the time or the safety to know the truth. Mechcanical engineering is interesting. As Terry of Loricraft and I said last night as the lathe was switched off. You can't CAD draw the problems away. You find out by doing. Thank goodness this is right as CAD has ruined so many things. My advice to anyone wanting sucess is do 10% the old way. More than that is stupid as CAD is so good for the 90%. The 10% can be made CAD when correct. Bearing design is so much easier when real. In a bearing sucess or faliure is a whisker difference. 90% can be known limits. That won't help you one little bit. What it will do is impress people who like numbers and makes sure the design is repeatable. The latter is important. Small design differences mean each new bearing is new. That's why my Garrard bearings are exactly the same as the old ones with small refinements. One I changed was 4.92 mm to 6 mm for motor shafts. That caused much fear. It works fine because the nominal of the pulley is 6.33 mm. By using 52 Hz the shaft is the pulley. A 78 pulley is provided as it also is an oil deflector. That helps the design greatly as 78 is at the limit of the motor voltage due to inductance. To get 78 to run directly needs 20 minutes of running to get the oil to conform in the bearings. The oil has to be a primitive type to get close to the needs. Most modern oils do not suit.
Given the choice I would make the motor shaft 5 mm and reduce the platter rim to suit. That would be 10.5 inch x 4.92/6.33 = 8.16 inch or 207.3 mm. Now that looks interesting as a larger flywheel is nice. The problem is repositioning the idler. Best of luck on that. 4.92mm as best we know is 5 mm ground and lapped ( and hardened ). The reason this isn't a good idea is no two Garrard motors are exactly alike unlike synchronous types. The shaded pole is like synchronous at low loads. Garrard had a range of pulley's to fit. My idea needs a regenerator to work. For all that the Garrard motor is a far better device if sound quality is imporatnt ( it seldom is in reality, money usually comes first ). Having never tried 5 mm as the drive it might slip. The 6 mm I do use is fine.
A 401 at 60 Hz is 6.33 mm /1.2 or about 5.3 mm. That is a wall thickness of 0.18 mm. That is bonkers and yet that was how it was done and done very well. When people use a regenerator a 50 Hz pulley is better. As 4 mm would have been more logical as shaft size Garrard must have found it unworkable. As 4.92mm is neither imperial nor metric it was a choice. Manganese Bronze who made the London Taxi-cabs made the bearings. They were hot pressed on a die.
I always quote inches an mm together. Much is still inches and great that it is. 1" machined is a low cost 25mm. If 10.5 inches, best to quote it that way. The Linn plattrer from memory 297 mm OD, that might be 11.7 inches when designed.
My friend Martina battled the last 10 dB out of the design. In my opinion she went too far and it has cost her a fortune ( not £2000, more like a house ). The Loricarft 501 is a better use of money and is not cheap as it cost a fortune also to get right ( mostly time taken and people having no idea how to make it even though engineers ). The 501 is a exact generic of the Swindon built 301/401. All it has is a bigger motor run at it's best point. The bearings whilst the same are very slighly better. Some people " upgrade " the 401 bearing. That is all wrong. The -79dB would be possible with the 401 bearing. A ceramic ball conversion as Loricarft predicted drilled a hole in the 401 spindle given enough use. The 301 is only 55 Rockwell hardness which is fine for the bearing type ( flat ) . The 501 uses 64 Rockwell ( I guess Linn to be that and I know SME to be that , Ariston claimed the same ) . 200 is possible and almost for fun the turntable I am working on might have that. My interest in that is just a perfected Rega clone bearing already in use. The ultra hard bearing is made by the same process as hardening crankshafts. Even so the ceramic ball might kill it given time ( months ). Most 301's of 60 years of age are still as new where it matters. The Rega bearing is 8 mm wide and about 45 mm long. I was told it comes from an aircraft wheel bearing ( an element by SKF ). It has wonderful spec whilst being cheap. I imagine Roy being at Ford meant he knew who and how to ask to get that. Although costing peanuts to make I doubt it has any great problems and might be almost as good as it gets.
