RTA 11T crossover and binding post work

keithpgdrb

Hey all,

Finally getting around to replacing the binding posts on one of my RTA 11t speakers, as it was broken off previous to my owning it.

so I figured, while I'm back there opening things up, should I change out the caps? These were made in 90-92, so while not "vintage", they could probably use a change out? seems easy enough. The 3000 tweeter was dropped in when the old 2000's blew out. again, before my ownership.

So I guess my question is, are there any recommended cap changes when using the 3000 tweeter? I recall that it was a direct drop in replacement, but I figured I'd ask the experts here. Look forward to hearing what everyone has to say. Here's some pics as well.

keithpgdrb

after further research on the site, It seems I have the RTA 11TL. same question applies though.

agfrost

Those are nice speakers, and I think you'd do well to do some investigation/modification. A few observations:

1) It would be good to verify (by looking at the crossover) whether you have 11Ts or 11TLs. You said above that original SL2000 tweeters were swapped out--do you know this for a fact? I ask because there are many, many cases where the sticker on the back doesn't give the correct model. I notice that your RTAs have the "wing" above the tweeter--This was part of the TL model, but not of the T. If you pull a crossover to look at the values of the parts, you'll know for sure. (TLs have 12/16/34uF caps whereas the T's have 12/12/34uF; TL's have a single 1.5 ohm resistor while the T has 2.0 and 2.7 resistors; The TL does not have a polyswitch while the T does. (It's "invisible" looking at the crossover, but the small inductor is a different value in the two models also). You can find the schematics at the top of the Vintage Speaker page. Find out for sure, as you want your crossover to match your tweeter.

2) IMO these speakers are well worth updating the crossovers, if you're planning on keeping them. I've done the crossovers on a pair of RTA11TL (in addition to buying RD0198 tweeters), and was very happy with the outcome. They sounded good when I rebuilt them, and were good enough to show well the differences as I brought in better gear to pair with them.

Edit: Here's a link that contains a picture of my stock crossovers. (actually, only one was that of an 11TL, and *it* was labeled an 11T crossover (incorrect sticker on it).

F1nut

^Excellent advice^


keithpgdrb, that close up pic of the tweeter.....that tweeter's dome has gone south. After figuring out what model you have, replace the tweeters as well.

11tsteve

here is a link from my 11T's, which is what started my journey in these Forums.

http://www.polkaudio.com/forums/showthread.php?130965-crossover-upgrades-11T

I have two sets of crossovers for the 11T's, one with square boards and one with round boards. There are pics of both in the thread if you would like to see.
I originally redid the crossovers with Sonicap Gen I and Mills 12W resistors, and have since switched out the resistors with Mundorf MOX (except the .5 Ohm for the polyswitch, which remains a Mills). My ears said the MOX are more transparent, and really let the replacement RDO-194 tweets shine. Comparatively, the Mills seemed just slightly veiled.
Mine had broken binding posts as well, and at the time, I just ordered some cheap "normal" posts from Parts Express, which worked fine at the time. But, having said that.... these have been out of my rig for some time and have recently been put back into the line up. Having worked on other speakers, I have had the opportunity to use better posts, and I have to recommend you spend a little extra. I will be buying a set of Cardas to replace these cheap ones. The Cardas, if nothing else, are more solid, and hold whatever connector you may be using with more authority. My MIT cables with bananas are solid in my speaks with Cardas, and much too loose in the cheap ones.
Better posts are money well spent.

keithpgdrb

No, I do not know for sure that the original tweeter was the 2000 version. I believe now that it was not. The friend who replaced the tweeters told me he got the upgraded version. I assumed that meant from 2000 to 3000. But I believe there was an upgrade that had a different dome, but the number was the same in the 3000 family? having looked at the crossover with your excellent info, I do indeed have the 11TL, which is great news for me. as far as the tweeters go, they should be fine, as they were replaced in sometime in the mid 2000's. I've taken a better close up of the tweeter from the above pic. is it bad? works fine as far as I can tell.

Unfortunately, I already ordered the Dayton audio 5 way binding posts, so those will be the ones I use. They get reviewed well across the board, and I think they will do well. are they top of the line? No. but I think the quality will be good.

So, if I update the 3 caps, what should I use? I was just going to get the dayton 1% or 5% poly caps originally. I'm looking into the suggestions made so far.

F1nut

But I believe there was an upgrade that had a different dome, but the number was the same in the 3000 family?

Nope, there was only one version of the SL3000. There is a new replacement called the RD0198-1, which is much, much better than the SL3000.

I've taken a better close up of the tweeter from the above pic. is it bad?

