TL Mod & The SDA-2B's, GREEN LIGHT!

audiocr381ve

I'm going to put in an order for parts on Friday. I've decided to use Dayton Caps because the Sonicaps will break the bank.

After much thought and research, I've decided to perform the upgrade on the stock crossover boards. I know I gave many around here a hard time about keeping the originals intact, but as one guy mentioned, it wouldn't be hard to put the original parts back in.

I will document the process as best as I can with photographs to add to the other really helpful threads on this upgrade.

I'll undoubtedly need the help of those willing throughout this entire process. I am very much new to this and will ask many very "obvious" questions that aren't so obvious to me. Please bare with me!

First, I'd like for you guys to confirm my parts list.

GOAL
Perform the "TL Mod" to my SDA-2B's

Parts List
2x 12uF Dayton Capacitors Link These are the correct ones right? These have to be matched as well? Can I order these from Dayton matched? Please advise...
2x 20 uF Dayton Capacitors Link
2x 40uF Dayton Capacitors Link

2x 2.7ohm 12-watt Mills resistors for the polyswitch? I read somewhere that these are unnecessary? Please advise...

I'm going to have to wait on purchasing the tweeters for about a month because I don't have the dough to shell out on them. Can I install the items listed above and keep the RDO-194's in until the cash becomes available?

For future purchase (about a month).
2x 5.8uF Capacitors. Not sure what to do here. These have to be custom made and "matched" correct? Please advise...
2x RDO-198 Tweeters

Guys, I seriously appreciate the help. Also, special thanks to Ones&Zero's for the help on putting this list together.

On3s&Z3r0s

Regarding the "matched" thing... if you buy the Dayton Precision 1% you're basically buying matched capacitors because the actual capacitance value will be within 1% of the stated value. (If you were to buy caps from Sonic Craft you would ask for them to be matched, and they would give you caps that are within 1% of each other but could be, say, 3% to 5% away from their stated value. Even 5% is well within spec for the crossover, so no worries there, but folks like the values to be close to each other for left/right balance.)

If you are using Daytons, I'd think it would be fine to save some coin by using the regular caps for the 20uF and 40uF, but it might be good to wait for a second opinion.

Regarding the 2.7ohm resistors, those replace stock resistors on the board. If you decided to use a resistor instead of a jumper in place of the polyswitch, you'd use a value somewhere in 0.1 to 0.5 ohms.

audiocr381ve

On3s&Z3r0s wrote: »

Regarding the "matched" thing... if you buy the Dayton Precision 1% you're basically buying matched capacitors because the actual capacitance value will be within 1% of the stated value. (If you were to buy caps from Sonic Craft you would ask for them to be matched, and they would give you caps that are within 1% of each other but could be, say, 3% to 5% away from their stated value. Even 5% is well within spec for the crossover, so no worries there, but folks like the values to be close to each other for left/right balance.)

If you are using Daytons, I'd think it would be fine to save some coin by using the regular caps for the 20uF and 40uF, but it might be good to wait for a second opinion.

Regarding the 2.7ohm resistors, those replace stock resistors on the board. If you decided to use a resistor instead of a jumper in place of the polyswitch, you'd use a value somewhere in 0.1 to 0.5 ohms.

Thanks for the response Ones. Could you give me a little more info about the Polyswitch? I bumped into a thread where the general consensus was to remove them? I could be sounding stupid right now and not knowing it :redface:

By the way, I gave you a shoutout at the end of my original post, don't know if you caught that

Conradicles

I could be wrong, but I am pretty sure you need the 2.7 ohm resistor to replace the stock resistor. Then, add a .5 ohm resistor in place of the polyswitch if you so desire.

Have fun and you can get a 5.6 uf Dayton for the TL mod. It meets specs.

Conradicles

Here is a list of parts taken from the DIY thread here on Club Polk:
SDA 2B
12uF capacitor
20uF capacitor
40uF capacitor
2.7 ohm resistor
.4mH inductor
1.25mH inductor
2.5mH inductor
16mH inductor

Here are a few threads that will give you some good info:
http://www.polkaudio.com/forums/showthread.php?t=46489
http://www.polkaudio.com/forums/showthread.php?t=62106
http://www.polkaudio.com/forums/showthread.php?t=74945
http://www.polkaudio.com/forums/showthread.php?t=75918
http://www.polkaudio.com/forums/showthread.php?t=87121
http://www.polkaudio.com/forums/showthread.php?t=66784

audiocr381ve

Okay, one thing I'm still unsure of.

