Super Tower III HELP NEEDED! Tweeter circuit problem.

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oliverbubbles

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Post has been modified as I found problem and info on it. More info after initial post. Thank you for any help you may offer.

Been a fan of any VMPS I’ve heard for a while. Have only been around the vintage models and subs. Own several. Last week I was lucky enough to purchase these along with some BK gear after talking to seller for a few months.




Let me first say: HOLY CRAP these things are HEAVY! I don’t think the 300# each I’ve seen them described as is a stretch at all. And massive! Only other speakers I have dimensionally bigger (from front perspective) are my Acoustat 2+2. And these things do not get visually overpowered by those.
Only the normal things wrong: the passives needed refoamed (or replaced), and one of the JVC ribbons is shot. All else is great. I had some spare already foamed matching passives from early tallboy subs. Swapped them in. Putty appeared to be very similar for the tuning. This brings me to my first question: with the difference in cabinet sizes between the tallboys and the STIII’s I would think tuning to be at least somewhat different. Here’s a pic of the passives.




Very little putty on these and no lead weight that I can see.
The original passives looked to be identical other than the putty is a little messier.
Anyone have thoughts on this very low amount of weight for tuning?

Next is the bass driver compliment.
These STIII’s appear to have the same 15 as the earlier tallboys, only with a black cone instead of the earlier white. Are these the same? Or is the earlier or latter (white vs black cones) better? I have spare white cone versions. Pics:
. White cone version.

black cone version with phase plug. The white cone has dust cap.


The 12’s look like normal VMPS 12. Similar to the original in the tallboy? But with phase plug and RUBBER surround. The rubber surround is something I’ve not seen on the classic VMPS before.




The 10’s are a driver I don’t recognize at all. All carbon fiber look. Even the dust cap. Rubber surround and rubber gasket. Cast aluminum basket.





Mids are carbon looking cones, phase plugs, rubber surrounds.


 
Focal tweets with JBL (or possibly clone) ribbon tweeters.

So, the biggest question: does anyone have an extra JBL or clone? Or know of a good replacement that I could replace both with (proper crossover updates would be needed)?
Also, a couple of the focal surrounds are deteriorating slightly. I’ve ready the replacement for these is the later Morel, which is not nearly as liked. So I would prefer to repair these. I know the foams used to be easily available pretty cheap. I’m having a difficult time finding those at present. Does anyone know where the focal surrounds can be found? Or a sheet of proper foam material to cut some from?

On a couple more notes:
I have a set of Misco 12’s and a set of Goldwood 15’s.
Would either of these be better to use than the VMPS drivers? I know the Goldwood is a better built driver. But will it actually improve things?
Is there an acceptable upgrade for the passives at this time?


« Last Edit: 4 Jul 2022, 01:04 am by oliverbubbles »

davidc1

Re: Super Tower III new acquisition and questions.
« Reply #1 on: 19 Jun 2022, 09:09 pm »
These are interesting. It appears you have one of the later models of the STIII, yet you have the old JVC ribbon super tweeter. I'm thinking the original super tweeter must have been replaced. These are not JBL, they are JVC. These were the first ribbon super tweeters Brian ever used. You will very occasionally find them on eBay. I'm trying to remember the name, and better regarded one's that were original.


I just purchased some STIII's last year and have redone surrounds on the 10's (they were foam) and all the Focal 120's. You must have missed my post about fixing them.

If you take a close look at the Focals, you'll probably find that many of them have surrounds that are disintegrating or or pulling away from the diaphragm.

You can have Focal repair them, for only about $60 each plus shipping to NY. They pay for return shipping. However, they will replace the fiberglass diaphragm with the titanium one. It will probably take a couple of months.

You can also just replace the surrounds yourself. There is a company from the Netherlands that make the surrounds and publish videos about it on YouTube. They sell through eBay or direct.

Keep in mind though that this repair is labor intensive since you have to clean off all the goop, be careful not to misalign the VC, or break the delicate wires.

I had mine replace using the surrounds I mentioned, but the work done by a local but well known speaker repair guy for about $70 each.

If you are interested, reply to this post and I'll give you more info.



oliverbubbles

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Re: Super Tower III new acquisition and questions.
« Reply #2 on: 4 Jul 2022, 12:26 am »
Thank you David.
You are correct: JVC, not JBL. Not sure why I typed that in that location while I got it correct in earlier location in same post. You are also correct: the focal surrounds could use a little love. They’re not completely shot, but have signs of starting the crack and release.
I have them playing and they sound great (at lower to low/moderate volumes). They actually always sound great! Never sonically falter, they just shut my amp down. Have already done in a Marantz receiver. On second Onkyo 7.1 TX-RZ610 now. They sound great. Again, if I try to crank them at all, they shut down the amp. Or maybe I should say, amp goes into protection mode. All drivers sound perfect with my ear to them. Even the tweeters and mids sound fine individually through a paper towel tube. Only the one ribbon not working at all.
How low does the impedance drop on these things? Is that my amp issue? I’ve been afraid to hook them to my Aragon. Don’t want to damage that unit. I can replace the others cheaper than I can fix the Aragon.
If it’s just an impedance issue, the Aragon should handle them all day long. Or I can use my BK 200’s.
Thoughts?
Help? Please.

oliverbubbles

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Re: Super Tower III new acquisition and questions.
« Reply #3 on: 4 Jul 2022, 01:01 am »
My last reply to David got me busy on the trouble. I currently have it narrowed to the tweeter circuit in the cabinet with the damaged JVC ribbon. All the Focals are working. But very close listening with just the high circuit, leads me to believe a crossover problem allowing too much low frequency signal getting to the tweets in this cabinet. I can hear a very faint vibration on certain music, in the focal of this cabinet that is not present in the other.
I have disconnected the ribbon from the circuit and it did not effect the trouble.
Would the burnt ribbon cause this in this “series” crossover design? Or us it more likely that the crossover issue is what damaged to ribbon?

Am currently using without bight circuit in this cabinet and the problem is gone.

duck851

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Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #4 on: 5 Jul 2022, 06:37 pm »



I have one good and one bad each of the Focal and JVC. I don’t think you’re far from me if you want them they’re yours.

oliverbubbles

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Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #5 on: 6 Jul 2022, 01:00 am »
That would be AWESOME!
That would save me from having to make crossover adjustments with different drivers.
PM sent

davidc1

Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #6 on: 6 Jul 2022, 01:11 am »
That's assuming of course that the crossover was modified before the JVC ribbon super tweeter was put in the speaker. Because again, I do not think that was the original super Tweeter... Almost absolutely positive about that. So, when the JVC was put in there was the crossover changed or not.?

oliverbubbles

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Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #7 on: 6 Jul 2022, 11:43 pm »
Tough there’s no way to be 100%, everything I’m seeing tells me that these are original as they are. Nothing looks out of place, from the messy factory soldering to the screw holes and drywall screws. All looks factory.
But the ribbon circuit (from the few schematics I’ve seen) does not appear to be part of the series circuit. It appears to be separate for the ribbon. So that should be fairly easy to verify as long as I can find a circuit using the Focals and the JVC ribbon. The Foster Ribbons, Beston ribbons, JVC clones, and authentic JVC would all use different crossovers I would expect.

Stimpy

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Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #8 on: 7 Jul 2022, 12:50 pm »
Just curious.  Do the JVC ribbons mount flush to the cabinet, or are they rebated into the wood?  I was wondering if that would offer a clue as to if the JVC ribbons are stock or not?

Also, Parts Express has Foster planar tweeters on sale very cheap.  Just $14.98 each.  If the JVC's don't work out, perhaps the Foster's could be a usable alternate?

https://www.parts-express.com/Foster-E100T10-Ribbon-Tweeter-8-Ohm-279-468

Good luck.

Oh, there's an eBay seller, that offers custom faceplates for that Foster tweeter.  That would make mounting much easier.

https://www.ebay.com/sch/Other-Vintage-Electronics/183079/m.html?item=194793728204&_ssn=chris-1111

oliverbubbles

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Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #9 on: 7 Jul 2022, 11:52 pm »
All the tweeters are routed into the baffle in what appears to be a single, continuous routing.


Thanks for the links. I’ll look at the Fosters. I wonder if they are same ones Brian used.
I need ribbons for my Super Towers as well. That may be an option for those.

I haven’t thought of changing faceplates. I have a good friend with a welding/ fabricating company. He could easily make on his plasma table. Great idea.

oliverbubbles

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Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #10 on: 8 Jul 2022, 02:15 am »
Stumpy:
That Foster tweeter at PE is an open back unit. Nice tweet at a great price, but would need to somehow seal the rear of tweeter to the rest of the cabinet. Not sure how that could be done without greatly affecting the tweeters response.
For the money, I may very well give it a shot in the Super Towers.

Stimpy

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Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #11 on: 8 Jul 2022, 08:57 pm »
Stumpy:
That Foster tweeter at PE is an open back unit. Nice tweet at a great price, but would need to somehow seal the rear of tweeter to the rest of the cabinet. Not sure how that could be done without greatly affecting the tweeters response.
For the money, I may very well give it a shot in the Super Towers.

Sorry about that.  I didn't even think about the Foster's being open back.  Maybe your friend could cut a new solid back plate, to block the rear wave.  That's what Infinity did with Emits.

davidc1

Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #12 on: 21 Mar 2024, 07:34 pm »
Stumpy:
That Foster tweeter at PE is an open back unit. Nice tweet at a great price, but would need to somehow seal the rear of tweeter to the rest of the cabinet. Not sure how that could be done without greatly affecting the tweeters response.
For the money, I may very well give it a shot in the Super Towers.

Good Afternoon,

I am also an owner of some ST III's. I am putting them back together after fixing the surrounds of the Focal T120 tweeters, but I've run into a problem with the woofer wiring. I've followed some diagrams, but the 15" is out of phase with the other 3 woofers.

Did you, by chance, take any pictures of ANY of the wiring or have any diagrams of it at all? The schematic on this website, which some people have said is correct, still results in the out of phase 15". Even if your pictures may just barely show any connections, that would be great. Thank you.

davidc1

Re: Super Tower III HELP NEEDED! Tweeter circuit problem.
« Reply #13 on: 2 Apr 2024, 11:14 pm »
and now, as I've finally finished the wiring, the woofers were ok. Turns out if you use the battery test to check for polarity, you have to do it from the cabinet inputs. I thought you could connect to any of the woofers and they would all respond normally. But, if you connect the battery to one of the woofers, three will be in phase, and one will be out of phase.