I stand corrected, that tweeter looks good. I must have been seeing reflections on the dome that made it look creased.

Unfortunately, I already ordered the Dayton audio 5 way binding posts

You can send them back without a problem, they aren't very good. The Cardas are worth every penny.

So, if I update the 3 caps, what should I use?

Not if, just do it! Good choices would be either Sonicap or Clarity. Don't forget to upgrade the resistors as well. Mills 12 watt are a good choice.

keithpgdrb

damn, sonicaps dont have a 34uf. was hoping to get them all from the same place to avoid double shipping. have to mix in something else for the 34uf.

george daniel

Get 2 of the 17uf,,piggyback and you are good to go-- or call-- they will make some custom values if you ask nicely.

keithpgdrb

must have too much easter on the brain to have not thought of that.

keithpgdrb

wow, I did not realize how expensive these were. Going to be $114 per speaker before shipping and taxes. I'll need to wait I think. especially if I'm thinking of getting the new tweeters. I suppose in the big picture, its a lot of improvement for little money. but you have to have the money. I'll do the posts, then hit the crossover caps when there is a sale.

11tsteve

up to you, but in my crossovers, I used a Jantzen 33 uF which was within the original cap's +/-.

Sonicraft has a 20% off sale a few times a year, and was when I bought my caps and resistors. It was quite a savings. you would probably save enough to pay for a new set of Cardas posts...:cheesygrin:

skrol

If it helps, here is a thread of my RTA-11TL upgrade project. http://www.polkaudio.com/forums/showthread.php?73017-RTA11TL-Upgrade-Project&highlight=RTA-11TL+Modification . There are some lessons learned in this one.

Your crossover is a little different than mine. Where you have a 16uf cap, mine had a 12uF mylar with a 4.4uF electrolytic in parallel. Before I started the project I spoke to the engineer who designed the TL version and he said that it would be this way and recommended that I change it to a single 16uF non-electrolytic. I went with Clarity caps for the tweeter caps and Jantzen for mid-woofer the 34uF where it is less critical.

A lesson learned: Since I could not find a 16uF, I tried a 15uF with a 1uF in parallel. Don't do this. The 1uF will act as a bypass cap and it doesn't sound right. You are better off just going with a 15uF if you can't get a 16uF. Or, you can use equal values in parallel (ie. two 8uF in parallel). However, SonicCraft offers a 16uF SoniCap.

keithpgdrb

when you guys replaced your binding posts, I assume you had to widen the hole that the posts went in yes? so you drilled out the plastic? yes?. after the new post is in place, did you seal it up with something? was thinking of just using some hot glue around the area when I was done.

keithpgdrb

also, could you link me to the cardas posts that were recommended. I'm considering them.

11tsteve

i used these in my infinity RSbs, and will most likely use them when I replace the crappy Parts Express ones in my 11T's.

When I installed mine in the 11T's, I didn't have to drill anything. I unscrewed the post, it fit through the hole, and then reapplied the nut. The cheap ones have a ring in place that seals the hole, the Cardas come with a nylon washer to seal.

http://www.soniccraft.com/products/connections/bindingpost/cardas_ccgg.htm

keithpgdrb

Huh. I would have thought that there would have been a standard hole size for the posts to mount to. I would like to avoid drilling anything out. The parts express ones are thicker then the existing hole. as far as the posted cardas posts,I am warry of the posts that are set at a fixed width on a plate. is there a standard width that all posts use? I would find that hard to believe. I'd hate to order them, and have them not fit.

I cant thank you enough for the link to those posts. I'll have to really think about this. I just dont think I want to spend $70 on binding posts. There must be quality posts out there for less.

This whole process is getting more expensive then I thought It would be! lol.. thats ok though. just means delayed satisfaction.

11tsteve

You can take the posts off of the plate and put them in the pre-existing holes. The plate doesn't need to be used.

I went through this same question in my head because the Parts Express ones I used also had that plate, and I really thought I had ordered something wrong.
Look through the Sonicraft site.... there is a straight copper Cardas post for $24.50/pr, and Vampire also has a less expensive but still high quality post.

http://www.soniccraft.com/products/connections/bindingpost.htm

It is your money and you have to do what ever you want. I only mentioned it because I have used both cheap and better posts, and I personally found the Cardas easier to install(better mounting hardware), and provide a much more solid connection for my banana connectors than the cheap ones. But I don't know really what you have already bought, and I haven't done quite enough crossover work to know about standard sizes of posts. I know I didn't drill my 11T's. but had to drill my Infinity's because the had small wire clip connector instead of posts.