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Piezos MELTED!!! [message #51066] Mon, 07 May 2007 19:52 Go to next message
themilford is currently offline  themilford
Messages: 66
Registered: May 2009
Viscount
Hey guys,

I gave my pair of Two Pi to a dear friend about a year ago. He just used them to DJ a gig and ran them super loud for about 7 hours at a loft party. He asked me to take a look at them because they we're no longer sounding right... i listened to them and realized the tweeters were not making any sound.

So, I opened them up and pulled the tweeters and the backs of the drivers were melted... The terminals had melted right off of the drivers! I realize it could have been that the 20ohm resistors were mounted to close to the drivers and heated up and melted them.

I opened up the driver and pulled out the voice coil/element and ran some signal through... and they still worked! it's just the back plastic cover that is melted.

Sooo... does anybody here have an extra blown pair of KSN drivers that I could steel the back covers off of?

Or does anybody wanna sell me a pair them? I'd like to get these up and running again for my friend. He loves them and promised me he wouldn't be using to DJ any longer. And just to be safe I will be mounting the resistors away from the tweeters

Cheers,
David

Smokin'! [message #51069 is a reply to message #51066] Tue, 08 May 2007 11:04 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)

I don't know whether to laugh or not! That's hilarious and would be inexpensive to solve but I don't have spares for those old CTS tweeters anymore. You may be in luck though - Seems like I heard someone eventually purchased tooling for the CTS tweeters. Hopefully someone will chime in with more information.


Re: Smokin'! [message #51070 is a reply to message #51069] Tue, 08 May 2007 12:20 Go to previous messageGo to next message
themilford is currently offline  themilford
Messages: 66
Registered: May 2009
Viscount
Hey Wayne,

Yeah... it was funny. He was like "umm... do you think you could listen to these... they don't sound "right"".

The tabs melted right off of the drivers! and the back "cups" are all mishapen. I'll try to post pictures this weekend maybe.

also, in my travels I saw the KSn1038s available in Australia... could this be the new manufacturer?

Re: Smokin'! [message #51071 is a reply to message #51069] Tue, 08 May 2007 12:29 Go to previous messageGo to next message
themilford is currently offline  themilford
Messages: 66
Registered: May 2009
Viscount
like here:

http://www.wagner.net.au/speakers/34-Instrument.pdf

and here:

http://www.speakersplus.com.au/product_info.php?cPath=76&products_id=365&osCsid=96d47c007bb07a5e02e4250be3012e79

Re: Piezos MELTED!!! [message #51072 is a reply to message #51066] Tue, 08 May 2007 14:47 Go to previous messageGo to next message
Shane is currently offline  Shane
Messages: 1117
Registered: May 2009
Illuminati (3rd Degree)
Wow!!

I once had the domes off a pair of Polk Monitor 10's just "float" off out into the room when we played them too loud for too long. Found them laying on the floor in front of each speaker. They were expensive to replace.

Re: Piezos MELTED!!! [message #51073 is a reply to message #51066] Wed, 09 May 2007 07:00 Go to previous messageGo to next message
jimbop is currently offline  jimbop
Messages: 60
Registered: May 2009
Location: Colorado Springs, CO
Viscount
I once had a pair of small cabinets built with inexpensive 12" drivers. A friend used them for a small apartment party, driven by an 800-watt PA amp. The cones burst into flames during the party!!

Re: Smokin'! [message #51074 is a reply to message #51069] Wed, 09 May 2007 23:14 Go to previous messageGo to next message
Paul C. is currently offline  Paul C.
Messages: 218
Registered: May 2009
Master
Genuine CTS piezos are becoming availabe through Martin Sound (link below). So far, they just have what were the most popular models.

I think the elements and backs of the KSN1016a's, KSN1001a's and 1005a's fit your 1038's. I think you can simply pull the back section of the 1016a and replace your 1038's element and back.

There are two versions of the larger 1800 hz piezo drivers. One version of each model had only a tiny 22 ohm 1/2 w resistor inside. The "Powerline Series" had a tiny lightbulb and poly switch (I think) to form a protection circuit that was good up to 400 w.

I had a 10 pc Tower of Power style R&B band that often played in the local civic center. Just a few blocks away was a large communications tower (Datacom) with a gazillion antennas and a major intersection. Our old Peavey PA amp would pick up radio signals at times, we could hear the voices at low levels. But a few times, we think it was HF oscillation from RF, completely inaudible, would toast the KSN1025a's (aka 2x6 horn) in our PA speakers.

When I say toast, I am talking smoke coming out of the horn, as if a smoldering cigarette were inside. Upon removal, we found the back cover melted. You will see the better "Powerline" version on the Martin site as Cat No 0934. We didn't have those... we had the cheapo versions.


well... [message #51075 is a reply to message #51074] Thu, 10 May 2007 09:17 Go to previous messageGo to next message
themilford is currently offline  themilford
Messages: 66
Registered: May 2009
Viscount
If your positive one of these units backs will fit the 1038 I'll just buy the cheapest ones.



Re: well... [message #51076 is a reply to message #51075] Thu, 10 May 2007 10:34 Go to previous messageGo to next message
Paul C. is currently offline  Paul C.
Messages: 218
Registered: May 2009
Master
The KSN1016a is the one.

Did you get the right part? [message #51146 is a reply to message #51076] Mon, 28 May 2007 17:57 Go to previous message
Paul C. is currently offline  Paul C.
Messages: 218
Registered: May 2009
Master
Did you get the right part to fix your 1038?

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