Working on SDA SRS2's Part II. Crossover time...

avguytx

Wow. It really didn't dawn on me what the physical size of the Solen PB 130uf cap would be till I actually got them. Wow. This will be an interesting stage of the upgrades to these speakers as the real estate on the boards is rather small. But, since I'm in the waiting mode for awhile for (4) RD0's and (2) of my MW6509's are at Polk for evaluation against the new "replacements", I guess I'll go ahead and tackle this job now. At least I have some time for it!

Which other SDA's use these big a$$ 130uf caps? Is it just the original SRS and SRS2's? Wait...looked in the Compendium and see them on the SDA 1's, 1B's, 2B's, and the CRS+'s. They only seem to be on the Dimensional drivers, too. Interesting.

Here are a couple of pictures of all the caps and resistors with a can of Coke for the sake of perspective. More to add to this thread as time rolls along.

ka7niq

WHAT version of the SRS 2's do you have ?
It seems the crossovers are different.
I have the pin/blade version, the later ones.

I also used to own EV Interface D's, larger brother to the Interface C's.
AWESOME speakers BTW.

I have had GREAT luck with the Clarity Caps from Madisound, and used Solens before too.

You do plan on upgrading the resistors too, right ?

I have seen resistors change values over the years, and caps change values too.

Caps LOSE capaicatance, and this sometimes shifts the crossover point upwards, leading to a veiled sound.

Hey, about those new tweeters for our speakers.

Polk is out of em, but I was going to buy 4 of them.

ka7niq

I SEE you have the old SRS 2's, mine do not have the 130 mf monster caps.
Mine also have the 6510 and 6511 drivers.

I printed out both schematics, but can not read the values too well of the parts.

Hate to order wrong caps and parts.

avguytx

ka7niq wrote: »

WHAT version of the SRS 2's do you have ? It seems the crossovers are different. I have the pin/blade version, the later ones.

I have the blade/blade versions. 1986 or so.

ka7niq wrote: »

I also used to own EV Interface D's, larger brother to the Interface C's. AWESOME speakers BTW.

Yeah, I would like to have a pair of those. I almost bought a pair but they didn't have the original woofers and finding them is darn hard.

ka7niq wrote: »

You do plan on upgrading the resistors too, right ? I have seen resistors change values over the years, and caps change values too.

Yes, the resistors are in the first picture on the far right. Mills 12 watters. They are pretty good sized by themselves.

ka7niq wrote: »

Hey, about those new tweeters for our speakers. Polk is out of em, but I was going to buy 4 of them.

Oh, I know that all too well! I had them ordered and paid for on a Monday and they were shipping them out...I thought. But, thanks to some other Polkies in here, their orders made it in just a smidgen before mine did! I will have those as soon as they are back in stock. I think the estimate is about 4 weeks out or so.

I got the stock crossovers out of the cabinets and they are ready to roll. I may start on that tomorrow night. I do dread trying to find the real estate for that big a$$ 130uf and 56uf cap. Sheesh...

hearingimpared

I love big cans!!!:D

avguytx

I think it's just the 194's that are OOS but I could be wrong.

F1nut

Wait...looked in the Compendium and see them on the SDA 1's, 1B's, 2B's, and the CRS+'s.

Kip, for the record neither the blade/blade or pin/blade 2B's use a 130uF cap and only the earliest (1986) blade/blade version of the CRS+ used them.

avguytx

My bad. I looked at it wrong as it's the 2A and not the 2B

ka7niq

avguytx wrote: »

I have the blade/blade versions. 1986 or so.



Yeah, I would like to have a pair of those. I almost bought a pair but they didn't have the original woofers and finding them is darn hard.



Yes, the resistors are in the first picture on the far right. Mills 12 watters. They are pretty good sized by themselves.



Oh, I know that all too well! I had them ordered and paid for on a Monday and they were shipping them out...I thought. But, thanks to some other Policies in here, their orders made it in just a smidgen before mine did! I will have those as soon as they are back in stock. I think the estimate is about 4 weeks out or so.

I got the stock crossovers out of the cabinets and they are ready to roll. I may start on that tomorrow night. I do dread trying to find the real estate for that big a$$ 130uf and 56uf cap. Sheesh...

Plenty of room in the cabinet for them, just Hot Glue em and run longer leads if ya have to ?

Bear in mind Solens take awhile to break in, but it will be worth it in the long run!
The Mills are excellent sounding resistors.
Sand Cast resistors can sound harsh, the Mills are smooth.

I would wrap the crossover in Fiberglass Blanket, and use bread ties to secure it with.
This will turn some sound into heat, and keep from modulating the crossover parts.

Better damping behind the midrange/bass drivers might be an area to look at ?
Polk used Dacron pads, Acoustastuff is MUCH better, wasn't available back then.

