RTA11TL Upgrades

skrol

Hi, I have been a long term Polk fan but it has been a while since I posted.

I have a set of RTA11TL's since new and am getting the upgrade bug. I see from this wonderful forum that a tweeter upgrade is available from Polk (RD0198-1). This will likely be a starting point. I also see that some folks (byteme) have done a great job of documenting x-over upgrades. I will also plan to upgrade mine. I also got the RTA11TL_rev2 schematic. This forum is so great!

I do have some questions. I assume that in order to optimize the x-over for the RD0198-1 tweeters some mods are necessary.

Can anyone specifically describe the necessary changes?

Also, in byteme's description of his mods, there was no mention of the 1.55mH inductor that appears in the RTA11TL_rev2 schematic.

Is this inductor eliminated, retained as is or is there an upgraded component recommended?

Thanks
Stan

heiney9

Nope. The RD0198-1 is a "direct drop in" replacement. No x-over mod necessary. I highly recommend it, but not nec to modify with the RD0's.

Good luck

H9

skrol

When you say that you highly recommend it, do you mean keeping the same component values and just upgrading the quality of components?

Also, I assume the the 1.5mH stays in the circuit?

Thanks for the quick reply,
Stan

heiney9

skrol wrote: »

When you say that you highly recommend it, do you mean keeping the same component values and just upgrading the quality of components?

Also, I assume the the 1.5mH stays in the circuit?

Thanks for the quick reply,
Stan

Yes, same (or close) component values using higher quality and now 15 year newer parts. My 5B's and 1C's have upgraded x-overs as well as RD0's and I recommend it 110%. Keep in mind the original parts specifications were anywhere between 10 and 20% tolerance so a 33uF cap can be replaced with a smaller a larger cap within 10-20% tolerance if you can't find an exact replacement.

Many recommend Sonicaps, they are excellent but pricey. They were used in my SDA's but not my 5B's.......too much money for a speaker in a 2nd system. I used Solens in the 5B's and have been very happy. I am going to try Clarity caps just for the high end in the 5B's (same price point as Solens) to see if I can get them to integrate just a bit better. Not unhappy wiht the Solens, but I am tweeker

Mills or Mundorf wire wound resistors are also well worth the few dollars they cost to replace the old inductive (sand) resistors.

I'd have to look at the different schematics for the 11TL's about the inductor issue. Maybe Ben will chime in.

Best thing to do it visually look at your x-overs and buy the parts according to what is already there. Polk tended to make a few changes on the fly that didn't always necessarily make it to a schematic. Nothing dramatic but always check to see what you have compared to the schematic.

H9

zingo

I recommend Dayton Audio or Jantzen capacitors if you don't want buy the premium Sonicaps. Don't get me wrong, Sonicaps are fantastic, but if you want to spend a lot less and still have a good sound, try either of the other two. I also suggest Mill resistors as heiney was saying.

As far as the inductor goes, yes it stays in the circuit and the reason it may not have been mentioned is because it is usually not replaced in an upgrade/modification unless it is broken/inoperable. Inductors don't have the age issues that capacitors do and may not have the sound improvements new resistors do. The inductors have the right specs for the Polk speakers they are in and usually there is no need to change them.

skrol

Thank you all very much. Now to collect some parts and have some fun.
Stan

ben62670

skrol wrote: »

When you say that you highly recommend it, do you mean keeping the same component values and just upgrading the quality of components?

Also, I assume the the 1.5mH stays in the circuit?

Thanks for the quick reply,
Stan

The inductors are air core, and do not need to be replaced. You could replace it with a newer lower resistance inductor, but Polk used pretty good pieces then. Copper was still cheap. I have done a shootout with Solen's, Jantzen's, and Dayton's caps. For cheaper caps the Dayton's were the best IMHO. Next step up is the Sonicaps. These are real nice for the highs;) They were the closest to running an active XO out of all I tried.

skrol

Next question... Are the RD0198-1 tweeters made by Peerless? Anyone have a datasheet for these?

Anyone have a datasheet for the MW6501?

I am playing around with OrCAD/PSpice and am trying to build speaker driver models.

Thanks
Stan

MillerLiteScott

Skrol,

The RDO 198's are built for Polk to Polks specification and the info is proprietary. I do not think Peerless builds them.

This thread is of interest to me because I will be redoing the crossovers in my RTA 11t's latter this year with Sonicaps and Mills resistors. I already have the RDO 194. I know they are not the same but similar enough.

Scott

ben62670

skrol wrote: »

Next question... Are the RD0198-1 tweeters made by Peerless? Anyone have a datasheet for these?

Anyone have a datasheet for the MW6501?

I am playing around with OrCAD/PSpice and am trying to build speaker driver models.

