My Pro-ject Xpression III started with the rumble (or recently got worse). Cinellipro and I have talked before and he has been very helpful with info, time and more! :) Hopefully this solves my problem. Otherwise, my table is still under warranty. And a "to the top" action for this thread for anyone else that is experiencing this problem with the Pro-ject turntable.
Pro-ject RM RPM 5 5.1 6 6.1etc. Owners Fixed
I own a Pro-ject RM6 SB turntable and love the turntable. However, it has always had a low end rumble once the needle hits the record. I tried ignoring it attributing the issue to record surface noise or one of the other compromises of living with vinyl. I recently discovered that this is a common problem with many Pro-ject models. At the urging of my not-so-local dealer I replaced the OEM footers with a set of threaded Edensound brass footers which yielded a dramatic improvement in everything except the rumble (I consider THREADED brass footers a mandatory investment). I then placed a cork mat between the subplatter and platter and silicone between the cartridge and headshell, minimal improvement if any on those two. The low end rumble continued and it really wasn’t that noticeable or intrusive once the music started, or so I thought.
I started my internet search and found a bunch of postings about the rumble problem inherent with certain Pro-ject TTs. There’s even a youtube video on the problem. I then came across a site from an RPM5 owner who claimed to have resolved the rumble problem found in Pro-ject turntables. He shows the before and after effects graphically on a spectrum analyzer identifying the low-end rumble with peaks at 50 and 100hz before and after his method of fixing it. Go here if you want to read more.
http://www.theapplechap.com/TheAppleChap/Blog/Entries/2011/5/24_Enhancing_the_sound_from_Pro-ject_turntables_by_removing_rumble.html
He provides a beautiful narrative on the fix and his science seems solid, but obtaining the parts needed seems a little complicated and he is waiting for Pro-ject to come up with a retrofit solution. Anyway, I discovered the repair can be done easily, for cheap, and now. Using his method, kind of, the fix is to install four rubber grommets (I’m not saying or recommending that you should do this, I just want to share my story). Based on the AppleChap’s approach, I went to Grainger.com and ordered a package of 1/8” ID 3/16”OD rubber grommets part number 3MRT4. They don’t sell them individually so I had to purchase a packet of 100 for an astounding $4.20 plus shipping.
The grommets arrived 3 days later. I then removed the platter, located the 4 screws that hold the rubber suspension (rubber band) in place. I removed one screw, inserted the grommet around the washer surrounding the screw and re-screwed it in place. It might be a little tricky at first as the suspension is tightly fit. I did this three more times, and four minutes later I was done. An important note the rubber band fits between the lips of each grommet, not above or below, unlike the pictures shown in AppleChap’s method. This isolates and decouples the rubber band from the screw and plinth. Also, I had to make sure that the screws were placed back correctly because any shift in the motor’s original position may cause the edges of the motor to touch the rubber grommet. If that would have happened I could have shaved the side of the lip of each grommet that faces the motor.
I returned the platter to its home and played a record. The second the needle hit the record, there was no rumble. It had disappeared, like magic. The grommets not only eliminated the rumble, but it cleaned up the soundstage and things that were previously masked were revealed. An amazing transformation! AppleChap also recommends changing the belt to a round instead of flat belt; less surface area to transfer resonance. I ordered a belt but it had not arrived yet.
I started my internet search and found a bunch of postings about the rumble problem inherent with certain Pro-ject TTs. There’s even a youtube video on the problem. I then came across a site from an RPM5 owner who claimed to have resolved the rumble problem found in Pro-ject turntables. He shows the before and after effects graphically on a spectrum analyzer identifying the low-end rumble with peaks at 50 and 100hz before and after his method of fixing it. Go here if you want to read more.
http://www.theapplechap.com/TheAppleChap/Blog/Entries/2011/5/24_Enhancing_the_sound_from_Pro-ject_turntables_by_removing_rumble.html
He provides a beautiful narrative on the fix and his science seems solid, but obtaining the parts needed seems a little complicated and he is waiting for Pro-ject to come up with a retrofit solution. Anyway, I discovered the repair can be done easily, for cheap, and now. Using his method, kind of, the fix is to install four rubber grommets (I’m not saying or recommending that you should do this, I just want to share my story). Based on the AppleChap’s approach, I went to Grainger.com and ordered a package of 1/8” ID 3/16”OD rubber grommets part number 3MRT4. They don’t sell them individually so I had to purchase a packet of 100 for an astounding $4.20 plus shipping.
