Re-capping questions/help

mn_polk_guy

Ive been around the forum here for about a year now and been collecting various polk models. I want to start updating all my crossovers.

Ive completed several mods, including h-nuts, sonic barrier, glued magnets and seams and also new gaskets where needed. I have not replaced tweeters yet, Due to wanting to do TL mods and just get all 198s.

Im new to crossovers so Im kind of lost on exactly what needs to be removed and replaced. Ive started a parts list for the 8 pairs I'd like to do. I want to TL my 5s, 7s, 11t, and 2bs as they all have sl2000's. The 4.6, 5jr+ and 8TLs all use sl2500.

Ive downloaded all the crossover pdfs. So from what I understand I should replace the capacitors and resistors, replace polyswitches with resistors and most the TL mods are done by adding a 5.8 uf capacitor in parallel with a 2 ohm resistor in the highpass section, plus a cap and inductor coil change. Which caps and resistors are preferred? Ive been looking on sonic craft. Does it make sense to get most of the parts fpr all the crossovers in pone shot to save on shipping?

Any and all help, answers and wisdom is appreciated. This is alot of info to take in and Im sure I've left alot out. Thanks!

F1nut

The only non-TL ones that can be TL'd are the 2B's.

Schurkey

I suggest you leave the inductors alone, at least for now. Replacement inductors are tougher to source than capacitors, in part because Polk didn't specify what the DC resistance or even the wire gauge size is for the older models.

Resistors are relatively easy, the Mills are smaller than the non-inductive wire-wound "ceramic block" style, so they fit the circuit boards better.

Getting rid of the electrolytic caps is the major point. Lose the polyswitches if you trust your amp to not clip.

mn_polk_guy

So are the gen 1 sonic caps and vishay mills resistors a good choice? What are other good options if i cant find all the values i need?

I had seen this thread https://forum.polkaudio.com/discussion/160343/monitor-7-tl-project#latest and also theres a montior 5b sl3000 mod crossover pdf. On here that was used in westmassguys thread. Thats where i got the idea. So I figure could do both my 5s and 7s.

Also for the 11T could I just purchase a set of 11TL crossovers and just rebuild and drop those in? I also realize I would have to find or make the wave guides. Id like to have the 11T and 5s to use 198s since thats whats in my 8tls and i use these for home theater.

F1nut

Ha, sorry I've never seen the 5TL mod schematic before. I stand corrected.

IIRC, the 11T and 11TL use different drivers. You cannot buy 11TL crossovers from Polk.

mn_polk_guy

My 11ts have 6510s all the way around. Acording to the 11tl crossover they are the same. And Theres a pair of tl crossovers on the bay im watching.

F1nut

Well damn, it's one of those other RTA models then.

skrol

I believe the RTA-11T has different PR's than the TL.

I picked up a pair of 5B in very nice condition that I'm thinking about doing the SL-3000 mod (TL).

westmassguy

The Monitor 5 SL3000 mod works with the Monitor 7, and the Monitor 10 SL3000 mod works for the RTA-11. Neither are sanctioned, but both work perfectly.

mn_polk_guy

Thank you for the input westmassguy. With. The three Tl mods I will need a .27mH inductor what is a good source for those? Also I have all my caps and resistor in a cart on sonic craft. I selected all gen 1 200v caps. For resistors most of them I selected 5w but a couple 12w when there wasnt a 5w available. All vishay mills.

I see on the 2b you parallel a 10 and 30 to get the 40 - I figured I could do this on my Monitor 11 with a 10 and 34 to get as close to the 45 that is required. Also for the Monitor 11s I need a 4.9uf I chose a 5uf. And last but not least my they dont have a 13.5uf for my 4.6 and 5jr - I selected 13s. Are all those values in spec and can I request ones closer to what is needed?

The final this is should the chassis wire be replace and whats a good brand for that?

Thank you!

pitdogg2

buy all 12 watt resistors, it's good insurance. Most of us get our inductors here

https://www.hificollective.co.uk/inductors/jantzen-air-core-wire-coils.html

big inductors by Erse or the Jantzen c-coil are popular.

I like to get as close to half as possible when paralleling caps.

I let @westmassguy take it from here he is much wiser than I.

westmassguy

mn_polk_guy wrote: »

Thank you for the input westmassguy. With. The three Tl mods I will need a .27mH inductor what is a good source for those? Also I have all my caps and resistor in a cart on sonic craft. I selected all gen 1 200v caps. For resistors most of them I selected 5w but a couple 12w when there wasnt a 5w available. All vishay mills.

