Newbie With CRS+

stogie

Newbie here with a pair of CRS+'s that I bought new in the late 80's. They have been in the closet for at leat ten years now, but I've been reading this forum for awhile and you guys have got me fired up to refresh them and fire 'em up. I was going to start by repacling the tweeters, epoxing the magnets, dynamat the baskets and resealing the gaskets if need be and maybe the binding posts. Then at a later date move on to the crossovers and interconcect and maybe recover the grills. I was wondering if it would be possible to buy a set of "Larry's rings" for the drivers, tweeters, ps, binding post plates (if avaiable)? I will be doing mods in stages and don't want to tear up the MDF during multiple removals. Also what is the part number and source for the gold binding posts. Thanks in advance for any help- looking forward to chatting with you all as work progresses. PS: I have a picture of the speakers that I will try to attach.

hochpt21

Welcome!

And great speakers. I think you need to have 10 posts to PM anyone, but when you get there, PM Toolfan to see if he is still making or has any rings for your model.

It looks like you have done some research and I think your plans so far are a great start.

TennMan

Welcome to the forum! Before you replace the tweeters with new RDO-194 replacements, consider upgrading the crossovers at the same time. Do the TL upgrade to them so you can use the better RDO-198 tweeter. The cost of doing the crossover with the TL upgrade is just slightly more and the cost of the better RDO-198 tweeter is the same as the RDO-194. Either one is $48+ tax. Also add new low LCR inductors to your list of mods. Next to the RDO-198 tweeter, new ERSE Super Q inductors is the best upgrade I have done to my speakers.

stogie

TennMan, I guess the RDO198's won't be an option unless I do the "TL" crossover upgrade at the same time, is this correct? I think the 194's can be done can be done separate of a crossover upgrade- that is what I remember reading on the forum. Is the inductor upgrade done in conjunction with the crossovers or can that be done prior or post. Does the inductor upgrade lower the impendence, if so by how much? I believe the speakers are 6 ohm now. Thanks

nspindel

Hi stogie. Welcome to Club Polk, you have certainly come to the right place! The binding posts you are looking for are the Cardas CCGR's, available from soniccraft.com. TennMan is correct, do not buy the RD-0194. Hold off until you are ready to do your crossover work, and with the addition of one extra cap you are able to use the RD-0198 tweeter. This is what is known as the "TL mod".

You've got the pin-blade single-tweeter CRS+, that's the one you want, so take your time and do it right. I've already done the exact project you are looking to do, and I have a thread documenting all the changes here:

http://www.polkaudio.com/forums/showthread.php?137026-My-new-4.1TL-s-are-complete!

I am also just now finishing replacing my binding post cups with VR3's plates and replacing the internal chassis wire with Cardas Litz, and re-doing my grills.

One question for you - in your photo, on the speaker where you are showing the rear, there is something on the speaker at 7:00 on the passive radiator. What is that? Hopefully you have not drilled through the cabinet?

F1nut

One question for you - in your photo, on the speaker where you are showing the rear, there is something on the speaker at 7:00 on the passive radiator. What is that? Hopefully you have not drilled through the cabinet?

That's the plug covering the location of original SDA socket before Polk changed from the CRS blade/blade to the binding post mounted CRS+ pin/blade. It's suppose to be there.



stogie, I'll echo the suggestions on doing the TL upgrade now. Besides, those original caps and resistors are junk compared to todays offerings.

Does the inductor upgrade lower the impendence

Depends on the inductor used. Don't worry about that right now as it can be done later, if at all.

For the rings, you want Toolfan66.

stogie

nsindel, Thanks for the binding post information, I will research and order. Yes, I believe I will wait on the tweeters and do the "TL" modification. I looked at the link, beautiful job on you speakers. I will save that link and refer back to it as I progress. Regarding your last question: There is a capped hole on each speakers. That is the way they came out of the box in 1988 or '89. I have read here that Polk used old parts as they were moving from model to model. It is my belief that they were old speaker backs from a pervious model that has the interconnect plug in that location. Could be wrong though. I'm open for other thoughts on their origin and maybe the best way to fill the hole (maybe a dowel) or just leave it as is.

nspindel

Never saw that before, good to know. Learned something new!

stogie

F1nut, Yeah I thought those holes might be from an older model. I don't have enough confidence yet to tackle the crossover, even though I've done a little circuit board soldering a long, long time ago. Heck I haven't even opened them up yet. I'm gonna get comfortable doing some of the easier stuff and take a look at the boards. No hurry though, I want to take my time and enjoy my new hobby. I will PM Toolfan66 when I get enough posts.