The grommets arrived 3 days later. I then removed the platter, located the 4 screws that hold the rubber suspension (rubber band) in place. I removed one screw, inserted the grommet around the washer surrounding the screw and re-screwed it in place. It might be a little tricky at first as the suspension is tightly fit. I did this three more times, and four minutes later I was done. An important note the rubber band fits between the lips of each grommet, not above or below, unlike the pictures shown in AppleChap’s method. This isolates and decouples the rubber band from the screw and plinth. Also, I had to make sure that the screws were placed back correctly because any shift in the motor’s original position may cause the edges of the motor to touch the rubber grommet. If that would have happened I could have shaved the side of the lip of each grommet that faces the motor.
I returned the platter to its home and played a record. The second the needle hit the record, there was no rumble. It had disappeared, like magic. The grommets not only eliminated the rumble, but it cleaned up the soundstage and things that were previously masked were revealed. An amazing transformation! AppleChap also recommends changing the belt to a round instead of flat belt; less surface area to transfer resonance. I ordered a belt but it had not arrived yet.
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- 19 posts total
The 4 additional rubber grommets problem did not fix my problem of excessive woofer movement at volumes at close to double normal listening levels (party mode I guess you can call it). I am lucky I am not getting this at normal or just above normal levels and I will have to keep an eye on the volume level. Hopefully it does not get worse. Here is a link to a thread on what some people might think is going on: resonant frequency |
Discovered one more effective resonance reducing method for the RM or RPM 6 series turntable. As you know the plinth transmits vibration to the tonearm from the motor. The tonearm assembly is connected to a recessed section of the the plinth with only three screws. You can remove the screws and install a square piece of rubber that fits into the recessed area, or use the grommets to isolate the tonearm plinth. The rubber square I used was 2 1/2 x 2 1/2 by 1/8 thick. Be careful holding the tonearm at the removal of the last screw as the cartridge will be exposed. You will need to adjust the VTF and the tonearm lift the same height as the thickness of the rubber square. Easy to do with two smaller allen wrenches. Installing the rubber square was less than 10 minutes and getting the VTF and tonearm hold adjusted was another 10 minutes. In my system, it continued to significantly improve all the elements of the soundstage already mentioned. |
Thank you so much Cinellipro for bumping this thread. I have a RM5.1 SE with a Sumiko Blackbird cartridge, and the rumble has irritated me since the day I got it. It seems to disappear once the music starts, but I knew it was lurking in the background, mucking things up. I saw Applechap's blog a long time ago and contacted Sumiko about a USA version of the fix, but could not get a response. I gave up and decided to live with it until I could afford a table upgrade. Anyway, after seeing this thread I ordered the grommets from Grainger, installed them with no problem, and the difference was like night and day! Amazing improvement. The new belt arrived today and after a quick listen, I think it helps too, although the fit seems looser than the old one. I have 96 extra grommets if anybody needs any! |
A little off topic but I was intrigued by Carlmans suggestion to screw down the motor with the transport screw. I recently purchased a Perspective and I'm having quite a bit of trouble stabilizing the platter to the plinth. It's reacting to every step I make. I set my tracking force to the recommended settings, set the deck up as instructed and the platter just won't cooperate. Is this the solution? Unfortunately I don't have the set-up screw, does anyone know the thread/length size? Also does this grommet issue reflect in the Perspective's design as well? Finally, I tried putting my round VPI belt on the platter prior to reading this thread an had no luck making it work. It seems the flat platter rim is to small for the belt. |
- 19 posts total