Infinity Qa's - HELP!!!!

[OMI]

I BOLLYIED a Pioneer SX-780 and a pair of Infinity Qa's for $40.00 this A.M. Brought them home tonight. The wife was in a pissy mood (I know that NEVER happens with you).... Went out to the car and was taking the first speaker out of the back seat and the wife decided to step into the garage and start whining and nagging.... Lost my grip and the speaker fell to the floor and hit on a corner and smashed the hell out of it :tears: :cry: .... At that point the wife realized she screwed up and shut up.... But the damage was done.... I was going to reveneer them in Red Oak (have some left from another project) any way... But now additional work...

Question #1

What is the best material to use to build the corner back up???


So now I have them both out and hook them up to the receiver and test them out. The woofers sound great, but the tweets need some work. I have seen some other info that these tweets can be rebuilt fairly easily. I was sorta expecting this any way.

Question #2

How do I rebuild the tweets and where do I get the diaphragms from?


Thanks...

[Charivari]

Sorry to hear about that OMI. Hopefully someone else will be able to chime in with some helpful info on how to fix the damage.

As to Question #2, what's the deal here? Are the tweeters intermittent or completely non-functional? While the EMITs are prone to being burned out due to clipping amps, there are several other possibilities as to why your tweeters may not be working. The most obvious one is that the fuse for the tweeter is bad. It may look good visually, but it could still be open, so check with a multimeter. The other problem is very common with these older Infinities, the 5 ohm pot is corroded. You can check this again with a MM and see whether you're reading any continuity across the pot or if it's highly intermittent. Refer to the instructions here (http://audiokarma.org/forums/showpost.php?p=545795&postcount=4) for fixing those.

If everything checks out and the tweeter(s) still isn't working, pull it and check to see if the VC (etched pattern glued to the Mylar diaphragm) is open. It'll read like a regular driving if it's good. If you're reading nothing across there, then I'll sound like a broken record and tell you to ask Army to get you in touch with his buddy who repairs these drivers.

Good luck.
- JP

[OMI]

Getting sound, but there is a background scratchy / rattle noise that is there from the tweets(both speakers).

No pots on these. They are 2 way... One 10 inch woofer and the tweet. There is a fuse next too the speaker terminals and that is it...

[Charivari]

That's interesting, the crossover schematics show a pot on the tweeter, which is pretty much a standard on these older Infinities. It's unlikely to be inside, though not entirely impossible, so the schematics must be wrong. At any rate, if you're hearing scratchy music, but music none-the-less, then your tweeters are most likely not the fault here. The only moving parts of the EMITs are the Mylar diaphragm that "flutters like a flag in a magnetic breeze", nothing to rub. So, I still think you're hearing some dirty contact elsewhere in the speaker, be it dirty fuse contact (it can happen), dirty spade connections on the drivers, maybe a weak cap in the crossover, or bad wires hooking everything up inside. I'd clean around the fuse holder and then pull the woofers and tweeters to look around inside to see how things have handled the last ~25-30 years.

Now, could it be possible that the VCs on the woofers are rubbing due to rotting surrounds or drooping spiders and that you're just thinking that's coming out of the tweeters?

- JP

[OMI]

Will pull 'em apart and see... Does need a good cleaning... Here are a few pics...

Thanks...

[OMI]

Thanks.. I will ck it out this weekend...

[hakka26]

Bondo

[OMI]

Got around to looking at the tweets yesterday as I have started the re-veneering project. I took each one apart and did not see any breaks in the ribbons. I cleaned the contacts and also cleaned up the fuse and fuse holder with some deoxit. Put 'em all back together and hooked 'em up one at a time to my garage receiver and WE HAVE SOUND!!!!!
One of the tweets did look like there was some separation of the ribbon from the plastic base material. Reading through the other link on repair (Bobby Shred) and he talked about an light epoxy coating??? Any one tried that???

Also did a search on ebay and they do sell NEW diaphragms for MUCHO $$$$$$$....

MUCHO $$$$$$$$ is last resort... As these seem to be working now, but not sure of the one that have some separation???

omi

[OMI]

Here are 2 pics of the diaphragm in the tweet. Notice that the metal strips are coming up in a few locations. Is that a problem? Anyone know best method to re-attach??? Super glue???? Or????

[Charivari]

Um yes, that could be a problem as the trace is now very susceptible to breaking. In the 'Infinity Information on the Net' sticky, there's a link to Bobby Shred's page on EMIT repair. There you may find a couple of suggestions that'll work to stick the traces down, such as rear window defroster repair goop. If you'd rather someone else do it, get ahold of Army, he has someone he can recommend for repairs.

- JP

[Damage]

Those are most likely beyond help. Whatever you do, do not try to use tape to mask the area off when applying the defroster repair stuff.

I have decided to replace my tweeters with real ribbon tweeters. But it's really expensive to do so.

[Nakdoc]

Rounded corners cost extra! Reduce diffraction. Drop the other one!

I would think Stupor glue would work. apply a dot and press down with wax paper to keep the sticking to a minimum. You will have to shim the other side a bit.

[Kencat]

OMI,

I have a line on new diaphragms if you are interested. Approx 20$ CDN plus shipping. PN 751-3722.

(no affliation, just a source I have discovered)

Let me know.

[maildude1960]

Kencat, what are those speakers in your avatar?

[Kencat]

Kencat, what are those speakers in your avatar?

Infinity Quantum 2.

[Kencat]

Maildude,

check out this site to explore most of the Infinity line-up of speakers:

http://www.infinity-classics.de/infinity/models/Quantum-series-1976/index-Quantum.htm

[Army]

Here are 2 pics of the diaphragm in the tweet. Notice that the metal strips are coming up in a few locations. Is that a problem? Anyone know best method to re-attach??? Super glue???? Or????

I got a hold of my Buddy that has repaired quite a few of the emits and emims and he recommends a good quality clear fingernail polish. If they have seperated too far to lay flat, carefully fold them over themselves and then apply two light coats of nail polish. Should do the trick :thmbsp: