[BobM]

I've been experiencing a subsonic rumble problem with my VPI table ever since I got my Hagerman Trumpet phono preamp. According to Jim Hagerman, the frequency extremes were not truncated, thereby optomizing the design and throughput, and allowing everything to come through.

I've tried many different things with no success (see more details on this thread: http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1228934026)

Just wondering about a record mat. The VPI platter is not supposed to be used with a record mat. It's design is intended to couple the record to the "vinyl like" composite platter. But what might a record mat do for me here? Might it help dampen these vibrations? What do they do for the sound (I would expect a dampening there as well, no)?

Any thoughts? Any recommendations on which ones to try? Anyone with practical experience using a mat on a VPI platter?

Thanks,
Bob

[TheChairGuy]

Bob, as you know, I have a VPI HW-19 Mk. III...with the old lead/cork/rubber platter (and inner and custom-made outer record clamp).

Despite what VPI says, the platter is a poor interface with the record itself.  Go get a Herbie's Way Excellent II...whatever thickness works with your VTA (if you pay attention to such things) to improve upon that.  But, if you have rumble, I don't think that will do much of anything for that issue....but your overall playback experience should improve.

For $100.00, VPI sells a new, much improved, much harder, higher-grade spindle and bearing.  It uses grease instead of oil...ostensibly for better bearing damping (and less noise).  It's quite an upgrade for the deck.  That might well help your issue.

http://www.vpiindustries.com/products_hw19.htm

Also, you might want to try Herbie's Tube dampers if microphony is part of the reason for your subsonic issues....or just a mortite top-hat (like a yarmulke for your tubes) on top to dampen the tubes.  Don't use plast-i-clay as it might ooze due to high temps, this one you need mortite rope caulk for

John

[Wayner]

Bob,

I have been using a mat on my VPI Hw-19jr as well. Like John says, the table needs a mat. I do have to ask if you have the platter on the shaft fairly straight? A few thousands of an inch of wobble is probably OK, but the more it wobbles, the more "wow" you will get. This addes up to lots of surface noise (especially in between tracks). Along time ago, I had a company tool up a mat for myself. It was about $85 dollars for a steel rule die and I had to buy 50 mats (I only have a couple left and can't sell any more). I have found a material that you can buy locally that works pretty well. It is used to line shelves with an it's made out of some kind of synthetic rubber, about a 1/16" think. I'd try some of that first to see if it does what you want. Some guys use this stuff to line the inside of their toolbox with. The kind I'm thinking of is a checkerboard pattern with every other "square" is actually a hole. It's light and seems to dull down the noise.

I've also tried silicone dots on the platter, but I didn't want to apply the dots directly to the acrylic platter of the VPI, so I found some 110 pound card stock (heavy construction paper) and put the self adhesive dots on that, cut the paper round and that was a nice mat. If you want to go thru the work of making one, just to find out.

Otherwise, there is John's suggestion.

Wayner

[Wayner]

Bob,

I got a felt mat if you want that.

PM me if you are interested. (However, I don't like felt mats 'cause they static up like a bastard).

W

[BobM]

Thanks - I've tried tube dampers and found they rob the dynamics on the phono stage, but help on my preamp.

I've got the same platter. I've contacted VPI about the new bearing and very well my try that down the road. I've looked at my existing MK III bearing and noticed that the little rounded hardened tip (it's not a ball bearing on mine) is a little flattened from use. Yes, this may be a contributing factor and I think going with a new $100 bearing rig is a better idea than a $150 mat (the Herbie's "Grungebuster"). I did put a note into Herbie asking him his opinion on whether the Grungebuster or the Excellent II would be a better option for me to try.

I'm still skeptical about mats in general though, but willing to give it a try. Maybe someone in the NY Circle has one that I could try out and see what's what.

Wayner - please PM me, or post more info on your home design mat (not the felt one, the one I should be able to find locally). I'll give it a try. As for platter wobble, there is none that I can detect when looking at the bottom edge of the platter as it spins. If you see a wobble, VPI recommended taking the platter off the bearing, turning it a quarter turn or so and reseating it. Keep trying this until the wobble is gone. Sometimes it's just a matter of aligning thesee things correctly and one positioin may be better than another.

Enjoy,
Bob

[TheChairGuy]

Bob,

I just read the string over at Audiogon forums you posted and replied to....EAR C-1002 as a backing to your Corian plinth underside is probably not a bad thing to try, as well. The color is a grey/silver with mine...quite muted and not likely to kill aesthetics for you.

Under-$30 will buy you a goodly sized sheet at Michael Percy Audio and you can cut to size.  When you go above 0.1" thick, your cuts are abberant with a long pair of scissors, but if you keep it under this thickness, you can cut it pretty nicely with a sharp scissors.  Otherwise, you'll need a pastry cutter or other, hardier tool. 

