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Driver gasket material


DavidR

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I know a lot has been discussed about replacement materials for driver gasketing material. The material I found on my AR91s seems very similar to the craft foam my wife uses. Its foamed neoprene and can come with or without an adhesive backing. It is available at places like Michael's and A.C. Moore and, of course ebay. The most common thickness is 2mm which seems a tad thicker than what came out of the woofer - but that's probably thinner because of being used.

http://www.michaels.com/creatology-adhesive-foam-sheet/M10032002.html?dwvar_M10032002_color=Black#q=craft%2Bfoam%2Bsheets&start=3

Does anyone have any thoughts on this material or anyone used it?

On another thought (going out on a limb here and outside of the box thinking) has anyone ever seen silicone high vacuum grease? I use it on the intake gaskets of my MG. Its very thick and won't move if used sparingly. Does anyone think it might work on used gaskets in place of adhesives?

silicone grease.pdf

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Hi David

No idea about the grease but Roy turned me on to that foam for gaskets some time ago and I've used it with success. It's mentioned on page 12 of my KLH Model Eight restoration guide, attached to Post #1 here: http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=6387

Kent

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Hi David

I've used the thinner sheets (not sure of the thickness), non-adhesive. But I'm sure there would be applications where thicker or adhesive-backed would be better. Also, I've been meaning to get a circle cutter for making gaskets. Maybe something like this http://www.amazon.com/gp/product/B001CEAMCY/ref=ox_sc_sfl_title_3?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

Yes--Roy has been a tremendous resource for many of us. He shares his knowledge and experience freely. A great asset to this hobby of ours.

Kent

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Hi David......................................................................................................................................................................................................................

Yes--Roy has been a tremendous resource for many of us. He shares his knowledge and experience freely. A great asset to this hobby of ours.

Kent

Yes (+1) I agree totally. There are many helpful and knowledgeable members here; such as yourself.

I like that circle cutter. Looks like a nice one. I have a very old one I always use for my automotive hobby. Its probably time to upgrade. They never seem to make them big enough to get you big circles. That's when you get resourceful and use a thumbtack, string and exacto knife.

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I don't know if I am talking about a different thing here, but the thin strips of sticky backed foam is very easy to form into circles to make a gasket. I used this to make an acoustic seal for my speakers. I bought a 2m length, but you can get any length you want. You should be able to get this in the USA

http://www.falconacoustics.co.uk/cabinet-parts-accessories/dedshete-wadding-acoustic-foam-gasket-ls35a-loudspeaker-cabinet/loudspeaker-gasket-neoprene-self-adhesive-12mm-wide.html

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Maybe I'm living in the past, but I think there's nothing sounder for the job at hand than material that's inherent flowing, like some kind of not-oily putty or the high-class version called "duct seal." Use as little as possible.

Easy enough to work with and remove. Another possibility is stuff sold as "draft stop" in caulk-gun tubes which is a not very sticky rubber cement and peels off like a charm when settled.

Foam insulations are bulky and are stiff in ways undesirable for driver mounting and yet not quite air impervious either.

Ben

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Hi ben,

Thanks for your input. The 'duct seal' is a material used commonly by electricians. It can dry out over time.

The original gasket material in my AR91s is very similar (if not the identical)to foamed neoprene.

I haven't heard of 'draft stop' but will keep an eye out for it.

I had the same experience Frank Marsi did with his AR9s >>> The original gasket was not properly aligned to the screw holes.

This is the reason I don't want to used them again. I seem to remember members saying you could flip them over and

get a second use from the originals.

I'm leaning toward the one-sided adhesive type as that will hold the gasket in place as I lower and align the woofer with the screw holes.

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I'm leaning toward the one-sided adhesive type as that will hold the gasket in place as I lower and align the woofer with the screw holes.

First of all, David and my old friend Kent, thank you for the very kind words. Ultimately it is a two-way street. Hey, Kent is my KLH radio guy! :)

Some of the later grey AR foam gaskets can be re-used, but many are not worthy...and the white foam gaskets are almost always shot.

