RTA 12s - Need to find replacement drivers.

scottbringe

I have a very old pair of RTA 12s (sn #12 - 00826) and they are in need of repair. The passive radiators seem fine but I need to replace the mid-basses and tweets. Anybody have any idea where I can get these?

drumminman

Best bet is to search here and on ebay for the exact MW. While others may fit, their parameters will be enough different that the sound quality of the speaker will be negatively affected.

Don't know if Polk has new replacement drivers for the older models, but you can check with them as well.

Pull one of the MW's to get the Polk model number off the back.

scottbringe

Thanks for the reply man!

Yeah, the guys at Madisound told me to try Scan Speak P17WJ00 for the mid-bass and Audax 1" textile dome for the tweeter. If only I had the original specs on the drivers I could find something with similar characteristics (QTS, VAS, DC resistance, excursion blah blah blah...). Anyway, I asked the guys at Madisound if their recommendation was a stab in the dark or if they had some actual data to back up the recommendation. They said it was a stab in the dark and the results would be unpredictable, so for almost $500 I decided that was too expensive for an experiment. For that price I'll get a couple Audio Nirvana full range drivers and build cabinets. Or scrap the 12s crossovers, get an electrronic crossover, another amp and play with other drivers in the cabinets.

I've had these things packed away for 10 years and should have fixed'em up years ago when the drivers were available. I can't believe peerless stopped making that tweeter; it was an "Evergreen among tweeters", that was their marketing speil:) and was true. They were very good tweeters for the money.

Still holding out hope for an answer from Polk Audio!

links to those drivers if anybody else wants to try'em and let me know how it works out:)
http://www.madisoundspeakerstore.com/scanspeak-woofers-6-7/scanspeak-classic-p17wj00-6.5-woofer/
http://www.madisoundspeakerstore.com/audax-soft-dome-tweeters/audax-tw025a1-12x9-1-textile-dome-tweeter-with-ferrofluid/

gdb

1-866-764-1801 pick up the phone and ask what's available. CP members get a discount BTW

skrol

Please don't FrankinPolk them with non Polk drivers! We can help. We just need to find out what the model numbers of the drivers are. If you remove the driver, there should be a sticker on the back with the model number (MW-6xxx). If you post a pic of the tweeter, we can figure that one out too.
Stan

drumminman

Post pics of these speakers so we can see what they look like.

FYI, geppy1 is the CP resident expert on RTA 12's.

pitdogg2

I just guessing but would they not be mw6500 or mw6600? since both of those are very early drivers.

I do believe Keith put up a thread listing all the incarnations of those at one time.

scottbringe

Yes MW6500 drivers, tweeters are not labeled.

scottbringe

Here are some pictures of sn#12-00826, crossover#22-00626. Sorry the pictures aren't very good, I took'em with my laptop as my digital camera was stolen:(

The other speaker is sn#12-00835 with crossover#22-00639.

scottbringe

"FrankinPolk", I like that, very funny but yeah I'd like to avoid that myself.

scottbringe

Not all of the drive units are blown but I just thought that since I'm refurbishing them I might as well replace them all so they're matched. Needless to say the top hats are in need of grille cloth but just getting the drive units would be beyond my wildest dreams:)

pitdogg2

the tweeters are peerless. you would just have to replace the blown 6500's. there have been many on Ebay recently. If it were me i wouldn't get all new drivers just replace the ones that don't work.

scottbringe

Yeah! I just bit the bullet and ordered the drive units from Polk. Thanks for the advice guys, I hope these replacement drivers are acceptable as the tweeter isn't the original peerless. Polk said the replacement for the MW6500 is MW6503 and the tweeter is the SL2000. I won't know the true result until a couple hundred hours of burn in and I guess I might want to change out the caps in the crossovers (apparently caps can drift over time)? Probably take out those crappy fuses in the crossover as they must be in the circuit path of the tweeter. Any advice on tweaking these?

drumminman

scottbringe wrote: »

Yeah! I just bit the bullet and ordered the drive units from Polk. Thanks for the advice guys, I hope these replacement drivers are acceptable as the tweeter isn't the original peerless. Polk said the replacement for the MW6500 is MW6503 and the tweeter is the SL2000. I won't know the true result until a couple hundred hours of burn in and I guess I might want to change out the caps in the crossovers (apparently caps can drift over time)? Probably take out those crappy fuses in the crossover as they must be in the circuit path of the tweeter. Any advice on tweaking these?

Re: tweaking, the electrolytics do have a life span, and the ones in your 12's have probably passed their use by date. But another consideration is the advancement in cap and resistor quality in the 30 years since those were built. Modern film caps are simply way better than what Polk had access to when they designed and built your speaks.

Don't know if your 12's have both an upper and lower Xover (I don't think they do - it would be attached to the inside of the binding post cup), but high quality caps and resistors would not be that expensive. This is a highly recommended mod!

scottbringe

drumminman wrote: »

Re: tweaking, the electrolytics do have a life span, and the ones in your 12's have probably passed their use by date. But another consideration is the advancement in cap and resistor quality in the 30 years since those were built. Modern film caps are simply way better than what Polk had access to when they designed and built your speaks.

Don't know if your 12's have both an upper and lower Xover (I don't think they do - it would be attached to the inside of the binding post cup), but high quality caps and resistors would not be that expensive. This is a highly recommended mod!

Thanks for all the help guys, finding this forum has been a godsend. I'll keep you posted as I progress. Hmmm I wonder what shape the old Thoebe and Son of Ampzilla are in:) It's going to be so nice to have a "real" Hi-Fi system again, guess I'll have to start looking for a turntable since I found a box of albums that are in really good shape (very surprised).

scottbringe

Replaced the blown drivers (1 tweeter and 1 midbass in each). The new drivers blend nicely with the old, the speakers image well and sound quite good. I'm still going to replace the caps and resitors in the crossovers and may take out the fuses. Had to modify the new tweeter slightly; I filed the bottom 2 screw holes so they'd match up with the existing metal mounting plate and glued rubber backing to the plastic faceplate so it wouldn't resonate.

Just wanted to thank you all for the good advice.