Advice Sought: Replace my RTA12B 's ?

rexx

I have a pair of Polk RTA12B speakers, purchased in 1983, in fine condition. They sound great -- to me, anyway. But after 25 years I am wondering whether they might be a little tired. Do speakers wear out?

I see that J&R and Amazon are selling JBL ES90's for $500/pair. Would more modern speakers sound better?

As you can surely tell, I am an audio novice. I listen to music all the time, and I'm willing to spend money on it, but I'm no audiophile.

FYI, my amps are Adcom: GFP-555II PreAmp, GFA-555II Amp, ACE-515 AC Enhancer.

NJPOLKER

I guess just about anything can wear out but if they sound good they must be fine. However the capacitors and resistors should be replaced for the shelf life is around the 20 year mark. If you keep them it would be a good idea to replace them.

heiney9

Spend a couple hundred $$$ replace the tweeter's with RD0194-1 and upgrade the aging caps and resistors and you'll have the speakers you remember when new.

Hell no on the JBL's. You'll be extremely disappointed if you compare the JBL's to the RTA's. Many of the companies (this includes Polk as well to a certain degree) don;t make them like they used to. Polk still makes a reputable line for 2ch music in the LSi's. You'll notice they are more expensive.............there is a reason for that.

If you want something a little different look for a used pair of SDA's.

H9

AudioGenics

you have some nice equipment in your system.

Polk Audio are some of the finest on the market past, present, and future

Their Customer Service will certainly provide excellent support in any repair that may be needed. 25 years is PROOF of that.

It "sounds" like that was also 25 years Trouble Free ......

rexx

Yes, 25 years with no trouble is a good thing indeed!

Sounds like refurbishment is the way to go. (Especially after looking at the prices of the LSi's!)

When I take the top cover off, I see a circuit board and what I guess is the tweeter. (See attached photos.) Is that where all this replacing needs to be done?

I actually know how to use a soldering iron, so this might be possible for me to do.

Where does one get the necessary parts? Directly from Polk?

NJPOLKER

Nice Peerless tweeters too you'll want to keep those.

NJPOLKER

It should be easy to update the x-overs. You see the capasitors and resistors behind the tweeters. You will write down the values of each and replace them with exact values but new hi-performance components. The caps are the round blue things and yelloe oval shaped things. The resistors are a off white rectangular thing. There is a schematic available here to which you can view.

NJPOLKER

http://www.polkaudio.com/forums/attachment.php?attachmentid=18712&d=1155781986

This should be the schematic but always double check the values of components.

NJPOLKER

I'd suggest Obbligato caps but they do not have the exact values need for the high pass and you really don't want to piggy back those caps since they are real visible.
I'd go to http://www.madisound.com/index.php and look at Clarity caps for the high pass or http://www.parts-express.com/home.cfm and defiantly http://soniccraft.com/ and look at the Sonicaps for the high pass.

jon s

Replace the HF drivers and all the caps (except the bypass caps, just discard them). I upgraded a pair of RTA-12Cs with all Sonicaps and Mills resistors. The Polks are the sweetest speakers I have right now, their only weakness is that the bass is a bit "light".

Going with Sonicaps is NOT inexpensive, costing several hundred dollars to replace almost two dozen caps. I swear the RTA-12s are the most complex crossovers Polk made. In addition to the crossover on top of the cabinet, there are four more caps inside attached to the binding post plates inside the cabinet.

You can read what I did here...

heiney9

NJPOLKER wrote: »

Nice Peerless tweeters too you'll want to keep those.

Yep, really no need to get the RD0 replacements. I incorrectly assumed since they are 12B's they had the sl2000 tweeter.

The peerless is a very sweet sounding tweet so I would keep it.

H9

AudioGenics

just a suggestion...
maybe you are close to another Club Polk member that has prior experience.
can have a couple of cold beers and discuss and work on the 12B's

but its fun to DIY too !

NJPOLKER

jon s
Its been about a year since an update on the performance of the 12's unless I've missed it.

geppy1

My I ask, what are the seial numbers on your croosovers and cabinets?? keith

jon s

NJPOLKER wrote: »

jon s
Its been about a year since an update on the performance of the 12's unless I've missed it.

there was an odd effect on the sound when I first installed the Sonicaps. After about a month, the sound effect disappeared overnight. Comparing the RTA12s with my Sony SS-M9 speakers, the Polks were smoother, easier on the ears. the Sonys were a bit harsher, better depth and of course the Sony had better bass.

Still, the Polks were picked as the better speaker when compared with the $3500 Sonys by some friends when we did an A/B test. They all remarked how grainy or rough the Sony was in the mid-range. The Polks had a bit of a laidback midrange.

I still want to remove the vinyl "woodgrain" and re-veneer the speakers with real wood, but the top of the cabinet is posing a problem with the pass-through cable connectors and the rubber mats.

AudioGenics

perhaps you could seal and refinish the cabinet top
then
pass the wires behind the cabinet externally.
keeping the speaker interconnections that would otherwise be internally to the cabinet
dressed neatly

DQ10 Dahlquist had much of its components exposed for example

just a suggestion...

engtaz

Try different amps. Maybe your tired of the sound. I switched to a tube amp/receiver and the RTA12B woke up.

Dawgfish

Keep those RTA-12Bs. I love mine! The only thing I would consider replacing mine with would be a set of SDAs. There are some folks here on the board who own both SDAs and RTA-12s who will tell you they don't necesarily like the SDAs better than the RTA-12s. They just sound different.

You have some nice gear there, but the Adcom GFP-555 preamp was not one of Adcom's best efforts. I have a Parasound preamp paired with a GFA-555 amp powering my RTA-12Bs and I'm extremely happy with the setup. If I were in your shoes and looking to replace something to improve the sound, the preamp would be my first choice. You can find some pretty good deals on used pres here on the board, Audiogon, and your local Craigs Lists. I don't want to sound like I'm putting your system down, because I'm not, I'm just saying replacing the GFP-555 pre will be the quickest/most cost effective way to improve the performace of your system. I betcha a nice tube/pre would be just the ticket with the GFA-555 and those RTA-12Bs.

rexx

geppy1 wrote: »

My I ask, what are the seial numbers on your croosovers and cabinets?? keith

Cabinets:
L: L12B 17968
R: R12B 17736

Circuit Boards ("RTA 12B TDO Filter System"):
L: 22 15078
R: 22 15079

rmaiers

I have a set of RTA-12B and a set of SDA-2B speakers and have now had a chance to listen to both pair in my 2 channel system. (Hafler DH-500 amp and DH-110 preamp).

I agree that one set is not significantly better than the other. They do sound different but I would be hard pressed to say which I like better.