Regarding the 2.7ohm resistors, those replace stock resistors on the board. If you decided to use a resistor instead of a jumper in place of the polyswitch, you'd use a value somewhere in 0.1 to 0.5 ohms.

I could be wrong, but I am pretty sure you need the 2.7 ohm resistor to replace the stock resistor. Then, add a .5 ohm resistor in place of the polyswitch if you so desire.

So I gather I definitely need 2x 2.7 ohm resistors, should I use the Mills resistors with the Dayton's?

Conrad, thanks for the help. I didn't even factor in the inductors to the parts list! I don't believe I saw those on Gimpod's site? Where can I find those?

Here is my parts list so far... PLEASE NOTE THE DIFFERENT CAPACITORS IN THE SHOPPING CART.

Is this right so far?

audiocr381ve

Updated Parts List attached. If someone could please review the list and verify each part for me, it would be a huge help for a guy who's only cap purchase was a flex-fit one size fits all

Notice some of the Dayton Cap's are different "models" for lack of a better word.

Conradicles

I would go with the Mills resistors instead of Daytons. The rest of you cart looks OK.
You will need:
(2) Mills 2.7 ohm
(2) Mills 0.5 ohm

The stock inductors are fine, but some have changed them with good results. Personally if this is your 1st time rebuilding crossovers, I would leave the inductors alone.

Joe08867

The list looks good, but after all this debate and all why are you going Dayton? I have nothing against them except I heard a huge difference between Dayton, Sonicap and Clarity Caps. And I believe most here have said the same to you.

Is it cost? If so I have no answer but to save up more and wait. But if it is just cause you think they will be fine then try them. The TL mod will help with the grainy sound I got from my Dayton upgrade. That is why I swapped them out for Sonicaps.

And like Conradicles said I would go Mills resistors over Dayton's all day...

Face

Dayton resistors are junk.

pitdogg2

save your money do it right and do it once.
sonic caps and mills unless sonic caps don't have the values then I'd recommend Clearity cap,Axon or Solen in that order
you won't be disappointed

heiney9

Dayton is middle of the road. Wait until you can afford the Sonicaps, they are very much worth it. If you just can't spend that much look at Clarity Caps PX or SA series, I feel they are better sounding than the Dayton's. Smoother, less grain and a bit more open and airy.

The Mills resistors are the ones to get. Remember these are in the signal path and it does matter. Dayton resistors are very mediocre sounding.

H9

heiney9

If you are really in a money crunch it's perfectly acceptable and pretty standard to use Sonicaps for the high pass and Dayton's for the low pass. Use Mills resistors at all locations.

It's obviously the best to use all the same brand caps, but the compromise as stated above works really well and eases the budget concerns. This is how my 1C's were done. Sonicaps on the high pass and Axon caps on the low pass.

H9

pitdogg2

heiney9 wrote: »

This is how my 1c's were done. Sonicaps on the high pass and Axon caps on the low pass.
H9

same as my SDA2A's money well spent worth the wait to save for them

Toolfan66

You have lots of info now audioc381ve..I still don't see anything negitive being said about upgrading crossovers..

Save up for sonicaps and mills you will be glad you did..

headrott

TOOLFORLIFEFAN wrote: »

Save up for sonicaps and mills you will be glad you did..

Fully agree!!

Greg

inspiredsports

heiney9 wrote: »

If you are really in a money crunch it's perfectly acceptable and pretty standard to use Sonicaps for the high pass and Dayton's for the low pass. Use Mills resistors at all locations.

It's obviously the best to use all the same brand caps, but the compromise as stated above works really well and eases the budget concerns. This is how my 1C's were done. Sonicaps on the high pass and Axon caps on the low pass.

H9

TOOLFORLIFEFAN wrote: »

Save up for sonicaps and mills you will be glad you did..

Leave the stock inductors in place.

Use a .5 ohm resistor in place of the removed polyswitch.

Use Mills 12W (MRA-12) Resistors at all locations (http://www.soniccraft.com/mills_resistors.htm).

Use Sonicaps Gen 1 (or other even better brand) on the high-pass and Sonicaps (or Axon as a second choice) on the low pass (http://www.soniccraft.com/sonicaps.htm). Avoid Dayton.

