The ARM, the arm, the arm(s), open to airborne contaminants, he ran screaming from the room.
Some thoughts on dust covers
Over the course of time there have been many discussions concerning the subject of dust covers. They tend to revolve around the central question: Should the dust cover be down or up while playing records? Some of these discussions have been nasty, consequently I have refrained from participation. It is hoped that I can provide some common sense that was given to me by someone of unquestioned authority many years ago. During college and after, from 1970 to ~1980 I worked in HiFi retail, selling high end lines of audio equipment. One of these lines was Thorens. Sometime around 1977 or 1978, if memory serves, Thorens introduced their new TD126, as a top of the line TT with their own arm and I sold the first one at our store to very good customer. He came back very unhappy after the first night of frustration with it. The problem was that with the dust cover closed some of his favorite records were hitting tangentally on the very back were the platter came closest to the dust cover when it was in the closed position. I called the manufacturer's rep and he set up a three cornered phone call with himself, the Chief Engineer of Thorens at the time, and me. I don't recall the man's name, but it doesn't matter, it is what he said that matters, then and now. The Chief Engineer explained that the problem was caused because the hole in the offending records was slightly off center so there was an eccentricity as such a record rotates about the spindle. The solution was simplicity itself, the dust cover should be removed always when playing records. That the intent of the cover is to protect the turntable when not in use. I pointed out that we lived in a semi-arrid environment (San Diego, CA) which is dusty to which he replied that if the environment was too dusty for records it should also be considered unhealthy for people to be breathing the air. He recommended are filtration, not dust covers to address environmental concerns. The rep asked about air bourne feedback from speakers and the Thorens guy laughed and said that if that was a problem in a given system, relying of the dust cover was a very flimsy and ineffective solution and that proper measures should be instituted to provide meaningful distance and isolation to ameliorate the problem. So the often offered extremes: a) Always play your records with the dust cover down, or b) put the dust cover away in it's box and never use it, should both be recognized for what they are are - not solutions at all. First principles: Identify the problem(s), seek solutions and alternatives, prioritize.
Showing 9 responses by elliottbnewcombjr
Impractical, don’t kid yourself, it’s a problem needing solution. Expensive TT’s (any TT) without a dust cover is an incomplete solution, an abomination, they should be ashamed of themselves. I go for dust minimization and dust barrier, uncover to play. My forced air supply vent (end of the run) at that end is blocked, the return air vent on the far wall somehow pulls enough for comfort all seasons. You’ve caught a glimpse of dust in sun beams. It is pure folly to think invisible contaminants are not gathering and accumulating on all possible surfaces of your very finely manufactured stylus, cantilever, arm pivots, bearings, TT: anything left open to the air. At least a cloth cover when not in use. Hinged, playing while closed: as I said, even if I cannot hear/prove it, I cannot get the concept of reflected microphonics out of my mind, so prior TT, I left it up/open (level the TT when weight is shifted thusly) or don’t attach the hinges, lift it off. Vibrations in the space from the speakers reaching the surface of the LP? I cannot sense any movement getting involved? If I had my rear ports open, that would be an issue, but they are sealed since I moved to this space 46 years ago. The speaker's tops are slanted and delicate things do not vibrate/move, things in front/sides all have a combo of felt feet/no touch each other rule and all artwork corners have tak at the corners. I get many opportunities to see dust movement in variously directed sun beams, my TT is in front 3 windows facing south and one from right side catching late afternoon/sunset rays. Speakers Off/on, the dust in the rays does not reveal change of air movement in the TT's vicinity. The only clue I have.
|
my method of speaker toe-in and rear slant, thus inward and upward directivity, is part of why I don’t seem to get vibrations on the surface of the LP between/behind the sealed boxes I think. Your setup may be part of the solution, or .......
