Looking for opinions on SDA-1C x-over upgrade plan

Paden501

Hey all.

I'm contemplating a crossover upgrade for my 1Cs. I think I'm headed down the right path, but I wanted to put my plan in front of everybody for suggestions. I'm pretty-much new to upgrading crossovers and I've done my research (as much as I could) here on the site and this is what I've come up with.

Capacitors:
I think that I'm going to use Clarity Caps PX series for the 4.4uf, 12uf, 20uf and 40uf caps in each box. I can't seem to find anything that fits the bill nicely for the 750pf cap though. So if anybody has any suggestions for that, I'm all ears.

Resistors:
I'm leaning toward Murdoff MOX resistors... If that's a bad idea, somebody please slap me and point me in the right direction.

I'll just be using the stock inductors (seems to be what everybody's doing from what I've read). I'll also be sticking with the SL2000s at least for now, because I don't have the extra $200 for the RD0s right now.

PLEASE give me suggestions here. I'm open to all ideas.

Also, what should I be doing with the polyswitch? Some people are keeping it, some removing it, some replacing it with a resistor.... I personally like the idea of a resistor but what resistance?

Thanks!

Face

Paden501 wrote: »

Capacitors:
I think that I'm going to use Clarity Caps PX series for the 4.4uf, 12uf, 20uf and 40uf caps in each box. I can't seem to find anything that fits the bill nicely for the 750pf cap though. So if anybody has any suggestions for that, I'm all ears.

Claritcap makes some nice caps. Ignore the 750pf's, those are only bypass caps and are not to be replaced when upgrading to better quality caps.

Resistors:
I'm leaning toward Murdoff MOX resistors... If that's a bad idea, somebody please slap me and point me in the right direction.

MOX aren't bad. They're pretty transparent but have a slight sheen to them. On the other hand, Mills are a little colored but have a little warmth to them. If your call.

I'll just be using the stock inductors (seems to be what everybody's doing from what I've read). I'll also be sticking with the SL2000s at least for now, because I don't have the extra $200 for the RD0s right now.

I agree, leave the inductors alone. As for the RD0's, start saving, they're well worth it.

Also, what should I be doing with the polyswitch? Some people are keeping it, some removing it, some replacing it with a resistor.... I personally like the idea of a resistor but what resistance?

What are you using as a power amp? If it's a receiver, leave them in or replace them with new poly switches. If you're using an external amp, you can either bypass them and install jumpers or replace them with a .5ohm resistor.

Enjoy!

heiney9

As Face says forget the 750uF those were there because the caps they bypassed were not premium caps. You will now be using premium caps.

Also do start saving for RD0's. I did the x-overs in a pair of 5B's with sl2000 and they became unlistenable to me with the new parts. The RD0's are worth every penny and more. Also don't forget the break in period 100-150 hours, but more like 300 hrs.

GL and have fun

H9

Paden501

Thanks for the quick replys guys.

Thats great news about the 750pf.... the only acceptable replacements that i've found were very expensive.


I think I'll go the .5ohm resistor route for the polyswitch. I'm using a Hafler DH220 for amplification, and I don't usually go past half way on my pre-amp dial for volume, so I'm not terribly worried about the protection.

I'm not sure what to do about resistors - MOX vs. Mills....

Any suggestions? (even outside these two types)

Also, is it worthwhile to upgrade the SDA interconnect cable while I'm at it? I don't use the one with the built in isolation transformer, and I'm not terribly familiar with what interconnect upgrades do for you as far as music quality. Can somebody educate me?

Thanks.

NJPOLKER

http://www.partsconnexion.com/resistors_duelund.html

These would work but are kind of long so you will have to plan well. They are not cheap either but hell I am spending your money.

heiney9

The Duelands are very nice resistors but overkill for this application. If you were perhaps using the Clarity "MR" or "ESA" line then the Dueland's would be more appropriate, but that just IMHO.

H9

P.s. go with the Mundorf and PX series and start saving for the RD0's.

Paden501

Thanks for the comments both NJPOLKER and H9.

The Duelands are a little rich for my blood sadly, as are the Clarity MR and ESAs (I was tempted though).

If I go with the Mundorf, I'll have to use either a 6.8ohm or an 8.2 ohm for the 7.5ohm. Is that going to be a problem?

I could also use 2 -- such as a 3.3ohm and a 3.9ohm in series should give me 7.2ohm... is that a good or bad idea?

Thanks again.

heiney9

Yeah, I forgot about who offers what values. It might be better to order Mills from Sonic Craft as they have 7.5 ohm 12W Mills for $3.85/ea. Don't get the 5W

You'll have to pay a double shipping charge ordering from 2 places, but in the end the extra money is well spent, IMO.

http://www.soniccraft.com/mills_resistors.htm

Face

If you can swing it, the ESA's are the best bang for the buck as far as high end caps go.

For resistors, Sonic Craft should have everything, plus excellent service to boot.

Paden501

I think I'll go with Mills then. It doesn't sounds like anybody's been terribly dissapointed by the Mills anyway, and they're easy enough to change and cheap enough that if I hate it I can always do something different.

It's looking like with the PX caps and Mills resistors I can do this for about $120 + tax and shipping, which is well within my budget. I probably won't do any buying until the first of the month but I'm probably going to get into my speakers this week sometime and verify that there aren't any suprise values in there.

thanks all again for the help.

Paden501

I doubt I can swing the price difference. The SA's alone are like another $100 add on to the cost and the ESAs are even more.

Unless you tell me that the difference is BIG, I probably will stick with PX.

heiney9

I'm sure there will be a difference, but since you don;t have RD0's yet, take the money you'd save between the PX and ESA's and buy the RD0's. The RD0's are worth the money spent more than the ESA's at this point in your journey.

