RTA-12B help - binding posts & tweeters

techlectic

Been doing a lot of forum reading and that has inspired me to do some upgrades on my RTA-12B and maybe my monitor 10Bs too. I ordered one set of the RDO194-As and intended to replace the SL1000s in my RTA-12Bs first. First thing I discovered was that they are not the same footprint. I had read that the screw holes didn't aline, but I didn't realize that they wouldn't even fit in the recessed area in the tweeter bracket that holds the tweeter. I'm wondering how others have dealt with that issue.

When moving my speaker away from the wall I accidentally pushed it up against the wall, and due to the fact that I have banana plugs, both binding posts snapped right off. Flimsy little things. I've read of others replacing those with better ones. Vampires seem popular but I think I'm going to have to go with whatever I can find at Fry's or another electronics store.

I pulled the plug out but the wire is so short there isn't enough room to pull the crossover completely out so I can remove the standoffs and get to the back of the binding posts. Anyone else dealt with this already? Is there any alternative to removing the passive radiator.

I'll do a follow-up with pictures.

I suspect the 10Bs are going to get the new tweeters and a crossover refresh, so I may just move the SL2000s from them to the 12Bs for the time being.

11tsteve

there should be 4 screws or plastic push pins holding the crossover pcb to the plug. if you get the board off the plug it will give you more room. there will most likely be globs of goo in there you might have to deal with to change the posts. if you had to, you could desolder the wires going to the leads for the posts which should free the cup entirely.
i just redid my posts and recapped the crossovers on my 11T's and took pictures of everything before i disassembled. it took the pressure off of remembering every little detail since i am new to this.

drumminman

I completely modded my 12C's about a year ago, including replacing the BP's. While that's your immediate need consider doing a full bore mod. You have no idear how good they can sound until you do. Here's a link to the best RTA 12 mod I've seen:

http://www.polkaudio.com/forums/showthread.php?116480-RTA-12C-s-upgraded-for-forum-member-w-pics&highlight=geoff727

Geoff 727 did great work and great documentation! Don't know how your tweeters mount, but on the 12's he did they were tight, but snapped into place.

techlectic

The width of the SL2000 in my Monitor 10Bs is the same as the RDO194, so it is a drop-in replacement there. However the width of the SL1000 from my RTA-12Bs is 3/32" smaller. I don't see any way to make it work cleanly. I really don't want to grind that much off of the tweeter and having the tweeter bracket routed out seems like an expensive proposition. I guess what geoff727 must have done is just drilled new screw holes in the tweeter bracket and not bothered about it actually being on top of the bracket rather than being recessed into it. I guess it's not much of a difference in real time alignment, but it really doesn't seem very clean to me. The magnet is wider too so it makes contact with the bracket unless the hole in the bracket is widened.

I got the binding posts off after I removed the crossover board from the standoffs. I realized that I had done this before - I replaced one set of binding posts on my 10Bs with replacements from Polk a long time ago. They are bigger and sturdier and gold-plated, so I think they are a worthy replacement part. I like the ones I got from Fry's though - unlike the Polks, there is no plastic on them.

I put one of the RDO194s in one of my Monitor 10Bs, and initial impressions are not favorable. It sounds to me as though the RDO194s are not as efficient as the SL2000s, as the highs and upper mids seem not as loud. The whole speaker seems not as loud. And the cymbals aren't as crisp. I'll give them some time to break in, but at this point I'm questioning the wisdom of my purchase.

soundfreak1

if I'm not mistaken the sl 1000 uses a different size capacitor then the 2000 s also I believe the rdo194 is the replacement for the s l 2000 you may have ordered the wrong speaker replacement for the 1000 I could be wrong on this and I'm sure somebody will chime in. it might be just you have to change the capacitor also. not positive on this but somebody a jump in here.

drumminman

Hey techlectic, if the RD0194's don't sound good in your 10B's there's something wrong. Not sure what direction to point you, but that doesn't seem right. Have you done anything to the crossovers, any mods? If the whole speaker isn't as loud as before the mod it could be that you damaged one of the solder joints when you replaced the binding posts. Check all your connections. Swap the SL1000 back in to see if the speaker volume returns to what it was before the binding post repair.

It's almost universal that folks who replace the SL1000 with the 194 report improved sound.

Re: your RTA 12B's, can you post some pics of the top end with the tweeter mount? While it should be a snug fit, it should fit.

dorokusai

It's universal that you cannot just drop in a RD-0194 for an SL-1000. The frame and design is not the same and you have to router the changes into the bracket. This has been stated in dozens of threads and posts on the forum....they are not drop-in replacements. Depending on your frame, this can get even worse as the leads will not have enough room to reach the terminals, and it appears that's also a problem here. Wherever you read on this forum, that it was easy, was totally wrong.

drumminman

dorokusai wrote: »

It's universal that you cannot just drop in a RD-0194 for an SL-1000. The frame and design is not the same and you have to router the changes into the bracket. This has been stated in dozens of threads and posts on the forum....they are not drop-in replacements. Depending on your frame, this can get even worse as the leads will not have enough room to reach the terminals, and it appears that's also a problem here. Wherever you read on this forum, that it was easy, was totally wrong.

Hey Doro,

I got some of the info on the 194 replacement for the SL1000 here, See Post # 42:
: http://www.polkaudio.com/forums/showthread.php?116480-RTA-12C-s-upgraded-for-forum-member-w-pics/page2&highlight=geoff727

Not sure what kind of tweeter mount he has, but if they're the 12B's I would think it's the painted MDF plate thing like what's pictured.

drumminman

dorokusai wrote: »

It's universal that you cannot just drop in a RD-0194 for an SL-1000. The frame and design is not the same and you have to router the changes into the bracket. This has been stated in dozens of threads and posts on the forum....they are not drop-in replacements. Depending on your frame, this can get even worse as the leads will not have enough room to reach the terminals, and it appears that's also a problem here. Wherever you read on this forum, that it was easy, was totally wrong.

