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#1
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I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the
last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! |
#2
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On Sat, 1 Jan 2011 12:04:08 -0800, Roy wrote
(in article ): I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! Sounds to me like you need to take some measurements and see where the clearance issues actually lie. I don't know the Pro*ject table in question, and my suggestions are general for turntables that have the platter assembly suspended on springs. If the turntable platter/sub-chassis has a suspension then I suspect that the suspension has sagged. In some tables, it's possible to adjust screws inside the springs that the platter/sub-chassis sits on to raise of lower the assembly. So it might yield to adjustment. If you can raise (or lower depending on the design) the sub-chassis as it sits on its springs, be careful to use a level on the PLATTER to make sure that you adjust all the suspension springs exactly the same amount. Turntables need to remain level. Other than that, I suggest that you contact Sumiko, the importer/distributor (if you're in the USA) in Berkeley Ca. and talk to one of their technicians. |
#3
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On 1/1/2011 12:04 PM, Roy wrote:
I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! without looking at the specific TT, I would be willing to guarantee you that the TT has a suspension that has sagged, it probably has some rubber or plastic components (grommets, maybe) that have compressed or expanded, replace them, or shim them, not the platter to sub platter mating surface. It should cost almost nothing to repair unless the suspension components need to be replaced, and then cost would depend on how you elected to fix them. I've had similar issues when I used a Craftsman TT (no, not Sears, the UK company), and it used short lengths of elastic rubber for the suspension. |
#4
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Thanks for the advice. I'll pursue!
On Jan 2, 12:06=A0pm, Bill Noble wrote: On 1/1/2011 12:04 PM, Roy wrote: I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! without looking at the specific TT, I would be willing to guarantee you that the TT has a suspension that has sagged, it probably has some rubber or plastic components (grommets, maybe) that have compressed or expanded, replace them, or shim them, not the platter to sub platter mating surface. =A0It should cost almost nothing to repair unless the suspension components need to be replaced, and then cost would depend on how you elected to fix them. =A0I've had similar issues when I used a Craftsman TT (no, not Sears, the UK company), and it used short lengths of elastic rubber for the suspension. |
#5
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"Roy" wrote in message
... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! Strange, I thought the Project 1.2 was not a suspended subchassis turntable, I though it was very basic much like the Rega Planar 3? Is this not the case? If it is then the only answer is that the bearing housing on the underside has come unscrewed. If is is a suspended subchassis design then it sound like one of the springs has either broken or come unfixed. D |
#6
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"Roy" wrote in message
... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. -- Trevor Wilson www.rageaudio.com.au |
#7
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On 1/5/2011 3:54 PM, Trevor Wilson wrote:
wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. if it is a diecast platter, just replace with aluminum or other metal of your choice - any machine shop could make it for you |
#8
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On Sat, 8 Jan 2011 07:20:41 -0800, Bill Noble wrote
(in article ): On 1/5/2011 3:54 PM, Trevor Wilson wrote: wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. if it is a diecast platter, just replace with aluminum or other metal of your choice - any machine shop could make it for you It's probably not worth it. After all, one can buy a pretty good Rega, Music Hall or even a new Pro*Ject 'table for less than $300. |
#9
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"Audio Empire" wrote in message
On Sat, 8 Jan 2011 07:20:41 -0800, Bill Noble wrote (in article ): On 1/5/2011 3:54 PM, Trevor Wilson wrote: wrote in message ... **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. if it is a diecast platter, just replace with aluminum or other metal of your choice - any machine shop could make it for you It's probably not worth it. After all, one can buy a pretty good Rega, Music Hall or even a new Pro*Ject 'table for less than $300. If a manufacturer sold me a turntable with a sagging platter and did not stand behind it, it would be the last turntable of that brand that I ever bought. |