I have no doubt what Mike says about the ESA's being super fantastic, but unless you have lots of $$$ to get both the ESA's and RD0's at the same time.................go the more economical route with the PX line and get the RD0's ASAP.

H9

Face

If you could swing it, you could use ESA's for the 12uf and 4.4uf(2.2uf x 2 in parallel) and use PX's for the lows. ESA's for the 20uf and 40uf positions would only be a subtle improvement.

NJPOLKER

Paden,
Are these guys the best or what!!!

Paden501

NJ, these guys know everything!

Face,
I may be able to swing ESA's for the 12 and 4.4uf.... I'll have to price it out in the morning. If I do decide on the ESAs for the highs, are the mills still a good resistor choice or should I realistically be looking at the Duelands?

As far as the RD0s go, it's not an issue of 'if' so much as 'when'... it's just that with a new house this month and xmas next month, I don't have a whole lot of expendable income right now.

Paden501

Face,

Would I be better off with 2x 2.2uf ESAs in series, or with a single 4.7uf ESA cap?

Toolfan66

This helps me as well as I will be doing the same soon to my 1C's, just need to be done with the holidays.

So do you leave the 750pf's in there place? or take them out?

Face

TOOLFORLIFEFAN wrote: »

This helps me as well as I will be doing the same soon to my 1C's, just need to be done with the holidays.

So do you leave the 750pf's in there place? or take them out?

Throw them in the closest round file.

Paden501 wrote: »

Face,
I may be able to swing ESA's for the 12 and 4.4uf.... I'll have to price it out in the morning. If I do decide on the ESAs for the highs, are the mills still a good resistor choice or should I realistically be looking at the Duelands?

As far as the RD0s go, it's not an issue of 'if' so much as 'when'... it's just that with a new house this month and xmas next month, I don't have a whole lot of expendable income right now.

Mills would still be fine. A single 4.7uf would still be within 10%, probably the same tolerance as the original part. Since that tweeter is attenuated compared to the top tweeter, I doubt you would notice a difference between 4.4uf and 4.7uf. But if you decide that you want to be exact, the two 2.2uf's would be in parallel, not series.

Paden501

Ok so 2x 2.2uf gets me closer to the original. The tolerance on the ESAs is +- 3%, which for the 4.7uf is +-.141uf . for 2x 2.2uf the tolerance on each is +- .066uf, or a stack up of +- .132uf.

So I'll probably go with 2x 2.2uf caps.


So let me make sure I understand everybody correctly. I should remove and throw away the 750pf capacitor, not just leave it alone.? Correct?

Thanks,

heiney9

Throw it away. One last comment...........I personally think for your particular situation the ESA's are over kill, IMO.

Rock on with whatever you choose.......take pics and follow up

H9

Paden501

I really don't know what to do here H9. I probably agree with you that ESAs are overkill, but at the same time I want to make an upgrade that I can grow into. It's just hard to balance that.

The difference in using ESAs for the highs vs. PX all around is about $90. While that's money, it's not going to break the bank so I'm leaning toward just going for it.

I'll be sure to photograph the entire journey.

heiney9

Well, then I agree with the using the ESA's if your looking to grow into it and, your correct $90 won't break the bank, but it is (1) RD0 tweet and no matter how much you spend on caps the RD0's will always be the better sounding upgrade. That's why it's always my opinion to do the tweets first and x-overs 2nd. The two together are simply outstanding!

But your definitely on the right path and I don't want you having any remorse. The sooner you get them done the sooner you'll be able to enjoy the very large improvement the x-overs and RD0's provide.

H9

heiney9

Here are some pics a polkie did for another polkie just last night




You have 1C's? Do you have the single board (as in the pics) or the split boards?

If the ESA's are larger like the SA series you're really going to have to plan to get them all on the board securely. The PX line are 250v so they are physically smaller.

H9

Paden501

I'm not sure which boards I have. I haven't actually broken into my cabinets just yet. I'll have to do that this week.

I see what you're saying about the size of things. The ESAs looked pretty large, much like the SAs.

What resistors are on that board?

Thanks a bunch.

heiney9

Paden501 wrote: »

What resistors are on that board?

Thanks a bunch.

Those are the Mundorf resistors. The owner decided to get the parts all from the same supplier (Madisound) and they don;t carry Mills.

There is a thread (w/pics) somewhere on CP showing the split board and all the caps mounted. Can't remember if it's easier with the split board or more difficult.

H9

Paden501

Yeah I saw that somewhere along the line. Either way, I'll have to plan out how to make everything fit.

Thanks.

Paden501

Ok I dug into the speakers today and it looks like I've got the single board design.

There's a sticker on the 12uf cap, reading "SDA 1C BE1618-A 4/22/88". Thought that was kind-of cool.

heiney9

The sticker on the cap is the x-over model #. At one time Polk carried replacements.

Have fun

H9

Conradicles

Those Clarity Caps look nice H9. Somebody did a nice clean job. Sweet.

Conradicles

heiney9 wrote: »

Here are some pics a polkie did for another polkie just last night




You have 1C's? Do you have the single board (as in the pics) or the split boards?

If the ESA's are larger like the SA series you're really going to have to plan to get them all on the board securely. The PX line are 250v so they are physically smaller.

H9

I see the 2.7 ohm Mundorf, but the other 2 are different values than 7.5 ohm. Does this mean that you just need to get close to the 15 ohm total when the 2 are added together?

heiney9

Conradicles wrote: »

I see the 2.7 ohm Mundorf, but the other 2 are different values than 7.5 ohm. Does this mean that you just need to get close to the 15 ohm total when the 2 are added together?

I believe so since Mundorf (or rather Madisound) didn't have the exact value. Sonicraft has the exact values of Mills.