It is hard to say if 301 is better than 401. I use a 401 myself ( will do when my lastest gets finished . LP12 for now ). As time goes by mid number 301's seem best to me ( 50 000 ish ). 301 is still at todays prices a bargain. The rumble is high. Seldom worse that my favotrite recordings.
I had an arguement with someone recently over motors. I built my mistake and it works great. I won't be sharing that. It has some horrible problems that I am getting to grips with. Nearly everything is not in text books or if it is you are told not to bother. One problem almost seems from the spirit world. The fix is bonkers and not easy to understand. I hate when that happens. A similar one is the shorted turn. As I had predicted to have less vibration the motor needs a load. The need is about > 1000 % greater than my wildest estimate. Where this person and I fell out is if you like he saw the engineering as the bolt on devices that transform awful into usable. I wasn't interested in that as to me that was like trying to perfect the wheel by looking at polygons. I will find an infinitely sided polygon to be best. I was interested in the magnetic structure. My conjecture was right. And yet text books take you away from that. I suspect I will find their sage advice will be true. In this world you never know if you don't try. Nothing is fact that isn't observed. It's other peoples facts. Alas, seldom do we have the time or the safety to know the truth. Mechcanical engineering is interesting. As Terry of Loricraft and I said last night as the lathe was switched off. You can't CAD draw the problems away. You find out by doing. Thank goodness this is right as CAD has ruined so many things. My advice to anyone wanting sucess is do 10% the old way. More than that is stupid as CAD is so good for the 90%. The 10% can be made CAD when correct. Bearing design is so much easier when real. In a bearing sucess or faliure is a whisker difference. 90% can be known limits. That won't help you one little bit. What it will do is impress people who like numbers and makes sure the design is repeatable. The latter is important. Small design differences mean each new bearing is new. That's why my Garrard bearings are exactly the same as the old ones with small refinements. One I changed was 4.92 mm to 6 mm for motor shafts. That caused much fear. It works fine because the nominal of the pulley is 6.33 mm. By using 52 Hz the shaft is the pulley. A 78 pulley is provided as it also is an oil deflector. That helps the design greatly as 78 is at the limit of the motor voltage due to inductance. To get 78 to run directly needs 20 minutes of running to get the oil to conform in the bearings. The oil has to be a primitive type to get close to the needs. Most modern oils do not suit.
Given the choice I would make the motor shaft 5 mm and reduce the platter rim to suit. That would be 10.5 inch x 4.92/6.33 = 8.16 inch or 207.3 mm. Now that looks interesting as a larger flywheel is nice. The problem is repositioning the idler. Best of luck on that. 4.92mm as best we know is 5 mm ground and lapped ( and hardened ). The reason this isn't a good idea is no two Garrard motors are exactly alike unlike synchronous types. The shaded pole is like synchronous at low loads. Garrard had a range of pulley's to fit. My idea needs a regenerator to work. For all that the Garrard motor is a far better device if sound quality is imporatnt ( it seldom is in reality, money usually comes first ). Having never tried 5 mm as the drive it might slip. The 6 mm I do use is fine.
A 401 at 60 Hz is 6.33 mm /1.2 or about 5.3 mm. That is a wall thickness of 0.18 mm. That is bonkers and yet that was how it was done and done very well. When people use a regenerator a 50 Hz pulley is better. As 4 mm would have been more logical as shaft size Garrard must have found it unworkable. As 4.92mm is neither imperial nor metric it was a choice. Manganese Bronze who made the London Taxi-cabs made the bearings. They were hot pressed on a die.
I always quote inches an mm together. Much is still inches and great that it is. 1" machined is a low cost 25mm. If 10.5 inches, best to quote it that way. The Linn plattrer from memory 297 mm OD, that might be 11.7 inches when designed.