#10
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On Sat, 8 Jan 2011 18:18:11 -0800, Arny Krueger wrote
(in article ): "Audio Empire" wrote in message On Sat, 8 Jan 2011 07:20:41 -0800, Bill Noble wrote (in article ): On 1/5/2011 3:54 PM, Trevor Wilson wrote: wrote in message ... **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. if it is a diecast platter, just replace with aluminum or other metal of your choice - any machine shop could make it for you It's probably not worth it. After all, one can buy a pretty good Rega, Music Hall or even a new Pro*Ject 'table for less than $300. If a manufacturer sold me a turntable with a sagging platter and did not stand behind it, it would be the last turntable of that brand that I ever bought. Well, I think it would depend upon the circumstances. The Pro*ject 1.2 was a cheap table IIRC, and it IS 10 years old. Even Rolls-Royce won't stand behind a 10 year old Rolls other than to supply replacement parts. |
#11
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Audio Empire wrote:
On Sat, 8 Jan 2011 18:18:11 -0800, Arny Krueger wrote (in article ): "Audio Empire" wrote in message On Sat, 8 Jan 2011 07:20:41 -0800, Bill Noble wrote (in article ): On 1/5/2011 3:54 PM, Trevor Wilson wrote: wrote in message ... **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. if it is a diecast platter, just replace with aluminum or other metal of your choice - any machine shop could make it for you It's probably not worth it. After all, one can buy a pretty good Rega, Music Hall or even a new Pro*Ject 'table for less than $300. If a manufacturer sold me a turntable with a sagging platter and did not stand behind it, it would be the last turntable of that brand that I ever bought. Well, I think it would depend upon the circumstances. The Pro*ject 1.2 was a cheap table IIRC, and it IS 10 years old. Even Rolls-Royce won't stand behind a 10 year old Rolls other than to supply replacement parts. **Regardless of legal and moral obligations, when manufacturers make really stupid mistakes, they should ensure that those mistakes are rectified. A sagging platter is just ridiculous. Turntable platter technology is hardly rocket science. An example: Recently, I've had occaision to service a Counterpoint product. The original parts are NLA. Although the unit is 20 years old, the manufacturer has provided exemplary backup service, guiding me to suitable replacement parts, even though he has no chance of making a profit from that assistance. -- Trevor Wilson www.rageaudio.com.au |
#12
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"Trevor Wilson" wrote in message
... Audio Empire wrote: On Sat, 8 Jan 2011 18:18:11 -0800, Arny Krueger wrote (in article ): "Audio Empire" wrote in message On Sat, 8 Jan 2011 07:20:41 -0800, Bill Noble wrote (in article ): On 1/5/2011 3:54 PM, Trevor Wilson wrote: wrote in message ... **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. if it is a diecast platter, just replace with aluminum or other metal of your choice - any machine shop could make it for you It's probably not worth it. After all, one can buy a pretty good Rega, Music Hall or even a new Pro*Ject 'table for less than $300. If a manufacturer sold me a turntable with a sagging platter and did not stand behind it, it would be the last turntable of that brand that I ever bought. Well, I think it would depend upon the circumstances. The Pro*ject 1.2 was a cheap table IIRC, and it IS 10 years old. Even Rolls-Royce won't stand behind a 10 year old Rolls other than to supply replacement parts. **Regardless of legal and moral obligations, when manufacturers make really stupid mistakes, they should ensure that those mistakes are rectified. A sagging platter is just ridiculous. Turntable platter technology is hardly rocket science. An example: Recently, I've had occaision to service a Counterpoint product. The original parts are NLA. Although the unit is 20 years old, the manufacturer has provided exemplary backup service, guiding me to suitable replacement parts, even though he has no chance of making a profit from that assistance. Counterpoint has always provided good personal service. The SA-2 Preamp I owned was one of the most satisfactory long-term purchases I ever made. Included personal advice as to optimal loading for my Accuphase AC2 cartridge. |
#13
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On 1/8/2011 12:12 PM, Audio Empire wrote:
On Sat, 8 Jan 2011 07:20:41 -0800, Bill Noble wrote (in ): On 1/5/2011 3:54 PM, Trevor Wilson wrote: wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. if it is a diecast platter, just replace with aluminum or other metal of your choice - any machine shop could make it for you It's probably not worth it. After all, one can buy a pretty good Rega, Music Hall or even a new Pro*Ject 'table for less than $300. well, i would be surprised if machining a platter cost more than $50 to $80, I'd probably just make a new platter and be done with it, but it isn't my TT, after all |
