Fulton FMI speakers. Model and parts reference thread.

[JoshHendi]

I have the Fulton 100 series. I’m currently trying to repair one speaker, but without much luck. If anybody knows how to repair these, let me know. I left my record player and receiver on one night and heard a loud bang and the speakers no longer broadcast at full sound, but just really quiet. I thought it was the capacitor, couldn’t find an exact copy, so put in a similar one with no luck. I think all the speakers are fine, just need to figure out the power and if there’s anything else wrong with the crossover wiring.

If you haven't already, use a DMM and measure the resistance of each driver, and verify they are all okay and not blown. Also while you have the speakers open, you might as well replace the capacitors since they need it anyways. Dayton Audio films are a good affordable option

 

[Nitsuj2000]

If you haven't already, use a DMM and measure the resistance of each driver, and verify they are all okay and not blown. Also while you have the speakers open, you might as well replace the capacitors since they need it anyways. Dayton Audio films are a good affordable option

Thank you, Josh, I really appreciate the help, I’ll try doing that. I went all over Seattle trying to find that capacitor, but no luck, ordered a similar 6uf 50v capacitor but didn’t work, anyway, I’ll take a look at Dayton audio. Btw I see you’re in Spokane, my girlfriends from there and I actually got these speakers from her grandparents home in Richland. I’m having fun learning about their history and Robert Fulton’s unique way of doing audio, I think he was on to something.

Cheers,

Justin

 

[setup1]

I wanted to create the thread for the Fulton FMI enthusiasts as a reference/database for his products. There are some FMI threads out there roaming around, but want this thread to be the one-stop-shop for his products and parts information. I will continuously monitor and update this original post with any speaker models, parts, recordings etc that anyone can offer.

Please post replies with any additional information or discussion. Specific the driver make/model/stamps would be great. Below is what I can gather from memory and will add as much info as possible. Eventually, this original post will be the spot for FMI product information

Here is a Google Drive link where I will add all of my pictures and documentation, as well as any others posted on this thread.

---Speakers---
FMI-60
2-way, 2 drivers
Tweeter: Peerless MT-225
Woofer: Rola 8" - stamped 2203 25492

FMI-80
2-way, 3 drivers
Tweeters (x2): Peerless MT-225
Woofer: Rola 8" - stamped 2203 25492

FMI-100
2-way, 5 drivers
Tweeters (x4): Peerless MT-225
Woofer: RTR 10"

FMI-120
3-way, 3 drivers
Tweeter Peerless MT-225
Midrange: ?
Woofer: RTR 12" (stamped 2407 or 2409)

Fulton J Modular
4-way, 11 drivers
Super tweeters (x6): electrostatic panels
Tweeters (x2): Peerless MT-225
Woofer: Rola 8" - stamped 2203 25492
Upper-bass woofer: RTR 10" (Stamped 2405)
Lower-bass woofer: RTR 12" (Stamped 2407 or 2409)

Fulton Premier's

Fulton E Modular's

Fulton Nuance's


---Accessories---
Speaker terminal connectors
Brown's speaker cables (roughly 10 gauge)
Gold's speaker cables (roughly 4 gauge)
Turntable mat

---Albums (Label: ARK)---
Fulton Gold Series Volume I

Thanks for posting this!

I remember reading articles about Robert Fulton/FMI by Neil Levenson on Fanfare back in the 80s.

 

[JoshHendi]

Btw I see you’re in Spokane, my girlfriends from there and I actually got these speakers from her grandparents home in Richland. I’m having fun learning about their history and Robert Fulton’s unique way of doing audio, I think he was on to something.

That's funny Im actually from Tri-Cities

Yea Fulton was a legit genius when it came to music & electrical engineering. Im doing my best to collect as much of his stuff as I can (check the link in my signature). I have a few albums from his label Ark and all the recordings are stellar

 

[Murry]

I knew Bob Fulton and he stayed at my home during one of his Road Trips. I had the J’s and he updated them to the Premieres. I would like to have any information regarding the crossover components and speakers. I did keep the RTR electrostatic. The still sound incredible.

 

[JoshHendi]

@Murry you can use the link in my signature to view/download all the documentation I have collected on FMI

 

[Murry]

I am looking for the link, not the greatest computer guy, 81 yrs. But I don’t seem to know which button to press. Murry Kahn @hotmail.com

 

[Murry]

We’ll never know for sure. My guess is that it was some manufacturing mistake. I think RTR OEM-built the 80s for Fulton and probably the first batches were wired in reverse polarity. Since absolute polarity can never be guaranteed due to the random reversals in recordings, the 80 works fine alone either way. But once it needed to be combined with other drivers, as in the J, the 80 had to be connected in reverse. By then the 80’s internal reversed polarity had been perpetuated in the thousands of speakers already produced. So they had to keep the 80 consistently reversed. Just my guess. Things like that do happen in manufacturing.

 

[Murry]

I am looking for the link, not the greatest computer guy, 81 yrs. But I don’t seem to know which button to press. Murry Kahn @hotmail.com

I can’t say for sure about the reverse polarity. It might be because, as I was told, that the 80’s were originally used as a monitor when Bob was recording. The size was to go alongside his Revox which he had modified electronically. I doubt if he ever left anything as he found it and that included his own speakers. His constant tampering with the J’s caused Holt to break from his support.

 

[JoshHendi]

@Murry try this link: https://drive.google.com/drive/folders/1jLPmQd3EFOcIgeG8yR04mFyCryhd7fq0

There is a detailed copy of Premier crossovers in there (pulled from a different post, not mine). Though the tricky thing, as you said, is that the chance of two Js/Premiers being setup/wired the exact same is probably fairly rare as he liked to tinker and/or modify per fit

BTW, I will soon be listing some extra pair of FMI-80s that have not been getting any use

 

[Lenco803]

I took apart a set of my FMI-80s today for recap. These are verified original and the wiring in mine are slightly different than the schematic going around. Attaching both as reference. The difference being the polarity connection of the woofer

So, infact all three drivers are connected in reverse polarity, which is interesting because in the J manual, it advised to connect the 80s in reverse polarity to the main crossover unit, bringing the polarity back to 'normal'

I took apart a set of my FMI-80s today for recap. These are verified original and the wiring in mine are slightly different than the schematic going around. Attaching both as reference. The difference being the polarity connection of the woofer

So, infact all three drivers are connected in reverse polarity, which is interesting because in the J manual, it advised to connect the 80s in reverse polarity to the main crossover unit, bringing the polarity back to 'normal'

What type of connection are the tweeters in? Series? Is the cap seeing 16ohm’s total wired this way?

 

[Brian Beck]

In parallel.

 

[Lenco803]

In parallel.

Thanks Brian. I have a set of FMI 80's that I'm driving with Radio Craftsmen 500 amps and the combination is fantastic! My wooding working buddy is making me a new set cabinets and I'm going to build up another set. I was studying the x-over and it doesn't make sense to me.

Question: So the capacitor is seeing a 4ohm load from the tweeters (8ohm in parallel is 4ohms) and the cap value is 6uf. The x-over freq is 1600Hz but when I look up the formula for a 1st order x-over it calculates a 28uf cap. If the cap is really seeing 16ohms you get 6.2uf. Do you know what is going on here?

 

[Brian Beck]

I wouldn’t bank too much on the stated crossover point of 1600 Hz. It’s more complicated than just calculating the cap value needed to work with a 4-ohm load to achieve a 1600 Hz roll-off. The 6uF cap with 4 ohms gives a 6,600Hz -3dB high-pass roll off. But the tweeters are a more complicated load than a 4 ohm resistor and the woofer is rolling off mechanically. The Rola woofer has a smooth roll-off without big peaks and so no low-pass filter was needed. Essentially the Rola is almost a full-range driver and the tweeters are like super tweeters to just fill in what’s missing from the woofer’s response. It works…

 

[Lenco803]

I wouldn’t bank too much on the stated crossover point of 1600 Hz. It’s more complicated than just calculating the cap value needed to work with a 4-ohm load to achieve a 1600 Hz roll-off. The 6uF cap with 4 ohms gives a 6,600Hz -3dB high-pass roll off. But the tweeters are a more complicated load than a 4 ohm resistor and the woofer is rolling off mechanically. The Rola woofer has a smooth roll-off without big peaks and so no low-pass filter was needed. Essentially the Rola is almost a full-range driver and the tweeters are like super tweeters to just fill in what’s missing from the woofer’s response. It works…

Ok, makes sense now as the low end specs for the Peerless are pretty close to the high-pass design of the x-over.

 

[Lenco803]

I wouldn’t bank too much on the stated crossover point of 1600 Hz. It’s more complicated than just calculating the cap value needed to work with a 4-ohm load to achieve a 1600 Hz roll-off. The 6uF cap with 4 ohms gives a 6,600Hz -3dB high-pass roll off. But the tweeters are a more complicated load than a 4 ohm resistor and the woofer is rolling off mechanically. The Rola woofer has a smooth roll-off without big peaks and so no low-pass filter was needed. Essentially the Rola is almost a full-range driver and the tweeters are like super tweeters to just fill in what’s missing from the woofer’s response. It works…

Thanks for clarifying Brain! Another question. If I can’t get my hands on the 8ohm Peerless tweets could I sub 16ohm versions and drop the cap down to 3uf essentially would hit the same x-over freq?

 

[Brian Beck]

Thanks for clarifying Brain! Another question. If I can’t get my hands on the 8ohm Peerless tweets could I sub 16ohm versions and drop the cap down to 3uf essentially would hit the same x-over freq?

I can’t be 100% certain without comparing the complex impedance plots of each type of tweeter, but my guess is, yes, that should work.

 

[Dannyboy311]

So a pair of fulton nuances in.mint condition came up near me,
I had never heard of them, and started researching.
These were owned by a older woman, and look to be mint.
They want $600, I'm guessing that's reasonable due to rarity, I believe they cost $600 new in the 70s ironicly, here's a pic.
I love finding time capsule condition stuff like this, lol

 

[Tenknits]

Does anyone know what the pot at the back of the FMI 100s is supposed to do? The little pot just above the terminals. I have played with mine and can't discern that they do very much. Thanks y'all.

 

[JoshHendi]

Does anyone know what the pot at the back of the FMI 100s is supposed to do? The little pot just above the terminals. I have played with mine and can't discern that they do very much. Thanks y'all.

Tweeter level adjustment... All four tweeters should be inline with this pot for a simple volume/level adjustment. Wouldn't be surprised if it was limited on it's range/effect