Thanks
Stan

Sorry no data sheets. Polk proprietary info only;)
Be

skrol

Where do you recommend buying the caps, resistors, etc.?

ben62670

Parts list
2 12uf $40 sonicaps $9 for Dayton's
2 16uf $48 sonicaps $11 for Dayton's
2 34uf $20 for Jantzen's
2 1.5r 12w resistors $7
Dayton's, and Jantzen's are from PE
http://www.Partsexpress.com
and sonicaps are from
http://www.soniccraft.com/sonicaps.htm

skrol

Thanks

ben62670

No problem:)

jimiles

I rebuilt my RTA15TL crossovers last winter. I used Jantzen Z-Superior and Obbligato capacitors, Jantzen foil inductors, Duelund silver-graphite resistors, Neotech wire, and Cardas Rhodium binding posts. Some of those components are a little spendy, but I don't regret any part of the investment. :cool:

All of these components are HUGE :eek: compared to the stock components, so you'll need to completely remove the stock crossover pcb from the terminal cup and mount all of the new components on a 1x6 in the bottom of the cabinet.

For your shopping pleasure; I got the Jantzen gear at PartsExpress, the Obbligato caps from Diyhifisupply, and everything else from Partsconnexion.

Good luck on your project!

Jake

F1nut

I like Obbligato caps. No glare, detailed, yet warm.....what I would call a musical sounding cap. I just wish their size selection was greater.

jimiles

F1nut wrote: »

I like Obbligato caps. No glare, detailed, yet warm.....what I would call a musical sounding cap. I just wish their size selection was greater.

I used 2.2uF Copper-case Obbligato caps with 10uF Jantzen Z-Superiors to create the 12uF caps in the tweeter circuit. I used a pair of the 10uF Obbligato film-oil caps in the woofer circuit.

Like the Sonicap and Clarity SA, they are a nice step up from something like a Solen or Datyon for a VERY reasonable price. F1 is correct, the Obbligato size selection is just abysmal, and they were out of stock on the larger sizes for about 3 months this winter. The 12uF value that is so common in Polk networks must not be common in the rest of the speaker universe, because hardly any of the higher-end capacitor lines have that value.

If you guys want to go completely bug-eyed reading about caps, check out Tony Gee's cap test. Of course this is only one man's opinion, but it does give a general idea of what's available and how it fares.

http://www.humblehomemadehifi.com/Cap.html

jimiles

Hi Stan,

One more idea for your project. When you get the crossovers done to your satisfaction, get some vibrapods to set the speakers on. The vibrapods uncouple the speaker from the floor.

I bought two Cuisinart end-grain cutting boards, arranged the vibrapods on the cutting boards, and then set the speakers on the vibrapods. The improvement in bass clarity on my RTA15s is amazing. :eek:

Jake

skrol

jimiles wrote: »

...If you guys want to go completely bug-eyed reading about caps, check out Tony Gee's cap test. Of course this is only one man's opinion, but it does give a general idea of what's available and how it fares.

http://www.humblehomemadehifi.com/Cap.html

Already been there. I knew that quality caps can make a difference but this guy makes it an art.

I often struggle to put the nuances of sound quality out of my mind and just listen and enjoy the music. But for me, and likely you all, the sound quality is part of the enjoyment. I have been generally satisfied with the sound quality of my RTA11TLs but know they could be better. Now it is my time to tinker (not to mention that the electrolytic caps are likely drying out). I really don't, however, want to get to the point that I am listening to capacitors and being distracted from music. I just want the satisfaction of improving the sound quality.

Back to upgrades...
I looked at PartsExpress and Soniccraft. Are there other good sources?

Stan

heiney9

skrol wrote: »

Already been there. I knew that quality caps can make a difference but this guy makes it an art.

I often struggle to put the nuances of sound quality out of my mind and just listen and enjoy the music. But for me, and likely you all, the sound quality is part of the enjoyment. I have been generally satisfied with the sound quality of my RTA11TLs but know they could be better. Now it is my time to tinker (not to mention that the electrolytic caps are likely drying out). I really don't, however, want to get to the point that I am listening to capacitors and being distracted from music. I just want the satisfaction of improving the sound quality.

Back to upgrades...
I looked at PartsExpress and Soniccraft. Are there other good sources?

Stan

www.madisound.com carries Clarity caps which are another cost effective alternative. The Bennic resistors they carry are just as nice as the Mills and are the non-inductive wire wound type.

H9

jimiles

heiney9 wrote: »

www.madisound.com carries Clarity caps which are another cost effective alternative. The Bennic resistors they carry are just as nice as the Mills and are the non-inductive wire wound type.

H9

I heard ClarityCaps in another speaker (Bottlehead Straight-8), and thought they sounded nice. Another great thing about Clarity is that Madisound stocks Polk-requsite 12uF value. Clarity now has an Enhanced SA line that features some of the anti-resonance technology as the drug-dealer-expensive MR range at a more sane price point. Unfortunately, Caps&Coils in the Netherlands is the only place I've seen those, though. I've never ordered from those guys, so I can't speak to how export friendly they are.