SDA CRS+ Cap upgrade question

bcline

Question for the experts. Looking at upgrading a set of CRS+ crossovers. As you probably know, the dimensional array circuit has 2-130uF caps (making a 260 uF capacitance) for the circuit. Have a tight budget right now and film caps are going to cost about $60 to $70 per speaker (that is the cheapest going with Solen or Daytons). My question is if I was to go with new electrolytic caps on this circuit instead of film, how and what would this affect on the sound? I would still go film on all the other caps and go with high quality film on the tweeter. Since this cap really affects the dimensional array driver, am I really going to hear the affect of this cost cutting move?

2nd Question... is there much difference between using Dayton non-inductive resistors vs Mills?

F1nut

You should use all film, they do make a difference even for the dimensional driver.

Do not use Solen or Dayton for the tweeter.

Mills are cheap enough for any budget.

westmassguy

I had the same dilemma when I first got my 2As (Same generation, and same crossover). You can always revisit the crossovers. My 1st upgrade consisted of Sonicaps and Mills for the Hi-Pass, Dayton 5% for the Lo-Pass shunts, and new electrolytics for the two 130uf caps. I knew at some point the electrolytics would be replaced. It took 6-8 months before I hand enough discretionary income to buy six 90uf Daytons, which was the least expensive option. Shortly after I also did a non-sanctioned "TL Mod", which made the 2As outstanding: http://www.polkaudio.com/forums/showthread.php?143984-My-2As-Finally-Finished...Almost
As F1 suggests, do the Mills Resistors. The Daytons are Sandcast, and no better than the ones in your crossovers now.

zingo

I prefer the Mundorf MOX resistors, and film caps are the best, but you always can revisit the crossover when you have more funds as stated above.

Good luck!

nspindel

My two cents, having done this project:

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

If you look at the schematics, you'll notice that the two 130uF caps per speaker were dropped in later versions of the CRS+. If I were in your shoes, I would take the money that you'd be spending on those massive caps and put it towards a pair of Tony's boards, two 6511 new-stock drivers, two RD-0198 tweeters, and the correct inductors in order to upgrade your CRS+'s to 4.1TL spec. You've already got the single tweeter cabinet. You'll end up with a much better pair of speakers in the end!

westmassguy

nspindel wrote: »

My two cents, having done this project:

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

If you look at the schematics, you'll notice that the two 130uF caps per speaker were dropped in later versions of the CRS+. If I were in your shoes, I would take the money that you'd be spending on those massive caps and put it towards a pair of Tony's boards, two 6511 new-stock drivers, two RD-0198 tweeters, and the correct inductors in order to upgrade your CRS+'s to 4.1TL spec. You've already got the single tweeter cabinet. You'll end up with a much better pair of speakers in the end!

The cabinet volume is different, and the PRs are tuned differently

nspindel

Ouch!

nspindel

If the older cabinets were larger, you could compensate for the cabinet volume with something like Sonic Barrier, correct? Are the PR's the same size and screw hole configuration? I've seen the passives on eBay before. Just wondering how out of the question this mod would be. 260uF per side of decent film caps is a lot of dosh.

westmassguy

By the time you add in 2 PRs, and 2 new or salvaged replacement drivers, plus the boards, plus at least 4 inductors, you're well past what he would spend for the caps

nspindel

Depends on the caps. To get that much Sonicap capacitance would be over $700. I suspect that's why the OP is asking about Solens and Daytons. It may cost a bit more to do this than to use cheap caps, but the end result will be so much better I would think.

westmassguy

nspindel wrote: »

Depends on the caps. To get that much Sonicap capacitance would be over $700. I suspect that's why the OP is asking about Solens and Daytons. It may cost a bit more to do this than to use cheap caps, but the end result will be so much better I would think.

