I'd like to clone a Dragonfly

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I heard these little speakers at RMAF last fall and fell in love with them: http://www.sound-smith.com/products/Dragonfly_HiFi+_review.pdf

Does anybody recognize the drivers? All I know about the crossovers is that they are "phase correct" whatever that means. The fuse lamp behind the grille that tells you you are about to blow up the tweeter is pretty ingenious. I'm sure before it blows the resistance goes way up, so the loss of highs before it actually blows is another clue you're about to fry your expensive tweets. Any info would be appreciated.
If you like that design, you might consider also my Jordan with a ribbon mini-monitor or mass loaded transmissioin line (MLTL). The mini-monitor's thread on DIYAudio started back in 2005 at:


and later the MLTL thread is at:


Many of the mini-monitor links are dead but if you are interested, please contact me.

The Jordan with a ribbon mini-monitor and MLTL designs use the same crossover and the Jordan JX92S (Jordan's US Distributor for EAD Full Range Drivers) and Aurum Cantus G2si (Parts Express: the #1 source for audio, video & speaker building components) drivers which are still available for a total cost of $600. Both designs have been duplicated by numerous others.

Almost every unpowered Bose speaker used fuses in series with the tweeter.. It's been a long time, but I expect most of the current ones still do.

This is a fuse lamp, not a fuse. A fuse lamp looks like a fuse, but is actually a lamp. It starts to glow when the power is getting dangerously high, alerting the listener that he should back off on the volume. Secondly, just like any other incandescent bulb (or any conductor, including voice coils BTW) the resistance goes up as the temperature increases, offering a second level of protection. The third level of protection is the same as a conventional fuse, it opens up, breaking the circuit to the tweeter.

These lamps were used in vintage tuners and receivers receivers for dial lights, but I don't believe they've ever been used in exactly this manner before in a speaker. I do know that many vintage speakers used incandescent bulb in the internal crossover for the increasing resistance protection scheme, but did offer the visual feedback or the fuse style protection.

But that's not what I care about, these speakers SOUND absolutely wonderful, better than all but a few megabuck speakers at the show.
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"These lamps were used in vintage tuners and receivers receivers for dial lights, but I don't believe they've ever been used in exactly this manner before in a speaker."

I personaly took few of them out of old Bose speakers...you are not listening what people tell you, it has been used extensively in 70ties and 80ties

McIntosh used these often too...this is from Roger Russell's page:

Red and yellow indicator lights were mounted in the front of the bass cabinet at the bottom right. The yellow light was connected directly to the system input. It became visible when the input to the system approached rated power. It served only as a warning indicator. If the system was driven excessively hard, the main fuse would blow. If the system continued to be driven after the fuse blew, the yellow light would still be seen but no sound would be heard. The red light was connected directly across the tweeter fuse. It could only be seen if the high frequency fuse blew and the system continued to be driven at high power. Protection circuits were included for the lights.
Looks like a Davis mid-bass. I'm with adason on the external fuse, besides his objections they will be a diffraction object.

And why didn't they use screws with proper heads???


Thanks Dave, good call on the Davis. It looks like he's added some sort of yellow "dope." Any guesses on what that is or the tweeter ID?

Davis 13mp5g 5" Graphite Midbass 297-562

Too bad it's NLA from PE.
That one is NLA as well. The review I linked to says it's doped paper, not Kevlar. I called PE and they say they haven't carried Davis products for around six years. The only useful info he had was that the country of origin is France. It looks like an interesting driver, if anyone knows how to get a hold of some I would greatly appreciate it. I'm starting to think the crossover is a simple 1st order affair. The tech support guy at PE couldn't even tell me what they used to sell for.

EDIT: Bing found what Google couldn't! It's Davis Acoustics, not Davis Electronics as PE has them listed. http://www.davis-acoustics.com/, and ironically, Sound-smith is the exclusive US distributor: http://www.sound-smith.com/davis/index.html

I agree, it looks like Kevlar in the photo, not doped paper. You can easily see the weave. $83 isn't too bad. Here's a fuzzy link to the spec sheet (Sound-smith's links go back to the mfr's site and don't work):http://www.parts-express.com/pdf/297-564.pdf
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Well, looks like many companies still sell their products, but I was'n able to find their own homepage. This is the address you can contact whatever is left of them... :)
AAC Applications Acoustiques de Composites
ZI Chemin de la Poterie
Tél. +33 (0)2 43 79 03 60
Fax +33 (0)2 43 79 20 91
Yep- it's AAC that purchased the tooling of the old company, and slowly some products are either being reintroduced, or new offerings arise. Madisound, Solen, Meniscus, and a couple others sell a lot of their current product lineup; which isn't large in size. The TW025A2 something is what it looks like, and that is a $30 driver.
The Madisound Speaker Store

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