SDA CRS+ Cap upgrade question

Toolfan66

I know the weighting is different I have both sets of PR's, what I am saying is you won't hear a difference, and if there is a difference it's so small it's not worth looking for them, and I wish I still had the other set of cabinets I had to measure them, but they never seemed to be different.

But I will say the same will hold true as the PR's the change is so small it won't make a big difference if any. Remember these are the same crossovers and drivers used in the 2B's..

I would still upgrade the OP's speakers to 4.1tl's using Tonys boards..

Sometimes I feel there is to much overthinking with these SDA's, Polk was even known to use this and that as they evolved, and look at what has been done on this forum, they have become what one could call a DIY speaker.

Not everyone here has followed the same rule with upgrades, some ideas have scared me, others have pushed me..

westmassguy

I respectfully disagree. The OP would be scrapping two perfectly fine crossovers which can be easily modified and upgraded to TL status and four woofers. He would then have to purchase 2 new boards, 6 new inductors, and four new woofers. I don't see any logic to that.

Toolfan66

FUN !!!!!!

There is no logic in putting a $7000 supercharger in a car that's runs just fine but we do anyways.

westmassguy

Apples and oranges. The supercharger is going to make the car sound meaner and go faster. I've tested my fully modified 2ATLs against fully modified 2BTLs, side by side, and there's no difference in sound quality, depth or width of soundstage. Even sweep test tones and discreet test tones down to 17.5 Hz revealed no differences. The only downside to the 2As is the < 4 ohm impedance, which requires an amp able to handle the load.

F1nut

westmassguy wrote: »

Not true. According to the SDA Handbook, The 3rd generation CRS+s the OP has measure 12.5 X 20 X 9.5., same as the 2nd generation. The 4th generation CRS+s cabinets measure 12.75 X 20 X 10.125. That's an 8% difference. The driver's T/S parameters between the 3rd and 4th generations are also different as are the weighting of the PRs.

I have 4th generation CRS+ (now 4.1TL) that measure 12.75 X 20 X 9.5. If you add the PR cover you get 10.125. The 12.5 measurement is a typo as is the weight of the 3.1TL at 180 lbs., it's actually 101 lbs. Don't believe everything in print, Polk never changed the size of the CRS/CRS+ cabinet.

nspindel

Then I revert back to my original opinion. Modify these to 4.1 TL spec and don't look back.

westmassguy

F1nut wrote: »

I have 4th generation CRS+ (now 4.1TL) that measure 12.75 X 20 X 9.5. If you add the PR cover you get 10.125. The 12.5 measurement is a typo as is the weight of the 3.1TL at 180 lbs., it's actually 101 lbs. Don't believe everything in print, Polk never changed the size of the CRS/CRS+ cabinet.

Thanks FI, that clarifies one anomaly, however I can't fathom scrapping a perfectly good pair of crossovers, and set of woofers.

nspindel

Sell the woofers. As for the crossovers, he's going to pull them apart anyway.

westmassguy

nspindel wrote: »

Then I revert back to my original opinion. Modify these to 4.1 TL spec and don't look back.

Then it's up to the OP to decide if he wants to fork over for 2 new boards, 6 new inductors, and four new woofers, caps, resistors, and TL Mod, or keep the crossovers and woofers he has, and do the caps, resistors, TL Mod, and possibly the 2 "Full Complement Sub-Bass Drive"/Dimensional inductors at a later date.

Toolfan66

nspindel wrote: »

Then I revert back to my original opinion. Modify these to 4.1 TL spec and don't look back.

This^^^^^

nspindel wrote: »

Sell the woofers. As for the crossovers, he's going to pull them apart anyway.

And This!!! ^^^^^^^


I haven't seen my original crossovers in years....



Thanks Jesse, that's what I thought....

Toolfan66

westmassguy wrote: »

Then it's up to the OP to decide if he wants to fork over for 2 new boards, 6 new inductors, and four new woofers, caps, resistors, and TL Mod, or keep the crossovers and woofers he has, and do the caps, resistors, TL Mod, and possibly the 2 "Full Complement Sub-Bass Drive"/Dimensional inductors at a later date.

Upgrading the inductors is a must IMO, so might as well do it all, the OP will be pleased...


Oh and Tonys boards blow the stock boards away...

westmassguy

The OP is doing these for a friend, with a limited budget. Did we forget that? I didn't, and I'll stick with my recommendations. The OP and his friend can decide. The OP can also contact me directly, and I'd be more than happy to walk him through the process.

nspindel

westmassguy wrote: »

Then it's up to the OP to decide if he wants to fork over for 2 new boards, 6 new inductors, and four new woofers, caps, resistors, and TL Mod, or keep the crossovers and woofers he has, and do the caps, resistors, TL Mod, and possibly the 2 "Full Complement Sub-Bass Drive"/Dimensional inductors at a later date.

