Fulton Musical Industries

[Brian Beck]

PS: I would urge caution when handling that white powder on the frames. It might contain toxic cadmium or chromium compounds. Since the base metal is steel, the white powder has to be the product of the corrosion of the originally-yellow coating or plating. If you must disturb it, I would do so outdoors with gloves and a respirator on. I may be overly cautious here, but better to be safe than sorry. Perhaps others with a metallurgical background can comment.

 

[jglennny1a]

J Woofer terminals, crossover, back

Hi Brian,

Thank you very much for your reply, and the warning about the residue.

I've posted photos of the terminals, open back, and crossover. Even though I had read about the car solenoids, it was kind of a shock to see them all. There is some more of that residue on the brackets holding in parts of the crossover, and at the terminals to the solenoids. I didn't touch that.

I'll upload these photos and respond to your questions in a separate post.

Best,
John

 

[jglennny1a]

J Woofers' provenance and future hopes

Hi Brian,
This pair of J woofers was purchased new sometime before 1977 for use in a system with Magnaplanar Tympani III tweeter and midrange panels (see attached diagram. Mr. Fulton made passive crossovers (what I assume are high-pass filters) for the signal cables going from the power amp to the Magnaplanars. This diagram does not show the ARC D76 that Terry eventually used to power the Magnaplanars, and the ARC EC4 crossover (at 100 & 1000 Hz) that he used to separate the signal after the ARC SP3 preamp to the D76 and PhaseLinear 400 he used for the J woofers.

My professional background is in film, video, and audio production and post production. I have a lot of options when it comes to mid-tweeter to try with the J's. This may sound like blasphemy, but my first instinct is to put my Yamaha NS10's on top of the J's and go from there. Probably anathema, but I'll see how it goes. I have numerous other options for the “satellites” including Focal Solo6Bes, Dynaudio BM15s, BlueSky System Ones. And I could always look for a pair of FMI 80s.

I don't know whether the J's play. Thanks for the reference to the eBay seller who has the NOS 12" drivers. They seem quite reasonable in price. That residue is worrisome, as you pointed out. There is also the same residue on some of the crossover metal parts. I laughed when I saw it on the solenoid terminals--it looks like the kind of corrosion you'd see on a car battery terminal. But the solenoids themselves are impressively clean and shiny.

Not sure what to do about that corrosion for the moment, but it does make the re-sealing the cabinet with weatherstripping a priority if I’m going to bring them in my house to see whether they work. When I opened the back, it looked like there had never been any sealing gasket.

My main goal is to use the J’s as subs/woofers for one of the sets of monitors I already have. I have three Bryston 4BSTs and two Bryston 10B crossovers, so I’ll start with that set up. I also have an ARC D76, which came along with the J’s from Terry’s estate, but I don’t know yet whether that’s working. Another friend inherited the Magnaplanars and they are due back from the factory this week after refurbishing, so we may try to reunite that system, which was a great musical experience.

I have the original manual for these Js, and it’s a bit different from the one on the AK site (which I think you may have uploaded, no?). I’ll work on shrinking the PDF for upload here.
In any case, the last page, with the diagram for terminal wiring for Tetra Amplification with an external crossover has some hand-drawn notes. I’ll upload that page.
What it boils down to is the following
-The top two horizontal strips are irrelevant, since they are for mid/tweet.
-In the diagram, there are shorting plugs in both the bottom two terminal strips, Upper Woofer and Sub-woofer
-In the instructions, it says to remove the shorting plugs from the Upper and Sub strips
-Shorting bars connect neg. to neg and pos. to pos from Upper Woof to Sub Woof
-Signal cable from the power amp is connected to the SubWoof strip.

In other hand drawings, this arrangement is marked for subwoofer crossed over between 90-100 Hz. Slope is not indicated. The same drawing says that pulling the shorting plug on the Sub strip would allow crossover at up to 110Hz, and that pulling the Sub strip’s shorting plug will yield more bass.

I’m trying to make sense out of this.
What does the shorting plug do?
What do the shorting bars do?
--I mean what effect on the crossover do they have? Point, slope, gain balance? Is this information known or documented anywhere? I assume the points of the internal crossover are what the manual is suggesting for the points to be used by an external crossover. I have to say, a 64Hz crossover point worries me. So many rooms have an acoustic bump around that frequency. But who am I to say. I’ll experiment. Fortunately the Bryston crossovers will enable that.

