Rega speed stability vs. LP12 Platterspeed results

[watercourse]

I don't think there is consensus about the TT-PSU. For some, they just can't hear a difference. Luckily, it is easy to switch it in and out for quick comparison.

I just switched out the TT-PSU, reverted back to stock, and noticed a significant difference when playing the same passage. The TT-PSU was superior.

Playing Stokowski's Boris Godunov, I heard improvements in bass quality, soundstage depth, imaging, quieter background, and overall stability of sonic image. You can "see" into the recording a bit better. At a loud peak in the music, violins and trombones massing, the TT-PSU had an overall smoother, less grainy presentation than with stock.

Re: speed correction. I'll do the Feickert test with stock and post the differences after I go have some dim sum with the family. I'm interested in seeing the results. My motor has always run a bit fast, so no change there.

I'd say again that the sonic difference is perceptible in my system.

[watercourse]

mmmm... dim sum!

[mr.datsun]

I did have the white belt but sent it back because it made my table run slower. I hope to get the replacement belt soon. I went back to the stock black belt and my speeds increased.

atomlow thanks for posting the results.

With regards the white belt and slowness. I took readings as soon as I put the belt on. It was indeed a little slow but a lot closer than the 2 year old black belt which was fast. However, after say 6 LP plays and the next morning the white belt was almost spot on correct speed (constant green readings with Platterspeed) with the slight bias to deviate faster than target. This seems to indicate that the belt really needs to run in as I suspect that it stretches and tight belt = slower, looser belt = faster.

[watercourse]

OK, very interesting results. But first, two caveats: My TT is mounted where footfalls do cause vibrations which are audible, and which will affect the frequency spread that Platterspeed sees. So, I had to make sure that no one was walking to ensure a fair representation of TT-PSU/stock, and one/two belts in play. Second, my motor does run fast, even with the stock power supply.

So with the caveats, the results are:
1) The TT-PSU does narrow the speed "error bars" - rotational speed is maintained more consistently with the TT-PSU
2) Using only one belt is closer to target speed, but is prone to greater variability in speed
3) Using two belts causes the platter to be further away from target speed, but speed is most consistent

Now, if anyone can tell me why the heck my motor runs fast, I'll owe you a virtual beer.

Stock power supply, two belts:



TT-PSU with one belt:



TT-PSU with two belts:

[mawari]

Now, if anyone can tell me why the heck my motor runs fast, I'll owe you a virtual beer.

I'm not sure that an AC synchronous motor can run fast ( or slow ) consistently by small amounts. The spindle can only run at a multiple of the input frequency. The fact that the platter spins fast when the motor is driven from the mains or the generated frequency of the TT PSU would seem to confirm it is not the motor speed.

The question might be "can anyone tell me why the heck my pulley is too large or my sub platter too small or my belt not fitting closely enough in the pulley groove"

Very interesting results, as you say.

Paul

[Indydan]

Roy Gandy (Rega's owner) in Stereophile was quoted by Michael Fremer as saying:

"Gandy told me that the TT PSU offers a "small improvement" that can't be quantified. "It's not enormous," he admitted, adding that the better the incoming electricity, the less noticeable will be the sonic improvement."

If your home has good quality/clean electricity, it is possible that you won't notice much of a difference. Of course, incoming electricity can vary depending on the time of day. Maybe you could run a test late at night when power consumption is minimal, and another one during dinner time, when your neighbours will be using more power (microwaves, ovens, etc).

The TTPSU has other advantages. If you buy a gloss colored version of the P3-24, the plinth does not have a power button on it. It does slightly improve the appearance of the table. Of course, the push button selection of 33/45 RPM is also practical.

http://www.stereophile.com/turntables/7 ... index.html

[mawari]

[...] tight belt = slower, looser belt = faster.

Thinking about this, and it would make some sense. A loose belt would not fit so flush into the pulley groove, effectively increasing the pulley diameter, causing an increase in speed. Could be corrected by tensioning the pulley by moving the motor ( on those decks where the motor fitment allows this ) or indeed a new belt.

Fitting two belts reduces the tension on each belt, and would speed the deck up, all other things being equal.

I wonder if for those whose deck appear to run fast even with a new belt, if temporarily changing the belt for a loop of cotton thread would slow it down ? The cotton would be thin enough to sit flush in the pulley groove, minimum circumference. If it was still fast with this setup, I think the speed issue could then be isolated to a slighter small subplatter circumference, or slightly large pulley, and nothing to do with the belt. If however it fixes the speed, the problem may be belt tension, or an imperfect match between the belt profile and the pulley groove.

Paul

[watercourse]

Mawari - you got me thinking... I may owe you a virtual bottle of daiginjo if I figure this out !

[atomlow]

Nevermind, I just made a very dumb post. Now I see you are running very fast... Do you notice this when listening to music?

Are you sure you put the correct pulley on your turntable when you upgraded to dual belts? You should have the 60hz pulley?

[bacobits]

Oh you will know if you are using the wrong pulley.

[Lelolee]

OK, very interesting results. But first, two caveats: My TT is mounted where footfalls do cause vibrations which are audible, and which will affect the frequency spread that Platterspeed sees. So, I had to make sure that no one was walking to ensure a fair representation of TT-PSU/stock, and one/two belts in play. Second, my motor does run fast, even with the stock power supply.

So with the caveats, the results are:
1) The TT-PSU does narrow the speed "error bars" - rotational speed is maintained more consistently with the TT-PSU
2) Using only one belt is closer to target speed, but is prone to greater variability in speed
3) Using two belts causes the platter to be further away from target speed, but speed is most consistent

Now, if anyone can tell me why the heck my motor runs fast, I'll owe you a virtual beer.

Stock power supply, two belts:



TT-PSU with one belt:



TT-PSU with two belts:

Two things are making your turntable fast. One the white belts are thicker then the black one's and make the table run fast. Two, Michael Lim dual pulley are to large. 9.90mm on the digital calipers, stock 9.70mm. I'm back to the stock pulley.

[watercourse]

Ok, my table has always been noticeably (audibly) fast, so the pulley/belt are exacerbating an existing problem. I'll see if I can get the spindle farther away once I'm back home.
Just listened to DeVore Fidelity Gibbon X's at Pitch Perfect - all I can say is rad!!!!!

[radiance]

Hey guys,

can someone measure and tell the exact diameter of both the black and the white belt? IMHO the black belt has a diameter of 1.78 mm, is that correct? If the white belt has a larger diameter, is it 2.00mm then?

What is the belt material like? Is it simple NBR rubber? Interested in the Shore hardness value of the belt.

Thanks for any input here!

Regards

Rad

[Alec124c41]

OK, how do you do the screen capture from the iPhone?

Cheers,
Alec