Vinyl Audio

Equipment => Turntables => Topic started by: BSD2000 on February 27, 2012, 06:15:28 PM

Title: How far off is my Rega P25 platter speed?
Post by: BSD2000 on February 27, 2012, 06:15:28 PM
Click here to read the original article. (http://www.vinylaudio.net/archives/206/how-far-off-is-my-rega-p25-platter-speed)

So what do you guys think? Post your comments below.
Title: Re: How far off is my Rega P25 platter speed?
Post by: migkiller1971 on February 28, 2012, 09:15:33 AM
What kind of belt do you use? Can you compare speed with the white belt, Standard rega belt and a belt from turntablebasics.com? Different belt diameters will probably have an effect on speed. I've also read that we can get a Music Hall Control speed box to get the speed perfect.
Title: Re: How far off is my Rega P25 platter speed?
Post by: BSD2000 on February 28, 2012, 03:58:03 PM
What kind of belt do you use? Can you compare speed with the white belt, Standard rega belt and a belt from turntablebasics.com? Different belt diameters will probably have an effect on speed. I've also read that we can get a Music Hall Control speed box to get the speed perfect.

I use a single Rega white belt with the factory plastic motor pulley. I plan on trying the steel pulley from Turntablebasics.com to see if it makes a difference. I still have quite a few 45RPM records, so I think I'll stick with the single belt, 33/45 pulley for now. Although, since you use the dual belt pulley, your speed may be closer to 33 1/3 than mine since the added mass and torque required to spin two belts may bring your speed down just enough to correct the platter speed.

I'll try the original black belt today and see how it effects the speed.
Title: Re: How far off is my Rega P25 platter speed?
Post by: BSD2000 on February 28, 2012, 10:07:42 PM
[attach=1]
I just ordered a standard 33.3/45 rpm stainless steel pulley from LPTurntables, so it should be interesting how accurate the speed will be once it's installed.  ;D
Title: Re: How far off is my Rega P25 platter speed?
Post by: lshin80 on February 29, 2012, 12:50:21 PM
If I were you, I would be frustrated by this speed inaccuracy...I mean, if I'm going to buy a good turntable, I expect it to be 100% accurate and precise. What really puzzles me, is that this speed issue seems to be intentional. Other manufacturers don't seem to have any problem in making TTs with correct speed...
However, let me ask you a question: are you sure you want to correct the issue? That is, do you really notice the issue when playing records? Did you felt a remarkable difference when playing records with the VPI? Or is just for the sake of perfection? (Don't want to criticize, just curious.)
Title: Re: How far off is my Rega P25 platter speed?
Post by: migkiller1971 on February 29, 2012, 02:30:58 PM
However, let me ask you a question: are you sure you want to correct the issue? That is, do you really notice the issue when playing records? Did you felt a remarkable difference when playing records with the VPI? Or is just for the sake of perfection? (Don't want to criticize, just curious.)

The original recording session of  Kind of Blue By Miles Davis was recorded at 1.5% faster because of faulty recording machines and it had Stumped Musicians for years as they couldn't figure it out what Miles Did. I think Classic Records were the first to correct the problem by cutting the Lp at the correct speed. and Reviews have the correct speed as more expressive along with better pitch, instrumentation and everything else falls into place.
Title: Re: How far off is my Rega P25 platter speed?
Post by: BSD2000 on February 29, 2012, 11:55:09 PM
If I were you, I would be frustrated by this speed inaccuracy...I mean, if I'm going to buy a good turntable, I expect it to be 100% accurate and precise. What really puzzles me, is that this speed issue seems to be intentional. Other manufacturers don't seem to have any problem in making TTs with correct speed...
However, let me ask you a question: are you sure you want to correct the issue? That is, do you really notice the issue when playing records? Did you felt a remarkable difference when playing records with the VPI? Or is just for the sake of perfection? (Don't want to criticize, just curious.)


Well, it really wasn't until after experiencing the speed accuracy and stability of the VPI Scoutmaster that I began to notice the speed problem with my Rega P25. Overall, I still preferred my P25 over the Scoutmaster because the Rega felt more focused, more 3D and more 'alive' than the Scoutmaster. Some of my negative impressions of the Scoutmaster could have been the mismatch of my Zyx R100H on the JMW unipivot tonearm. I never got to try my Zyx Omega G (which weighs twice as much as the R100H) on the Scoutmaster. I still feel the strongest selling point of a Rega turntable is the fantastic, rock-solid precision of their tonearms. Even with the speed being off a bit, the Rega was more fun to listen to.

One aspect that I thought about while testing the speed was the different approaches manufacturers take with belt drive turntables, either a smaller belt on a sub platter located under the main platter (like a Rega), or a motor on the side of the turntable with a large belt around the circumference of the platter, like the VPI Scoutmaster. The platter on the VPI Scoutmaster was in the neighborhood of 12 pounds, with a massive, over sized, industrial strength main bearing; compared the lighter weight platter of my Rega. The motor on the VPI is also massive, and spins at a faster RPM. The larger, heavier platter (creating a flywheel effect) along with a faster, high torque motor is sure to produce a better regulated, stable and more accurate platter speed.

It really begs the question as to which design philosophy is better, what the pros and cons are for each design.

I actually considered keeping the Scoutmaster and replacing the tonearm with a Rega RB1000, just so I could have the best of both worlds.  :D

I did test my Technics (belt drive) and Denon (direct drive) turntables, the Technics was spot on with a little bit of wandering. The Denon was a bit slower (maybe 3-5 cents) but very stable. I'm still trying to find out where the speed adjustment is on the Denon.
Title: Re: How far off is my Rega P25 platter speed?
Post by: BSD2000 on March 16, 2012, 10:52:20 PM
UPDATE:

I received the stainless steel pulley for my P25, but I have a new problem. First, after taking the cover off the motor, I find the motor is a 50hz, 110v motor. Second, the Isokinetic Isosub GT sub platter is slightly lower than the stock sub platter and the new pulley is slight taller than the stock plastic pulley. The result? The belt is too close to the top edge of the Isosub GT sub platter. So, my options are to lower the motor or cut the new pulley so it's shorter. If it's not one thing, it's another.
Title: Re: How far off is my Rega P25 platter speed?
Post by: lshin80 on March 17, 2012, 07:46:27 AM
I'd cut the pulley and keep anything else intact.
Title: Re: How far off is my Rega P25 platter speed?
Post by: BSD2000 on March 17, 2012, 03:52:06 PM
Hmm... the plot thickens...

The plastic motor covers says 60hz, 115v; but the motor itself says 50hz, 110v - do they use the same motor for both models and just modify the PC board components for each model?
Title: Re: How far off is my Rega P25 platter speed?
Post by: BSD2000 on March 18, 2012, 02:42:49 AM
Ok, I cut down the pulley and installed it on the motor. I reassembled everything and tested it out - it's WORSE! It runs a LOT slower with the new pulley and about 40 cents slower with the old pulley.

I think the motor was damaged while removing the old pulley, even though the old pulley wasn't hard to remove, so I guess it doesn't take much to damage the motor. There is a LOT of up and down play in the motor now that wasn't there before removing the old pulley. The motor doesn't spin as freely either. Now what?

I guess it doesn't pay to mess with the motor on an older Rega turntable. I guess I'm stuck buying the Rega 24v motor upgrade and throwing this motor in the garbage.   >:(

The moral of the story: If you own an older Rega turntable, NEVER mess with the motor unless you are replacing it. You are taking a HUGE risk of destroying your finely tuned motor and making things much worse. If you did successfully swap out your pulley, you must have been very lucky. At this point, I don't trust anybody's opinion on the speed of their Rega's. Simple strobe testing doesn't seem to be enough evidence to prove speed accuracy, IMHO. Unless you play a 440hz musicians A test track and measure the results, you can't say for certain how accurate it really is.