Some combination of these suggestions should reduce your subsonic issues.  I also found silicone damping pot on my arm to be pretty decisive place to reduce subsonic issues, too.  My preamp has switchable subsonic filtering (18hz) and I hear no degradation with it on (using a small Gallo TR-1 sub that plays down to the mid-30's)....alternatively, using tone controls (bass/treble) has always been heard and I zealously switch them off

EDIT: Bob, the new spindle/bearing is quite an upgrade to the old.  My spindle was actually bent over time from use...the new one is much harder and better overall.  That might well be your most significant and cheapest fix to the issue.  Even if it is not - it will be a nice sonic advance for you in other ways.

Don't be skeptical about mats...their effect are quite large as proper 'interface' with belt drivers.  With Direct Drives, they are doubly important as they must perform significant damping duties, too

John

[BobM]

How would you adhere the EAR Isodamp? Rubber cement? Silicon? I agree that thinner might be better overall, as per the EAR website recommendations on their product.

I tried damping my arm in the past, but found that I experienced some loss of dynamic "life" with that option. it didn't change any of the subsonic issues. Most people with my arm don't recommend any damping, so I pulled it out.

Bob

[TheChairGuy]

Bob,

P. 19: http://www.percyaudio.com/Catalog.pdf

The SD-series is self adhesive....nothing to do but cut, peel and stick

Trivia: Well-Tempered and SME use EAR composites in the design of their products.  It's good stuff indeed and a little goes a long way

John

[Sonny]

I've been experiencing a subsonic rumble problem with my VPI table ever since I got my Hagerman Trumpet phono preamp. According to Jim Hagerman, the frequency extremes were not truncated, thereby optomizing the design and throughput, and allowing everything to come through.

I've tried many different things with no success (see more details on this thread: http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1228934026)

Just wondering about a record mat. The VPI platter is not supposed to be used with a record mat. It's design is intended to couple the record to the "vinyl like" composite platter. But what might a record mat do for me here? Might it help dampen these vibrations? What do they do for the sound (I would expect a dampening there as well, no)?

Any thoughts? Any recommendations on which ones to try? Anyone with practical experience using a mat on a VPI platter?

Thanks,
Bob

Bob, from my exprience of having three VPI tables, the Scout, Aries and now an older TNT 3.5, I know that this is not just a problem with VPI tables, but vinyl in general.  rumbles are normally caused by a number of things, including record warp, actual low frequencies on the records are amongst the most common in my experience.

For this reason, there are rumble filters...I have one that Phil Marchand of Marchand Electronics made for me a few years back, and it works wonders...the one I have, cuts off at 17hz...so, it works for me.  Currently I built a Bassiss from Phil's design and am now using that, so, my rumble filter is not in use.

If you'd like, I can send you my rumble filter for to try on your system.  I just as that you pay for shipping both ways...  If you like what it does, you can as phil to make one for you or perhaps, i can sell you mine.

Let me know.

Tuan

[Wayner]

This rumble junk is pure mechanical resonance from something not being very happy. I always say a table will let you know one way or another if it's happy or not. The mechanical nemesis is just another one of the scum vermin you will have to deal with. While filters are certainly a solution (and may in the end be the final solution), finding the true culprit should be the mission. When I was building my table, I thought I was dealing with motor hum, and it was, but there was also a mechanical signature there. The mechanics was from an unhappy motor vibrating like a bastard, until I figured out how to get all of that energy transfered to another place.

Here is a chance to discuss some basic rules of energy. Be it electrical or mechanical, energy cannot be created or destroyed, only changed in form. Therefore, to reach vinyl heaven, the offending source must be identified and delt with. If you think it's a bad bearing/shaft problem (with visual evidence) that is more than likely the source. My ARMOD table with the belt off, will spin for 5 to 6 minutes with a flick of my hand on the platter. There is no noise. If you hear any kind of rubbing or other kind of noise, it is a mechanical energy and it will find it's way up to your platter and tonearm.

John (and myself) use platiclay to deal with some of the other impossible to tame energy sources. That method is using plasticaly as a "transformer" if you will, to turn mechanical energy into heat. That is exactly what the plasticaly does.

If you can see woofer excursion in-between or during quiet passages, there is a mechanical culprit gumming up the works somewhere. I think you have found it. The mat idea will hopefully take you to the next level of quiet.

Wayner

[hifitommy]

it sounds more table related and needs to be dealt with at that level.  as for a mat, i used the acrylic on the vpi i had and the sota i now have.  hte 19III had its screw down clamp and the sota has its reflex unit. 

the only other arrangements i would consider are the periphery ring or vacuum.  if a periphery ring wont contact the cartridge, then thats the direction i would go.