Official Pro-Ject Fix For Turntable Rumble Now Launched

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moon unit
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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by moon unit » 10 Dec 2011 22:59

b-side wrote:I think any timings should be taken with a grain of salt. Recording a frequency test to the digital domain and measuring is bound to be more accurate. Observing a piece of tape on the platter edge spinning at 33 RPM is a coarse measurement sure to have a margin of error of several tenths of a second. I have taken this one step further and tried adding a piece of tape on the plinth so a "tick" sound is heard as they touch each revolution. Even this way, the margin of error between hearing and clicking the time still gives results varying by more than half a second. This is on my Xpression III with SpeedBox.
Wrong.

My times were consistent and repeatable using a digital stopwatch, I didn't just time it once each way and claim it was fast or slow. I first used a strobe but wanted to test the speed with a record playing, which is the only time it really matters. If you use the cartridge as a reference point you wil get consistent times, you would have to be ridiculously off to vary by half a second.

Is recording a frequency test to the digital domain and measuring bound to be more accurate? Probably, but regardless, I found it ran slow as well as Garven and Kurt so it is slow.

Laudanum
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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by Laudanum » 11 Dec 2011 13:09

I agree. You might not be able to measure to a consistent 1/10th of a second but you can definitely repeat a few times and get a consistent enough measurement indicating whether it is running fast or slow with a close enough number for reference. Not an absolutely precise time, that would require more advanced measurements, but definitely enough to confirm fast or slow. Whether you can hear it is another matter that would depend on some factors, none less important than ones particular ears.

b-side
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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by b-side » 13 Dec 2011 20:30

moon unit wrote: Wrong.
Geez, what's with the attitude? Who said anything about a strobe previously?

I was responding to the suggestion to use a piece of tape as described in this thread. I found this method to have a uselessly large margin of error - being off 1 to 2 /10ths of second on the observing and clicking can add up to a range of half second easily. There is a lot of well-intentioned but dubious science or methodology on this (and other audio) sites. I'd hate to see someone think their Turntable is junk because it didn't time right with a lo-fi method.

moon unit
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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by moon unit » 14 Dec 2011 02:19

I got an email yesterday from Kurt stating that Pro-Ject confirmed there was a problem with the 60hZ pulleys and they are looking into it to determine if it was a design error or production tolerance issues. He is estimating sometime in January for Pro-ject to fix the issue and ship the new pulleys to him.

If you have already bought a kit you will be supplied with the correct pulley once he receives them.

More props to Kurt, too bad he is not the US distributor...

Alec124c41
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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by Alec124c41 » 14 Dec 2011 04:20

b-side wrote:
moon unit wrote: Wrong.
Geez, what's with the attitude? Who said anything about a strobe previously?

I was responding to the suggestion to use a piece of tape as described in this thread. I found this method to have a uselessly large margin of error - being off 1 to 2 /10ths of second on the observing and clicking can add up to a range of half second easily. There is a lot of well-intentioned but dubious science or methodology on this (and other audio) sites. I'd hate to see someone think their Turntable is junk because it didn't time right with a lo-fi method.
Timing 100 rev with a piece of tape gives a fairly accurate idea of what the average speed of the turntable is. If it is within a second there is not too much problem, but if the discrepancy is more, it will tell you by how much, and in which direction. Knowing you are off by 20% is a pretty sure indicator that you have the wrong pulley, for instance.
Exact? No, but pretty close.
Useless? Not at all.

Cheers,
Alec

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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by Anti-Hero » 06 Jan 2012 16:33

I have been waiting for so long for an update, WHEN WILL PRO-JECT FIX, THEIR FIX? :lol:

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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by JonP » 18 Feb 2012 15:09

Hi,

I would like to provide an update regarding this kit which I fitted late last year. Recently I noticed a significant increase in hum at 200 hz and 400 hz. You will see from my previous posts that this was an issue as soon as I originally fitted the kit (and it was also an issue for Moon Unit, who fitted the kit to almost the same turntable / cartridge combination - RPM5 plus Ortofon Rondo - as me). It had never been an issue prior to fitting the kit, however the kit did dramatically reduce noise at other frequencies.

Anyway, I pulled off the platter, only to find that one of the new grommets had actually split. This seemed to have occured because I had to tighten the screws quite a lot in order to reduce the annoying hum at 200 hz and 400 hz (any lesser screw tension just made these humming noises too obtrusive).

After this, I installed the new grommets from the spare kit I purchased, but did not install the screws. As expected, the noise floor was about as perfect as one could reasonably expect - no audible hum at any frequency.

But then I realised that this configuration is mechanically flawed, because the tension of the drive belt pulls the motor at an angle towards the sub-platter, meaning that the pulley and drive belt angle are no longer perfectly aligned (tight screws facilitate this alignment). This caused the belt to "catch" very slightly every so often, producing a very soft clicking noise that you would likely never hear when music is playing. But it does mean the transport is compromised.

So I have found a different solution. I am now running the kit grommets, pulley and belt, but with no transit screws. But crucially, I have added a counterweight to the motor housing bracket on the opposite side to that of the sub-platter (i.e on the edge of the motor bracket nearest the edge of the plinth. The counter weight consists of 2 x 20 gram fishing sinkers, attached to the bracket by means of blu-tack (ugly, but it works perfectly). This counterweighting enables the transit screws to be left off, thereby significantly reducing the hum artifacts at 200 and 400 hz especially, whilst also letting the motor run at the correct angle relative to the sub-platter. The extra 40 grams of weight on the motor bracket also lets the motor bracket "settle" on the grommets - this is important since there is no longer any screws to hold it down.