My SUT to select which arm and impedance or PASS for MM just fits under the side of my TT, (normally I can see/move it’s two selector knobs, shown pushed too far underneath the TT here) I have to move my Preamp/Amp cabinet to work on it. Notice felt squares on the end of the dust cover It’s big, you need to plan for where it goes during play, some covers would be huge, it may determine where you place other equipment, it did in my setup. Some more felt on the face of the Reel to Reel Tape Player protects the cover when using the TT. Below, prior setup, SUT was on a shelf below the TT, actually harder to see the various markings, hard to position, but better now.
|
Related: Warps get helped, but for typical LPs, all that I play: I definitely want to use something at the center spindle to assist rigidity, minimize air pocket bulge below, eliminate potential of any movement, i.e. LP firmly in place to transmit groove info most completely to the stylus, the forces involved are tremendous. Sturdy designs like former Thorens TD124, Technics SP-15, current JVC TT81, I use somewhat heavy AT Disc Stabilizer, 300 grams
Clamps, and Retainers exist to reduce weight concerns for some designs, Ask your maker Luxman PD441, 444, 555 all have a special ’load reducing’ motor design, magnetics reduce 80% of the weight on the bearing, so I got my friend rubber retainers used to hold tape reels on spindles the same diameter, you just push them on.
I like the idea of vacuum hold, but not the idea of a running motor, so I wanted to also use weight at the perimeter, I tried Wayne’s Perimeter Ring, unsuccessfully as the ring’s weights hang down too low and touch the wide rim of the JVC TT81 Here it is shown upside down, with the centering jig you need
My Mitsubishi LT-5V Vertical TT has a very ingenious hinged arm with spring assisted center clamp/pull to release
In my garage/shop, to keep an 8 track and fit a dual cassette deck in the stack, I changed to a Sony Front Loading Drawer Type TT, too light of a mechanism for a weight, and no clearance to place anything on/off anyway.
I found an advanced stylus P Mount, and then an adapter to convert P mount to 1/2" standard. |
noromance"@elliottbnewcombjr Why not move the dining table set to the other end of the room?" You would think, right. Of course I have moved the table/chairs out, tossed down a rug ... to compare/prove it still sounds great with them there. I’m actually quite pleased with how versatile the room is. It’s one room, 14’ wide, 24’ long only 8’ high, with both music/dining at one end and living/video other end, a cross aisle to a 3 season porch just in front of these 2 listening chairs which simply turn around to join living/video which is oriented across the 14’ width behind them
Imaging is all Phantom in 2 Channel, the table and chairs may actually help with imaging once you accept that no sound is blocked, here we add a Christmas Tree which also blocks nothing except your mind if you think about it.
I add 3 leaves in the table for family gatherings a member pointed out that the piano might make vibrations, I thought so too. I have tried with my Amazing Bytes CD to start/stop/listen to all 29 1/3 octave test tones, I cannot get the piano to sing. The speakers are on 3 wheels, I can push them back into the corners when needed for holiday dinners, position/toe them in for one or two listeners, DBX Cross Dispersion Method as discussed here https://www.audiogon.com/systems/11516
|
mylogic I’ve witnessed Arlo Guthrie a few times yapping away, then he says "I know I’m supposed to be singing, but you can’t always do what you’re supposed to do’ And the stories are all related to where he started. You would love a Buckminster Fuller lecture, in 1967 that crazy man took an entire auditorium at Pratt Institute on a meandering thought trip and at the end of the hour slammed it home, OMG, I still remember it like it was last week. Vibrations getting to the surface are all related to the Dust Cover on/off issue, as is this fundamental question about equipment location. https://forum.audiogon.com/discussions/location-of-compoments?lastpage=true&page=2#2757920 Thorens, yeah, they should have had more clearance than that in that model.
|
wonderful to learn the word, a bit more from AI (numbers didn’t copy properly) AI Overview An undecillion is a number that is written as 1 followed by 36 zeros in the United States and 66 zeros in Great Britain. It is a very large number, so it is not used often. Explanation
.
.
Examples
|
dwettenice. I also found, the clearance between the top of the metal ring and the bottom of the cartridge body is an issue, my AT33PTGII, I had to skip the beginning of track 1, because the cartridge body rubbed on the metal ring. |
noromance hope no lasting effects, thank goodness for the weaker strains and the vaccines, Donna and I just dodged Covid, stayed with my brother in Maine for 3 days, he found his ’cold’ was Covid, we both tested neg. We flew to Tampa in Oct., we were the ONLY people wearing masks in two large airports, and everywhere we went on the 5 day trip home. I keep hearing "there’s a lot" of Covid out there. |