#14
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On Mon, 10 Jan 2011 07:15:43 -0800, Bill Noble wrote
(in article ): On 1/8/2011 12:12 PM, Audio Empire wrote: On Sat, 8 Jan 2011 07:20:41 -0800, Bill Noble wrote (in ): On 1/5/2011 3:54 PM, Trevor Wilson wrote: wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. if it is a diecast platter, just replace with aluminum or other metal of your choice - any machine shop could make it for you It's probably not worth it. After all, one can buy a pretty good Rega, Music Hall or even a new Pro*Ject 'table for less than $300. well, i would be surprised if machining a platter cost more than $50 to $80, I'd probably just make a new platter and be done with it, but it isn't my TT, after all I do a lot of classic auto restoration. Sometimes, on pre-war cars, one has to have parts made, so I have a lot of experience at this. Even small parts are very expensive to have machined. What it ends up being is something like $300 for, say, one piece of a hydraulic fluid reservoir or $400 for FIVE of them. It's the machine set-up costs that cost the money, not the actual machining of the parts themselves. I suspect that a new turntable platter would be a similar deal. |
#15
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"Audio Empire" wrote in message
I do a lot of classic auto restoration. Sometimes, on pre-war cars, one has to have parts made, so I have a lot of experience at this. Even small parts are very expensive to have machined. What it ends up being is something like $300 for, say, one piece of a hydraulic fluid reservoir or $400 for FIVE of them. It's the machine set-up costs that cost the money, not the actual machining of the parts themselves. I suspect that a new turntable platter would be a similar deal. Glad you said it first! A turntable platter would be the sort of thing you might want to have made from a solid piece of aluminum. I'm not going to do the math to calculate what sort of a solid piece of aluminum like that would weigh, but I can see parting ways with $50 or so, only to have just a piece of raw aluminum, and no machine work even planned... $500 for a nicely turned and balanced platter? Easy! |
#16
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On 1/5/2011 6:54 PM, Trevor Wilson wrote:
wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. Are you SERIOUS? The platter has sagged? Please! If the platter was made of butter, yeah, I could believe is. But even the crappiest imaginable diecast part if not going to sag except under some pretty extreme loads, like a stack of a couple of thousand LPs all at once, maybe. And cheap diecast Al isn't going to sag, it's going to crack. Aluminum is simply not going to cold- flow at those loadings. And the loading required to cause more than micron-type deflections is many orders of magnitude beyond what you would encounter. A more likely explanation is something like the platter bearing mount has slipped, the suspension has sagged or similar. But the claim that even the crappiest of diecast platters has sagged, essentially under it's own weight is, well, extraordinary. |
#17
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Dick Pierce wrote:
On 1/5/2011 6:54 PM, Trevor Wilson wrote: wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. Are you SERIOUS? The platter has sagged? Please! **I've seen the problem several times with cheap Pro-Ject turntables. When I saw the first one, I reacted the same way you just did - I refused to believe it. Explaining to a client was even more difficult. When I saw the second one, I was slightly less surprised. By the time the third one rolled along, I realised that there was a major problem. I also noted that more expensive Pro-Ject turntables did not exhibit the problem. If the platter was made of butter, yeah, I could believe is. But even the crappiest imaginable diecast part if not going to sag except under some pretty extreme loads, like a stack of a couple of thousand LPs all at once, maybe. And cheap diecast Al isn't going to sag, it's going to crack. Aluminum is simply not going to cold- flow at those loadings. And the loading required to cause more than micron-type deflections is many orders of magnitude beyond what you would encounter. **Regardless of what you, me and everyone else thinks, I've seen the effect several times. I don't know enough about metallurgy to understand what is occuring, but occuring it is. Or was. I've not seen the problem for several years. And to reiterate: The platter is some kind of cast alloy. It is not (pure) aluminium. I have never seen the problem with any other brand. A more likely explanation is something like the platter bearing mount has slipped, the suspension has sagged or similar. **More likely? Certainly. The reality is something else. Examining the platter form the side will reveal that the outside edge has sagged relative to the centre. Weird? Certainly. But the claim that even the crappiest of diecast platters has sagged, essentially under it's own weight is, well, extraordinary. **I agree. It is, however, the fact. -- Trevor Wilson www.rageaudio.com.au |