TennMan

stogie wrote: »

TennMan, I guess the RDO198's won't be an option unless I do the "TL" crossover upgrade at the same time, is this correct? I think the 194's can be done can be done separate of a crossover upgrade- that is what I remember reading on the forum. Is the inductor upgrade done in conjunction with the crossovers or can that be done prior or post. Does the inductor upgrade lower the impendence, if so by how much? I believe the speakers are 6 ohm now. Thanks

As others have already said the TL mod must be done to the crossover in order to use the 198s. The inductor upgrade can be done at any time. It is separate from the crossover upgrades. One thing I should have mentioned before is that if you change the inductors the impedance will drop. On my 2Bs the total resistance of the speaker measured at the rear terminals dropped from 4 ohms down to 3 ohms. I don't know how that relates to a drop in impedance but for sure you will need an amp capable of handling the load of the lower impedance.

stogie

If done, the inductor upgrade will be last or near last. As far as amps and preamps go, I've been doing a lot of research and reading the posts on this forum. They are definitely in my future. Right now all I have is a home theater setup with a Yamaha RX-V1000 supplying the power (105w/ch). I know the Polks need more power to get the most out of them, not only my CRS's but any future SDA's I may get. New thread on that.

Green '01

Your thread title "Newbie with CRS+" caught my attention.
I, too, have been accused of having CRS, but around here it means Can't Remember ****.
Sorry to yank your thread off track, but I couldn't resist.

Tekkis

Those are some nice looking CRS+ speakers and on a side note I know I suffer from C.R.S.

stogie

nspindle- regarding your reply in post #5. I followed the link you provided and noticed that the inductors on the circuit board are new and not brought over from the old boards. Do you have part numbers and a supplier's name? Are they drop in replacements? As I mentioned earlier, you did a beautiful job on your speakers and the crossovers.

nspindel

Yup. You can order them from parts express. When I bought them it was a bit over $40 for the six inductors, shipping included.

Here is the link to all the Jantzen air-core coils:

http://www.jantzen-audio.com/wp-cont...18-11-2013.pdf

You'll want these:

0.4mH 22GA - index #000-1489
1.25mH 20GA - index #000-1137
2.5mH 20GA - index #000-1695

stogie

thank you

nspindel

No prob.

nspindel

anonymouse wrote: »

I own a pair of highly modded CRS+ as well. IMHO, you biggest bang for the buck improvements will be in the capacitors and tweeter changes to 0198's with the TL mods. Everything else pales in comparison. I personally found the binding post changes to be mostly of cosmetic value, as well as the inductor changes. I'm not saying I found no difference, but it was really, really minor in my view. Larry's rings would probably rate next in value. I have those and they do make a difference. I did that along with the dynamat, so I cannot tell if it was the dynamat or the rings.

Have fun!

Pretty much agree with everything you're saying. The one exception I have with what you're saying is the large 16mH inductor. That makes a big difference. I don't know how much of a difference the smaller ones make, but for $40, as long as I was changing everything else it was a "might as well". Dynamat and the rings both make a big difference. But certainly the big bang for the buck comes with changing the caps and resistors, adding the TL cap, and changing the tweeters.

F1nut

so I cannot tell if it was the dynamat or the rings.

It was the rings, not subtle.

leftwinger57

Nspindel if you remember the posts where the CRS+ speakers that had that weird bolt arrangement.I don't think anyone to this day ever figured out what they were for.Some said to strenghten the interior others thought it was for some kind of mounting hardware.Anyway those also had those plugs or knockouts.

TennMan

nspindel wrote: »

Pretty much agree with everything you're saying. The one exception I have with what you're saying is the large 16mH inductor. That makes a big difference. I don't know how much of a difference the smaller ones make, but for $40, as long as I was changing everything else it was a "might as well". Dynamat and the rings both make a big difference. But certainly the big bang for the buck comes with changing the caps and resistors, adding the TL cap, and changing the tweeters.

