SDA 1.2TL Tweeter Protection Issue - Long
dorokusai
Posts: 25,577
This question is for Ken and any other SDA owners.
F1Nut and I, bridged my Parasound amps mono, 630wpc and listened to some tunes. We noticed that after about 15 minutes, the speakers "shutdown" or reduced volume at least halfway. Checked the amps, one was hotter than the other, but the current overload lights had not lit on the amps. Wasn't anything abnormal, just hot. They have a circuit which protects them from impedence drops, thus overload.
Anyways, we lowered the volume, checked connections, and hooked up a fan to cool the amps. Started playing music again, and after about 3.50 minutes, same thing happened. Barely any heat now, fan worked great, amps were cool.
Started flipping thru the SDA compendium, since it occurred to us that something seemed to be going into protect mode. The SDA 1.2TL and my, SDA1C have the same overload protection circuit...that is kind of irrelevant now, but we noted that for the future.
We started listening again at a lower volume, no problems, but then a soundstage shift occurred later that seemed odd. F1 said the top tweeter is the main stereo tweeter, and it quickly looked like the top right was blown. Replaced, and confirmed ...blown tweeter. Examined the blown one, and it was definetly fried around 3/4 of the outer edge of the dome.
SO, my questions are:
What do the SDA speakers do in protect mode? Shutdown 100% or just split voltage for a volume drop? F1 says that the 2B's shut down, I recall my Mon10B's clipping and dropping volume. I have not tested my 1C's yet.
Would or do, BOTH speakers shutdown? Or just one? I recall both my Mon10B's going into protect mode, BUT that was because of my receiver.
Any thoughts are appreciated. Thanks for reading.
F1Nut and I, bridged my Parasound amps mono, 630wpc and listened to some tunes. We noticed that after about 15 minutes, the speakers "shutdown" or reduced volume at least halfway. Checked the amps, one was hotter than the other, but the current overload lights had not lit on the amps. Wasn't anything abnormal, just hot. They have a circuit which protects them from impedence drops, thus overload.
Anyways, we lowered the volume, checked connections, and hooked up a fan to cool the amps. Started playing music again, and after about 3.50 minutes, same thing happened. Barely any heat now, fan worked great, amps were cool.
Started flipping thru the SDA compendium, since it occurred to us that something seemed to be going into protect mode. The SDA 1.2TL and my, SDA1C have the same overload protection circuit...that is kind of irrelevant now, but we noted that for the future.
We started listening again at a lower volume, no problems, but then a soundstage shift occurred later that seemed odd. F1 said the top tweeter is the main stereo tweeter, and it quickly looked like the top right was blown. Replaced, and confirmed ...blown tweeter. Examined the blown one, and it was definetly fried around 3/4 of the outer edge of the dome.
SO, my questions are:
What do the SDA speakers do in protect mode? Shutdown 100% or just split voltage for a volume drop? F1 says that the 2B's shut down, I recall my Mon10B's clipping and dropping volume. I have not tested my 1C's yet.
Would or do, BOTH speakers shutdown? Or just one? I recall both my Mon10B's going into protect mode, BUT that was because of my receiver.
Any thoughts are appreciated. Thanks for reading.
CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
Post edited by dorokusai on
Comments
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Another question:
What does 630wpc at 8ohms mean to a 6ohm speaker? I am puzzled....and having a beer, so that isn't helping.
CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint. -
The power rating will be higher than the 8 ohm power rating at 6 ohms. As the ohms get lower, the power the amp puts out will increase, and depending on amp, the distortion will to! lol!- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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You were using a modified SDA cable with an isolation transformer (AI-1) when you bridged mono, right?Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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Yes we were using the AI-1 interconnect.CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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Update: F1 was doing some more extensive listening, Pink Floyd type, and it happened again. He stated that it sounds more like a "mute" effect occurs, not a high/low signal specific shutdown.
