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Fostex FE103/10f3 4" Fullrange Alnico Drivers!!

zastin17

zastin17

Active Member
So I was about ready to throw this Akai 1800d in the trash. Power supply was destroyed by rats!! But the deck was free a few years back.

As for parts I need, it was about done for!!
I decided to pull the drivers as mabye they would be something worth keeping or not. Assuming they would be just garbage drivers ide toss out.

And this is what I was greeted too!!!!!!!! My jaw dropped. I know what these are!! And I can't freaking wait to build a cabinet!!

The cloth surround looks to have pulled away from the inner edge a bit from sitting. But the outer edge is still perfectly attached very firmly.

I hooked them into my homebuild 6L6 amplifier and these are absolutely outstanding in "free air" iggnoring the lower registeres for now.
AMAZING!!!

The textured midrange coherence is absolutely remarkable!!! I can't quiet wrap my head around how these drivers are just doing it!!

The highs are soo clean, so crisp, and not rolled off!! Unbelievable coherence! Seriously some of the very best upper mids I've heared!! Just redicuos!!

I'm sorry. But i'm spellbound!!!

Through all the expensive Ribbons panels, and Magical Esoteric speakers I have owned and experienced, these little drivers are very special, that mutch is absolutely clear!!
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Unit about ready for the dump:) mabye ile take the feet and grills last. Tape heads are already pulled and given to a friend who was in need of them;)
 
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kevintomb said:
I am a bit confused.
You did not realize they sounded good until you removed them?

Or you never heard them before today?
Click to expand...
I did not know they where anything special since the internal amp never worked. And grill covered up the cones.

I just assumed they would be little crap throw away" drivers" once I took them out. Definitely not Fostex drivers!
 
I bet they'll sound good in cabinets. My 4" klh drivers give nothing but good mids and highs "unboxed," but in little cabinets, sealed or not, they shine more than they have a right. Keep us posted on your progress. Hell, your cabinet baffles are already there!
 
Obviously you've never heard them!

Also, they're fullrange. No tweeter needed. No rolloff either. Transmission line is what I'm going to build.

I ignore frequencies that would obviously make no sense outside of a cabinet. And yes you can!! You just listen to the driver itself. Open baffle is better.

Lower frequency are more effected by anything around the driver than mid or high frequencies. Which is why tweeters sound very similar regardless of where you have them located.

Next is open baffle for more fun.

I see the anniversary additions of these little drivers going for over $700 a pair just for the drivers themselves. Especially in Japan.

Also, why waste the time and money to even make an anniversary edition of these drivers if they where not sought after...
http://glowinthedarkaudio.com/akai10F3.html
 
This is similar to when you don't agree with some jasper and they say you haven't heard them or don't understand them.

Well, I both heard and understood, that's why I disagree.
 
The problem with the early red cloth FE-103 variants at this stage is that typically the cloth surrounds tend to become much stiffer over time than when they were new decades ago thereby reducing their already meager low frequency output and making the upper midrange and high frequencies more prominent.

The other primary drawback with these drivers is that the treated cloth surrounds by their nature tend to cause sharp response resonance peaks that add a "tizziness" to the sound that is very unique to this series of drivers.

Radio Shack sold untold thousands of these Foster/Fostex manufactured drivers to hobbyists over the decades with the points of manufacture moving from Japan, to South Korea, to Taiwan, and eventually to China. The earliest versions had the creme colored cones with the red/orange cloth surrounds which ultimately morphed into black cones with black cloth surrounds and the chemicals used to treat the cloth surrounds also changed over the years as well, some models being much more prone to the surrounds stiffening to the point the drivers become non-functional.

I've collected many of these drivers over the years for frankenspeaker projects as they are just an inherently good sounding midrange frequencies driver when functioning as they should. Have fun!
 
This is what I built.for these drivers. They sound incredible! Zigmahornet 1/4 wave!

Absolutely phenomenal drivers!! And I can use other fullranges aswell if I ever wanted too, with little to no modifcations:)

Did a simple Notch filter for that well known 7khz peak on Fostex drivers which some people like.
I don't, as beatifull as it is on some music and the cool tone it creates. I find it's bright for me.

So I installed a filter and this completely flattened that typical 7k peak and made the entire fullrange driver sound far more balanced and more responsive in deeper bass frequencys!

Such a simple 2x component addition completely changed the sound of this entire driver!

Intresting how that peak was effecting the entire drivers behavior and changing the entirety of the mids a bit. Can't remember the term for that but it's intresting how I need to think of the driver as a "whole" and not just one part of a system.
Just a different way I need to think about it. Fullrange is very cool! But a fun new learning curve for me!!