THIS can have an even greater effect then changing caps!

Brad Starobin, the engineer from Polk, told me the Mylar Film caps in the Polk speakers are quite expensive.

Be aware that changing caps does not automatically make a speaker better, unless the caps are bad, OR bad sounding.

It CAN make it different sounding, but not always better.

My B&W 801's have Electrolytic caps, as did my Celestion SL 600's.

I FINALLY found a better sounding tweeter cap for the 801's, after 5 tries!

Yep, the original Electrolytic beat ALL added caps, except the Clarity Cap from Madisound.

SOMETIMES, the engineers are using the ESR of a particular cap to make the filter do what they want.

You CAN equal the value of a cap, but you will seldom match the original caps ESR.

This can be good, OR bad.

You CAN make a speaker better, but you can also make it worse too.

Just gotta be prepared, and TRUST your ears.

I wasted almost 100 bucks on Mundorf Supreme caps, and the STOCK B&W Electrolytics sounded better!

I have found sand cast resistors to be "all over the place" measurement wise, though SUPPOSED to be within 5 percent.

Precision Mills Wire Wound resistors always sound better in my experience, and I swap em out at once with NO afterthoughts.

Seriously, look at Acoustastuff to replace the Dacron behind the drivers.

Even Fiberglass should be better in theory, because it has better low frequency damping characteristics.

I think the SRS's are a just LITTLE too warm, and some extra or more effective damping will make them more neutral sounding.

F1nut

Brad Starobin, the engineer from Polk, told me the Mylar Film caps in the Polk speakers are quite expensive.

Yeah, maybe a few bucks compared to the $.25 electrolytics.

I wasted almost 100 bucks on Mundorf Supreme caps, and the STOCK B&W Electrolytics sounded better!

I've found that Mundorf Silver/Oil caps are wonderful with a very natural and laid back sound. Have you tried them?

danger boy

those are some freaking huge cans.. OMG! Why are you putting coke cans in your speakers? :rolleyes:

heiney9

ka7niq wrote: »

I SEE you have the old SRS 2's, mine do not have the 130 mf monster caps.
Mine also have the 6510 and 6511 drivers.

I printed out both schematics, but can not read the values too well of the parts.

Hate to order wrong caps and parts.

It's always best (especially with POLK) to pull the x-over and have a look see. Polk changed minor things on the fly and in many cases there might be a slight difference in parts compared to the printed schematic.

Always look first, it will save time and money.

H9

heiney9

ka7niq wrote: »

Bear in mind Solens take awhile to break in, but it will be worth it in the long run!
The Mills are excellent sounding resistors.
Sand Cast resistors can sound harsh, the Mills are smooth.

This is very true. While my 1C's have Sonic caps and Mills (came that way), I just redid the x-over in my Monitor 5b's about 2 months ago with Solens and Mills and I can tell you they are just now fully settled in. Granted this an office rig so it doesn't get the playing time the main rig does, but just in the past couple weeks or so they have really opened up.

I also can't stress enough the smooth sound of the RD0's for those not familiar with them.

H9

avguytx

Yeah, after about a month of play time on the 1C's, they sound a lot better than in the beginning. They lost some play time after I got the SRS2's until they were pulled from service while sending MW6509's to Polk. I figure they'll make it back in when the RD0-194's come back in supply. By then, the crossovers will be done, too.

ka7niq

F1nut wrote: »

Yeah, maybe a few bucks compared to the $.25 electrolytics.



I've found that Mundorf Silver/Oil caps are wonderful with a very natural and laid back sound. Have you tried them?

Just repeating what Brad Starobin told me about the cost of the Mylar Caps.

Never tried the Silver/Oils, but did try lesser Mundorfs.

The British Clarity Caps are wonderful devices, even beter then Auricaps, and less money too.

I used to be into Horns, and have a lot of friends into SET and Horns still.

On their advice I tried the Clarity Caps.

I find them to be good overall performers.

The Bennic Poly's are decent caps if money is a concern.

I have used Auricaps, Solens, Hoviland, Mundorfs, Sonicaps, Sidereal, and many others.

IMHO, there is NO "one best cap" for every circuit.

I try and concentrate on the tweeter cap.

To me, that is where the action is.

I used to try 3 or 4 caps in the tweeter circuit, until I got what I am after.

This takes a LOT of time, as caps must be broken in.

The Clarity Caps have done such a good job in several speakers I have tried em in I have caught myself using only them lately.

In 5 different speakers I tried em in, they were either the very best sounding, or close to the best.

Madisound has em at good prices.

They are probably what I will use in my SRS 2's, assuming they have the right values.

