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Post by Mr Whippy on Feb 18, 2015 19:06:26 GMT
What's it all about? Eh? Eh?
Spinning a disc of the shiney black stuff… Just how hard can it really be? Hmm? Hmm? Couldn't stop myself going into Harry Hill mode.
I have a few projects in mind with one being an LP12 clone. Never had any liking for the company but always liked the look of the deck - which, after all, is really a Thorens 150 in a smart plinth. Fancy trying an aluminium plinth and passive drive.
It's had me thinking what design elements go towards making a deck what it is. Do all sub-chassis designs have a particular style of presentation? Does a heavy platter automatically bring benefits? How sophisticated should the bearing be? Should the arm be totally issolated?
Any thought?
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Post by danielquinn on Feb 18, 2015 19:35:43 GMT
Empirically. I know only one thing. Dc motors are better than ac.
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Post by Deleted on Feb 18, 2015 19:41:03 GMT
Indeed. Congratulations to Linn for recognisng this and having the foresight and courage to pioneer this innovation in their latest offerings. British creativity and thinking outside the box are alive and well. Ivor surely deserves another gong in the honours list.
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Post by Greg on Feb 18, 2015 21:16:19 GMT
Nothing pioneering from Linn here. DC motors to drive TT's have been around for years. My knowledge is probably relatively recent but I know from personal use that Michell and Origin Live use them and probably several other companies long before Linn got involved. Nothing innovative here. It's just old stuff Linn now chooses to catch up with.
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Post by Deleted on Feb 18, 2015 21:18:47 GMT
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Post by John on Feb 19, 2015 6:36:57 GMT
Several big issues with tt design
Speed stability is a big one this why high end belt drives have such heavy plinths. Cartridge drag is the main reason for this. As you playing music you cartridge is causing friction and causing speed drift (what you want is speed stability). Different designs tackle this in different ways so with direct drives careful attention is paid to the motor to get speed stability and with rim drives torque is used to get this
Good isolation is also really important to help the cartridge pick up all that info from the LP
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Post by pinkie on Feb 19, 2015 7:06:42 GMT
Cartridge drag is not a factor for belt drives or dc motors as Arthur has proved repeatedly and as is now universally acknowledged. Bloody Martin Colloms and his dust bug. Yes you need to achieve speed stability, which will involve good servo design on a dc motor. Tip 1 - use a smaller pulley and higher speeds if possible. But the main issue is what you do with energy.
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Post by MartinT on Feb 19, 2015 7:11:41 GMT
Remember that Ivor wanted to make the LP12 direct drive, and it was only Panasonic's reluctance to supply the DD motor to him that led him to make it belt drive instead. Then came the marketing bollocks to support his chosen design. That u-turn has been well buried but caused the magazines and reviewers to virtually kill DD turntables dead, at least in the UK market.
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Post by John on Feb 19, 2015 7:16:17 GMT
Cartridge drag is not a factor for belt drives or dc motors as Arthur has proved repeatedly and as is now universally acknowledged. Bloody Martin Colloms and his dust bug. Yes you need to achieve speed stability, which will involve good servo design on a dc motor. Tip 1 - use a smaller pulley and higher speeds if possible. But the main issue is what you do with energy. Tip 1 is using torque to give you speed stability same as what the Salvation does with the rim drive |
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Post by danielquinn on Feb 19, 2015 9:37:57 GMT
I think but do not know for sure .
1] low mass /high mass is question of preference and implementation. One is not better than the other per se .
2] belt drive sprung sub chassis are flawed cause they cause movement between the motor and the belt relative to the subchasis . mounting the motor on the sub chasis will alleviate some of the problem , it will not elliminate it . However the solution , ellimination of springs causes an isolation problem. I suspect this is easier to cure than the problem springs introduce .
3] Somewhat ironically , the direct drive fanboyism as become analogous to the 70/80's flat earth fanboyism . Expect a backlash in 25 years
4] The effects of minor shifts in vta are exceedingly exaggerated .
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Post by danielquinn on Feb 19, 2015 9:46:34 GMT
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Post by MartinT on Feb 19, 2015 11:15:55 GMT
3] Somewhat ironically , the direct drive fanboyism... 4] The effects of minor shifts in vta are exceedingly exaggerated . I don't see point 3 as being any sort of major shift in thinking, more that a much maligned (through politics) form of motor drive has now been recognised as excellent by some, and must have always been.
Totally agree on point 4, it seems an American thing to be uber critical of VTA adjustment, even from record to record. |
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Post by Deleted on Feb 19, 2015 11:54:03 GMT
3] Somewhat ironically , the direct drive fanboyism... 4] The effects of minor shifts in vta are exceedingly exaggerated . I don't see point 3 as being any sort of major shift in thinking, more that a much maligned (through politics) form of motor drive has now been recognised as excellent by some, and must have always been.
Totally agree on point 4, it seems an American thing to be uber critical of VTA adjustment, even from record to record. Either there is something strange about my Technics U205 or the whole VTA bit is not critical. The arm on the Dual1019 is set up to allow for stacking (  ) and so is sloping down quite a bit with a single record playing. I tried packing the headshell to bring it more parallel but could hear bugger all difference. I never have been able to be arsed with all the mucking about that seems part and parcel of this hobby. The Americans (and some Brits) seem totally hung up on details - sod the music. |
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Post by Deleted on Feb 19, 2015 12:05:09 GMT
Indeed. Congratulations to Linn for recognisng this and having the foresight and courage to pioneer this innovation in their latest offerings. British creativity and thinking outside the box are alive and well. Ivor surely deserves another gong in the honours list. The only thing innovative about Linn's DC motor is the price. Other manufacturers pioneered this at reasonable cost years ago (Pink Triangle may have been first). |
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Post by John on Feb 19, 2015 16:12:28 GMT
I remember getting a demo of VTA on the fly and I thought I heard a very slight change and this was in the extremes of VTA but that was it and not really sure if I did.
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Post by Deleted on Feb 19, 2015 18:07:24 GMT
Indeed. Congratulations to Linn for recognisng this and having the foresight and courage to pioneer this innovation in their latest offerings. British creativity and thinking outside the box are alive and well. Ivor surely deserves another gong in the honours list. Other manufacturers pioneered this at reasonable cost years ago (Pink Triangle may have been first). Ivor would probably take that as a compliment |
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Post by Mr Whippy on Feb 19, 2015 18:45:23 GMT
….But the main issue is what you do with energy. Yes, it's the question of energy management that has me pondering… What DO you do with it? Transmit it? Damp it? Sink it? That and isolation from outside disturbances. Pink Triangle came up with the Pink Linnk dc power supply for the LP12. |
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Post by Mr Whippy on Feb 27, 2015 22:10:16 GMT
Anyone bother with a clamp?
Oracle used a curved washer and the record label was tensioned over it forcing contact with the platter mat.
And anyone heard of a dc idler mod?
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Post by MartinT on Feb 27, 2015 23:52:04 GMT
That's the rough principle behind the Michell clamp, too.
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Post by Mr Whippy on Mar 5, 2015 20:13:19 GMT
Anyone know a source for black delrin and acrylic bar 1" square?
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) and so is sloping down quite a bit with a single record playing. I tried packing the headshell to bring it more parallel but could hear bugger all difference. I never have been able to be arsed with all the mucking about that seems part and parcel of this hobby. The Americans (and some Brits) seem totally hung up on details - sod the music.