Of course, since I don't know ANYONE who is using the 24V motor upgrade and I haven't found a single, accurate, reliable and trustworthy review of kit, I'm on my own.

I did test the speed of the turntable and it looks like it's running 3.3% slower with the new pulley. For now, I'm going to let the motor run with the belt off and I'll check back in a few hours to see if the speed improved.

Time to in invest $225 for the 24V motor upgrade and hope for the best.   :(
Title: Re: How far off is my Rega P25 platter speed?
Post by: lshin80 on March 18, 2012, 07:49:08 AM
I'm sorry... :( :'(
Title: Re: How far off is my Rega P25 platter speed?
Post by: migkiller1971 on March 18, 2012, 12:22:39 PM
Ok, I cut down the pulley and installed it on the motor. I reassembled everything and tested it out - it's WORSE! It runs a LOT slower with the new pulley and about 40 cents slower with the old pulley.

I think the motor was damaged while removing the old pulley, even though the old pulley wasn't hard to remove, so I guess it doesn't take much to damage the motor. There is a LOT of up and down play in the motor now that wasn't there before removing the old pulley. The motor doesn't spin as freely either. Now what?

I guess it doesn't pay to mess with the motor on an older Rega turntable. I guess I'm stuck buying the Rega 24v motor upgrade and throwing this motor in the garbage.   >:(

The moral of the story: If you own an older Rega turntable, NEVER mess with the motor unless you are replacing it. You are taking a HUGE risk of destroying your finely tuned motor and making things much worse. If you did successfully swap out your pulley, you must have been very lucky. At this point, I don't trust anybody's opinion on the speed of their Rega's. Simple strobe testing doesn't seem to be enough evidence to prove speed accuracy, IMHO. Unless you play a 440hz musicians A test track and measure the results, you can't say for certain how accurate it really is.

Of course, since I don't know ANYONE who is using the 24V motor upgrade and I haven't found a single, accurate, reliable and trustworthy review of kit, I'm on my own.

I did test the speed of the turntable and it looks like it's running 3.3% slower with the new pulley. For now, I'm going to let the motor run with the belt off and I'll check back in a few hours to see if the speed improved.

Time to in invest $225 for the 24V motor upgrade and hope for the best.   :(


Damn it, i got here too late.... I also cut my Pulley up to the allen key hole. What I did was to place the Flat end of a screwDriver on the motor spindle forming a "T shape" and used my fingers to pull upward on the pulley very carefully keeping as much pressure off of the motor. it Came off without any trouble. My motor is ridiculously "Quiet" and would never mess with it. "My Best Guess" would be now that your motor has an Up and down motion, Does your belt follow suit? Can you see the belt go in an up and down motion? This could be the reason for it to go slower. Another thing that I noticed, was that our motor doesn't have a motor thrust bearing like the newer Rega TT. thrust bearing are supposed to steady the motor spindle, get rid of all the play and lower the floor noise.  If it were me, I would buy an after market Rega Motor thrust bearing before investing $225 on a new motor. If the Motor is shot than You can easily sell the Rega Motor thrust bearing as it works on many Rega turntables. i know at least one guy with a Rega P5 that changed the Thrust bearing after his P5 started making a TSK,TSK,TSK sound. Hope this helps

http://srm-tech.co.uk/shop/article_MTB2/Turntable-Motor-Thrust-Bearing.html?pse=apq (http://srm-tech.co.uk/shop/article_MTB2/Turntable-Motor-Thrust-Bearing.html?pse=apq)
Title: Re: How far off is my Rega P25 platter speed?
Post by: BSD2000 on March 18, 2012, 07:22:37 PM
Damn it, i got here too late.... I also cut my Pulley up to the allen key hole. What I did was to place the Flat end of a screw Driver on the motor spindle forming a "T shape" and used my fingers to pull upward on the pulley very carefully keeping as much pressure off of the motor. it Came off without any trouble. My motor is ridiculously "Quiet" and would never mess with it. "My Best Guess" would be now that your motor has an Up and down motion, Does your belt follow suit? Can you see the belt go in an up and down motion? This could be the reason for it to go slower. Another thing that I noticed, was that our motor doesn't have a motor thrust bearing like the newer Rega TT. thrust bearing are supposed to steady the motor spindle, get rid of all the play and lower the floor noise.  If it were me, I would buy an after market Rega Motor thrust bearing before investing $225 on a new motor. If the Motor is shot than You can easily sell the Rega Motor thrust bearing as it works on many Rega turntables. i know at least one guy with a Rega P5 that changed the Thrust bearing after his P5 started making a TSK,TSK,TSK sound. Hope this helps