So much better? I respectfully disagree. My 2ATLs are easily a match for a similarly equipped pair of 2Bs. And his crossovers are exactly the same as mine. The 260uf (total) shunt caps do not need to be high-end caps like the Hi-Pass, or even the regular Lo-Pass shunt caps. They operate in conjunction with the 5.6mh inductor as part of the "Full Complement Sub-Bass Drive", and only below 150Hz. Daytons or Solens will do just fine in that position.

bcline

Thanks for all the replies. I figured most of you would say to go with films, but I'm doing this for a friend's set who is on a limited budget. Yes we may go electrolytic now and upgrade the large caps later. What no one has addressed is what do I lose with the electrolytic vs. the films. I have heard the difference with the two on the high pass and have even heard the diff between Daytons vs Sonicap vs Clarity etc. What I want to know is what do you get on the low end drivers with the films vs electrolytic (soundwise) and will it still be better with the new electrolytic caps over the original or should I just leave the originals in for now until he can afford films for that part of the speaker.

bcline

No... we will not be going with Sonicaps on the low pass. $700 for CRS+ set is really not worth that cost. Might as well start looking for SRS speakers.
:-)

nspindel

westmassguy wrote: »

So much better? I respectfully disagree. My 2ATLs are easily a match for a similarly equipped pair of 2Bs. And his crossovers are exactly the same as mine. The 260uf (total) shunt caps do not need to be high-end caps like the Hi-Pass, or even the regular Lo-Pass shunt caps. They operate in conjunction with the 5.6mh inductor as part of the "Full Complement Sub-Bass Drive", and only below 150Hz. Daytons or Solens will do just fine in that position.

Fair enough. I've never heard any of the non-sanctioned TL's. I've always used Sonicaps across the board, I'm glad I've never owned a pair that needed 260uF per side!

nspindel

bcline wrote: »

No... we will not be going with Sonicaps on the low pass. $700 for CRS+ set is really not worth that cost. Might as well start looking for SRS speakers.
:-)

Oh trust me, you can spend a lot of cash on a pair of CRS+'s.........

bcline

WestMass... I too did a set of 2A speakers about five years ago. There is a thread somewhere on the forum for it. The guys here found a set of Solens with the right capacitance for a really cheap closeout price so I didn't have to wire a bunch up in parallel. I did use hot glue... sorry not professional... but I figured nobody would ever see it.

westmassguy

nspindel wrote: »

Oh trust me, you can spend a lot of cash on a pair of CRS+'s.........

Yeah you got Duelunds, sweet!

westmassguy

bcline wrote: »

WestMass... I too did a set of 2A speakers about five years ago. There is a thread somewhere on the forum for it. The guys here found a set of Solens with the right capacitance for a really cheap closeout price so I didn't have to wire a bunch up in parallel. I did use hot glue... sorry not professional... but I figured nobody would ever see it.

When I was looking, 2 Solen 130ufs were more expensive than 3 Dayton 90ufs, so went with them

F1nut

What I want to know is what do you get on the low end drivers with the films vs electrolytic (soundwise)

Mo' better bass.

westmassguy

F1nut wrote: »

Mo' better bass.

This^^^^^^^^
Plus, if you really want to increase the bass, replace the 5.6mh "Full Complement Sub-Bass Drive" or Dimensional Inductor for short. A 14 or 16 gauge Erse SuperQ Inductor will increase the bass output of the dimensional woofer below 150 Hz dramatically. Again, you don't have to do everything at once. Do the "Stereo" half of the crossover (which includes the Hi-Pass Tweeter section) with the best components you can afford. The "Dimensional" half can be reworked easily, once you can afford the film caps and the Inductors. That's more or less how I did my 2ATLs.

westmassguy

bcline wrote: »

Thanks for all the replies. I figured most of you would say to go with films, but I'm doing this for a friend's set who is on a limited budget. Yes we may go electrolytic now and upgrade the large caps later. What no one has addressed is what do I lose with the electrolytic vs. the films. I have heard the difference with the two on the high pass and have even heard the diff between Daytons vs Sonicap vs Clarity etc. What I want to know is what do you get on the low end drivers with the films vs electrolytic (soundwise) and will it still be better with the new electrolytic caps over the original or should I just leave the originals in for now until he can afford films for that part of the speaker.