I use the blue Clarity Caps, read this capacitor review ?
http://www.humblehomemadehifi.com/Cap.html

avguytx

Well, I spent the last couple of nights working on my crossovers and got them (almost) done. The only thing left is either taking off the tweeter protection or soldering a lead across them to bypass them. The tweeter section of the crossovers was fairly easy and the only hard hard (if there was one) would be having to make a couple of the resistors "stand up" since they're kind of large. Now, the low pass crossovers, on the other hand, were a biotch to say the least. Since the 130uf and 56uf crossovers are HUGE, it took a little planning out. But, I'm happy with the end results although (and you'll notice I'm sure), the caps weren't glued in a "mirror image" of each other. Oh well. They are done for the most part.

Also, since the distance of the 130/56uf caps from the circuit board were about 1" too short after having to sit on TOP of the 34uf caps, I took the solid ground wire from a 16/2 piece of house wiring for the extensions. I soldered them into place and put a little heat shrink on them. I had bought a roll of 18ga solid core wire and even though it would've worked, I thought this would do the job. Plus, I can take that roll back since it basically was $5 for 60 feet of wire that I only needed 4" from. Hmmm....:rolleyes: Thanks to F1 for the recommendations on what would be the best bet!

I still have to install some new terminals and figure out if I'm going to use an XLR style connection for the SDA terminals or use a single "banana" style connector. IIRC, on the blade/blade terminal, do both connections carry signal or just one? I'm so tired, I don't feel like going to look. Sigh. I'll burn that bridge when the time comes. I still have to wait on RD0-194 tweeters and my (2) 6509's to come back.

Well, here are a few pictures of the before and after of both halves of the crossovers. I have to get up at 4am because I am driving south to pick up a pair of SRS 2.3's for my best friend (birthday present) and on the way back, pick up a Carver M-1.5t which I'm getting for very reasonable. I'm anxious to get some more power on these and for the price, I can't beat it.

Here's the Hi Pass crossover in its stock form.



Here's the Hi Pass after the new caps and resistors are done.



Low Pass crossover before......



Low Pass crossover after.... Makes those BIG coils look small in the after shots, huh?



Them's some big @ss caps!

hearingimpared

Nice work! 300 to 400 hours of break-in time and you'll be grinning from ear to ear.

ka7niq

Dam Nice Job !
I am GLAD my SRS 2' do not have the huge caps yours do!
Might want to consider at least wrapping the crossover in Fiberglass sheet to cut down on the sound hitting the caps ?
Even a small soft plastic box stuffed with fiberglass can have advantages.

danger boy

HOLY SHEITE! those are HUGE! :eek: :eek: :eek:

F1nut

Damn! I didn't realize you had the split crossovers. Good job.

hearingimpared

ka7niq wrote: »

Might want to consider at least wrapping the crossover in Fiberglass sheet to cut down on the sound hitting the caps ?
Even a small soft plastic box stuffed with fiberglass can have advantages.

Does this really make a difference?

ka7niq

hearingimpared wrote: »

Does this really make a difference?

Well, B&W 801's have the crossover UNDERNEATH the cabinet.
Wilson go to great lengths to coat their crossover components,
Many really high end speakers place crossovers OUTSIDE the box.
So what do you think ?

I fall somewhere in the middle.

Why not at least TRY to reduce some sound getting into the crossover components ?
I think if you can easily protect the components from vibrations, why not.
Gotta be careful NOT to add too much mass inside the cabinet and reduce volume though.

heiney9

Nice job!! Those caps are HUGE. Don't get to discouraged because once you hear the new parts with the sl2000 you might want to poke your ears out with an ice pick . Hearingimpaired is correct they will mellow over time........in my experience a long time. Then when you get the tweets those will take time as well to break in.

All I can say is be patient and you will be rewarded. When I refreshed my Monitor 5b's I couldn't listen to the sl2000 tweeter anymore. So just be aware this might happen to you. You are only a couple weeks away from the RD0's being back in stock, right?

H9

ka7niq

H9 is correct about cap break in.
I have changed caps in several vintage speakers.
When caps change, they lose capacitance.
This shifts the crossover point upwards, resulting in a mellow sound.
This is because the woofer/mid in a 2 way system is now handling more of the highs, and the tweeter LESS of the highs.
A 6.5 inch woofer/mid like in the Polks starts to narrow it;s dispersion as the frequency is increased, also resulting in less high frequency energy in the room.'
Hence the mellow sound of vintage speakers.

Now, along you come,. and replace the caps.
The speaker now works as it was intended, but you are USED to the sound of the aging caps.

Two things happen, the caps do break in, but so do you.
It takes time for YOU to grow accustomed to the new, correct sound

You are not accustomed to the sound of a speaker working properly if you have aging caps.

