Re-Building Pair of 15" UFO Style BTLs

[sundownz 197]

Had a customer send in a pair of BTL 15s for me to re-build -- first time seeing the new UFO style BTLs in person. Very large and heavy motor on these guys -- also looks like they started using four separate magnets on these rather than a single large slug; presumably to prevent potential defects in the big slug.

In any event -- on to the to re-build... the original failure was a burnt up tinsel lead on one of the drivers... so I am using our double lead Z v.2 spiders on the re-builds.

* Original Failure Point

* I am using a Z v.3 coil -- it is similar in dimension to the BTL stock coil but it is 8-layers vs. 4-layers on the BTL coil... it is 60mm WW vs. 64mm WW on the original. Performance should be very similar in the end, though.

* I used a rear triple joint ring from the Z v.3 line on these.

* Original rear triple joint - just a bit dusty.

* Original basket spacers - these are here to make room for the extended top plate neck on this driver.

* Using these nuts to get the spacing right while waiting on the machined spacers.

-----

They are made of Delrin -- a super hard resin material :

Acetal Resin | DuPont ™ Delrin ®

-----

Based on customer input these will have two Z v.2 spiders and a Nightshade cone to go with the Z v.3 coil and triple joint ring

The new spacer was needed to make clearance for the triple joint ring so it will not hit the extended neck on the top plate.

---

* Double Leads

* Spacer installed.

* Split magnet

* Going to poke leads through, solder, and finish top triple joint this morning.

This is the first one -- second one will be the same.

---

T/S specs measured after short break-in period - should extend nice and low for the customer :

RE: 2.0 ohms

Fs: 31.8 Hz

Qes: 0.33

Qms: 7.66

Qts: 0.32

Le: 2.59 mH

Vas: 64 L

BL: 18.3 NA

Mms: 267g

Cms: 93 uM/N

Sens: 89.76 dB 1w/1m

[sundownz 197]

* Put a small pad on as the double leads can make a small tapping sound at high excursion. Probably not audible in-box but it makes me feel better!

[Notorious97200 339]

This will go to an happy customer !

[sundownz 197]

[swagger_wagon468 53]

Very sexy. I want Vids when installed.

[CrazyKenKid 64]

i am not going to lie I am not crazy about the @$$ on that sub lol!

[Duran 387]

I'm curious as to why you installed a new spacer and different basket?

[sundownz 197]

Per original post :

"The new spacer was needed to make clearance for the triple joint ring so it will not hit the extended neck on the top plate."

The black frame looks nicer

[sundownz 197]

The new spacer is 20mm thick vs ~12mm on the stock spacer pack.

We use a spacer on our SA line and upcoming Z v.3 line for the same reason -- so the triple joint ring doesn't hit the top plate

[altoncustomtech 773]

Sundown - Fi Hybrid... Interesting... Would be quite entertaining to see and hear these in person.

[sundownz 197]

I'll ship them out to the customer on Monday - I was pleased with the results. I think they will suit him nicely.

[Shogen 325]

looked intense... wish I could do that...

[Hostility 0]

jacob you should ask him to post some videos on here when hes done so we can see these in action!

[heckvr4 2]

nice, a friend of mine its rebuilding my 4 18's the same way...

im using nuts for spacer thou

and a different basket

Edited April 9, 2011 by heckvr4

[SubSam 21]

Ever tried one of the new N2 BtL's? I ran into the same problem with my N215; originally had the box tuned to 31 and had my tinsels fry up. Thinking I was playing below tuning too much and losing things mechanically, I tuned down to 26, same problem. Running a 2k zenon board, clamped 1600 watts RMS at 1.18 ohms (D2 coil/motor).

I wanted to try a Z v3 recone, I was very impressed with the vids on that. Any easy solution? Or would I require spacers and a new frame etc.?

[ford302redneck 15]

Ever tried one of the new N2 BtL's? I ran into the same problem with my N215; originally had the box tuned to 31 and had my tinsels fry up. Thinking I was playing below tuning too much and losing things mechanically, I tuned down to 26, same problem. Running a 2k zenon board, clamped 1600 watts RMS at 1.18 ohms (D2 coil/motor).

I wanted to try a Z v3 recone, I was very impressed with the vids on that. Any easy solution? Or would I require spacers and a new frame etc.?