#18
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Dick Pierce wrote:
On 1/5/2011 6:54 PM, Trevor Wilson wrote: wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. Are you SERIOUS? The platter has sagged? Please! **I just spoke with a mate who is very experienced in all kinds of metal-working technology. He said that such a problem, whilst unusual in good quality castings, is certainly not unheard of. Apparently, die casting causes all kinds of stresses in the material, which if not controlled, can lead to cracking and/or the deformation I described. -- Trevor Wilson www.rageaudio.com.au |
#19
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"Trevor Wilson" wrote in message
Dick Pierce wrote: On 1/5/2011 6:54 PM, Trevor Wilson wrote: wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. Are you SERIOUS? The platter has sagged? Please! **I just spoke with a mate who is very experienced in all kinds of metal-working technology. He said that such a problem, whilst unusual in good quality castings, is certainly not unheard of. Apparently, die casting causes all kinds of stresses in the material, which if not controlled, can lead to cracking and/or the deformation I described. In order for that sort of thing to happen, the casting has to be very thin. Usually turntable platters have far more thickness than is needed for mechanical strength, in order for there to be enough weight. I remember the 3.3 pound "lightweight" die cast platter for my AR turntable. It was pretty uniformly 1/4 - 3/8 inch thick. It would never sag under its own weight. |
#20
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On 1/11/2011 9:56 AM, Trevor Wilson wrote:
Dick Pierce wrote: Are you SERIOUS? The platter has sagged? Please! **I just spoke with a mate who is very experienced in all kinds of metal-working technology. He said that such a problem, whilst unusual in good quality castings, is certainly not unheard of. Apparently, die casting causes all kinds of stresses in the material, which if not controlled, can lead to cracking and/or the deformation I described. Merely another claim, and no less an extraordinary one at that. |
#21
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On Tue, 11 Jan 2011 10:42:24 -0800, Arny Krueger wrote
(in article ): "Trevor Wilson" wrote in message Dick Pierce wrote: On 1/5/2011 6:54 PM, Trevor Wilson wrote: wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove the mat and look at the platter from the side. You will probably note that the outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. Are you SERIOUS? The platter has sagged? Please! **I just spoke with a mate who is very experienced in all kinds of metal-working technology. He said that such a problem, whilst unusual in good quality castings, is certainly not unheard of. Apparently, die casting causes all kinds of stresses in the material, which if not controlled, can lead to cracking and/or the deformation I described. In order for that sort of thing to happen, the casting has to be very thin. Usually turntable platters have far more thickness than is needed for mechanical strength, in order for there to be enough weight. I remember the 3.3 pound "lightweight" die cast platter for my AR turntable. It was pretty uniformly 1/4 - 3/8 inch thick. It would never sag under its own weight. The AR tables were great products and were (mostly) very well made. In fact, I've a buddy who modified the sub-chassis on his late-sixties vintage AR 'table so that it could take another arm (the original AR arm was the 'table's Achilles heel - it was lousy) and his modified AR was every bit as good a Linn Sondeck LP-12. In fact, except in a few details, they were almost identical in the way they were designed. He installed an AudioQuest PT-6 arm (made by Jelco in Japan) on it, and as far as I know, he's still using it. When Teledyne bought AR, they changed the table somewhat. Instead of a having a straight-sided 12-inch platter, the Teledyne unit had a flared platter that was larger in diameter at the bottom of the rim than it was at the top. They also canned that awful Edgar Villchur arm in favor of a jeweled gimbal-mount arm from a Japanese source. The tables were so well made, that there are literally thousands of them still in use. The original units used two tiny "clock motors" and they are impossible to get belts for anymore (so I've been told) but the later, single-motor units (XA, XB etc.) still have belts available from places like "Needle Doctor" for about $20. I doubt if any AR platter has ever "sagged". |
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Posted to rec.audio.high-end
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On Jan 11, 12:03=A0pm, Dick Pierce wrote:
On 1/11/2011 9:56 AM, Trevor Wilson wrote: Dick Pierce wrote: Are you SERIOUS? The platter has sagged? Please! **I just spoke with a mate who is very experienced in all kinds of metal-working technology. He said that such a problem, whilst unusual i= n good quality castings, is certainly not unheard of. Apparently, die cas= ting causes all kinds of stresses in the material, which if not controlled, = can lead to cracking and/or the deformation I described. Merely another claim, and no less an extraordinary one at that. Dick, there are claims and there are claims. Your claims are just claims too. The thing is, Trevor's claims are based on observation. And you can't start beating the bias effects or psychoacoustics drum here. It's simple geometry. It would be pretty hard to mistakenly diagnose a sagging platter three times if one is even remotely careful in their observations. You have offered nothing to disprove Trevor's observations other than icredulity. You will have to do better than that if you want your claims to be accepted over Trevor's. Here is a link to another person making the same claim. http://www.diyaudio.com/forums/analo...one-turntable= -platter-problem.html |
#23
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Posted to rec.audio.high-end
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"Dick Pierce" wrote in message
On 1/11/2011 9:56 AM, Trevor Wilson wrote: Dick Pierce wrote: Are you SERIOUS? The platter has sagged? Please! Pretty weird. **I just spoke with a mate who is very experienced in all kinds of metal-working technology. He said that such a problem, whilst unusual in good quality castings, is certainly not unheard of. Apparently, die casting causes all kinds of stresses in the material, which if not controlled, can lead to cracking and/or the deformation I described. Merely another claim, and no less an extraordinary one at that. Detroit, being an automobile-making town, has a lot of die casting activity going on. I've heard from plant engineers of unfortunate things happening, particularly related to casting the cases of automatic transmissions, which are large and relatively thin. Massive cracking under stress and leaks due to porosity while unusual, do happen. However, having a casting slump under its own weight is AFAIK totally unheard of. Pro-ject truntables are said to be made in the once-communist Czech Republic in a factory that was actively making turntables during the decades of ruinous Soviet control. Iron curtain countries have a sad but lengthy history of cut corners and poor quality products. They may have figured out ways to cut corners that are even unheard of in Detroit! ;-) |
#24
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Posted to rec.audio.high-end
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On Jan 5, 3:54=A0pm, "Trevor Wilson" wrote:
"Roy" wrote in message ... I have an approximately 10 year old Pro-Ject 1.2 turntable. Over the last year, the big heavy platter has begun scraping as it spins, and has finally ground to a halt. If I elevate the platter, by putting a shim (two old CDs) between it and the sub-platter, that elevates it enough that it spins again, but with lots of wobble. Obviously not an ideal fix. I don't know what's happening, but I'm guessing the sub-platter (which is what actually spins, driven by the motor/belts) has descended/sunk a bit. Has anyone experienced anything similar with this turntable? Is there any way to fix this problem? Thanks in advance! **Common problem with some of the Pro-Ject TTs. The platter sags! Remove = the mat and look at the platter from the side. You will probably note that th= e outer rim has saged, relative to the spindle. Cheap, crappy die casting I guess. The only effective solution is to replace the platter. Your local distributor may still have stocks. Otherwise, you're screwed. It is not acceptable to use the platter in that condition. -- Trevor Wilsonwww.rageaudio.com.au You are guesing that it is a die cast platter? Pro Ject does use MDF for it's platters on a few of their cheapest models. Could the Pro Ject 1.2 be using MDF? http://www.project-audio.com/main.ph...ables&lang=3D= en "=95 The resonance-optimised platter is made of medium density fibre." http://www.project-audio.com/main.ph...urntables&lan= g=3Den "=95 MDF platter with felt mat " |
#25
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Posted to rec.audio.high-end
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"Scott" wrote in message
You are guesing that it is a die cast platter? Pro Ject does use MDF for it's platters on a few of their cheapest models. Could the Pro Ject 1.2 be using MDF? http://www.project-audio.com/main.ph...ables&lang=3D= en "=95 The resonance-optimised platter is made of medium density fibre." http://www.project-audio.com/main.ph...urntables&lan= g=3Den "=95 MDF platter with felt mat " MDF is well known to slump in high humidity. It is heavy enough that it could be an effective turntable platter if used in the right quantities. |
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