RTA12B mid-range took a dump

laotzu61

I hope i'm posting this in the right place. anyway, about a week ago, the left-hand, mid-range in the right channel
speaker took a dump. It may have happened due to a voltage surge during a storm. in any event, it is now very
scratchy, and sounds terrible. my question is; am I better off removing the speaker via the front screws and
disconnecting it until I find a replacement? also, what is a good source for a replacement? this really sucks---.
thanks for any help.

rmaiers

You can get a new replacement from Polk for $48.00 or you can find used ones on ebay or in the for sale section here. I have had to replace 3 mid-range drivers on my RTA-12Bs.

laotzu61

thanks for the info. i'll probably get a replacement from polk to be safe. is it okay to just disconnect the current one
in the interim and use the speakers without till I get a new one?

soundfreak1

What driver # is it as if mx6600 there are some jere available .

laotzu61

soundfreak1; I wouldn't know unless I take it out; would I? that's 1 reason i'm asking if that's ok at this point. also, I would think the speaker would sound better without the scratchy mid-range, but I don't know. thanks.

pitdogg2

Take it out and get the number off it. If it were mine I would not play while the broken woofer is out. Better safe than sorry.
Sounds to me that a magnet slipped. I would go ahead and JB Weld all the rest of my drivers magnets while I'm waiting and have these apart.

laotzu61

pitdogg2 wrote: »

Take it out and get the number off it. If it were mine I would not play while the broken woofer is out. Better safe than sorry.
Sounds to me that a magnet slipped. I would go ahead and JB Weld all the rest of my drivers magnets while I'm waiting and have these apart.

pittdog2; it's not the woofer--it's the left midrange in the right channel speaker. if it's not ok to remove it, i'd just as soon leave
it in till I get a replacement. can't live without the music however scratchy

---

Nightfall

laotzu61 wrote: »

pittdog2; it's not the woofer--it's the left midrange in the right channel speaker.

They're one in the same.

Unscrew the midwoofer, make not of which color is positive and which is ground, disconnect the woofer, get the model number off the back probably mw6600, screw the woofer back in while still disconnected so that you can still play the speakers, order a replacement.

Edit: Use electric tape or some other form of making sure the dangling wires that were once on the woofer don't touch each other.

laotzu61

Nightfall wrote: »

They're one in the same.

Unscrew the midwoofer, make not of which color is positive and which is ground, disconnect the woofer, get the model number off the back probably mw6600, screw the woofer back in while still disconnected so that you can still play the speakers, order a replacement.

thank you, nightfall. i'm on it. will I be dealing with solder connections, or some sort of plug-ins? thanks again.

Nightfall

No, they just pull on and off. Note my edit in post #8.

Nightfall

Also, the two different woofers are rolled off at different frequencies so they might sound... off, until you replace the broken one.

pitdogg2

laotzu61 wrote: »

thank you, nightfall. i'm on it. will I be dealing with solder connections, or some sort of plug-ins? thanks again.

only you can answer that. that is why we keep telling you to open it up and look.
1. some early models were soldered later they used fast on's
2. they used different woofers back in the day Nightfall and I know this it will either be mw6600 or maybe 6500 and it very well could be 6501.
3. real early models may of used different woofers for each woofer i.e. 6600 on left and 6500 on right as they were left and right speakers so the outer woofers were the bass and the inner were the mid range.

laotzu61

thanks, guys. I really appreciate the help. get back to ya later.

drumminman

I have RTA 12C's, and mine use MW6600X mw's; I suspect yours do too. What are you driving these with? Might want to do a little detective work to prevent this from happening in the future.

I bought mine new in 1984, and have never replaced anything out of necessity. Now mods, that's another story . . .

EndersShadow

laotzu61 wrote: »

I hope i'm posting this in the right place. anyway, about a week ago, the left-hand, mid-range in the right channel
speaker took a dump. It may have happened due to a voltage surge during a storm. in any event, it is now very
scratchy, and sounds terrible. my question is; am I better off removing the speaker via the front screws and
disconnecting it until I find a replacement? also, what is a good source for a replacement? this really sucks---.
thanks for any help.

Someone here recently was selling some woofers for the 12's IIRC...

Boom, here we go: http://www.polkaudio.com/forums/showthread.php?148389-Pair-%282%29-Polk-Audio-MW-6600X-drivers-for-RTA-SDA-Monitor-10Bs

laotzu61

drumminman wrote: »

I have RTA 12C's, and mine use MW6600X mw's; I suspect yours do too. What are you driving these with? Might want to do a little detective work to prevent this from happening in the future.

I bought mine new in 1984, and have never replaced anything out of necessity. Now mods, that's another story . . .

parasound hca-1200, which I suspect may have taked somewhat of a hit during the storm also.

laotzu61

well, it's an mw6600x; 1 blue wire and 1 white wire. not sure which is considered positive and which negative, but they are
soldered connections and it appears as tho the white may be bad. don't see any cracks in the speaker. wondering if I should clip
both until I can fix it and put the speaker back in, or just leave as is until I can repair the solder connection if that's it, or until
I just replace the speaker

---

pitdogg2

laotzu61 wrote: »

well, it's an mw6600x; 1 blue wire and 1 white wire. not sure which is considered positive and which negative, but they are
soldered connections and it appears as tho the white may be bad. don't see any cracks in the speaker. wondering if I should clip
both until I can fix it and put the speaker back in, or just leave as is until I can repair the solder connection if that's it, or until
I just replace the speaker

---

blue is positive white neutral. you could crimp on some fast on's but you'd need to get all solder off tabs first. That would be my route. Push in on woofer do you feel scratchy? If yes it's not long for this world unless you can adjust the magnet, but that does not sound like the problem as you stated. I WOULD however JB weld all driver magnets and Dynamat extreme the baskets while you're in there.

laotzu61

so, here is what I've done. pulled the speaker out; it's not cracked, but the solder joint to the white wire looks pretty bad at best. put it back in and it sounded worse. may have pulled on the wire to much. took it back out, clipped the 2 wires and taped them and marked them, and now they're hanging. put the speaker back in and now I have to adjust the balance to the left channel to compensate, which sounds goofy, but whatever. physics, I guess. remember this all started after a very bad thunderstorm in which I should have turned everything off, but didn't, like a dummy, thinking the surge protector would do it's job. subsequently also, when I adjust the line level knobs on the parasound, the standby led cuts in, which it never did before. according to the manual, "this red led will come on whenever you first turn the unit on. it will light for 4 to 5 seconds while the circuit is stabilizing before the protection relays click on. it will also light up whenever there is a short circuit or fault which triggers the protection relays." so---what am I looking at now as far as the parasound? not sure I want to know.

drumminman

Have you looked at the Xover(s) to see if any of those components are fried? Remember there's a lower one as well as one on top.

BTW, I've never heard of Polk soldering wires to speakers. All the Polks I've seen us the quick connect push on connectors. Wonder if some previous owner has done some work on those.

laotzu61

i'll look at the crossovers tomorrow. wouldn't the fuse protect them? as far as the soldering, looking at the job that was done, you're probably right about a previous repair.

laotzu61

drumminman wrote: »

Have you looked at the Xover(s) to see if any of those components are fried? Remember there's a lower one as well as one on top.

BTW, I've never heard of Polk soldering wires to speakers. All the Polks I've seen us the quick connect push on connectors. Wonder if some previous owner has done some work on those.[/QUOTE
now that the speaker wires are disconnected, can I get the quick connect push on connectors from polk or wherever and crimp those on?

pitdogg2

drumminman wrote: »

BTW, I've never heard of Polk soldering wires to speakers. All the Polks I've seen us the quick connect push on connectors. Wonder if some previous owner has done some work on those.

Polk did solder some of the older speakers I've seen Monitor10's & 7's soldered

laotzu61

thanks, pitdogg2. can I crimp on some quick connect push on connectors now that the 2 wires are clipped off? where would I get some? thanks again.

pitdogg2

laotzu61 wrote: »

thanks, pitdogg2. can I crimp on some quick connect push on connectors now that the 2 wires are clipped off? where would I get some? thanks again.

I buy mine at auto supply store. i.e. autozone, advanced auto.
I buy the gold plated you'll also need a crimper wire stripper to go with it to crimp properly.

laotzu61

pitdogg2; is there a specific size I need to ask for? thanks very much.

laotzu61

I have yet another question now. took the top-hats off, and I can't hear anything coming specifically out of the tweeters. fuses are good. is this normal??

Nightfall

laotzu61 wrote: »

I have yet another question now. took the top-hats off, and I can't hear anything coming specifically out of the tweeters. fuses are good. is this normal??

Yikes, not at all. Try wiring the tweeters, one at a time, directly to the speaker taps on the back of your amp at a very low volume. If you have tone controls of any kind turn the bass to -(as far as it goes). Any sound?

Schurkey

How does a lightning strike fry a speaker? I don't get how the surge goes through the transformer, rectifier, through the power transistors, and into the speaker crossover..

laotzu61

anyone know what amp fuses are used in the crossovers? I have the rta12b specs and can't find anything regarding this. also, schurkey, i'm starting to lean towards a bad solder connection. then again, why would that come into play only after the thunderstorm? btw, we now have another bad one coming thru, and I have everything disconnected this time. last one also blew out the uverse tv and internet and the techs had to come in.

drumminman

laotzu61 wrote: »

anyone know what amp fuses are used in the crossovers? I have the rta12b specs and can't find anything regarding this.

3/4 amp fast blo. It's on the schematic for the RTA 12b (orig); it's also what my 12C's came with.