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Picked up a pair of Polk RTA-12Cs... and bummer...

Jon S

Jon S

Super Member
I just picked up a pair of Polk RTA-12Cs... they look to be in really good condition but after getting them home, the bummer appeared. Looked at the crossover and it shows a blown polyswitch for the tweeter. I now have to take the crossover apart and test the drivers as well. any advice would be helpful...

:tears:
 

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What is the model number on the tweeter? I have two that look like that one and you can even buy replacements from Polk for $48 each.
 
Jon S said:
I just picked up a pair of Polk RTA-12Cs... they look to be in really good condition but after getting them home, the bummer appeared. Looked at the crossover and it shows a blown polyswitch for the tweeter. I now have to take the crossover apart and test the drivers as well. any advice would be helpful...

:tears:
Click to expand...

Post same question on PolkAudio boards and you will get plenty of advice...also a area to post directly to Polk CS.They excell in customer service...and if you need replacement parts you get 10% off and free shipping for being a forum member..which of course is free...

http://www.polkaudio.com/forums/
 
PartsExpress sells the Polyswitches; be advised that many "audiophiles" feel that they're sonically evil :-) You might want to consider bypassing (if you're not the type who is likely to overdrive the tweeters) and/or replacing the Polyswitch with a 1A fast-blow fuse (which is what Polk used for the tweeters in the olden days).
 
I'd be inclined to put it back original.

From memory- you might want to double-check with "Polk experts"... the .50 amp version of the Polyswitch (as Parts Express sells) is probably the best match... it seems to be used on more tweeters than any other, IME.

Regards,
Gordon.
 
You don't "have" to use the polyswitch and they definitely get weaker with age...especially if they were "tripped" and heated up quite a bit. I removed them completely out of my SDA's but I'm also running close to 400wpc on them and not pushing them to their limit. Otherwise, you can call Polk customer service and they will send you a new pair for free. I have some around here, too, just in case.
 
Scrap the polyswitches and run fuses instead. Those are a killer pair of Polks. Those are the SL-2000 tweeters and the new replacements from Polk are supposed to be a big improvement.
 
i am planning to upgrade all the caps on the crossover and bypass the polyswitch. i do not abuse the speakers so i think i can safely operate without them. i also just rebuilt a polk 10b set and ordered a pair of silk tweeters to replace the sl1000 but i just might use them in the rta12s instead.
 
merrylander said:
What is the model number on the tweeter? I have two that look like that one and you can even buy replacements from Polk for $48 each.
Click to expand...

they are the infamous SL2000... not well regarded because of their +5 dB peak at 12,000-13,000 Hz. Makes the speakers sound bright and shrill. The only redeeming value with the SL1000/2000 tweeters are that they had amazing dispersion which improved their imaging. the replacement Polk tweeters are silk domed and while smoother in the top, does not image as well...
 
merrylander said:
Well I have two SL2000s that are surplus because I replaced them in my Monitor 10Bs.
Click to expand...

did u want to sell them? I am trying to get some spare parts for the Polks because I understand they have a tendency to "fall apart" as they age... the magnets fall off the back of the speakers as the epoxy they used fail. I still need to find some 6 1/2 midbass drivers and a 10- and 12-inch passive radiators. I also have a couple of Polk Monitor 10Bs which I currently use. I also have a pair of Polk LSi15s, while highly regarded, seems to lack the open soundstage the older Polks had.
 
I just bypassed the blown polycap and tried the speaker out. while the midrange was fine, the tweeter was completely silent. checked the tweeter itself and it shows continuity so thats not the problem. any ideas where the problem may be?
 
Jon S said:
they are the infamous SL2000... not well regarded because of their +5 dB peak at 12,000-13,000 Hz. Makes the speakers sound bright and shrill. The only redeeming value with the SL1000/2000 tweeters are that they had amazing dispersion which improved their imaging. the replacement Polk tweeters are silk domed and while smoother in the top, does not image as well...
Click to expand...

How many hours are on the RD0 tweeters? No, they don't image their best out of the box but once broken in, they do an awesome job. I have a few hundred hours on the silk domes in my SRS II's and they are fantastic.

Jon S said:
I just bypassed the blown polycap and tried the speaker out. while the midrange was fine, the tweeter was completely silent. checked the tweeter itself and it shows continuity so thats not the problem. any ideas where the problem may be?
Click to expand...

What about swapping the tweeter from one side to the other? Everything ok then? Did you try playing music just thru the tweeter without the crossover at all? Do it at low output and you won't hurt the tweeter...maybe turn the bass all the way down on your amp/receiver/pre, etc.
 
I hooked up a different tweeter to the crossover, still no joy. so something is amiss in the crossover.
 
Jon S said:
they are the infamous SL2000... not well regarded because of their +5 dB peak at 12,000-13,000 Hz. Makes the speakers sound bright and shrill.
Click to expand...

Beyond harmonic overtones and cymbals, there isn't much going on at 12kHz. I personally think the SL2000 tweeters have a bad rep for nothing.
 
The sl2000 is the best polk tweeter and I've heard them all including the replacements which were dull and lifeless to me. My sl2000's aren't harsh or bright at all. In fact they are smooth and silky especially with tube gear.
 
cornhulio said:
The sl2000 is the best polk tweeter and I've heard them all including the replacements which were dull and lifeless to me. My sl2000's aren't harsh or bright at all. In fact they are smooth and silky especially with tube gear.
Click to expand...
Ok Carl. :D

I can't wait, tomorrow the Sl2000's from my SDA 2B's go bye bye!

To Jon,
Have you tried what Ken mentioned to you on CP?
 
cornhulio said:
The sl2000 is the best polk tweeter and I've heard them all including the replacements which were dull and lifeless to me. My sl2000's aren't harsh or bright at all. In fact they are smooth and silky especially with tube gear.
Click to expand...

You forgot to mention the fact that you add a 2.2uF cap in series with your SL2000's and actually disconnect others. In fact, someone posted a graph showing the results of adding that 2.2uF cap to the SL2000 and the resulting 29dB suck out at around 3kHz!!!
 
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