What I am planning to do initially is leave things the way I found them, follow the diagrams I have (even though they are somewhat contradictory regarding the shorting plugs), crossover at 100Hz to the “satellites” and see what happens. I’m assuming that this arrangement is somehow using the internal crossover between the sub and upper woofers, despite the fact that the full spectrum (<100Hz) of signal is being sent to both sub and upper via the shorting bars. I’m speculating, but maybe pulling the shorting plug takes the internal crossover out of the signal path, and each driver gets the <100Hz signal and it produces what it can based on the laws of physics and each driver’s inherent limitations in its enclosure. But obviously I could be way, way off.

Are there any Never-Do/Must-Do’s regarding removing/installing shorting plugs and bars? Don't want to ruin anything or get electrocuted. Those solenoids look dangerous.

Many thanks,

John

 

[Brian Beck]

Wow, a lot to digest here. I had guessed that these might be set up for Maggies after seeing your posted sketch depicting panels of some kind. That would make sense in that "70s" time period, and you've since confirmed it. Your crossovers are different from the usual J Modular configuration intended for use with FMI-80s. The J crossover typically used "only" 5 solenoids, not 8. I'm guessing that your woofers were specially made or modified, as Fulton often did, for use with those Maggies. Therefore, making them work with 80s in a J Modular configuration would likely require a complete rebuild of the crossover, and might be in the "too hard" category, depending on your abilities and wishes. By the way, do not fear electrocution from those solenoids. They're harmless electrically, unless you're pumping hundreds of watts of audio into the woofer with the backs off and probing things with wet fingers - pretty unlikely. But that would be true for any speaker driven very, very hard. As to the white corrosion powder, I had it in mine too, not only on the woofer frames but on exposed metals in the crossover parts. A friend did my crossover refurbishment and he cleaned it all out for me. I would have cautioned him about the possibility of toxic compounds on the speaker frames had it occurred to me then. It may be something harmless such as a zinc compound, but I really don't know. My guess is that formaldehyde has acted as a catalyst to promote this corrosion, whatever it is. The particle board used to make these cabinets would have outgassed formaldehyde for a few years after construction into the enclosed interior space. Also, manufacturing processes for fiberglass batting is known to have used formaldehyde. Normally these raw materials would slowly release this vapor into open spaces where the concentration can't build up. But inside a sealed speaker cabinet, the formaldehyde levels might have gotten pretty high. Just a guess. I'm sure there's nothing to worry about with regard to formaldehyde now, nearly 40 years later. But the lingering effect on the internal metals is visible. I would just leave it alone and replace the gasket when you reseal the system. It's doubtful that it could have much of an effect on the crossover's electrical function, except for the wipers of adjustable pots, which you can squirt with a contact cleaner and exercise repeatedly.

In my opinion, it would be best to reunite the original Maggie-Fulton system. Is that a possibility? Can one of you "buy out" the other? That is the only system that you know has been set up correctly (assuming you still have the passive crossovers shown in the sketch). Otherwise you've just got to try various "satellite" options and listen. As to the jumper configuration, I really don't know how he had this crossover wired. I was planning someday to do a detailed circuit analysis of the J crossover, but I just haven't had time. Anyway, yours are different. Maybe Jeff Medwin, if he's still monitoring this thread, will have some thoughts. I wish I could help you more on the crossover set up. I think your instinct to just follow what Fulton had sketched out makes the most sense, especially with Maggies. The J Modular instructions might no longer apply in this unique case.

Keep us posted.

 

[Brian Beck]

From http://corrosion-doctors.org/Principles/Theory.htm:

"Corrosion is the primary means by which metals deteriorate. Most metals corrode on contact with water (and moisture in the air), acids, bases, salts, oils, aggressive metal polishes, and other solid and liquid chemicals. Metals will also corrode when exposed to gaseous materials like acid vapors, formaldehyde gas, ammonia gas, and sulfur containing gases. Corrosion specifically refers to any process involving the deterioration or degradation of metal components. The best known case is that of the rusting of steel. Corrosion processes are usually electrochemical in nature, having the essential features of a battery."

 

[jglennny1a]

"My grade in metallurgy class was a J"

Hi Brian,

Thank you once again for your thoughtful and kind consideration and response. I'll check out the corrosion-doctors.com site further.

I showed the photos of the white powder on my driver and a photo of the NOS driver from the eBay seller of the NOS RTR 12" to a friend who is a highly experienced art conservator specializing in sculpture and objects (i.e., a metallurgist and electrochemistry PhD) and she said:
"Heavy metals in coating materials is a real concern so you should be hyper cautious. I'm not sure what to recommend. You need to get all the power off before you bring them into your home. Wet paper towel would be an approach, placing the speaker into a plastic bag so that as you wipe them down all the powder drops into the bag. Buy disposable gloves, a respirator is only as good as the fit. You could get one of those white masks at the hardware store, making sure it is rated for use with mold (those white masks have gotten fairly sophisticated over the last few years, and often there are several to choose from, or order some over the web)."

I'm also going to call the eBay seller and ask him what he thinks. He must have dealt with this before, since he talks about restoring speakers on his site.

Interesting regarding the different crossover. Based on the documents I have, there appears to have been a lot of customization done on these units. I don't have the Fulton-made crossovers, but I'm uploading now one of the circuit diagrams that are among the papers. It looks like it might be some kind of filter or crossover. There are some other, rougher versions of this circuit on other pieces of paper. I'll upload them if you're interested or think someone would be. It's like a detective novel.

Another "customization" on these J's appears to be the unfinished wood slat across two thirds of the rear port/vent for the down-firing woofer. I thought it might be just something Terry added a little haphazardly, until I inspected it closely: the fit is very tight, and the wood on the inside in both units is mitered at the same angle, somewhat less than 45 degrees, and with the exact same size opening.

I will keep you posted on my progress.

One last question: given the concern regarding the possible toxic corrosion on the 12" driver, and the severity of my metallurgist friend's warning, I feel obliged to check the 10" driver. I've found no way to access it without damaging the particle board. Any ideas?

Best,

John

 

[Brian Beck]

Your chemist friend seems to know her stuff. But, if you simply reseal the cabinet, nothing is going to get out into your house. I think you risk more exposure by trying up clean it outside even with mask and gloves. I'd leave it alone unless you really need to fix something.

The 10" woofer is accessible from the back with the main cover off. At the top there is a smaller enclosure. Follow the wires up from the crossover. You'll see screws that can be removed. This driver has a rubber surround and it usually survives the decades in great shape. As long as the voice coil doesn't rub you're OK. I rotated mine 180 degrees when I remounted to orient the pull of gravity in the opposite direction from that of the first 40 years, just as a precaution. Some have re-coned this driver, but I think that's a mistake unless they are obviously damaged. Usually these are the best preserved of the Fulton drivers. It's nearly impossible to duplicate the stiffness, mass, spring constants and damping properties of the original cone, surround and spider with new materials. "If it ain't broke, don't fix it."

The J woofers I've seen all have a section of 2"x4" wood covering the rear of the bottom slot. Fulton might have experimented with a shorter piece for his client in this particular Maggie system. Probably original and I would leave it alone.

The sketch shows simple line-level crossovers before the power amps in a bi-amplification arrangement for the Maggies. These would be pretty easy to build into a small aluminum box, but again, it all depends on your goals. I guess what I'm suggesting is that you decide what you want to do with the woofers first. Reconstruct the original Maggie system (you could do worse!) or add small satellites? Otherwise I wouldn't be "fixing" anything yet. Hate to discourage DIY but you may not even need to do any repairs here.

I will be traveling for the next several days, so, if I don't reply to this thread right away it's not for lack of interest. Maybe someone else can chime in too.

 

[jglennny1a]

HazMat R Us

Hi Brian,

I think I'll get some good gasket material and seal it up for now, at least until I can see if things seem to be functional. If things aren't working then it's a whole new ballgame.

I'll let you know what happens. Safe travels and thanks again for your gracious assistance.

John

 

[Loupgarou]

Some FMI-80's on ebay now...
http://www.ebay.com/itm/Vintage-Aud...rs-/261541471632?ssPageName=ADME:B:SS:US:1123

 

[jglennny1a]

J Woofers on eBay now

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=161376747435&

They look like they're newer and in better shape than the ones I recently acquired. The shorting plugs look newer. The screw-gain control is in a different place. In the photos they look to be in better shape. The crossover has fewer solenoids than mine.

And most importantly! No mysterious and possibly toxic white corroded residue on the downfiring woofer frame, as the J woofers I just got have.

I do have some relevant news on that: my Art Conservator friend with the x-ray fluoroscope has agreed to test the residue for toxic heavy metals. I will keep us posted on the progress of this testing. It will take a couple-three weeks. But I can't move them into my house and test them without knowing whether I would be introducing toxic materials. (if you're interested in more details, PM me and we can talk.)

One salient item in the eBay photos is that I see the exact same unfinished wood closing off the rear port of the downfiring woofer. That provides real evidence that this is a real Fulton mod.

Unfortunately, if the x-ray fluoroscopy testing reveals toxic metals in the corrosion, the J woofers I have will need to be disposed of in a responsible manner. I would never bring them into my home, as much as it pains me.