http://srm-tech.co.uk/shop/article_MTB2/Turntable-Motor-Thrust-Bearing.html?pse=apq (http://srm-tech.co.uk/shop/article_MTB2/Turntable-Motor-Thrust-Bearing.html?pse=apq)

My Rega P25 motor does have a thrust bearing, but I had it removed in the pictures I posted. The speed was running slow with the thrust bearing installed and there was a slight dragging sound. Today, I removed the thrust bearing and retested the speed. I attached a video with the results. Without the thrust bearing, the dragging noise is gone and the speed is closer to what it should be. I don't notice any up and down wandering when it's running with the thrust bearing removed.

The end result is that I'm basically back where I started, minus the thrust bearing - about 20 cents over the correct speed.

The next question is, what type of grease should I use with the bearing? It was kind of dry with a small, flat, worn spot on it. Without the bearing on the motor, it runs noise free. The spring in the thrust bearing cup puts a lot of upward pressure on the shaft, so the bushings inside the motor become more important; yet there's nothing you can do to grease them.


Firefox or Opera
Title: Re: How far off is my Rega P25 platter speed?
Post by: migkiller1971 on March 18, 2012, 08:54:02 PM
Damn it, i got here too late.... I also cut my Pulley up to the allen key hole. What I did was to place the Flat end of a screw Driver on the motor spindle forming a "T shape" and used my fingers to pull upward on the pulley very carefully keeping as much pressure off of the motor. it Came off without any trouble. My motor is ridiculously "Quiet" and would never mess with it. "My Best Guess" would be now that your motor has an Up and down motion, Does your belt follow suit? Can you see the belt go in an up and down motion? This could be the reason for it to go slower. Another thing that I noticed, was that our motor doesn't have a motor thrust bearing like the newer Rega TT. thrust bearing are supposed to steady the motor spindle, get rid of all the play and lower the floor noise.  If it were me, I would buy an after market Rega Motor thrust bearing before investing $225 on a new motor. If the Motor is shot than You can easily sell the Rega Motor thrust bearing as it works on many Rega turntables. i know at least one guy with a Rega P5 that changed the Thrust bearing after his P5 started making a TSK,TSK,TSK sound. Hope this helps

http://srm-tech.co.uk/shop/article_MTB2/Turntable-Motor-Thrust-Bearing.html?pse=apq (http://srm-tech.co.uk/shop/article_MTB2/Turntable-Motor-Thrust-Bearing.html?pse=apq)

My Rega P25 motor does have a thrust bearing, but I had it removed in the pictures I posted. The speed was running slow with the thrust bearing installed and there was a slight dragging sound. Today, I removed the thrust bearing and retested the speed. I attached a video with the results. Without the thrust bearing, the dragging noise is gone and the speed is closer to what it should be. I don't notice any up and down wandering when it's running with the thrust bearing removed.

The end result is that I'm basically back where I started, minus the thrust bearing - about 20 cents over the correct speed.