These days I mostly use Parts Express 3/8" "gasketing tape" or strips of black "speaker sealing caulk".

http://www.parts-express.com/cat/gasketing-tape-caulk/318

PE's caulk is very similar to a black 3M automotive caulk which was very popular in this forum some years ago. Both are very close to the original AR putty. PE's "gasketing tape" is an adhesive backed high density foam, not the typical weather stripping foam found in hardware stores. It is usually too thick for tweeters, however, as it will distort thin or plastic mounting flanges. Craft foam or small strips of putty are best for tweeters.

Duct seal is not as good as the above items, but it works...and is very inexpensive. It is the "AR putty" sold on Ebay. You can purchase it at Lowes or Home Depot for a fraction of the Ebay price.

"Mortite" or the clay-like weather stripping material found in hardware stores in rolls was used for years, but the above items are softer and more versatile.

Avoid plumbers putty...too soft and porous.

Roy

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Hi ben,

Thanks for your input. The 'duct seal' is a material used commonly by electricians. It can dry out over time.

The original gasket material in my AR91s is very similar (if not the identical)to foamed neoprene.

I haven't heard of 'draft stop' but will keep an eye out for it.

I had the same experience Frank Marsi did with his AR9s >>> The original gasket was not properly aligned to the screw holes.

This is the reason I don't want to used them again. I seem to remember members saying you could flip them over and

get a second use from the originals.

I'm leaning toward the one-sided adhesive type as that will hold the gasket in place as I lower and align the woofer with the screw holes.

9-18-14

Just when I thought I got away, they pulled my right back in again!

Did some one mention my name?

Did I hear my name in the distance? “When I’m calling you-ooo-oooo …….”

I heard something about holes in rubber or something. I got scared, I thought I was dreaming and I heard her say there’s a hole in the rubber. Good Gosh! Heavens to mer-ga-troy!

But, seriously folks…..

I’ve been reverse using that closed-cell gasket over and over again, as far back as with my original 3as and every speaker since. Granted, it’s not the best way to seal the enclosure and I’m sure that I must have a slight degree of air leakage by using the old gaskets, but in many cases I’ve found double gaskets in most cabinets to be still somewhat usable if you take your time and watch what da hell you’re doing.

The common method of torqueing down each screw systematically much like you’d do with any metal to metal application is what I practice. That’s why those heavy machine screws and ‘T’-nuts are so good in our cabinets. In fact if it wasn’t for AR’s forethought in using that machine screw method, my speakers would’ve been trashed long ago, perish the thought.

I must admit my method is really half-assed, but I’ve never felt air leakage, except from you know where, and we’re not talking about the space shuttle’s use of ‘O’-rings here either. I gleefully admit that I am wrong though.

If and when I get off of my bottom and refurbish the fleet of all my speakers and bring them to a point to where site greats such as RoyC and other top ranking officials here would gush and be proud of me. I’m still enjoying my system of LSTs and will probably use P.E. stuff, cause I have two rolls here already. Personally I’m even planning on seeing other fore-fathers on this site like the great “Johnie-O” and perhaps a few others, like “Minh”, Bret, SteveF, Pete B, JKent, Mean-Gene GeneK, KKantor, Carlspeak, the too fabulous for words “Dynaco-Dan” and countless others if I’m that lucky? You people know who are, so please don’t be insulted if I haven’t mentioned your name.

I find it more important enjoying the sound of ARs and throwing vinyl on the tables and just ‘getting-off’ on the music, period. I’m a ‘throw-back’ to the late ‘60s- early ‘70s when we would just close our eyes and nod our heads up and down and groove, period.

I still do that stuff you know.

But, to be more serious and speaking rationally, however much of a struggle it is for me. it’s quite possible that a number of my blown woofers may have been caused by my ‘bum-job’ of not replacing the gaskets with a suitable newer closed-cell gasket? So, I remain guilty.

You see, that’s a pitfall of being lazy, we can all agree, but I think my blown woofers are actually caused by over-driving at high volumes with perhaps a touch too much bass-control attenuation. No, there’s no real amp-clipping going on here.

The AR-9s are in a state of dormancy presently because I haven’t had ‘recreational time’ to properly enjoy them and work on that system, so I’m solely enjoying my main system.

I’ve also lived to ask and tell the tale of how many systems can one person use at a time?

I decided to mostly listen to music and not allow myself to get so lost in system building.

This of course occurred after establishing the LST’s as the main holy temple of sound for me and even that’s not completed yet.