Don't compromise (especially on the high-pass). Remember, this is a 20 year mod and you will regret compromising . . . you will hear the difference.

Adding a 5.8uf bypass cap over the first 2.7 ohm resistor and upgrading to RDO198's (TL's) is the icing on the cake.

Using all Sonicaps, yes, you will be in the $350 range (TL'd), but you will have speakers that run with those costing 10 times that upgrade budget, and they will do it for 20+ more years. That's $17.50 per year!

Everyone here encouraging you to spend more of your hard-earned is doing so because we've been-there, done-that and ended up doing it again to get it right

audiocr381ve

First of all, a HUGE thanks to all who jumped in this thread.

Looks like Sonicaps are a MUST. The only way I can afford to go with the more expensive caps is to do the mod in sections, which will be cool to hear the way things sound after each cap.

So now, here is my question, what comes first? I'll have just under a $100 this Friday to spend.

And just to be clear, the 12uF caps are the "high-pass" section?

heiney9

My recommendation is to wait until you scrape the cash together for the entire upgrade. If you are hell bent on doing this in stages start with the low pass part first.

Whay can't you wait? A few days ago you were so skeptical that you weren't sure it was even worth it, now you can't wait a few weeks or a month?

H9

inspiredsports

High-pass in red. 12uf is the high-pass cap.

Just pretend you did this without the benefit of Club Polk, and then did it over and over again until you learned by yourself. That would be sometime next year. If you wait a couple months for your funds to accumulate, you will still be a year ahead of where you would have been without CP! (and you would have spent even more time AND money before you got it right)

2B's are special speakers and worth getting right.

Patience, grasshopper. :biggrin:

audiocr381ve

heiney9 wrote: »

My recommendation is to wait until you scrape the cash together for the entire upgrade. If you are hell bent on doing this in stages start with the low pass part first.

Whay can't you wait? A few days ago you were so skeptical that you weren't sure it was even worth it, now you can't wait a few weeks or a month?

H9

I didn't say I couldn't wait. I said I would have $100 to spend this Friday Waiting is my life, I have a 10 month old and a wife.

Somebody in another thread suggested you do it in sections to hear what's going on at each stage. I thought it would be interesting. But I'd want to make sure I could fit all the parts in correctly at each stage.

Any other opinions on proceeding given the current situation? ($100 to spend now) Should I wait too buy all parts or start the mod in sections?

audiocr381ve

inspiredsports wrote: »

High-pass in red. 12uf is the high-pass cap.

Just pretend you did this without the benefit of Club Polk, and then did it over and over again until you learned by yourself. That would be sometime next year. If you wait a couple months for your funds to accumulate, you will still be a year ahead of where you would have been without CP! (and you would have spent even more time AND money before you got it right)

2B's are special speakers and worth getting right.

Patience, grasshopper. :biggrin:

Haha, good point!

I shall be patient

heiney9

audiocr381ve wrote: »

I But I'd want to make sure I could fit all the parts in correctly at each stage.

That is one of the issues for sure. Perhaps if you can find (the search function is a bit of a challenge) enough good photo's those might give you some good insight on how to mount things.

I am sort of the opposite, I just like to pull things apart once and be done with it. Partly because the more you pull thing apart the more chance there is to damage something or strip some screw holes out, etc, etc.

But you do it however you feel you want to. Either way will work in the end. I forget, do these have RD0194-1's in them already? If not and they have the sl2000's get new tweets before anything.

Also if you are TL'ing them then you have to get RD0198-1's before you do the high pass. That only makes sense to me.

I am reminded of a buddy who wanted to put a new/better suspension on his car. The shocks were worn as were the springs. He did it in stages; springs first w/old worn shocks......not good. I told him replace them both at the same time.

H9

H9

audiocr381ve

heiney9 wrote: »

That is one of the issues for sure. Perhaps if you can find (the search function is a bit of a challenge) enough good photo's those might give you some good insight on how to mount things.

I am sort of the opposite, I just like to pull things apart once and be done with it. Partly because the more you pull thing apart the more chance there is to damage something or strip some screw holes out, etc, etc.

But you do it however you feel you want to. Either way will work in the end. I forget, do these have RD0194-1's in them already? If not and they have the sl2000's get new tweets before anything.

Also if you are TL'ing them then you have to get RD0198-1's before you do the high pass.

