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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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14th Jan 2022, 11:26 am | #1 |
Octode
Join Date: Dec 2006
Location: Colchester, Essex, UK.
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SME 3009 11 mproved. Exploded drawings ?
Are there any exploded drawings of the SME 3009 11 improved?
Mike. |
18th Jan 2022, 9:11 am | #2 |
Octode
Join Date: Dec 2006
Location: Colchester, Essex, UK.
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Re: SME 3009 11 mproved. Exploded drawings ?
I found them on vinyl engine site. SME service manual and SME parts list.
All very useful. Anyone know the size of the base grommets for the four plinth small wood screws for the same arm? Mike. |
18th Jan 2022, 9:24 am | #3 |
Dekatron
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Location: Oxford, UK.
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Re: SME 3009 11 mproved. Exploded drawings ?
Knowing SME's philosophy of making absolutely everything in-house (other than the tapered arm tube, which comes from Chicago White Metal), those grommets are probably unique.
Craig
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18th Jan 2022, 10:40 am | #4 |
Dekatron
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Location: Rugeley, Staffordshire, UK.
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Re: SME 3009 11 mproved. Exploded drawings ?
I'm not so sure Craig. I seem to recall that mine were just like the ones I used to get for free from my place of work. I couldn't categorically say that they weren't a unique size, but I doubt if using a grommet of 'a suitable size' would make a real difference. In other words, if it slots into the mounting foot's aperture and seems right, it's ok. The biggest mistake is over or under tightening.
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18th Jan 2022, 12:20 pm | #5 |
Dekatron
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Re: SME 3009 11 mproved. Exploded drawings ?
I have to say I'm not certain what the purpose of the grommets are. SME also supplied "hard washers" to replace the O rings. These were whatever size fits in the recess the grommet goes in and allows the arm to be tightened into solid contact with the arm board.
Later arms like the IV and V attached to the arm board without any resilient element. Craig Craig
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18th Jan 2022, 12:44 pm | #6 |
Dekatron
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Re: SME 3009 11 mproved. Exploded drawings ?
I think the original intention was that a little vertical compliance at the arm pillar would effect some kind of rumble filtering, bearing in mind that idler drive was the norm when the SME was introduced. The idea was current at the time - Walton's Decca ARI arm used a similar system.
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18th Jan 2022, 2:58 pm | #7 |
Dekatron
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Re: SME 3009 11 mproved. Exploded drawings ?
If you do the sum, the resonance frequency of a compliant system only depends on the compression. That is true of any spring-mass system, where the resonance only depends on how much the spring stretches.
Since the compression is tiny, the resonance cut off is in the kHz range, and does nothing for rumble frequencies. Craig
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18th Jan 2022, 3:31 pm | #8 |
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Re: SME 3009 11 mproved. Exploded drawings ?
OK - just had to remind me of this by working it out again. If you have a static stretch of a spring deltaL, omega is simply root (g/deltaL) So if the weight of the SME arm compresses the grommets by 0.1mm (a reasonable assumption), omega is root (9.81/10^-4) = 300 radians per second, or about 50Hz.
That is actually lower than I thought. But the thing is that it is a low pass filter. So everything below 50Hz gets through and then it cuts at 12dB per octave as a second order filter. So rumble frequencies get through unattenuated. In fact the Q will be pretty low because of the damping of the grommet rubber. I guess that is why SME abandoned the rubber grommets. Craig PS the effect of the equation is interesting - to get a resonance frequency of 1Hz means you have to have a static stretch when you attach the mass of 27cm.
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18th Jan 2022, 8:50 pm | #9 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
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Re: SME 3009 11 mproved. Exploded drawings ?
Reckon Steve's right about simply using grommets that fit. I have a box of assorted grommets and the closest match in terms of size is indistinguishable from the original SME item.
The grommets were always a mystery to me as I thought that a rigid (ie, non-compliant) relationship between stylus and groove was important in terms of trying to replicate the action of the original cutter. In any event the SME grommet issue has been the subject of debate in audio circles for decades. My advice to Mike would be to experiment. When I did this many moons ago I decided that grommetless was the way to go although admittedly it was a subjective judgement and my ears were a lot younger then. Of the two experimental decks one was idler driven and the other was belt drive. Both were mounted in substantial plinths and the cartridge was a Shure M55E if memory serves. One thing to watch out for is that removing the grommets affects the vertical tracking angle (VTA) and this needs to be readjusted in order to make a valid comparison. As a slight aside, I found a simple thin card gasket beneficial in terms of bonding the baseplate to the motor board in grommetless mode. Alan |
21st Jan 2022, 1:16 pm | #10 |
Octode
Join Date: Dec 2006
Location: Colchester, Essex, UK.
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Re: SME 3009 11 mproved. Exploded drawings ?
Going off on a slight tangent, but still same arm, what is the purpose of the side adjustable weight.? Is this to do with weight/bias of the particular cartridge that is fitted to the arm. ?
Mike. |
21st Jan 2022, 1:58 pm | #11 | |
Heptode
Join Date: Oct 2007
Location: Southampton, Hampshire, UK.
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Re: SME 3009 11 mproved. Exploded drawings ?
Quote:
Moving the whole rider weight left to right laterally balances the arm depending on the weight of the cartridge fitted. |
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21st Jan 2022, 2:19 pm | #12 |
Octode
Join Date: Dec 2006
Location: Colchester, Essex, UK.
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Re: SME 3009 11 mproved. Exploded drawings ?
This must be to counterbalance the "S" offset curve of the arm I assume ?
Mike. |
21st Jan 2022, 2:27 pm | #13 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
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Re: SME 3009 11 mproved. Exploded drawings ?
Yes and without the lateral balance adjustment the arm would tend to twist inwards thus lifting the outermost of the knife edge bearings from its groove.
Alan |