The next question is, what type of grease should I use with the bearing? It was kind of dry with a small, flat, worn spot on it. Without the bearing on the motor, it runs noise free. The spring in the thrust bearing cup puts a lot of upward pressure on the shaft, so the bushings inside the motor become more important; yet there's nothing you can do to grease them.


http://www.vinylaudio.net/forum/video/Speed.wmv (http://www.vinylaudio.net/forum/video/Speed.wmv)

So we do have a thrust bearing!! That Picture is crazy! I'm no expert but That makes no sense, So the Bearing sits on top of the Spring? after time and so many revolutions, you would think that the spring would wear out at the end where it meets the bearing. If you look at the thrust bearing from SRM, There is no spring but an allen key nut that looks like it has a Cup Design for the bearing to sit in and move freely. anything is better than $225 buck for a new motor. And I have not heard any positives reviews on that. Sooner or later mine will eventual act up and I'll know exactly what to look for.

(http://i1223.photobucket.com/albums/dd513/Migkiller1971/IMG_5650.jpg)
Title: Re: How far off is my Rega P25 platter speed?
Post by: migkiller1971 on March 19, 2012, 12:25:54 AM
Damn it, i got here too late.... I also cut my Pulley up to the allen key hole. What I did was to place the Flat end of a screw Driver on the motor spindle forming a "T shape" and used my fingers to pull upward on the pulley very carefully keeping as much pressure off of the motor. it Came off without any trouble. My motor is ridiculously "Quiet" and would never mess with it. "My Best Guess" would be now that your motor has an Up and down motion, Does your belt follow suit? Can you see the belt go in an up and down motion? This could be the reason for it to go slower. Another thing that I noticed, was that our motor doesn't have a motor thrust bearing like the newer Rega TT. thrust bearing are supposed to steady the motor spindle, get rid of all the play and lower the floor noise.  If it were me, I would buy an after market Rega Motor thrust bearing before investing $225 on a new motor. If the Motor is shot than You can easily sell the Rega Motor thrust bearing as it works on many Rega turntables. i know at least one guy with a Rega P5 that changed the Thrust bearing after his P5 started making a TSK,TSK,TSK sound. Hope this helps

http://srm-tech.co.uk/shop/article_MTB2/Turntable-Motor-Thrust-Bearing.html?pse=apq (http://srm-tech.co.uk/shop/article_MTB2/Turntable-Motor-Thrust-Bearing.html?pse=apq)




The next question is, what type of grease should I use with the bearing? It was kind of dry with a small, flat, worn spot on it. Without the bearing on the motor, it runs noise free. The spring in the thrust bearing cup puts a lot of upward pressure on the shaft, so the bushings inside the motor become more important; yet there's nothing you can do to grease them.


http://www.vinylaudio.net/forum/video/Speed.wmv (http://www.vinylaudio.net/forum/video/Speed.wmv)


molybdenum grease
Title: Re: How far off is my Rega P25 platter speed?
Post by: BSD2000 on March 19, 2012, 12:28:29 AM
So we do have a thrust bearing!! That Picture is crazy! I'm no expert but That makes no sense, So the Bearing sits on top of the Spring? after time and so many revolutions, you would think that the spring would wear out at the end where it meets the bearing. If you look at the thrust bearing from SRM, There is no spring but an allen key nut that looks like it has a Cup Design for the bearing to sit in and move freely. anything is better than $225 buck for a new motor. And I have not heard any positives reviews on that. Sooner or later mine will eventual act up and I'll know exactly what to look for.

(http://i1223.photobucket.com/albums/dd513/Migkiller1971/IMG_5650.jpg)

it looks like the ball bearing doesn't move - the spring locks it into a stationary position and the motor shaft just spins in contact with the bearing surface. There was a small amount of red grease on the ball when I pulled it out so I'm guessing some type of axle grease is being used.

Did you see the LP Turntables replacement thrust bearing? (http://lpturntables.blogspot.com/2011/06/motor-thrust-bearing-upgrades-for-rega.html) It looks promising for under $13. To bad it takes weeks to receive anything in the mail from them.  :-X  :)

I think the stock bearing spring is to stiff and puts to much upward pressure on the motors internal bushings. What would be ideal is just enough pressure to 'float' the shaft motor and stabilize it. Too much pressure can effect the drag on the motor, slowing it down.

Does anyone know what the two round adjustment pots are for on the motor PC board?

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