I don't see how your frying up tinsels with only 1600RMS? I have half the tinsels has a BTL, and has put upwards of 2k on my Q, without any problems. I was literately reaching mechanical limits and clipping(I didn't know at the time, I oscoped my headunit to find it clips at my normal listening volume) and hasn't had any problems.

So having double the tinsels and same power, I don't see how your frying them.

[jonbearsmt 919]

im reconing a BTL today.. burned leads. coil is fine nice and shinny.. leads are toast

[SubSam 21]

Ever tried one of the new N2 BtL's? I ran into the same problem with my N215; originally had the box tuned to 31 and had my tinsels fry up. Thinking I was playing below tuning too much and losing things mechanically, I tuned down to 26, same problem. Running a 2k zenon board, clamped 1600 watts RMS at 1.18 ohms (D2 coil/motor).

I wanted to try a Z v3 recone, I was very impressed with the vids on that. Any easy solution? Or would I require spacers and a new frame etc.?

I don't see how your frying up tinsels with only 1600RMS? I have half the tinsels has a BTL, and has put upwards of 2k on my Q, without any problems. I was literately reaching mechanical limits and clipping(I didn't know at the time, I oscoped my headunit to find it clips at my normal listening volume) and hasn't had any problems.

So having double the tinsels and same power, I don't see how your frying them.

Me either lol my UFO BtL had zero issues on the same amp, now with gains lowered and 150 amp fuses in tact on 12.8V MINIMUM (dropping from 14.8V)

I did burp as few times on a saz-3500 along with some 30 sec bassrace on the first one (31 Hz), might've done some damage there but I babied the 2nd and cooked the tinsels playing "love for money" after a few 23 Hz burps with 26Hz tuning unclipped. Pressure tested the box to 30 psi with the ports blocked, was still convinced I must have had a baffle issue so I tore it up and rebuilt it recently, I'm nervous to try again. Must be as phase issue, I even built a loading wall for cone control but scrapped it for now as it takes away from aesthetic appeal which I do get judged on. (I like to compete in every class I can, with no intention of winning however). The coils are perfect, just the tinsels pop the spiders out playing too low. Sewn in, the tinsels must see more heat or something.

No hate on Fi either, I am a loyal customer personally with two Q15s and this my 2nd BtL. I install for fun and only recommend Fi SSDs and Qs to my friends, along with a few Sundown SAs mixed in the bunch (SA-12 = super easy box design/tuning for a beastly low end), never heard a complaint from a single person. I'm sure I am somehow to blame for my fail; my box is complicated mostly due to space restrictions and aesthetic considerations (4.84 cubic net, in the trunk, with a custom amp rack, AND a full size spare- truly a daily driver). But at this point I will try anything.

[ford302redneck 15]

I'm not exactly pointing at you as the problem, so hope you didn't take it that way.

In reality all tinsels under the right conditions can fry, so its not just the type Fi uses.

I know I like the sandwich style a WHOLE lot better than the original. And I know the failure rate was cut drastically. Not that the old tinsels was the problem, it was more user error that would cause them to "snap".

[SubSam 21]

Oh no worries, I would be the first to blame myself, as no speaker will break itself; I was defending Fi against my desire for sundown soft parts. I decided to get another Fi recone, skipping the high xmax coil this time. I got a curious tip about the 8ga wires I run to the woofer from another person who ran into the same issue, so I will also solder direct leads this time as the clamp terminals offer little contact surface and/or stability for the wire. I actually didn't consider that before, I will let everyone know if I see an improvement. Either way, less voltage drop, less heat, more dbs, so it will be an improvement.

[ford302redneck 15]

Oh no worries, I would be the first to blame myself, as no speaker will break itself; I was defending Fi against my desire for sundown soft parts. I decided to get another Fi recone, skipping the high xmax coil this time. I got a curious tip about the 8ga wires I run to the woofer from another person who ran into the same issue, so I will also solder direct leads this time as the clamp terminals offer little contact surface and/or stability for the wire. I actually didn't consider that before, I will let everyone know if I see an improvement. Either way, less voltage drop, less heat, more dbs, so it will be an improvement.

Why did you go with the stock coil over the HiXmax?