The 1st generation CRS+ used four 6510 drivers, the final version used two 6510's and two 6511's. He would only need two new woofers, not four. He can get two new-stock 6511's from Polk for $48 each, and probably sell the extra 6510's for $35 each. The six new inductors he would need for the crossover would cost him $40 for Jantzens. He'd also need 16mH inductors. I used Solens, they are pricey, but I'm sure there are cheaper options - Jantzen does make one. I bet if he tried hard enough he could find someone here who has updated the SDA inductor to sell him the stock 16mH inductors cheap enough. Or he could use Erse Super Q's. The caps would be a net savings to him, as there's 260uF per side that he would not need.

westmassguy

I did some quick math. If he keeps what he has, and does all Sonicaps for the Hi & Lo-Pass, Mills Resistors, TL Mod, and does NP electrolytics for the 260ufs, the total is $230.00 plus tax and shipping. If he does the 260uf with Daytons or Solens, it's an additional $200.00. That's $430.00, with no changes to the drivers, PRs, or internal cabling.
If he builds new crossovers, all Sonicaps, Mills Resistors, TL Mod, Inductors, Boards, Connectors & Cables, plus two Erse SuperQs for the 16mh Inductors, the total is $480-$500.00. This would also require purchasing 2 MW6511s, possibly two PRs.
If he does Daytons or Solens for the Lo-Pass Section, both options would cheaper, but the keeping the original crossovers would still end up the least expensive route. Let's not forget the additional time required to fabricate all new internal cabling, and mountings for the new crossovers.

drumminman

nspindel wrote: »

I bet if he tried hard enough he could find someone here who has updated the SDA inductor to sell him the stock 16mH inductors cheap enough.

I have two stock SDA inductors from my 2.3TL's, 16 mH. PM me it interested.

nspindel

Assuming your numbers are correct, to me the extra $50 or so plus a bit more time seems worth it. I'd rather have a pair of final generation speakers than an unsanctioned design. But that's just me.

westmassguy

Again, it's up to the OP to decide. As for unsanctioned, the TL mod for single tweeter, 3rd generation SDAs was debated at length. The general consensus was that it should work, but no one had done it and reported back, except for me. I ever spoke with Jesse about it at least twice, and he concurred.

F1nut

The TL mod will work as the high frequency circuit is exactly the same.

westmassguy

F1nut wrote: »

The TL mod will work as the high frequency circuit is exactly the same.

Thank you Jesse

nspindel

Never said it wouldn't work. I'm saying I'd rather have the later generation design.

bcline

Well, I should have known better than to get back on the forum and let everyone talk me into spending more money. I know what I will do for my friend now, but as for myself and the SDA - 2As I own. I have now purchased the ERSE super Q inductors and thus I am adding a power amp to my system. Decided to go with a Parasound New Classic Model 2250. Getting a great deal on it as I have a friend who runs a high end audio/home-theater business here. Since we go back over 30 years together, I'm getting a new one for less than a lot of people are paying for used ones. So, I talked myself into taking the plunge. I talked to the sales people at Parasound and the guy there said he loved the SDA line. (I was making sure this amp was a common ground amp). I'll use the Onkyo 806 to power the HT speakers and preamp out to the Parasound. So here I go again. Hey, it's just money.

westmassguy

bcline wrote: »

Well, I should have known better than to get back on the forum and let everyone talk me into spending more money. I know what I will do for my friend now, but as for myself and the SDA - 2As I own. I have now purchased the ERSE super Q inductors and thus I am adding a power amp to my system. Decided to go with a Parasound New Classic Model 2250. Getting a great deal on it as I have a friend who runs a high end audio/home-theater business here. Since we go back over 30 years together, I'm getting a new one for less than a lot of people are paying for used ones. So, I talked myself into taking the plunge. I talked to the sales people at Parasound and the guy there said he loved the SDA line. (I was making sure this amp was a common ground amp). I'll use the Onkyo 806 to power the HT speakers and preamp out to the Parasound. So here I go again. Hey, it's just money.

Excellent choice. The Erse can be soldered directly to the upper half of the crossover like I did, or mounted remotely with extension wires and spade connectors.

nspindel

bcline wrote: »

Hey, it's just money.

Good signature right there!

Congrats!!

bcline

Hey it looks like you replaced your polyswitch with a resistor. What resistance did you use. I was testing the polyswitches on mine and most were 0.5 ohm. Is your resistor a 0.5 ohm or some other value. Also, is the inductor I'm replacing the really large square air core found on that board?

westmassguy

bcline wrote: »

Hey it looks like you replaced your polyswitch with a resistor. What resistance did you use. I was testing the polyswitches on mine and most were 0.5 ohm. Is your resistor a 0.5 ohm or some other value. Also, is the inductor I'm replacing the really large square air core found on that board?

As a rule, I always use 0.5 ohm resistors in place of the Polyswitches. It's the value Polk used, in most cases, when they either added them or eliminated them. The 5.6mh Erse Inductor you see going off to the side, replaces the large Inductor that's wound around the spool the crossover is attached to. De-solder the two leads from the existing Inductor, and fold them over inside the spool. As I said previously, the new Inductor can be soldered directly to the circuit board like I did, or mounted remotely.

bcline

I'm pretty sure this is it, but better safe than sorry. The inductor I have the arrow pointing at is what we are talking about... right?

westmassguy

bcline wrote: »

I'm pretty sure this is it, but better safe than sorry. The inductor I have the arrow pointing at is what we are talking about... right?

No, that's the 2.5mh inductor. That doesn't get changed. The 5.6mh inductor is wound around the outside of the big black spool the crossover is attached to.

bcline

Got it. Glad I asked. Like I said better safe... Thanks.

bcline

Got the Parasound 2250 in today and hooked her in. Why did I not do this a long time ago. I'm blown away playing an SACD of Brothers in Arms (Dire Straits) and that is at low volume (kids are asleep).

westmassguy

Your receivers were probably soft clipping and you may not have noticed it. Bass suffers, and there may have been distortion in the higher frequencies. Our ears become adjusted to it. Now that you have the new amp, all the drivers are getting everything they need. Wait till you get the new inductors installed. Are you changing out the Polyswitches too?