I see on the 2b you parallel a 10 and 30 to get the 40 - I figured I could do this on my Monitor 11 with a 10 and 34 to get as close to the 45 that is required. Also for the Monitor 11s I need a 4.9uf I chose a 5uf. And last but not least my they dont have a 13.5uf for my 4.6 and 5jr - I selected 13s. Are all those values in spec and can I request ones closer to what is needed?

The final this is should the chassis wire be replace and whats a good brand for that?

Thank you!

HiFi Collective in the UK is about the only place you can special order the correct Jantzen Inductor. Parts Express won't special order anymore.

I use two 20uf, not a 10 and a 30. Better to keep them close in value.

Do you have the rare, original RTA-11s, or the RTA-11 Towers with the D'apolitio MTM arrangement? If you have the 1983, original RTA-11s, you cannot TL them.

Sonicap can hand select 13.5uf Caps, but they'll cost a bit more.

Go with 10 or 12 watt Mills, or Vishay/Mills, not 5 watt if possible.

mn_polk_guy

I have both of the 11s. The original ones that are like a bigger monitor ten and a the RTA 11t which are the ones I want to TL

mn_polk_guy

So I changed my selections some. Im assuming go with a .47ohm resistor as i dont see a .5 ohm.

Edit: found the 2.7 was 12 watt from vishay mills

mn_polk_guy

Also here at the 11t. I want to TL these guys. The peerless monitor 11s are in my account photo.

pitdogg2

mn_polk_guy wrote: »

So I changed my selections some. Im assuming go with a .47ohm resistor as i dont see a .5 ohm.

Edit: found the 2.7 was 12 watt from vishay mills

I ordered my .5ohm 12 watt Vashay-Mills from hifi collective when i ordered my inductors.

westmassguy

The Peerless Monitor/RTA 11 cannot be tl'd, but the vertical RTA-11 certainly can. Use the Monitor 10 SL3000 mod as your guide. I have used the .47 in place of the .5 ohm. Doubt anyone would notice a .03 ohm difference.
You can download the Jantzen Air core Catalog here: http://www.jantzen-audio.com/air-cored-coil/
The closest they have is .27mH @.49 ohms Part# 000-1640
It's the same for both pairs of crossovers, so you'll need 4.

skrol

Thanks. I was having trouble finding an inductor with the right ESR.

mn_polk_guy

mn_polk_guy

Got a box of sonicaps and resistors today, just finished my first crossover ever. Started with my m4.6s. One cap, one resistor

mn_polk_guy

Quick question. Im starting my 2BTL recap today. Do I remove the 750pf and leave that out?

F1nut

Yes

mn_polk_guy

Thank you @F1nut

cortico

Question- why the 12w resistor for this application? Really depends on the cross over design, but if the schematic calls for 5w, 12w would seem overkill, no?

F1nut

It's not hard to smoke a 5 watt resistor.

pitdogg2

Over kill or not it is cheap insurance.

cortico

I am gathering that my tweeters are at risk with 250 watts RMS per channel

Schurkey

cortico wrote: »

I am gathering that my tweeters are at risk with 250 watts RMS per channel

Only if there's more high-frequency information in the source material than usual, or there's a fault with your equipment that causes more high-frequencies to be delivered to the tweeters.

A music signal shouldn't be a problem. A distorted signal or test frequencies could be.

A bass driver--or a group of mid/bass drivers--have heavy wire windings on the voice coil and take a lot of current because there's a lot of bass information in typical music. Tweeters may have similar impedance to the bass drivers, but they've got fine-wire windings in the voice coil in part because there's not as much high-frequency signal in the music. They don't draw as much current.

pitdogg2

cortico wrote: »

I am gathering that my tweeters are at risk with 250 watts RMS per channel

Do you drive you car with the gas pedal to the floor only?

Many here have very manly amps (I'm not in that list) very high current and RMS yet they have no problem at all. I run a Carver TFM45 rated at 375rms. I get no where near full throttle. Yet having that extra headroom is nice.

audioluvr

Schurkey wrote: »

A music signal shouldn't be a problem. A distorted signal or test frequencies could be.

I agree here. Certain tracks of music with heavily distorted high frequency electric guitar notes can cause excessive movement of the tweeter which could heat up the coil and since Polk tweeters don't use ferrofluid they can begin to fail at high volumes especially if that tweeter's manufacturing tolerances wasn't spot on. Ferrofluid tweeters are often less efficient though so it's a give and take here. Also Polk tweeters use a solid wire instead of a braided copper wire to connect the voice coil and at that juncture at 15,000 to 20,000 cycles per second the wire can heat up and break. Sonic clarity is improved with solid wire though so again, give and take.

dromunds

I'm currently running a Carver M500t (Dennis Miller Mark II mods) that's also somewhere around 375 watts per channel, while I'm waiting for my monoblocks to get back from repair and as said that extra headroom is desirable. Just don't stomp down the accelerator.