Hey Doro,

I got some of the info on the 194 replacement for the SL1000 here, Post # 42:
http://www.polkaudio.com/forums/showthread.php?116480-RTA-12C-s-upgraded-for-forum-member-w-pics/page2&highlight=geoff727


Although it's for the RTA 12C I thought the tweeter mount would be the same as the 12B - the painted MDF plate thing like what's pictured.

techlectic

I see now from the RTA12C upgrade thread that geoff727 didn't bother with the fit of the tweeter into the routed-out part of the tweeter bracket. When I read it before, I thought the "snapping into place" was referring to the tweeter going into the recessed area, but now I think it's just referring to the magnet going into the hole that goes all the way through the bracket. As I mentioned, the magnet of the RDO194 is wider than that of either the SL1000 or SL2000.

Attaching some pics of the Monitor 12b tweeter situation.

geoff727

drumminman wrote: »

Hey Doro,

I got some of the info on the 194 replacement for the SL1000 here, Post # 42:
http://www.polkaudio.com/forums/showthread.php?116480-RTA-12C-s-upgraded-for-forum-member-w-pics/page2&highlight=geoff727


Although it's for the RTA 12C I thought the tweeter mount would be the same as the 12B - the painted MDF plate thing like what's pictured.

Hey,

Thought I'd drop in here, briefly. The original tweeters on those 12's were the 2000's, not the 1000's. The 1000's were the earlier silver-facepate models with the small black Polk Audio letters. I've not measured the physical dimensions of the various faceplates, so I can't comment on that.

The beveled black structures that the tweeters were mounted on, on that pair of 12's were formed out of some type of plastic. They were quite easy to work with, clean, paint, etc.

The faceplates of the 194's were ever-so-slightly larger than the faceplates of the 2000's, and the outer lip of the 194's faceplates rested on top of the mounting structure, to the tune of no more than about 1/32" (however thick the outer part of the tweeter's faceplate is). If you enlarge the pictures in posts 14 and 15, it's pretty clear. It was actually a cleaner, neater installation than the stock 2000's. I could have 'taken down' the outer 1/64" around the 194's faceplate for a "perfect" flush mounting, but they mounted so nicely and securely as-is, there was no reason to mess with them.

Hope all's going well! Take care.

G~

geoff727

techlectic wrote: »

I see now from the RTA12C upgrade thread that geoff727 didn't bother with the fit of the tweeter into the routed-out part of the tweeter bracket. When I read it before, I thought the "snapping into place" was referring to the tweeter going into the recessed area, but now I think it's just referring to the magnet going into the hole that goes all the way through the bracket. As I mentioned, the magnet of the RDO194 is wider than that of either the SL1000 or SL2000.

Attaching some pics of the Monitor 12b tweeter situation.

Now, what you just showed in picture 1 doesn't look anything like what was on those 12's I did. If your 194's really fit like that, then ya it's time for some handy work. And, the magnets fit just fine for me, with room to spare. It was the faceplate back lip that had to snap into place.

transmaster

What you need to get yourself is a Dremel Trio. The are designed to do just what you need here.

geppy1

They set up like this

Late RTA 12B late 1983- early 1984 use 6600X drivers and SL1000 tweeters
Look like a Peerless and are the same size. RD0194s will not just drop in the plate and it needs to be modified

Early RTA 12Cs Same as above

Late RTA 12Cs Late 1985 to 1987
Uses 6501 drivers and SL2000s . The late 12Cs use a different and larger tweeter mounting plate then the RTA 12Bs and the RD0194 drops pretty much right in in place of the SL2000


As for the sound difference betweeen the 194 and the 2000. The 194 is a more mellow tweeter.. You have to decide if you like that or the 2000. I would give it some time.

dorokusai

Geppy that can vary wildly as I have owned some RTA12C with SL1000 tweeters. It's an awful lineup to follow up with specifics but WAY better than trying to nail down Monitor series variations. Even Polk isn't sure of the configurations that have been produced since our forum and other members have produced models they have zero documentation or records of production.

I've scoured some back history in the archives at Polk HQ and it's a mess honestly. I've even spoken with Raife about a Compendium idea but even as regimented and thorough as he is, it would be a daunting task....and he's got way too much high end on hand to worry about this....or does he?? : - )

geppy1

Geppy that can vary wildly as I have owned some RTA12C with SL1000 tweeters

Correct Mark, I mentioned early 12Cs have Sl 1000s 1984- to late 85 See the above about early and late 12Cs. Would i lie to you???? The late 12B and early 12C are the same speaker. In fact I have seen 12Cs from Jan of 84 18,220ish numbered below 12Bss (18,343)from April of 84. Same exact speaker. They were pretty good and consistant mid 84 on to 87 as far as things coming they way they said they should .

It is the 1981- late 83 12Bs I find most interesting. Same xovers same 6600 drivers but 4 different peerless used. All sound slightly different. I have owned or taken apart or had others check and take theirs apart any RTA 12s I see or hear of. . As many as I can find. I suspect over 75 pairs have been documented . I also have a theory as to why the SN on the cabinets and x overs are so far off from each other during 1981 to early 83. Three to four thousand off. Before and after that they are much much closer To long to explain here.

I have Monitor 10s down pretty well also. Other then that no idea.