H9

Very good point H9. I'm gonna follow your lead on this one and wait until all the parts come in. Should be another month before I put the order in.

I have the RDO-194's in. The Polk service center is 30 minutes from where I am so I'm gonna pick them up when this thing starts coming together.

I'm gonna update my parts list

chandler9a

this sounds great audiocr381ve. Keep us posted, I have been pondering how to do my SDA 2A's for a while now. not very easy for those of us who have never done it but a good challenge non the less.

I would personally do it all at once and do it right, even if it took longer.

Good luck!

nspindel

+1 for being patient, save more money, and do it right, once. You've been saying how great they sound now, so enjoy them stock for a while longer while you continue to save up. The longer you do that, the more solid your memory of how they sound now will be after the upgrade, so you'll be in a better position to appreciate the difference.

audiocr381ve

nspindel wrote: »

+1 for being patient, save more money, and do it right, once. You've been saying how great they sound now, so enjoy them stock for a while longer while you continue to save up. The longer you do that, the more solid your memory of how they sound now will be after the upgrade, so you'll be in a better position to appreciate the difference.

Wise words, thanks Nspindel. I hope you would chime in when I get started on this project soon.

george daniel

another vote for DIRTFT--- stages--nope--while you are in the neighborhood you might want to consider the aftermarket rings that Larry has so kindly made available to the community--you have a pair of potentially stellar speakers with the proper tweaks and front end--have fun and enjoy.

On3s&Z3r0s

I agree on the waiting a bit. I had mine stock for about six months before I messed with them. It's kinda validating to listen a while thinking, "Wow, these are good" before you mod them and think, "Wow! These are better!" when you're done.

Anyway, couple things... since you asked about the polyswitch... Polk included them to protect the tweeters. Too much power (e.g. the amp is clipping) and the polyswitch will briefly shut down the tweeter circuit until it cools down. As they age, they can get flaky and they certainly don't help sound quality. They start out with a resistance of about .2ohms and after they are tripped their resistance goes up. Some people just remove them entirely, replacing them only with a jumper. Some people replace them with a resistor to mimic their resistance. This thread has a discussion of whether the resistor helps or hurts the overall sound quality.

It's important to note that if you replace them with anything (other than a new polyswitch) your tweeters are not protected from power spikes. If your party-happy buddies or toddler decides to see what your stereo sounds like when turned up to 11, you could be buying new tweeters.

The other thing you'll probably want to remove when you do the upgrade is the 750pF Silver Mica cap. It's unnecessary when replacing the stock HF caps with better ones. You can just remove it and not replace it with anything (no jumper even), because it's in parallel with the 12uF cap. The polyswitch is at S1 on the board and the silver mica is at C4. (I'm 99% sure about the labeling on the PCB and in the pic below. I don't have it in front of me so maybe someone else can confirm.)

audiocr381ve

On3s&Z3r0s wrote: »

I agree on the waiting a bit. I had mine stock for about six months before I messed with them. It's kinda validating to listen a while thinking, "Wow, these are good" before you mod them and think, "Wow! These are better!" when you're done.

Anyway, couple things... since you asked about the polyswitch... Polk included them to protect the tweeters. Too much power (e.g. the amp is clipping) and the polyswitch will briefly shut down the tweeter circuit until it cools down. As they age, they can get flaky and they certainly don't help sound quality. They start out with a resistance of about .2ohms and after they are tripped their resistance goes up. Some people just remove them entirely, replacing them only with a jumper. Some people replace them with a resistor to mimic their resistance. This thread has a discussion of whether the resistor helps or hurts the overall sound quality.

It's important to note that if you replace them with anything (other than a new polyswitch) your tweeters are not protected from power spikes. If your party-happy buddies or toddler decides to see what your stereo sounds like when turned up to 11, you could be buying new tweeters.

The other thing you'll probably want to remove when you do the upgrade is the 750pF Silver Mica cap. It's unnecessary when replacing the stock HF caps with better ones. You can just remove it and not replace it with anything (no jumper even), because it's in parallel with the 12uF cap. The polyswitch is at S1 on the board and the silver mica is at C4. (I'm 99% sure about the labeling on the PCB and in the pic below. I don't have it in front of me so maybe someone else can confirm.)

That's awesome information! Thanks Ones.

inspiredsports

I would read thread #13 here . . . http://www.polkaudio.com/forums/showthread.php?t=73470, then order the .5 ohm as I suggested above