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RP6 help?
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BackinBlack View Drop Down
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Points: 2020 		Post Options Post Options   Thanks (0) Thanks(0)   Quote BackinBlack Quote  Post ReplyReply Direct Link To This Post Posted: 20 Aug 2017 at 10:11pm
i would still suspect the pulley as being incorrect diameter. If the bearing was tight and over loading the motor, the speed would be unstable. Remember that these are not high torque drives. The motor is synchronous and designed to run at 250 rpm at 50Hz supply frequency, if the load is such that it "slips" torque varies and speed reduces and there is a degree of instability until synchronous speed is regained.
As a matter of interest, the TT-PSU has 2 fixed frequency quartz crystal driven oscillators, followed by divider and sine shaping circuitry to give the 50 and 67.5 Hz frequencies, so no tweaking is possible to adjust the frequencies. The anti vibration circuits, just adjust the amplitude (and phase lag) of the 2nd phase necessary for the 2 phase motor.
Assuming that it's still in warranty I'd be inclined to make it the retailers problem, after all it is running over 2% slow, not a smalll margin of error.
Just listen, if it sounds good to you, enjoy it.
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Points: 16298 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 21 Aug 2017 at 5:02am
I agree with Ian (BackinBlack) on this, and if it's a new turntable it should go back.

It would not be the first time a Rega pulley has been wrong. I should have taken mine back many years ago but at the time I felt intimidated by the dealer and all the brouhaha about this "perfect" audiophile turntable... Unhappy
That none should be able to buy or sell without a smartphone and the knowledge in how to use apps
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Points: 8998 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 21 Aug 2017 at 6:33am
We're going in circles here although I agree with your thinking guys...
Originally posted by Fatmangolf Fatmangolf wrote:

It is a new piece of hi-fi equipment and should be right. I suggest you ask for a replacement and well done on checking it Steve.


...only the TT PSU is "brand new", I understand the RP6 is second hand...

Originally posted by frimleygreener frimleygreener wrote:

... Or maybe the previous owner applied a non recommended lubricant? Is it a problem to check and resolve this?


Checking the bearing oil will not stop the unit being sent back to a dealer or Rega (if this is possible for the 2nd owner) but it could fix the potential problem. You will see above that I listed an oversized pulley as one of three most likely causes although a thick belt would have the same effect, which is why I asked about the speed with the two different belts.
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Points: 9 		Post Options Post Options   Thanks (0) Thanks(0)   Quote frimleygreener Quote  Post ReplyReply Direct Link To This Post Posted: 21 Aug 2017 at 8:18am
I will check out the percentage variation with both belts via 33 and 45....both belts are brand spanking new(well less than 10 hours playing time on each).As an aside,when I first coupled the table to the TT-PSU the platter would not turn at all: it needed a "push start",but that does not seem an out of the ordinary procedure after trawling many a forum dedicated to Rega turntables. After cleaning all the "contact points(pulley/sub platter) with 100% pure Isopropyl alcohol(not easy to acquire these days) the table now starts without a prompt.
  I have also read frankly scary advice about applying super glue to the pulley as in some cases they work lose...something I am not willing to try due to lack of engineering skills and the potential "damage" it may cause if the "advice" is not to be trusted.
Thank you all for the fantastic response and advice....I will try cleaning out the bearing well and shaft and applying the Rega approved lubricant today....and report back!Once again,thank you very much!
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Points: 2020 		Post Options Post Options   Thanks (0) Thanks(0)   Quote BackinBlack Quote  Post ReplyReply Direct Link To This Post Posted: 21 Aug 2017 at 9:17am
I missed/misunderstood that the TT is 2nd hand, but the TT-PSU is new. People have followed "advice" from well meaning "experts" on the Infernet with some strange oils/lubricants and even if the correct original oil has been used it can dry out if not serviced.
A good clean and application of the correct oil ( sorry Jon, I wouldn't recommend using 3in1 in anything that you're not going to clean afterwards) should get it all spinning freely.
The exact speed discrepancy will be an interesting excercise.
As an aside, I use a twin belt arrangement with a pulley from Deco Audio, a much better drive arrangement when you don't need the 33/45 pulley option.
Just listen, if it sounds good to you, enjoy it.
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Points: 9 		Post Options Post Options   Thanks (0) Thanks(0)   Quote frimleygreener Quote  Post ReplyReply Direct Link To This Post Posted: 21 Aug 2017 at 10:46am
Thanks all:) for the terrific and well founded advice! After a complete clean and oil change the RP6 now running at a constant 33.72 rpm....something I am reliably informed is part and parcel of the RP6 "sound",and is built in by Rega....now to spin some records(fancy some Weather Report,a good test of any set up)....all I have to do now is wait eagerly for my Graham Slee PSU1!
Many thanks again....sage and sound advice from all..very much appreciated:)
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Points: 8998 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 21 Aug 2017 at 6:59pm
Happy ending, well done Steve! I am pleased it was the easiest one to fix, the dry bearing well. I agree completely Ian, the 3-in-1 was just for the speed test and would have been thoroughly cleaned out afterwards I assure you. I'd missed Steve's mention of the Rega bearing oil.

The pulley superglue is not as scary as it sounds. I use a RP8 dual pulley on my Gorbe's dc motor with a tiny bit of superglue I applied with a cocktail stick. Always have the spindle horizontal so you don't ruin the motor!
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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