I LOST a neat chart showing loss of capacitance vs years for caps.:eek:

It will open your eyes. :cool:

ka7niq

I couldn't find the chart I wanted to show about capacitor aging.
But here is a simplified one that says about the same thing.
http://my.execpc.com/~endlr/aging.html

From this chart we can see that ONLY Aluminum Electrolytic age badly.

The film type caps do not, less then 1 percent over their lifespan.

So, it would appear the changes we hear in replacing the Mylar caps in our Polk SDA speakers come from using a better cap, and not from a change of capacitance values ?

The Aluminum Electrolytic are another matter altogether.
They can REALLY change values!

read-alot

If you like to read-a-lot........ like everything written take with a grain of salt.

http://sound.westhost.com/articles/capacitors.htm

hearingimpared

read-alot wrote: »

If you like to read-a-lot........ like everything written take with a grain of salt.

http://sound.westhost.com/articles/capacitors.htm

I've read-a-lot of Rod's stuff and he makes a very convincing arguement againt tweak-o-rama but my ears tell me differently.

danger boy

When i had the crossovers redone in my Monitor 7A's, right away I noticed better highs.. that was about two months ago. it really brought new life to them again. they were as described earlier, to laid back because of the ailing caps.

ka7niq

read-alot wrote: »

If you like to read-a-lot........ like everything written take with a grain of salt.

http://sound.westhost.com/articles/capacitors.htm

I respect Rods writings, but do not always agree with everything he says.
My ears also tell me differently.

Getting rid of the electrolytic caps in my B&W 801's tweeter high pass made all the difference in the world.
I was SHOCKED that B&W did not hear this, with all the engineering time they put into their flagship.

IMHO, they couild of at LEAST put a Mylar in there ?

avguytx

ka7niq wrote: »

Now, along you come,. and replace the caps.
The speaker now works as it was intended, but you are USED to the sound of the aging caps.

Two things happen, the caps do break in, but so do you.
It takes time for YOU to grow accustomed to the new, correct sound

You are not accustomed to the sound of a speaker working properly if you have aging caps.

Don't worry...this ain't my first (crossover) rodeo. I've been doing this stuff for 25 years so replacing the parts is no biggie. Designing them from start to finish is another thing, though, which I've done as well. I've probably redone about 20 pairs of speakers thru the years, built about 10 pairs of home speakers, built single amp IASCA (car stereo crap) competition systems w/complete passive systems, etc.

My first set of home speakers I built was at 14 years old. My uncle was an amazing cabinet builder/furniture builder/woodworker (etc) and, growing up in Arkansas, we went to the Klipsch plant in Hope, AR back in 1979 or 80 and Mr. Klipsch was kind enough to give us the plans, crossover designs, etc for a set of LaScalas. I had saved tons of money mowing yards, paper routes, etc, and bought all of the EV drivers I needed and had a local friend (that built/installed sound systems for churches in my hometown) help me do the crossovers. Once finished, they were simply amazing. They were used at many a party, school functions and personal listening and never let me down. I think they are even still in the basement at my best friends parents house in Arkansas. I'll have to dig thru some pictures when I'm home again and see if I have some of the pics as we were building them.

ka7niq

avguytx wrote: »

Don't worry...this ain't my first (crossover) rodeo. I've been doing this stuff for 25 years so replacing the parts is no biggie. Designing them from start to finish is another thing, though, which I've done as well. I've probably redone about 20 pairs of speakers thru the years, built about 10 pairs of home speakers, built single amp IASCA (car stereo crap) competition systems w/complete passive systems, etc.

My first set of home speakers I built was at 14 years old. My uncle was an amazing cabinet builder/furniture builder/woodworker (etc) and, growing up in Arkansas, we went to the Klipsch plant in Hope, AR back in 1979 or 80 and Mr. Klipsch was kind enough to give us the plans, crossover designs, etc for a set of LaScalas. I had saved tons of money mowing yards, paper routes, etc, and bought all of the EV drivers I needed and had a local friend (that built/installed sound systems for churches in my hometown) help me do the crossovers. Once finished, they were simply amazing. They were used at many a party, school functions and personal listening and never let me down. I think they are even still in the basement at my best friends parents house in Arkansas. I'll have to dig thru some pictures when I'm home again and see if I have some of the pics as we were building them.

How COOL !
I have some TC Sounds LMS 4000 15" drivers if ya know what those are.
Into Bass too, LOL
My kids cars THUMP like you would not believe!
HAD the TC Sounds 15"s in 9.5 cu ft boxes sealed, but Q was way too high for corner mounting, boomy!

Shook the house though.
I also have an SVS Ultra passive cylinder sub just sitting here.

I used Cadence Wild Beast car stereo 15" drivers in place of the TC Sounds.

Not QUITE the impact, but much faster and musical due to correct final Q for corner mounted subs.

Lets SEE if I can post a pic of one of the monsters ?