Bargain Jaycar Foster ribbon array with FE207E?

OzMikeH

Member
2007-03-18 9:22 am
Was shopping for bits for my 10kHz 24dB/oct active XO when I found these ribbons on special, Again.

http://www.jaycar.com.au/productVie...d2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

That prompted me to search on here to see what people have done with these ribbons. I'm considering using Two of these per channel wired in parallel for 4 ohms which would be a good efficiency match for my 207s. It should help vertical dispersion a bit too.
I'm using a couple of TA10.1 amps which are happy driving 4 ohms.

(before anyone says "You won't hear much difference that high" - Unfortunately I can hear a lot better than 99% of people above 15k)

A pair of these is about three times the price of the FT17H so I'm expecting a reasonable improvement, or would it be a mess? It's hard to tell if I can get 2 of these close enough together to form an effective line array.

Any thoughts?
 

OzMikeH

Member
2007-03-18 9:22 am
These beasties.

Looks like they need a waveguide, might mount them from the inside of the baffle and go nuts with the roundover bit.

Bugger it, I'll get some and have a tinker with my singulars, figure out what I want to do before I start on the Curvy Changs.
I'm out of action for any heavy work for the next couple of weeks, can't wear shoes until my foot heals up. I hurt it doing things that I should have been wearing shoes for....

Edit: Sorry about that ^^^^ it isn't a swear word in Australia. Stuff it instead. :D
 

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OzMikeH

Member
2007-03-18 9:22 am
They arrived today.
Not exactlky as shown in the pictures, the four philips head screws come from the back, the threads protude slightly from the front.

the rolled threads in the front steel plate are stickong out the front as well.

the last slot to the bottom edge is 19mm, so if two were used in a mni line array the distance between the two groups of emission holes would be 38mm.
 

aleexman

Member
2007-12-19 7:20 am
im very interested and wishing to make some bookshelfs using these and other jaycar drivers. I believe they would require an additional mid-range driver but this would complicate the crossover design which I am very shakey with. Any thoughts on how to design such a crossover? For bookshelfs are one of these tweeters per channel sufficient?
 

OzMikeH

Member
2007-03-18 9:22 am
Alex: You could make some good bookshelf speakers using a 6 inch or 8 inch fullrange driver.

I am intending to use these with some Fostex FE207E which cover 30Hz to 12kHz in the right box.

You could use these simply with an FE207E with the right series capacitor and the right inductor in parallel with the Fe207E run full range.

These are only useful as a supertweeter, on top of a fullrange driver or as part of a three or four way system.

Dave, I cant upload the pictures, I'm doing exactly the same as I normally do and it isn't working. Mine all have the number 0151 on the back.

Some of these have gouges on the back, they were poorly packaged.
I pulled one apart to see if I can trim one end off to get two of these closer together on a single custom front plate. a 38mm gap is too big. It looks way too hard, I have emailed you the photos directly, the only thing I could do is a deep, hornlike waveguide to couple them together.

If anyone else wants high res pictures of these, (including the insides) PM me.

If you decide to take yours apart be careful, the magnetic field is pretty strong but the plastic dowels help a lot when putting it back together.

(On a second look the picture posted earlier is spot-on)
 

OzMikeH

Member
2007-03-18 9:22 am
Front plate removed.
note the recessed screw threads on the fornt plate. not sure why they've done this. If you wanted to remove the protruding screws you'd have the drill the holes out larger, clean the swarf off the magnets, then use cap screws through the front with nuts on the back.
 

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OzMikeH

Member
2007-03-18 9:22 am
Here's the back plate, note the chips on the magnets and the loose fibres sticking out of the fibreglass circuit board.
Interesting arrangement of north south north magnetic feild with the current effectively going up one side and down the other. It explains why there's two rows of slots in the front.
Build quality is nowhere near as high as I expected, this is consumer grade boom box stuff.
I haven't had a listen yet, I'm not expecting much.
 

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Re: Bargain Jaycar Foster ribbons

The Foster ribbons look very much like the old (70s>80s) Infinity EMIM mids and EMIT tweeters. The EMITs were supposed to be excellent, although I heard they are a trifle fragile. I was a bit suprised that Jaycar are selling similar ribbons for SO much, esp considering they are "surplus" items which look (judging by disassembly pics in previous posts) nowhere near the build quality of the "expensive" ribbons with which Jaycar compared them.

Question to Dave D. Why would you throw away the waveguide? Like previous posters I was thinking of building waveguides for my Infinity tweeters, hoping that it might load them a bit better and, hopefully, extend their lifespan etc. BTW I foolishly pulled apart one EMIT tweeter (out of curiousity) and had an anxious time getting it back together because of the extremely powerful magnet forces.
 

OzMikeH

Member
2007-03-18 9:22 am
Moderator, please move this to alternative loudspeakers thread, its not really appropriate for fullrange anymore.

These weren't too scary to put back together, there are plastic dowels and holes in the plates, so everything is held apart by a couple of millimetres untill it is aligned with the dowels.

I'm seriously disappointed with these. I was expecting a bargain and I got what I paid for.
I can't use them as a line array and I bought 2 pairs.
I've been wondering what to do with them and today I saw a pair of these earmuffs.
They are very comfortable with huge cups, a strap across the top of your head (not shown) and good foam earpads. the lack of a frame across the back of the cups is good too. Chopping the back off and leaving a couple of rings with earpads will support the ribbons very neatly and very close to my ears with a small volume of air. If I can keep that volume of air down I should be able to get some bass out of these. The diaphragm surface area is pretty close to that of fostex's similar headphones but the excursion is a big unknown.
I expect it will be useless but several hours of searching has not shown if anyone has tried it. For that reason alone I think it's worth doing the experiment and sharing the results. (maybe it's completely stupid idea but I don't need the second pair)
 

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OzMikeH

Member
2007-03-18 9:22 am
Moderator, please move this thread to ESL and alternative.

I hacked up the earmuffs and stuck a set of drivers on them with silicone for a quick test. I tried them straight off the PC's sound card, these need some power to drive. A few days later I put my Trends TA10.1 amp back together, again off the PC's standard sound card which isn't very good.

After a bit of a thrashing to loosen the diaphragms up these sounded very good. Extreme top end is a little hot, I'm not sure if that's the T-amp, the sound card or the drivers. I cut some circles of low density open cell wavy foam as used in computer board packaging. Much more balanced with the foam inside and it'll keep any grit out of the drivers.

I listened to a variety of music for a couple of hours. Particularly impressive was The Butterfly Effect's Imago album. Drums and bass were sharp, concise and clear, Much better than my Shure E3 canalphones.

No evidence of the membranes slapping the magnets even at VERY high volumes.
I'm going to try filling up some of the dead space inside the cups with something solid next. These are rather heavy, they need a strap across the top of the head.