Another thing to consider, is the crossover point, which is below 2K as I recall. The woofers not only supply the low bass, but also cover a good deal of the range of the human voice, so those 20uf shunt caps should be the best you can afford as well.

bcline

westmassguy wrote: »

This^^^^^^^^
Plus, if you really want to increase the bass, replace the 5.6mh "Full Complement Sub-Bass Drive" or Dimensional Inductor for short. A 14 or 16 gauge Erse SuperQ Inductor will increase the bass output of the dimensional woofer below 150 Hz dramatically. Again, you don't have to do everything at once. Do the "Stereo" half of the crossover (which includes the Hi-Pass Tweeter section) with the best components you can afford. The "Dimensional" half can be reworked easily, once you can afford the film caps and the Inductors. That's more or less how I did my 2ATLs.

So only replace that inductor... (I'm now thinking about my SDA 2As I did back in 2009 which have the same layout)... The other two inductors are OK and do not need replaced? Is that because this is parallel "shunt" wired and the other two are in series? I don't really understand what the inductors functions are in this circuit so I'm just curious to know.

westmassguy

Leave the other inductors in place, they're fine. This particular inductor provides a path to ground, below 150hz, for the dimensional woofer to operate in tandem with the stereo woofer. It's a very unique arrangement. If it's not there, it's out of phase with the stereo driver, and reduces bass response. They got around it with the original SDA-2 by adding a sub base driver. They made this inductor with a relatively high resistance, to keep the overall speaker impedance high enough so amplifiers back in the day could handle the load. Replacing it with a very low resistance inductor, increases the low bass output on the dimensional woofer quite a bit. The trade off, is your 4 ohm 2As now drop well below that. If your amp can handle < 4 ohm loads you should be fine. There's a whole section in the SDA Handbook that explains all this.

bcline

I will have to think about that then. I'm still running an Onkyo TX-SR806 AV receiver on the system right now. It handles the 4 ohm speakers just fine without overheating, but I don't know if it will be able to handle 2 - 3 ohms which is what the SDA manual says you will essentially get. Not at a point right now to by new amp either, though it would be wonderful.

westmassguy

I'm surprised it's handling them now. Seem like a good AVR, but they run out of steam very quickly since all channels share the same power supply.

bcline

That particular receiver and the 805 were both given pretty high marks for current and true power ratings. So, they are good at handling them. Usually for music, I'm just in stereo mode so it is just powering the two SDA 2As. In surround mode, watching movies.. it doesn't seem to falter at all, but I usually don't crank up the movies as much as the stereo music. Eventually, I will move up to a high end system, but I'm not altogether unhappy now.

westmassguy

bcline wrote: »

That particular receiver and the 805 were both given pretty high marks for current and true power ratings. So, they are good at handling them. Usually for music, I'm just in stereo mode so it is just powering the two SDA 2As. In surround mode, watching movies.. it doesn't seem to falter at all, but I usually don't crank up the movies as much as the stereo music. Eventually, I will move up to a high end system, but I'm not altogether unhappy now.

That Receiver has pre-amp outputs, all you'll need is an additional power amp for the 2As. Your center and surrounds can still run off the Receiver. That's how mine is setup.

bcline

I didn't realize this. I will have to start looking for a good amp to stick on it. Always up for suggestions. Thanks.

westmassguy

bcline wrote: »

I didn't realize this. I will have to start looking for a good amp to stick on it. Always up for suggestions. Thanks.

Used Adcoms are popular, Carvers too. I use a Carver PM-350 Pro amp, which some find objectionable, however it's quiet, has a nice clean sound, and more power than I'll ever need for my 2ATLs, 450 watts/channel @ 4 or 2 ohms. Any amp you do consider, must be common ground, or it won't work with your 3rd generation CRS+.

Toolfan66

The cabinets are the same size, and yes the PR's have a different part number, but you would never know the difference between the two if I didn't tell you..

westmassguy

Toolfan66 wrote: »

The cabinets are the same size, and yes the PR's have a different part number, but you would never know the difference between the two if I didn't tell you..

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.