As the title says…P9 runs at 33 RPM with two EBLTs. The P9 power supply isn’t user adjustable AFAIK…
Has anyone adjusted motor distance to compensate for slower speed with the EBLT? Any other suggestions?
Thanks!
Jake
I am not sure how moving motor distance would change the speed? My understanding is that the rotational speed of the platter will be down to the ratio of the pully sizes, not the distance between them.
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Speak to Rega, perhaps? I’m sure they’d have a solution
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In my experience, changing the belt tension will likely have an effect on speed accuracy.
I would second the suggestion to speak to your Rega dealer, or Rega themselves.
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Really? I will have to speak to my engineer friends as to why this is. My rudimentary understanding is that pully sizes were responsible to speed not belt tension. You learn something new every day.
Your profile shows a Rega P6 and a Well Tempered, but not a P9. Maybe it’s a replacement for one of them. I really wouldn’t go moving the motor, as it will change tension and only potentially change the speed if it alters how the belt runs in the groove on the pulley.
The P9 has, I believe, speed adjustment inside the box, but this is really something that Rega or someone trained needs to do, as there are other adjustable settings that control motor vibration that must not be touched. I’ve read posts by Rega elsewhere that the EBLT absolutely does not change the speed, and it would be odd if it did. You are best speaking to your dealer.
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For the Neo PSU and the P10, the Rega manual states that new belts can run at slightly different speed. Odd that an adjustment is so complicated with the P9.
I checked my P10 when new and it wasn’t 100% accurate speed (though it was stable at that speed). The deviation was so small that I don’t think it was audible, but I adjusted it anyway. If I had had 33 instead of 33.33 it would have made me uneasy 
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Belt tension can have an effect on accuracy, as in fluctuations in the speed. But to the best of my understanding, it should not have an effect on the (average) speed itself.
Quite right Richard. It is indeed the way the Xerxes manual tells you how to adjust the speed.
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Thanks, that makes sense to me and where I was coming from with my initial comment.
Not quite so if I’m not mistaken. It suggests to change how high it rides on the pulley to adjust the speed. Stretching it is suggested as a means to achieve the correct height. Please correct me if I’m wrong.
Likely the pulley or subplatter is ever so slightly tapered.
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In mine too. Thanks for the advice!
Yes, considering a change from the P6 to the P9. Will do—thank you.
Yeah, 33 vs 33.3 is definitely audible, and it’s visually apparent the rotation is slower than 33.3. The table sounds awesome, but it lags.
As you are just trying it, I wonder if you’d be better getting a new Planar 8. The P9 is two generations ago and Rega turntables have come a long way. I tried a P9 years ago and it didn’t do much for me, whereas the current 8 and 10 are rather wonderful.
I’ve had the P8 at home for an extended demo and it is a great table. I feel like the P9 has most of the P8’s good qualities as well as a bigger, meatier presentation. And is quite a bit less money.
I opened up the power supply and was able to get it pretty darn close to 33.3 as fast as it will go. Older belts it was on time as originally set, the EBLT plays slower as I discovered with my P6 and the EBLT.
Re the Xerxes my understanding is the height the belt rides on the inner platter, 2mm above the bottom, determines the correct speed so stretching the belt to get the correct position on the inner platter is the way to obtain the correct speed. Which is kind of what I wrote.
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Yes, but is this a function of the tension or a function of the pulley being slightly tapered and changing the gear transmission ratio? The Xerxes manual does not say, but I would guess it’s the latter:
Whether the belt rides 1 mm lower or 1 mm higher on the pulley, it seems to me that the geometric difference in belt length, and therefore change of tension, should be the same if the pulley has a constant diameter. If the cause of the speed change is tension, and if the pulley diameter is constant, I would expect the same amount and direction of speed change whether the belt is high or low.
However, higher on the pulley increases speed, lower on the pulley decreases it. Which could mean, if the pulley is tapered, either a difference in tension or a difference in gear transmission ratio being the cause. I believe it’s the latter.
@Richard.Dane had commented that belt tension can affect speed and I replied to him. I wrote that the Xerxes manual says stretching the belt adjusts the speed, which it does.
I fit a new belt to my Xerxes and adjusted the speed to 33⅓ by stretching the belt. I never said it was a universal fix or offer a reason behind the mechanics of it because frankly it doesn’t bother me.
You try to help someone on here by commenting on a post and there’s always someone lurking, nitpicking.
I’m so close to leaving this forum again.
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