Could it be the cheap outlet strip used for connections?(This is my cheap outlet strip, by the way, F1 wanted that statement made
I am reaching here, but really need to find out.CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint. -
Update: Aforementioned problem does not occur when NOT in bridged mode. Single amplifier, 260wpc. Looks like it may be a bridged mode issue.CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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First, I have experienced this with my SRS's. Has always been the left channel for me and the left only. Amp has been warm, never hot. It always sounds like someone dropped a blanket over the speaker kind of "dulling" the sound. The highs just go-away. After volume reduction the sound comes back as suddenly as it left.
Ken has written before that the tweeter protection component in the crossovers does degrade with use, and that it will then kick in at lower and lower points. He recommended replacing them. I believe it's raife that has stated that he pulled his.
Given that the cut-out is still occurring, I'd say a little surgury is in order...
As to your follow-up question, if the current is available, your 630 should turn into something like 750 to 800 wpc into 6 ohms... I'd be shocked if you were actually pulling more than half the max...More later,
Tour...
Vox Copuli
Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb
"Death doesn't come with a Uhaul." - Dennis Gardner
"It's easy to get lost in price vs performance vs ego vs illusion." - doro
"There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD -
First off, the tweeter that blew today was going bad and it was just a matter of time before it died. I had noticed something funny going on about a week ago, so it had nothing to do with pumping mega watts into it. I took the tweeter apart for a look see and discovered that it smelled..kinda like fried electronics. I have 4 spares (3 now), so while I was in the mood I took them apart and discovered that one of them smells the same, but it tests ok. I also noticed that the cooling fluid appeared to be leaking, the same is true of the one that blew today. This got me thinking that perhaps the cooling fluid in the SL3000's gets old and can't perform it's job anymore leading to a cooked tweeter. I hope Ken can comment on this.
After further listening and checking I have determined that the left channel bridged amp is the problem as it finally went into standby and won't come out of it. We had noticed in the beginning that it was running hotter than the right channel amp, so we should have realized it had a problem right off the bat. Time for a trip to the repair shop.
While both amps were working the SDA's were really singing, very impressive to say the least.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Wonder if the tweeter took out the amp???Originally posted by F1nut
First off, the tweeter that blew today was going bad and it was just a matter of time before it died.
Been there... nothing quite as nausiating.......it smelled..kinda like fried electronics. [/B]
Will be interesting to read Ken's comments.
Gotta go sniff my tweeters now...More later,
Tour...
Vox Copuli
Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb
"Death doesn't come with a Uhaul." - Dennis Gardner
"It's easy to get lost in price vs performance vs ego vs illusion." - doro
"There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD -
Originally posted by Tour2ma
First, I have experienced this with my SRS's. Has always been the left channel for me and the left only. Amp has been warm, never hot. It always sounds like someone dropped a blanket over the speaker kind of "dulling" the sound. The highs just go-away. After volume reduction the sound comes back as suddenly as it left.
I have noticed the exact same thing except always in the right channel. Perfect description!Main System: Polk SDA SRS 1.2 Speakers, Sunfire Signature 600~two Amp, Carver C-16 Preamp, Carver TX-11b Tuner, Marantz 6350Q TT, Philips CDR-775 Recorder, Teac V-707RX Cassette Deck, Signal Cable Double Run Speaker Cable
Upstairs Den: Marantz 2325 Receiver, Marantz 5220 Cassette Deck, Marantz HD-880 Speakers, Marantz 6370Q TT
Exercise (Kabuki speaker) Room: Kenwood KR-9600 Receiver, Pioneer CS-99a Speakers, Sansui SP-X9000 Speakers (not pretty, but LOUD! ) -
Tours observation that the tweet may have fried the amp is a very good conclusion. What is that fluid? Is it conductive?Make it Funky!
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The tweeter that blew was on the right channel, the amp that isn't working properly was the left channel. The left amp was hotter than the right amp almost immediately.
The fluid is a "Ultra Low Viscosity" magnetic fluid and is suppose to be as thin as water. In the two smelly tweeters the fluid is sticky and no longer a liquid. Some of the other ones look like the fluid is becoming sticky. It is my thought that the fluid has a useful life span and that we may be seeing the end of it.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk