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I said the Loricraft 501 a better use of money than the L'art du Son version. The Audi RS8 and Lamborghini come to mind. Or Boxster verses top of the range. Some dislike the Boxster as it is afordable. Many say due to numbers made Boxster shows signs of being a complete design rather than a prototype that goes on sale. My friends 911 cousin showed signs of that. I rather like that it did. Weirdly the Mazda RX7 also has a hand built look.
Basically it is finished except choosing a motor ( 2 selected ). It has a few quirks I rather like. One I would love to do is give everyone a Denon DL 110 with a bespoke pre amp. Out of all cartridges I tried the Denon would allow the 75 uS to be done before the signal enters the op amp. Alas the last DL 110 have been made. I better not say more as Adam would not be best pleased. I had some ideas for isolation. I doubt they will be used as too chunky.
A turntable like this is yet another " me too " turntable. In the drugs industry something I can put together with a few cheap pills is sold for $7 a packet as an all in one cure. I am trying hard to say no to that. If not people should say no to me and buy a Rega. Every motorcar has to pass this test. Some win on load space and cup holders. Fair enough. When trying to find out how to repair a Renault Megane the autoparts guy said he knew exactly what the problem was " It's French ". When I looked shocked he said " Honest mate that's what's wrong " . He then said why " They are put together in a way to save money on labour. Units built up, then installed . It means a complete strip down to repair the heater ".
At least that sort of thing should be avoided in hi fi. Often even though simple, things are not built for a long life. How is anyone to know ?
The problem with belt drive turntables is the belt. I would be like having chain drive on a car. Not a stupid idea if repalcement ( and remembering )was easy to do. A chain in a car is a no no since the 1930's. Lets be clear. There is no such thing as a good belt drive turntable. When one gets into the high cost units they become objects of art. Belt drive is a very cheap way of doing an OK urntable. It was a way of AR selling speakers to design the first example in common use. AR speakers had bass, most turntables had rumble. That meant the selling feature of AR meant no sales until they offered a cheap solution. AR are claimed as the inventors of belt drive, Phillips were doing it in 1954 and doing it better. Farm machinery showed the how as did tape recorders in the 1940's.
I will upset a lot of people saying that. BTW. The AR turntable used springs as much as anything to isolate the record from the motor. That is a can of worms as the major weakness of belt drive is made worse that way. The vibration you don't want is dealt with. The ones you do want are also filtered. If a turntable is cheap enough all of that is reality and not to be overly objected to. The Elephants foot designs with a boot lace
belt. What on Earth is that all about ? Someone told me the 1/2 watt the LP12 uses is more than enough to make it work. A 50 CC moped is enough for London traffic. And ??
When a motorcar what makes it go is a mystery to most buyers. What they call a car is the look. When Adam will do that I can not tell. Going back to cars. If you took the worst car you can imagine then let a good engineer do a little work and a stylist it could be made into a must have. The Morris Marina and MGB V8 were generics of the Morris Minor who's designer made the all winning Mini. Mini won every competition it entered and had to be banned to stop it winning. The Marina was awful. And yet it sold in high numbers to those who demaded it. That customer type died. It was the last of the home mechanics. The Mini you see now is not a BMW design. The recent fat versions might be. I know one of the test engineers who drove it years ago ( Colleens brother in law ). The MGB V8 was if you like proof that a Ford Mustang type design could almost equal the proper designs. In belt drive an MGB V8 would be as good as it gets. The MGB V8 was a happy accident of a parts bin special that was better than it should have been. Zero devellopement cost and almost perfect within it's concept. Even the detuned engine was in reality a good move. That was the parent company playing games as the rival Triumph company had been absorbed and were pushing the TR7 over the MG. MG is a good example of making a silk purse from a sow's ear. They had to use what they were given since the 1920's. And yet they had sucess. The Datsun 280 was the same and no less good. The Cherry was the Japanese Morris Marina. I think the HL Marina worth restoring if a few MG parts fitted, A Cherry is not. There was an HL in black with leather seats and old style silver on black plates locally. It was stunnig. I don't remember seeing them in the 1970's. The guy has a Rover V8 before SD1 now in racing green. I am very jealous.
A turntable like this is yet another " me too " turntable. In the drugs industry something I can put together with a few cheap pills is sold for $7 a packet as an all in one cure. I am trying hard to say no to that. If not people should say no to me and buy a Rega. Every motorcar has to pass this test. Some win on load space and cup holders. Fair enough. When trying to find out how to repair a Renault Megane the autoparts guy said he knew exactly what the problem was " It's French ". When I looked shocked he said " Honest mate that's what's wrong " . He then said why " They are put together in a way to save money on labour. Units built up, then installed . It means a complete strip down to repair the heater ".
At least that sort of thing should be avoided in hi fi. Often even though simple, things are not built for a long life. How is anyone to know ?
The problem with belt drive turntables is the belt. I would be like having chain drive on a car. Not a stupid idea if repalcement ( and remembering )was easy to do. A chain in a car is a no no since the 1930's. Lets be clear. There is no such thing as a good belt drive turntable. When one gets into the high cost units they become objects of art. Belt drive is a very cheap way of doing an OK urntable. It was a way of AR selling speakers to design the first example in common use. AR speakers had bass, most turntables had rumble. That meant the selling feature of AR meant no sales until they offered a cheap solution. AR are claimed as the inventors of belt drive, Phillips were doing it in 1954 and doing it better. Farm machinery showed the how as did tape recorders in the 1940's.
I will upset a lot of people saying that. BTW. The AR turntable used springs as much as anything to isolate the record from the motor. That is a can of worms as the major weakness of belt drive is made worse that way. The vibration you don't want is dealt with. The ones you do want are also filtered. If a turntable is cheap enough all of that is reality and not to be overly objected to. The Elephants foot designs with a boot lace
belt. What on Earth is that all about ? Someone told me the 1/2 watt the LP12 uses is more than enough to make it work. A 50 CC moped is enough for London traffic. And ??
When a motorcar what makes it go is a mystery to most buyers. What they call a car is the look. When Adam will do that I can not tell. Going back to cars. If you took the worst car you can imagine then let a good engineer do a little work and a stylist it could be made into a must have. The Morris Marina and MGB V8 were generics of the Morris Minor who's designer made the all winning Mini. Mini won every competition it entered and had to be banned to stop it winning. The Marina was awful. And yet it sold in high numbers to those who demaded it. That customer type died. It was the last of the home mechanics. The Mini you see now is not a BMW design. The recent fat versions might be. I know one of the test engineers who drove it years ago ( Colleens brother in law ). The MGB V8 was if you like proof that a Ford Mustang type design could almost equal the proper designs. In belt drive an MGB V8 would be as good as it gets. The MGB V8 was a happy accident of a parts bin special that was better than it should have been. Zero devellopement cost and almost perfect within it's concept. Even the detuned engine was in reality a good move. That was the parent company playing games as the rival Triumph company had been absorbed and were pushing the TR7 over the MG. MG is a good example of making a silk purse from a sow's ear. They had to use what they were given since the 1920's. And yet they had sucess. The Datsun 280 was the same and no less good. The Cherry was the Japanese Morris Marina. I think the HL Marina worth restoring if a few MG parts fitted, A Cherry is not. There was an HL in black with leather seats and old style silver on black plates locally. It was stunnig. I don't remember seeing them in the 1970's. The guy has a Rover V8 before SD1 now in racing green. I am very jealous.
Can we get Adam to talk about this turntable?
For more about the AR turntable.
Edgar Villchur and AR turntable
For more about the AR turntable.
Edgar Villchur and AR turntable
A good reference - thank you.
AR had been well ahead of its time in those days. I notice that they shared views on subchassis suspension with Dual of those days (and later) insofar that both use what mechanical engineers swear on, a three point suspension. My late father always said that a three point suspension provided an ideal distribution of forces.
I'm happy to note that Dual remained true to this principle and kept subchassis suspension as a three point job right to the end.
I hope so as long as it doesn't brake rules of the forum.
I was to meet Mr V. Alas it didn't happen as my friend died who knew him. Sid warned me not to say anything the hi fi press would say. Mr V was asked how he made the turntable image so well. He thought it a rediculous question. Not really. The good compromise of the AR and clones is to not cause too many vertical movements. It is the out of phase stylus movements that we treat as the really important musical imformation ( it is said, seems true ). The belt drive problem is vibration taken by the belt. The so called setting up of an LP12 is making sure everything is at 180 or 90 degrees ( never was from the factory and they knew it ). And making sure there was no gyration of the bounce. A longer spring near the motor helped that. The most off centre near the arm base to allow rotaion and setting. Spit used as a lubricant. Hold the spring both ends to rotate and be gentle. In terms of imagine placement a very big deal. For all that an LP 12 sounds slightly drunk. I can live with that.
I was to meet Mr V. Alas it didn't happen as my friend died who knew him. Sid warned me not to say anything the hi fi press would say. Mr V was asked how he made the turntable image so well. He thought it a rediculous question. Not really. The good compromise of the AR and clones is to not cause too many vertical movements. It is the out of phase stylus movements that we treat as the really important musical imformation ( it is said, seems true ). The belt drive problem is vibration taken by the belt. The so called setting up of an LP12 is making sure everything is at 180 or 90 degrees ( never was from the factory and they knew it ). And making sure there was no gyration of the bounce. A longer spring near the motor helped that. The most off centre near the arm base to allow rotaion and setting. Spit used as a lubricant. Hold the spring both ends to rotate and be gentle. In terms of imagine placement a very big deal. For all that an LP 12 sounds slightly drunk. I can live with that.
A big improvement can be made with Dual turntables. The spring often is damped by a very well made piece of rubber that looks only to hold the spring. It is slightly too long to be 100 % effective. A bit like a car running all day on it's bump stops. If about 2 mm is trimmed off of the Dual rubbers it helps give a minute amount movement in the springs. Usually the movement if it exists at all is < 0.5 mm. Some non audio people might find that movement offputting. I suspect Dual put non audiophile customer needs first. The foam in the Thorens spring can be removed. It then requires more careful adjustment. In the days of radiograms all decks had springs. Even though crude they did a reasonable job. The saying if all else fails read the instructions comes to mind. How many times have I repaired a turntable that still had it's transtit screws tightened.
I think they get worse over time. Sharp knife and take off as little as possible. It is a 5 minute job. I dare say some acoustic fibre in the box would do some good. Enough to fill without touching top to bottom etc. Even the fibre is an acoustic short circuit of sorts.
Had a great mini brake near Minehead ( Kilve ). Went to the Bakelite museum which was well worth £5. Had a pint of cider for you Devan. Didn't see Hinkley Point although very close by. Did see Lundy Island as you do from Cornwall also. That island must be larger than obvious to be seen from so far away. It looks small.
Had a great mini brake near Minehead ( Kilve ). Went to the Bakelite museum which was well worth £5. Had a pint of cider for you Devan. Didn't see Hinkley Point although very close by. Did see Lundy Island as you do from Cornwall also. That island must be larger than obvious to be seen from so far away. It looks small.
In my view, the best looking place around in the country in my time was Ilfracombe. Surreaiistic location, town on top of a giant magma rock, it's almost out of a fairy tale.
If this was sometime near the end of last week, the cider reached me. I was talking about it with me wife during the vacation in Grece. All of a sudden, I though of cider, and not a bottle in sight, I think it was Friday, August 7. Most frustrating, to wish for something and not be able to find it. Anyway, I had me a bottle of Somersby cider today to help the lunch along.
