RTA 12 which model are these?

drumminman

geppy1 wrote: »

You are not going to believe this. I am changing/ redoing mine and today I received a whole set of parts from original 12Cs ANOTHER VARIATION I have never seen this I am reviewing this and checking parts dates but mid 19,000 with SL 2000s 6501s and a fuse REALLY it appears real. FYI polk often seems to have made xovers months ahead of time on RTA 12s and then had them sitting

Amazing. Do you think someone got in and "customized" them, or they came from the factory like that?

On a side note, I've assumed that higher model numbers for MW's = more recent designs. For example, early 12's came with 6500's and later versions with the 6600X. Yet the last version came with 6501's. Any insight into this?

geppy1

Not sure about the driver numbering but i know they do all sound different. Above I stated

RTA12C Mid 1985-1987 6501 drivers with SL 2000
Tall cabinet with rolled off outer drivers and two crossovers with poly switch

Based on parts i received from an original pair yesterday item I need to change that slightly Serial 21,000 late Jan of 85 SL2000 with a FUSE

RTA12C Early 1985-1987 6501 drivers with SL 2000
Tall cabinet with rolled off outer drivers and two crossovers with fuse (early) poly switch at leat by Dec of 85

DavidR

I am new to the Polk Forum and new to Polk speakers. I just picked up a pair of RTA12's and not sure which model I have. The tweeter is SL2000-T Silver Coil Dome with an inspection date of 1/1988. Neither speaker is labeled right or left. I'm assuming I have model C but after reading this thread I'm not too sure. If they are required to be set up R&L how do I determine which is which?

Pictures below.

Mr. Bubbles

Welcome to the forum.
Geppy seems to be the resident expert on this series. maybe he will respond. Chances are you will need to supply a little more info. I checked the schematics available in the sticky and do not find a 2 ohm resistor in any of them. That is the only part of the crossover I could make out a value on. congrats on owning a great pair of speakers.

DavidR

Thanks Mr.B
Here's a picture of a speaker.
These needed major cleaning and repair to one bottom riser.

drumminman

I see neither a polyswitch nor a fuse. Maybe someone has "worked" on those. How do they sound? Any issues?

Re: left and right speakers, try them out and then swap sides. When you have them positioned correctly, i.e. left on left etc., you'll be able to hear it. The imaging will be dramatically improved with a better, more open soundstage with increased overall clarity.

Mr. Bubbles

It looks to have the Poly-switch. The little blue deal next to the 2 ohm resistor.

DavidR

Yes, they have the poly switch.
They also measure 6.1 - 6.2 ohms resistance.
I only heard them when the seller played them. Been cleaning them and repairing the base on one.

drumminman

Mr. Bubbles wrote: »

It looks to have the Poly-switch. The little blue deal next to the 2 ohm resistor.

Didn't notice it as it looks different, smaller, than the one that was on my 2.3TL's.

DavidR

I just removed the round plastic speaker terminal housing on one of the spkrs.
It has a xover mounted to it and has a date of Feb 1988.

There was no serial numbers in the space provided for it on this terminal housing.
However, I noticed a label in the upper right corner on the back of each spkr and it
has a number with L12 XXXXXX on one and the other R12 XXXXXX. I assuming this is the Left and Right I need.

Nightfall

DavidR wrote: »

...L12 XXXXXX on one and the other R12 XXXXXX. I assuming this is the Left and Right I need.

Correct.

geppy1

Yes as nightfall indicated Those are very very late ones,like right before they stopped What are the serial numbers?? 27,000??

DavidR

These numbers came from a label located on the top RH corner of rear of the cabinet:
Polk Audio
Monitor Series
L12 23563
R12 23483

The tweeters had their own (same) label that begins with (I believe) 22 XXXXX
There were no serial numbers located on the speaker terminal where a space is provided for it.

DavidR

So are the RTA12C's a 4 ohm speaker like the website says or are they 8 ohm?

The SL2000 tweeters on eBay are listed as 8 ohm.
My RTAs measure 6.1/6.2 which is where most 8 ohm speakers test; as resistance and resistivity are two difference animals.

Hermitism

I just came across some RTA 12C Polks on Craigslist and remembered reading this thread. The posting has some good pictures of the speakers if it helps your discussion in distinguishing between the A, B, & C's..

http://indianapolis.craigslist.org/ele/4129335440.html

drumminman

Hermitism wrote: »

I just came across some RTA 12C Polks on Craigslist and remembered reading this thread. The posting has some good pictures of the speakers if it helps your discussion in distinguishing between the A, B, & C's..

http://indianapolis.craigslist.org/ele/4129335440.html

Mine are exactly like those, down to the SL1000 tweeter. Those are priced high, given that the Xovers haven't been touched since they rolled off the assembly line. Otherwise they look to be in good shape.

ViperZ

Just wanted to pick up an old thread. Which Polk RTA 12 are these?





One of the speakers has completely wrong woofers, so trying to figure out if it's worth driving to pick them up and replace the woofers with proper MW.

Thank you.

Nightfall

Those are the original RTA-12's, both midwofers play the same frequency ranges on those so there's lobing and imaging issues with them. With some upgrading and modding they're probably not too bad but the later ones are much better.

ViperZ

Thank you very much for your help. Are they worth $100, considering I'd still have to get two MW 6500s for one of them? Or should I hold off for a newer version?

Faustin

Keep in mind that whatever you buy, due to the age you are going to want to rebuild the crossovers. You can easily spend more money on these old Polk's than you will get back if you try to sell them. Once redone though, they are fine speakers. Here are a couple of before and after pics of my 12's. For what is worth, I have a spare set of complete c/o's for the later model 12's that I would be willing to karma to you for the cost of shipping if you decide to purchase the 12's. They are the double crossover used in the b's and c's. They have not been rebuilt but would give you the opportunity to convert them to mirrored image 12's. And remember........thus begins the path down the rabbit hole. PM me if interested.

ViperZ

Thank you so much for the offer. The guy is 1.5 hours away, so I'm still thinking whether to take a drive, and then like you said, take a path down the rabbit hole of upgrades.

CH46E

Man, I wish my 12b s looked that good!

Are thoes Dayton caps?

Faustin

Daytons on the low pass and Clarity ESA's on the high pass IIRC. Yours can look just as nice. Get em done!