Fostex 10F3

[jmillerdoc]

Hello,
I recently placed an impulse bid on eBay for these and won them. I was wondering if anybody had any idea of the T/S parameters for these or know of a good enclosure size for them. I was thinking of making a pair of mini double mouthed horns for these, possibly an adapted design from Frugal-horn's website. They are only rated for 3 watts which might work very well as a small listening set for my 2A3 SET. Any help at all in choosing an enclosure would be greatly appreciated.
Thanks,
Jeff

[planet10]

Out of interest what did you pay?

You'll have to measure the specs... they have been found to be all over the map due to different amounts of aging.

3W is on the low side of the power you need for these. I'm currently using 20 W.

Which driver is the "real" Fe103a??
Seeking suggestions for Fostex FE103A
Foster FE103A
Alnico question

dave

[jmillerdoc]

I paid more for shipping I think! No, really, I think I paid about $25 for the pair. I don't have the equipment to make measurements so I was thinking of building one of the Frugal Horn designs for the F103 and hope it works.

These are in excellent shape too, I think I was rather lucky that somebody else didn't spot these. I here they are quite collectible. I know they are not worth hundreds or anything but I think I bought them right.

[jmillerdoc]

The stated rating is 3W, is it OK to run them higher?
Jeff

[jmillerdoc]

Interesting, I just read your posts on the F103 and it's variants. These look like the F103 on the front but the back is like the 10F3, actually has the "10F3" on the back but definitely like the F103 with the "cyclops" eye in the middle. Any ideas why these appear to be a hybrid of the two?
Jeff

[planet10]

Originally Posted by jmillerdoc

I paid more for shipping I think! No, really, I think I paid about $25 for the pair.

Good ones have a nominal value of $75 USD.

The discolouration on your cones is the glue migrating from the surround. Before doing anything with them check to see if the surrounds are still attached at the cone.

As per one of those threads i linked i am currently enjoying a pair in Aiko. I have pictures in my camera.

dave

[planet10]

Originally Posted by jmillerdoc

The stated rating is 3W, is it OK to run them higher?

Yes. Power ratings on hifi speakers are largly meaningless.

dave

[planet10]

Originally Posted by jmillerdoc

Interesting, I just read your posts on the F103 and it's variants. These look like the F103 on the front but the back is like the 10F3, actually has the "10F3" on the back but definitely like the F103 with the "cyclops" eye in the middle. Any ideas why these appear to be a hybrid of the two?

The numbers have to do both with who they were being OEMed for and the date of manufacture. They are the same. They kept using the same basket until 2000 ... ~ a 40 year amortization period.

Cal has a set of 10F3 in his Jimmys and i've had at least one pair thru here.

dave

[jmillerdoc]

I am looking at the plans for the Aiko, it appears that there is not much space immediately behind the driver. Did you have to do any modifications to the inside of the speaker chamber to accommodate the large basket on the 10F3? Or does it just barely fit?

Any other adjustments needed to the Aiko plans to make it work for this driver? What kind of F3 can I expect (at best) with this arrangement?

I have a KT88 SE amp I recently built that I think will power these pretty well. You think 18 watts, give or take 2, will work alright with this design?

Would you recommend any particular treatment to this driver other than adding damping material to the basket and magnet frame?

The cone appears to be well adhered to the cone but it is difficult to really tell without applying much pressure to it. If it does come apart what type of glue is best used to put something like this driver back together?

Bunch of questions, I think I will stop for now..........
Thanks,
Jeff

[planet10]

I'm gonna post pictures in the other thread shortly, just need to edit them down to size. It shouldn't be a problem -- if you add the sB -- if you don't it could be a problem. In ours there is a magnet brace for the original driver that is getting in the way so it is a problem.

10 W should give adequate levels, as i said i'm currently using ~20 (PP EL34 triode/DynaMutt)

Mine (actually a clients that have been laying around for over a year) have the full treatment. I have 2 pair stashed, they will get the same treatment (but i may do a fancy colour -- i've yet to try red)

I just take a small flat blade screwdriver and see if i can lift the surround. Given the amount of discoloration i'd guess that if they are firmly attached they have already been fixed by the guy you bought them from. I use the same modpodge i use for cone pretreatment, white wood glue would do. I've posted the technique i've found works -- probably in one of the linked threads. I also have a text clipping stashed somewhere,

dave