Who was it in the great history of this site that said: “It’s All About the Music” ?

That statement is sooooo true.

Presently, it’s more fun playing with a few MC cartridges and SME 3009 arms and vintage turntables.

When the smoke clears and the dust settles in my life, I promise I will be back on this wonderful site begging for help/advice and sounding just like a new comer.

fm

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Whoa...........Frank speaks again. LOL

I believe you use some old Carver Phase Linear amps (aka Flame Linear). I had always remembered How Roy didn't have much good to say about Carver gear when he and Larry dropped off my 90s. After 2 years of dealing with lack of bass response at low volumes and being less than totally pleased with my modified Carver M-1.0t MkII pushing 510 wpc RMS

http://carvermk2.com/m10tmkII/m10tmkII.htm

I bought a new Emotiva XPA-2 Gen 2 class A/B amp at 500 wpc. Like day and night! Good-bye Carver. Just sumpthin' to keep in mind.

Thanks for the input.

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DavidR man, man DavidR, yeah but dem Carvers are 'Magnetic-Field' what-evers!

Bob C. was extremely prolific and can only be spoke of in his many periods of device development and the in between periods that separated each line of components. Personally I care for the ballsy, raw, stump pulling series one and series 2 stuff, after I kind of feel he swayed somewhat. His speakers are appealing also, though I never heard any, they seem to get good review and their designs are interesting.

Seek info on his newer tube amps and such, seek-out his history, quite a mind that he has, he’s wild and more than likely always was, in a good, and productive way I assume since 1972.

My 700 Series Two amps are completely rebuilt by those two great guys (original PL employees Ed and Dean) in the state of Washington and these amps are originals in 9.5+ cosmetic condition and are entirely in better electrical playing condition, better than new, really.

Main power ‘caps’ have been upped to twice their original capacity, 36 of the semi-conductor devices are new “On-Semi” (Motorola XX24s and 25s). Their face plates are blindingly bright and clean with an as-new appearance and the same newness inside electrically speaking, Ed was very thorough. Anything that may have been deficient from original was replaced at $1,000. a piece + $60.S/H.

That's to say: these amps are full-time ‘on’ and ready to give all of the amp power anyone could ask for in a home, there is a difference ya know?

Those amps you speak of are throw-backs to Carver’s ‘Magnetic-Field’, and “The Cube” amp era, an attempt at power on demand which many other newer lesser amps utilize today this was after PL went down and he moved on. Speaking of my amps, they're always‘balls-to-the-wall’ ready to go, 24/7/365 plus Beatles, Eight Days a Week and that too, cause that power is there ‘full-time’! You want fries with that? Has anyone ever released the count of numbers produced and actually sold? It’s almost like the 12,000 B-17’s and 16,000 B-24s produced.

I don’t know of many present day amps, except what other speak of and others that are in use today at high dollar areas for home or pro-sound reinforcement.

VTL or Boulder Tube-amps. Krell, ML himself etc, etc, they're many others out there I'm not aware of. For some reason I don’t believe those amps would have the same tone-quality though. I think and feel the same about my AR speakers, obviously! There are some extremely well versed, driven, rich and couldn't care about the dollar costs but, I drew my line years ago.

I remember coming off of a two month trip driving all across the great south west of this country in summer of 1973 when I called my family from Arizona and was told by my mother, a friend had bought me and my girlfriend, the beautiful Maria P. tickets for “Pink-Floyd’ in central jersey for the introduction concert of “Dark-Side” at the outdoor venue “Roosevelt-Stadium”. They had used PL amps by the score, I’ve read they used over 20 PL-700s and 30 PL400s. All of the amps were not revamped to use the new ‘fully-complementary’ circuitry, but of the original design. I’m sure the company who powered the concert had back-ups, but as an audience member, I didn’t hear or notice any break-downs or gaps in the sound?

I have never heard as big sounding PA since. The following year, I bought my first PL400 amp, still have it, but she needs a rebuild.

It’s like the newer cars today seem very powerful with 4 and 6 cylinder engines, but I won’t drive into a tree with them as I would’ve done with my 5500+ pound 1973 Buick Riviera with a 7.5 liter big block. Nor do any of the newer pieces of spit and plastic carry that feeling of again- 'balls to the wall' power and resiliency, stump-pulling power, like yesteryear power did!