If you are interested in buying these J woofers on eBay, I strongly suggest you ask to see both 12" and 10" drivers to see whether they have any residue. The 10" drivers are hard to get to without damaging the particle board that the inside of the cabinets are made from. I couldn't open the compartment for mine without risking damage, so I don't know their status. But they're easy to get to as described by Brian previously in this thread. Unless they are hermetically sealed somehow...

Bottom line: I will post the results of the x-ray fluoroscopy of the residue asap. These J's look much better than the ones I have. At a current price of $9.99, they look like a major bargain.

The storage facility where I have my J Woofers at the moment is adjacent to a bridge over the Gowanus Canal in Brooklyn, which is already an EPA Superfund toxic clean-up site. If I discover that the corrosion residue is toxic, I may be bidding on these clean-looking J's and watching my old J's become one more item for the EPA to dispose of. Just kidding. But it's tempting.


Best to all,

John

 

[atmasphere]

I used to have Js and Premieres many years ago.

One way I have used to remove cadmium dust from previously cad-plated metals, is, using a dust mask, spray some WD-40 onto a paper towel and use it as a dust rag to collect the dust from the object in mind. No good solutions here BTW- if there is a place in town where you can deposit toxic materials that is the way to dispose of the paper towels (store them in a plastic bad for disposal). This technique is not perfect- it relies on you to be thorough. But it can get you by in a pinch.

 

[jglennny1a]

Thanks for your response and the advice on mopping up the residue. Much appreciated.

The first thing that strikes me about your response (and please forgive me if I'm incorrectly reading into what you wrote) is that it seems you may have some knowledge that the original drivers' steel frames were cadmium-plated. Is this so, or am I just reading in too much?

In any case, from the research I've done since discovering the corrosion residue on the 12" woofer, and Brian's caution, it seems that cadmium, zinc, chromium, and nickel, or a combination of these were commonly used before the use of cadmium in non-essential (national defense, medical, etc.) manufacturing was limited due to the discovery of its toxic effects.

There is a full article on Cadmium Poisoning in Wikipedia: http://en.wikipedia.org/wiki/Cadmium_poisoning
An excerpt: "Cadmium is an extremely toxic metal commonly found in industrial workplaces. Due to its low permissible exposure limit, overexposures may occur even in situations where trace quantities of cadmium are found."

I don't see how I'd get rid of trace quantities without a total rebuild in a clean room. These are vented woofers spec'ed to produce frequencies down to 16Hz. That seems like an ideal environment for trace quantities to escape via the vents.

I'm sure I could find a way to dispose of the cadmium responsibly--if that's what it is. But could I ever be sure that I had gotten rid of it, or at least enough of it (whatever that might be) to feel comfortable bringing the cabinets into my house? There is just too much chance for stray particles to circulate and breathing it in, as opposed to skin contact, is the most dangerous form of exposure.

As I previously wrote, I am going to have the residue tested by people who are professionals in art conservation. As you may know, cadmium is used in many paints, and the other metals are used both in paint and in the creation and fabrication of non-painting art object--sculpture, etc. The art conservators are not only scientists with the expertise and equipment to provide a specific analysis, but are qualified to advise their clients about what should and should not be brought into one's home for safety concerns. I'll let everyone in this forum know the results in detail. I hope to have them in a few weeks.

Maybe it's just zinc oxide and I can mix it with Noxema and sell it to lifeguards for their noses. I can hope--there are current electroplating services that claim to be able to do zinc plating with a yellowish glow that looks sort of like the plating on the NOS RTR 12" drivers now being sold on eBay. I don't mean to sound an alarm about this unnecessarily, but it seems like we really ought to know about this.

Sorry for the long post: in summation (in other words, even longer):
1. Thank you atamasphere for your cleaning recommendation. Please advise if you have knowledge re: cadmium plating of the original drivers
2. I will post the raw data and recommendations as soon as the test results are back.
3. Does anyone know someone involved with the original manufacture of the drivers who could be informative regarding the electroplating of the steel frames?
4. I still would need to open the chamber for the 10" front-fring driver to examine it for residue. Brian graciously provided a step by step process of how to do that, which I followed, but the particle board is crumbling like burnt toast when I try to remove the access panel into which the leads to the driver are going. My option seems to be to get in there no matter what and make a new piece of particle board if the tests come back non-toxic. Any other suggestions on accessing the 10" driver from the rear?