I've been running this solution for a week now, and I am getting the best sound I have ever gotton from this turntable - even better than when the kit was first installed (and working properly).

Hopefuly this might help others who have come across this issue or would simply prefer to use the kit without having to re-fasten the transit screws (which are always going to re-couple the motor in some way to the chassis - something that I think should be avoided wherever possible).

In coming up with this solution I determined that the absolute correct counterweight needed to be 30 grams sitting directly on top of the upward-facing screw at the edge of the bracket, however I could not find any permanent 30 gram weight that could be fitted that close to the edge. Also, the 30 gram weight right on the edge did not settle the motor onto the grommets as much as I would have liked. Although there are 40 gram weights available, one of them is too large to fit (they will foul the platter). So I went for 2 x 20 gram weights and fitted them between the motor and that edge screw.

As for the ideal pulley height, with this setup it is such that the belt interfaces in height terms exactly at the midpoint of the sub-platter.

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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by Hawkeye666 » 18 Feb 2012 23:25

I've been following this issue since it first appeared on AppleChap's web site. Since I live in the US I have had to use all the "after market" fixes. Each has given me some relief from the rumble and hum but it was always still audible on the wind down track and at the very beginning of the records.

Then I re-leveled the table with a small bubble level, and gee, guess what? (Rhetorical question alert.) The table was level side to side but nowhere near front to back. Took care of that and now it is as clean as most DD Japanese tables. DOH!

moon unit
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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by moon unit » 19 Feb 2012 09:22

Nice tip Jon, I may have to try that with my table.

I've never heard the soft clicking noise though. I've run the table quite a bit playing a record at zero volume while experimenting at correcting the slow pulley speed with tape. Which I finally succeeded at doing...


Just a note to North American customers: I was told by Kurt Martens over three weeks ago that Pro-Ject was sending him a sample pulley to test and if he gave the ok they would put it into production. Why Pro-Ject itself could not test it themselves is the real question. They need one Canadian to test the speed of a 60 Hz pulley and a second Canadian to design a tonearm damper to fix the resonance issues with the 9cc arm???

JonP
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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by JonP » 19 Feb 2012 10:10

Hi Moon Unit,

It's possible that there are simply small differences in each turntable (nothing is perfect afterall) and that different issues come to surface with different setups. For example, the post just above resolved the issue by ensuring the turntable was level, but obviously you and I saw to that right from the get-go and that made no difference.

I actually only ever heard the clicking in a quiet room with the turntable spinning and no music. The click was very soft and I could not hear where it was coming from at first. I had to "zero-in" on the turntable and then got a torch out and saw the belt slipping on the subplatter every so often, producing the very soft click. Then when I shone the torch over at the pulley, I saw how it was getting pulled towards the sub-platter due to the tension of the drive belt. The angle looked really bad, so I began to test counterweights.

To be honest, I was never really keen on having to re-introduce the transport screws as I think the motor needs to be as physically de-coupled from the chassis as possible. Even just adding a blob of blu-tac to the motor bracket and having that blob of blu-tac barely touch the chassis produces a very loud harmonic at 200 hz.

I guess these turntables, being made of some sort of wood composite are each going to behave differently - just like wooden musical instruments each will have it's own unique character.

But I think that anyone who has fitted this kit should inspect it periodically to see that the grommets are in good order at the very least - as I say I was quite surprised to see that one had broken, especially when I did not tighten the screws any tighter (or so I thought) than as shown in the original tutorial. And they should also get a torch out to see if the pulley is being pulled towards the subplatter due to the tension on the drive belt. This in itself at the very least will cause additional friction over the pulley and could contribute to wear on the belt and even additional wow and flutter, let alone the possibility of the slippage I mentioned.

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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by kikigarel » 25 Feb 2012 13:18

Hi,

I've got a spare/unused European fix kit for sale. The price is €30 including shipping: if anyone is interested please get in touch.

Regards,

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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by Crispin Crunch » 17 Apr 2012 02:54

I implemented Moon Unit's rubber band fix and this significantly reduced but did not completely eliminate the rumble. The belt on my xpression iii still rides a wee bit below center. I haven't yet tried Flitzing the spindle nor oil on the spindle. I may also try the Grainger grommets and a round belt from turntableneedles.com as suggested in an earlier thread.

Immensely thankful for the vast cache of tribal knowledge documented here and on AK. Mostly just bumping the thread hoping there might be a positive update on the 60hz kit rev...

Garven
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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by Garven » 19 Apr 2012 19:10

Yeah, whatever happened with this kit?
I wrote Kurt Martens awhile back and he said he was waiting for Project to send him new parts to correct the speed error. I suppose I should write him again. To be honest, I was rather discouraged after I sent him an MP3 recording of the hum I'm getting at 45rpm and he basically answered that all turntables have hum so I'd just have to live with it. I rarely spin 45rpms so it's not the end of the world and the blue tack method has pretty much silenced the rumble at 33rpm, but I did spend $40 on a kit that's unusable.

Needless to say I'll never buy another Project product in my life!

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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by kindkid419 » 29 Apr 2012 03:18

I am now noticing a rumble too. bummer

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Re: Official Pro-Ject Fix For Turntable Rumble Now Launched

Post by egicar » 08 May 2012 15:15

Hi all,

I just received the kit and I'm thinking about a little mod.
The problem I see is about the contact between the motor transport holes (the two on the aluminium motor mount) and the screws. This contact can transmit the motor's vibrations to the turntable base.
May be a good solution to enlarge the holes and put into them a piece of silicone tube? So I'll have an insulator between the screws and the motor mount.

What do you think?

Thanks a lot in advance.

Ciao,
Egidio

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