Bless you for the thought, Nige, but you should have had two, one for me and one for you, I hate drinking alone,
If this was sometime near the end of last week, the cider reached me. I was talking about it with me wife during the vacation in Grece. All of a sudden, I though of cider, and not a bottle in sight, I think it was Friday, August 7. Most frustrating, to wish for something and not be able to find it. Anyway, I had me a bottle of Somersby cider today to help the lunch along.
Bless you for the thought, Nige, but you should have had two, one for me and one for you, I hate drinking alone,
Here's a possibly interesting approach.
I saw an ad on a local forum with a man selling a complete Dual 627 direct drive TT, with accomapying arm, in full owrking order, for a priceley sum of €35, only because the whole thing had no oxternal case at all, only the subchassis.
For that kind of money, how can you fail? That's their ater version of their Low Mass arm, the one with two mechanical filters, peaking at +2 dB at 9 Hz, which is next to perfection.
I saw an ad on a local forum with a man selling a complete Dual 627 direct drive TT, with accomapying arm, in full owrking order, for a priceley sum of €35, only because the whole thing had no oxternal case at all, only the subchassis.
For that kind of money, how can you fail? That's their ater version of their Low Mass arm, the one with two mechanical filters, peaking at +2 dB at 9 Hz, which is next to perfection.
People are silly. They buy Lenco's for silly money and not Dual.
Here is a bit of fun. I had used this circuit with 68 K and 100 nF as a 2 minute timer. It got me thinking what would work best for 50/60/67.5 Hz. A 3.2768 MHz crystal and 2 x 4060 best for 50 Hz. If you are prepared to tweak a bit the other frequecies are also easy to do, the first example I got almost spot on. By chance 4K7 was 50 Hz ( 49.934 +/- 0.0002 % ) . NPO ceramic was good enough ( 0.5 % measured ). Both results are not exactly text book. The voltage needs to be stable also. The 10 K was a pure guess. If using a DIL 16 socket just fold in the legs not needed. Seems OK to do that. The result is a square wave. A 6 pole filter should be OK if wanting sine waves . Chebishev is fine as the frequency is fixed. Being CMOS earth yourself when touching. I seems to have ones working where I forgot. Not worth the risk. Some say all semiconductors should be treated as if CMOS. 74HC have plenty of current so need no buffers to drive modest filters. Black is 0V. If using stripboard as here ( 25 x 50 mm ) drill between 8 & 9. Only 7 pins used.
Here is a bit of fun. I had used this circuit with 68 K and 100 nF as a 2 minute timer. It got me thinking what would work best for 50/60/67.5 Hz. A 3.2768 MHz crystal and 2 x 4060 best for 50 Hz. If you are prepared to tweak a bit the other frequecies are also easy to do, the first example I got almost spot on. By chance 4K7 was 50 Hz ( 49.934 +/- 0.0002 % ) . NPO ceramic was good enough ( 0.5 % measured ). Both results are not exactly text book. The voltage needs to be stable also. The 10 K was a pure guess. If using a DIL 16 socket just fold in the legs not needed. Seems OK to do that. The result is a square wave. A 6 pole filter should be OK if wanting sine waves . Chebishev is fine as the frequency is fixed. Being CMOS earth yourself when touching. I seems to have ones working where I forgot. Not worth the risk. Some say all semiconductors should be treated as if CMOS. 74HC have plenty of current so need no buffers to drive modest filters. Black is 0V. If using stripboard as here ( 25 x 50 mm ) drill between 8 & 9. Only 7 pins used.
An extra word. The frequency as I hoped is rock solid with NPO. They can equal crystals. 0.5% is how good my capacitance meter is. Notice although to design rules it is far from the 1/ 2.5RC. The Rules are > 50 pF > 1K Rin 2 x R. When 100 nF it is very good and close to the rules. The minimum usable frequency is 25 % that of the RC values and is available on pin 7. Thus you need 200 Hz from RC to have 50 Hz. That might help someone with only basic measuring gear. Polyester is 200 ppm as the down side. NPO 30 ppm. It is worth building the harder version. What I give here should work. As I don't trust frequency counters I calibrated the scope to be sure what I read is what I had. 12.5 Hz from the last port No3 if wondering.