Many thanks and best to all,

John

 

[Brian Beck]

Not vented

John,

A small point perhaps, given the heightened concerns here, but I wanted to discuss the "vented" issue. My J woofers are sealed, not vented. I've never seen a vented J cabinet. The front of the 12" down-firing cone is slot-loaded through three side slots, but the back of the driver, where the corrosion exists, is sealed inside the cabinet and is not in contact with the outside world (unless you open it). With new weatherstripping gaskets, these cabinets should be tomb-tight. The cone itself is a barrier from the back to the front. The exposed front surface has no exposed metal frame. The same is true for the 10" driver. Unless you need to replace a driver, best not to touch anything. Attempting to clean it up will almost certainly expose you to more of whatever this dust is than simply not disturbing it, even with gloves mask, WD-40 and a strong back wind.

RTR made these woofers. One of the two RTR founders recently passed away and the other is strictly incommunicado. I think your chemist will give us our answer. By the way, over the years, I've opened several old speaker cabinets to find similar corrosion products. I don't think this is unusual at all. Ditto for old amplifier chassis (never mind the lead solder!). I was too casual back then. I'd be more cautious now with any old speaker.

Perhaps the best advice is to treat these woofers like Indiana Jones would treat the Ark of the Covenant in Raiders of the Lost Ask. "Don't open the lid!"

 

[jglennny1a]

Ark Enlightened

Brian,
Thanks--right you are about “vented”--my bad on the nomenclature and conceptual understanding. I found an interesting piece at http://www.hifizine.com/2012/12/subwoofer-origami/ which has diagrams of many types of woofer baffling/loading schemes. However, I don’t see, at least as I understand it from looking and taking apart my J's, their design, though I may be mistaken.

The J's are unusual, in my experience at least, in that the front and rear slots are "vents" only in the sense that they vent the force created by the pressure of the woofer in that bottom, sealed space. It's unlike a vented or ported speaker or even a transmission line, which depends upon sound pressure from the back side of the woofer to have an escape route to the outside atmosphere with consequent acoustic effects.

Your analogy is both apt and hilarious—shut tight like the Ark of the Covenant, the J’s are two sealed-box drivers. Even Indy didn’t open the Ark.

Thanks for the clarification.

Best,

John

 

[jglennny1a]

Free J Subwoofers

I have been unable to progress on rehabilitating the pair of J subwoofers I got last summer and have posted about previously. I appreciate the generous advice I got in that quest.
But I can't store them any more, and I'm offering them for free to anyone who would come get them. I'm in Brooklyn, NY.

I have more photos if you're interested. You can see some earlier in this thread.

Please PM me if you wish to discuss.
Best,
JG

 

[JoshHendi]

I have been unable to progress on rehabilitating the pair of J subwoofers I got last summer and have posted about previously. I appreciate the generous advice I got in that quest.
But I can't store them any more, and I'm offering them for free to anyone who would come get them. I'm in Brooklyn, NY.

I have more photos if you're interested. You can see some earlier in this thread.

Please PM me if you wish to discuss.
Best,
JG

I think I saw your CL post a while ago and emailed you about these. What ended up happening to them? If they are still sitting around, shoot me a PM

 

[jglennny1a]

Good home found for J woofers

Hi Josh,
Yes, that was me on Craigslist. I posted the free offer here on AudioKarma for a while and was surprised to get no responses--my apologies for missing yours. But I did find someone who seems quite worthy of bestowing the J woofer cabinets upon. His name is Lars, and he just joined AudioKarma with the handle DuaneReade for the purposes of possibly getting some help with getting the J woofers up and running. I'm going to help him, but we may need to call in the cavalry.

In any case, I do have all the documentation from the original owner, and I believe I have most of it scanned, and I'd be happy to share all that stuff with the Fulton-interested community. I have a DropBox site I'll put it on and make it public for download.

I'll post an update in this thread regarding the migration of the cabinets and the availability of the documentation. I'll also PM you back when the DropBox site is set up.

Best,
John

 

[JoshHendi]

I found a FLAC recording composed and engineered by Robert Fulton.

Lincoln Mayorga - The Missing Linc

Needless to say, pure amazement and enjoyment listening on the J Modulars.

I will upload if anyone is interested?

 

[JoshHendi]

Does anyone know if the 10" woofer in the FMI-100 was the same used in the J Modular bass cab? While I do have both, I do not plan on getting to the 10" driver in the J's anytime soon. Mainly just curious...

As far as the drivers Fulton used, I have this so far...

ESR-6 tweeters from RTR, modified by Fulton
Peerless MT225 tweeters, used in the 60s, 80s, 100s
Rola 8" woofer for the 80s
RTR 12" woofer, downfiring in the J bass cabs

 

[timsclips]

I have been listening to a fully restored set of 100's in my computer room. Love the Peerless tweeters and I believe this uses a RTR 10"woofer. Very deep bass for an average size box speaker.