Incredible detail retrieval! Very comparable to planar magnetic in detail retrieval and Immediacy" really is amazing with the Dynamics to back it up!

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Those are really cool looking cabinets but the organ pipe configuration would likely tend to emphasize a certain range of bass frequencies. Vintage 4" extended range drivers are an interesting breed and if tempted you could always experiment with other drivers such as vintage Pioneer P-10L autosound speakers which also sound surprisingly good compared to the Foster/Fostex FE-103's.
 
zastin17 said:
This is what I built.for these drivers. They sound incredible! Zigmahornet 1/4 wave!

Absolutely phenomenal drivers!! And I can use other fullranges aswell if I ever wanted too, with little to no modifcations:)

Did a simple Notch filter for that well known 7khz peak on Fostex drivers which some people like.
I don't, as beatifull as it is on some music and the cool tone it creates. I find it's bright for me.

So I installed a filter and this completely flattened that typical 7k peak and made the entire fullrange driver sound far more balanced and more responsive in deeper bass frequencys!

Such a simple 2x component addition completely changed the sound of this entire driver!

Intresting how that peak was effecting the entire drivers behavior and changing the entirety of the mids a bit. Can't remember the term for that but it's intresting how I need to think of the driver as a "whole" and not just one part of a system.
Just a different way I need to think about it. Fullrange is very cool! But a fun new learning curve for me!!

Incredible detail retrieval! Very comparable to planar magnetic in detail retrieval and Immediacy" really is amazing with the Dynamics to back it up!

EB5w7Lf.jpg

gvezhBq.jpg
Click to expand...
May we prevail on you for the components used for your notch filter and description of how you wired it / schematic? Thanks!
 
(Sorry if too off topic - I can delete this if it's too far off the mark.)

I've got this one with a Kenwood name on it. It clearly looks like the FE103. (But it's clearly ferrite not alnico. Any big differences?)

I have NO idea what it came in or where to find another ... but I wonder if it'd work in the same kind of cabinet.
 

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I got my hands on a pair of Coral Holey Baskets a couple of months ago. They will probably wind up in open baffles, but I couldn't wait to hear them and wound up putting them in the cabs from a pair of Polk Monitor 30s. They fit perfect in these drivers. also unhooked the tweeters.
The things sound amazing, they aren't going to blow you away with bass, but the bass they do put out is very accurate. I had been listening to them for about a week or so using a pair of cosmetically challenged KLH 17s as speaker stands. I got to wondering if using the 8" driver from the 17s would give me more bass. I knew the KLH 8" ran full range anyway so I gave it a shot, unhooked the tweeter circuit and ran a jumper between the speakers. Now I have bass that you can feel when things get loud, but it's still accurate bass.
I now have three systems running full range drivers. The Franken Corals are being powered by a Nakamichi R-113. I have a pair of Bozak 8" B800BCs in open baffles being powered by a Denon PMA- 757 and a pair of 12" Zenith 49CZ852s powered by a modified Zenith 5G29 EL84 tube amp. The only box speakers I listen to anymore are my KLH 6s powered by a Sansui 881.
IMHO the human ear just prefers a coherent point source ie a full range driver. I've had literally tons of speakers over the years, Klipsch LaScalas, Polk SDAs, KEF 104/2, Wharfedale W70s, Linn Kanns, OLAs, JBL 4312s. They have all gone to good homes, none of my full range speakers are ever going anywhere.
Coral Holey Baskets

Coral Holey Baskets

  • Media owner bigaltx24
  • Date added
 
bigaltx24 said:
IMHO the human ear just prefers a coherent point source ie a full range driver
Click to expand...

This is my own experience.

I'm either going the Tang Band route, or if I luck up again and find another Sony TC-50 (which often have the Corals) for change like I once did and DID NOT buy it, then I may own some Coral Holey Baskets.
 
Coral Holey Basket re-coning complete. Provisionally mounted in simple open baffles starting the break-in process powered by recently scratch built Kyoto SEP El84 circuit. Neal’s speaker service in the Sierra foothills did the work - ended up using Cerwin Vega cones as the closest to the flat configuration of the original translucent drivers. Sound good so far but time will tell.
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Some small "full range" drivers have aquired cult status as being of astounding quality, Coral holey baskets being a prime example. While I'm not convinced that they, or similarly regarded drivers, are quite as fantastic as some claim, I am convinced that it's possible to get extremely good quality reproduction from a wide range of very modest drivers if they're mounted in suitable enclosures (or on open baffles if they're suitable). Sure, you're not going to get 20Hz - 20kHz within 3dB, and you won't get deafening SPLs, but they aren't necessary (in my opinion) to get very satisfying results.
I've had surprisingly good results from similar 4" drivers.
 
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