Carbon fibre for arms is funny stuff. Like wood, but less good. Dowel is great.
Here is a how to drive a synchronous motor. You will need an amplifier. The 4060 will live with overload to drive a strobe ( 220 R if doubtful. Ron shuts the current down as it is CMOS ) . It is 100 Hz as a light bulb gives twice the flashes on mains electricity compared with a LED. This design is first class and yet too much. To get it to work at 45 RPM would need > 40 dB extra gain. That would bring up hum from ripple. Better to use a cascade of passive filters and switch the resistors. The 1/3 rd harmonic is at 1/3 so that's almost - 10 dB already. Even 40 db filtering will do. A cosine wave can be pulled out at every second pole and give it some amplification with another TL074 ( LM324 is OK ) . HC49 crystals seem OK without current limiting as shown here. Better still to use a State Variable Filter type Wien bridge that also gives the cosine wave required. The boasted about crystal is the most unhelpful way to do it. NPO caps are as stable and the SVF will if using TL074 be close to calculated values. 10 nF NPO and 318 K ( 300K + 50 K variable ) are good starting points. See ESP audio for the SVF. Often 45 RPM needs 20% more volatge to offset inductance . Often that is well inside the voltage limits ( LP12, 90 and 115 V is fine as it is a 115 V motor. 115 V is too much for 33 1/3 ). The Strobe I show here is a first class way to adjust speed. Most 45 RPM stobe markings do not give exact speed. Put a coin on the platter and count the passes with a stop watch is not too bad. One finds the reaction time is abouit the same for each action. Say zero for the first pass. 30 seems a good count in 40 seconds. 25 in 45 seconds for 33 1/3. Sallen key filter although slightly more complex is cheaper for parts. The default values for Multiple feedback type is 1000 uF for the final op amp. The filter shown is - 90 dB @ 150 Hz. That's bonkers as the motor will reduce that to - 20 dB ( internal ) . Much as we do the best we can it is bad engineering to think this is good design.
Here is a how to drive a synchronous motor. You will need an amplifier. The 4060 will live with overload to drive a strobe ( 220 R if doubtful. Ron shuts the current down as it is CMOS ) . It is 100 Hz as a light bulb gives twice the flashes on mains electricity compared with a LED. This design is first class and yet too much. To get it to work at 45 RPM would need > 40 dB extra gain. That would bring up hum from ripple. Better to use a cascade of passive filters and switch the resistors. The 1/3 rd harmonic is at 1/3 so that's almost - 10 dB already. Even 40 db filtering will do. A cosine wave can be pulled out at every second pole and give it some amplification with another TL074 ( LM324 is OK ) . HC49 crystals seem OK without current limiting as shown here. Better still to use a State Variable Filter type Wien bridge that also gives the cosine wave required. The boasted about crystal is the most unhelpful way to do it. NPO caps are as stable and the SVF will if using TL074 be close to calculated values. 10 nF NPO and 318 K ( 300K + 50 K variable ) are good starting points. See ESP audio for the SVF. Often 45 RPM needs 20% more volatge to offset inductance . Often that is well inside the voltage limits ( LP12, 90 and 115 V is fine as it is a 115 V motor. 115 V is too much for 33 1/3 ). The Strobe I show here is a first class way to adjust speed. Most 45 RPM stobe markings do not give exact speed. Put a coin on the platter and count the passes with a stop watch is not too bad. One finds the reaction time is abouit the same for each action. Say zero for the first pass. 30 seems a good count in 40 seconds. 25 in 45 seconds for 33 1/3. Sallen key filter although slightly more complex is cheaper for parts. The default values for Multiple feedback type is 1000 uF for the final op amp. The filter shown is - 90 dB @ 150 Hz. That's bonkers as the motor will reduce that to - 20 dB ( internal ) . Much as we do the best we can it is bad engineering to think this is good design.
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