Forgive me. All here, but I have the same intensity of opinion for my amps as I do about my LSTs! Mule like and happy with it!

That’s why I’m here, I guess? Have mercy on me.

Speaking of my PL700s, they do put-out 550 to 700+ watts RMS /at 4 ohms per channel before clipping, they usually are just cruising along effortlessly and only warm to the touch even when reading 95+ degrees at the heat-sink. They are fan-cooled and utilize the full-complementary circuitry. I even use small digital thermometers above the heat sinks and dependent on ambient room temps and how at average volume range anywhere from 85F to 105F degrees, when I get crazy and it's a way of life, I should add, the two amps will draw up to 5amps according to the outboard power filter meter, it's driving over 200+watts at 4 ohms per speaker. I sometimes push about 275+watts/4 ohms with insanity controlling my mind, that's when usually correct myself and calm down before I damage the speakers.

I once thought of placing very small DC fans at each 2 amp fuse post on the LSTs. It's a fact, LSTs really are dependent on many watts to get them sounding at their best! In fact rite now I'm listening to a vinyl LP, the Doobie Bros. 'Stampede' at approx. 87+DB peaks and the amps are drawing 4.1amps, AC voltage from the wall is down from 120 to 118.1Volts, amps running at 99degrees, yet the amp's heat sinks feel only warm to the touch,

There is much misunderstanding some people have about PL amps. Once the amp’s circuitry that was later utilized by Phase Linear to build ‘pro-amps’ for the “Claire-Brothers’ and others, pro-sound reinforcement for the commercial segment was then later used in the consumer sales, and everything was changed as far as reliability goes. but it may have been too late when PL did make that change. When you look at the numbers produced it's staggering how many are around and most were used and abused to boot. We're talking 40+ year old amps today.

I truly do enjoy their sound quality and have for what, forty years now of personal ownership.

Research 1970's ‘Clair-Bros.’ and other world-wide pro-sound-reinforcement companies from the ‘Golden-Era’ and you will see these are a different animal than most of the world is aware of. Pink-Floyd, The Who, Queen, etc used PL. For me, a dyed in the wool AR-LST lover set up my ultimate system only with vintage gear and only what I was able to afford and especially liked for many reasons.

I, for one, abused my early PL’s as flirting with power like that because it was never before realized by myself or the rest of the world. Most other peeps and myself didn’t understand what this new PL power for the masses was, and didn't care, the power hungry mentality simply enjoyed the results.

I have total confidence in my main amps and assist them by using 4-inch fans on the heat-sinks full-time. I have no fears as I used to have while using the PL400’s. When I send my PL400s to “WattsAbundtant” to be refurbished, after which any fear will also disappear, with higher capacity power transistors, power caps, and a DC cut off circuit.

One of the only fears is the 4-ohm rating of the speakers which could present difficulty at times, a challenge for almost any amp, vintage or new, of course perhaps not for those newer Crowns and QC that has been mentioned on this site. I can’t creditably explain how much LST speakers absorb in watts just to run at somewhat high volumes, cause I don't believe it myself. Julian H.’s report from when he first tested the LST’s back in 1972 talked about this need for power to run them.

fm

*Cell-phone photo taken by a close friend a few months ago with available room light, bad lens distortion and other digital artifacts. The main speakers need to be placed closer together, but that may blend the 'stereo' effect too much.

Pardon the messy debris in the room, but I’ve got over 4700 vinyl used LPs and struggle with the aspect for room placement as only 1200 are in the room shown!

The other set of LSTs wrapped in black plastic on the left are still in the way of the main ones. I'm at the saturation point with too many speakers now, but can't bring myself to edit the collection down. Phone camera makes everything seem closer than it actually is.

fm

 

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If you're happy with your gear that's fine. I go back quite a ways with Carver gear and have (and had) lots of Carver stuff. I know about Bob's new tube amps but can't afford the price. All the Carver mag field power amps (Class G) have very little damping factor and it shows when you compare it to a modern amp with a Class A or A/B design. Lots of amps will out play his designs. Its not just about RMS watts or dynamic headroom. I will say my TX-11a tuner is still the best at pulling in stations; even better than my modern Rotel RT-1080.

Peace.

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