Original RTA 12 restoration and mods
Bigerik
Posts: 149
Hi folks.
I dug my old RTA 12's out of storage, with the intention of restoring them and putting them back into regular service. I've hunted around some, and found plenty of info on the later RTA 12's, but not much on the first gen. If the info exists, could someone please steer me in the right direction. If anyone has any thoughts on good mods, I'd love to hear them. Pics to foliow!
I dug my old RTA 12's out of storage, with the intention of restoring them and putting them back into regular service. I've hunted around some, and found plenty of info on the later RTA 12's, but not much on the first gen. If the info exists, could someone please steer me in the right direction. If anyone has any thoughts on good mods, I'd love to hear them. Pics to foliow!
Post edited by Bigerik on
Comments
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Hey Bigerik, long time no talk. Are you looking for advice concerning the crossovers only or any and all that can be done?Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Hey Jesse.
It's been a long time indeed. How's things with you?
I'm open to pretty well anything with these speakers. What did you have in mind?
Thanks -
I'm still sucking air, so I guess it's all good.
First thing would be crossover upgrades. Replace all the caps with high quality film and foil, I like Sonicaps. Replace the resistors with Mills 12 watt. You can get the values from the ones on the board or check if the schematic for yours is listed here. Adding spikes to the cabinet base will tighten up the bass and mids. Apply Dynamat Xtreme to the stamped steel mid-driver and PR baskets. Remove the fuse and clean the terminals and fuse ends with DeOxit, then treat with Pro Gold.
Replacing the binding posts with some of higher quality is a good idea because the ones Polk used are low quality, but I can't say I've ever heard a sonic improvement from doing so. More of a piece of mind deal.
Better mechanical fastening of the mids and PR net surprising results. Toolfan66 use to sell what we call Larry's Rings, but he hasn't made any for a while, so you can use Hurricane nuts instead. You would install these in the screw holes, then use 8-32 hex head bolts to attach the mids and PR. Be aware, installing the Hurricane nuts can be a bit tricking.
That should get you going.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Erik, you can sign up on the waiting list for rings here, http://www.polkaudio.com/forums/showthread.php?133409-THe-Official-quot-Larry-s-Rings-quot-waiting-list&p=2064496#post2064496Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Thanks Jesse.
Lots of good info. Added my name to the ring list too. Just in case! -
Well, it turns out that someone had swapped out one of the drivers (not in the picture) with a MW 6500. So looks like I need to source a silver MW 6500 also.
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Oops. That should have said someone swapped out the original MW 6500 with a MW 6502.
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They come up here now and then. Also, check eBay.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Thanks Gents. I'm sure i'll hunt up a pair eventually.
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Took a look at the underside of the circuit board and was quite surprised to not find traces on the other side. Rather, it had pretty crude point to point wiring. I'll try to get a picture of it. It looks home made in the worst sense of the word.
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Anyone know when Polk went to a printed circuit board for the RTA 12?
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Hmmm. I might turn these from a restoration project into a parts unit. More work then I figured on to get them where I want.
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Point to point is considered sonically better than PCB.
A project I recently completed taking the stock crossovers on PCB's from this.....
...to this.
Showing the point to point wiring.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Hmmm. I might turn these from a restoration project into a parts unit. More work then I figured on to get them where I want.
If the cabinets are the same size as the later RTA 12's, can you replace the crossovers and turn them into 12c's? -
Point to point is considered sonically better than PCB.
A project I recently completed taking the stock crossovers on PCB's from this.....
...to this.
Showing the point to point wiring.
I don't doubt the benefits of point to point wiring. When I used to build speakers, I would do it no other way. Just kinda underwhelmed by how Polk did it. -
If the cabinets are the same size as the later RTA 12's, can you replace the crossovers and turn them into 12c's?
I'd have to check the cabinet volume to answer that. However, the cabinets are not in that great a shape. They could stand a re veneering.
As I started looking at what needed to be done, the investment in time, effort and money didn't seem to make sense. If thr end result would be something akin to an SDA SRS, then thr investment might be worth it for me. -
Yup, they are going to be parted out. If I can get up to 100 posts, I'll throw an ad up in the classifieds.
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Might be a challenge to find some "silver" MW6500 drivers, I've been poking around for an extra or two for my early Monitor 5s with the "silver" basket MW6500...like looking for a needle in a haystack.
I've seen 4pr on ebay in the last two months -
I've seen 4pr on ebay in the last two months
And three more will be available soon. -
I'd JB weld them first our some sort of putty epoxy to keep them from slipping.
my .02 -
I'd JB weld them first our some sort of putty epoxy to keep them from slipping.
my .02
You mean before shipping? -
You mean before shipping?
Yes because after shipping it may not matter. My thought is to keep from slipping the best you could for anybody buying these. A frozen voice coil will mean refund on the driver, scarce enough as it is.