I completely agree. The changing to a low DCR 16mh inductor makes a big difference. Not only in bass but it seems to open up the midrange.

nspindel

leftwinger57 wrote: »

Nspindel if you remember the posts where the CRS+ speakers that had that weird bolt arrangement.I don't think anyone to this day ever figured out what they were for.Some said to strenghten the interior others thought it was for some kind of mounting hardware.Anyway those also had those plugs or knockouts.

I don't recall these posts. Mine don't have any strange bolt arrangement.

nspindel

anonymouse wrote: »

...I personally found the binding post changes to be mostly of cosmetic value...

This is correct as well. Binding posts are bling. But good bling!

mikemokr

leftwinger57 wrote: »

Nspindel if you remember the posts where the CRS+ speakers that had that weird bolt arrangement.I don't think anyone to this day ever figured out what they were for.Some said to strenghten the interior others thought it was for some kind of mounting hardware.Anyway those also had those plugs or knockouts.

Those weird bolts have nothing to do with your question nspindel but the issue of the plugs/holes came up in that thread too, re CRS+ I was looking at. The (different) CRS+ I wound up buying also have the holes where the IC jack was in the previous generation CRS, presumably using the same cabs. In fact one of the plugs is missing in my pair so I'll need to deal with that ... that'll be about my speed for my first "mod"!

TennMan

Here is a link to the comments I made after I installed the ERSE Super Q 16mh inductors. The Super Qs replaced the large inductor in the crossover that is for the dimensional driver. It plugs into the crossover board and can be easily replaced at any time. I didn't replace the smaller inductors that are soldered onto the crossover. Although it gets off topic a lot you should read the entire thread about the inductor for the dimensional driver circuit. There are other good threads about the inductors as well.

westmassguy

Changing the "Full Complement Sub-Bass Drive" or Dimensional Inductor in the 3rd, 4th and 5th generations will make a dramatic change in the bass below 150Hz. I think this is more noticeable in the smaller SDAs, CRS+ and 2A/2Bs, which only have two woofers to begin with, and the big boys with multiple Dimensional Drivers. The original 16mh inductors in the 4th and 5th generation are around 2.5-2.6 ohms. The Erse SuperQ Laminated Steel Inductor is 0.5-0.6 ohms. Large gauge air core inductors will be a bit higher. With my 2As, the original 5.6mh inductor was around 1.8-1.9 ohms, and the Erse SuperQ 14 gauge was around 0.25 ohms. The trade-off is lower overall impedance of the speaker. From the mouth of MP: "Depending on the model, reducing the DC resistance of these coils may take the minimum impedance down to around 2 ohms. If your amp doesn't mind, you shouldn't either."

stogie

On CRS+ crossover rebuild that nspindel did, I noticed that he used 30, 20 & 10uf caps where the Gimpod site said to use all 20uf. Are there benefits of one configuration over the other?

nspindel

No idea. I bought all the caps from Sal, that was what he gave me so that's what I used. Not sure if there is any difference, I certainly haven't encountered any problems.

F1nut

If possible it's better to split the cap values evenly.

agfrost

I did the same thing as Neil on my 2BTL crossover build (30uF + 10uF), having bought the caps from a CRS+ owner who decided against doing the upgrade.

Before gimpod's boards came into being, the 30 & 10 was the commonly-used combo, as that was the way to make it all most easily fit on the original boards, in the confines of the CRS+ cabinet. It was supposed that 30/10 would not fall into the "smaller cap acting as a bypass" effect that can happen when the values differ by too much. I've been well pleased with my work, but I haven't done a double-blind test against a board with 20uF in each position. :razz:

I know you're well aware of this, Jesse, and would have made the 20/20 choice if I was buying fresh from Sonicraft myself. Just adding some "history" to why/how Neil's crossovers came to be that way.

F1nut

Before gimpod's boards came into being, the 30 & 10 was the commonly-used combo, as that was the way to make it all most easily fit on the original boards, in the confines of the CRS+ cabinet. It was supposed that 30/10 would not fall into the "smaller cap acting as a bypass" effect that can happen when the values differ by too much.

100% on the money!