Modifications to the RTA 15TL

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  • decato
    decato Posts: 186
    edited February 2013
    ZLTFUL wrote: »
    Initial impressions...Wow. Just wow.
    I will do a full write up in a separate post but the upgrades have made a pretty significant difference.
    Thanks Brian.

    Excellent! Glad to hear you like the modifications.
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  • ZLTFUL
    ZLTFUL Posts: 5,648
    edited February 2013
    I have a little over the $200 Brian mentioned in his initial post. Prices have gone up a smidge since then but it is still ballpark.
    I went with Solen caps, Madisound Sidewinder inductors and Mills resistors.
    I didn't touch the stuffing at all.

    My next step with them is to dynamat the baskets. But I have a bunch of dynamat left over from a friend's car so that cost is minimal. I am also seriously considering a set of rings for them. I already have hurricane nuts but am on the fence vs doing the rings.
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
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  • pitdogg2
    pitdogg2 Posts: 25,436
    edited February 2013
    If it were me I'd get the Solens out of the high pass section. Never been a fan of those in that position.
    just my .02
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  • ZLTFUL
    ZLTFUL Posts: 5,648
    edited February 2013
    So far, I don't have any complaints. It is a huge imporvement over stock to my ears.
    I am actually going to track down a second set of terminal cups and do foil inductors with Sonicaps. Then I can do A/B comparisons. Having the plug on there makes experimentation a snap.
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
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  • ZLTFUL
    ZLTFUL Posts: 5,648
    edited February 2013
    I REALLY need to do up my review. Listening to some Miles Davis...oh hell yeah...
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
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  • cincycat13
    cincycat13 Posts: 882
    edited February 2013
    I look forward to your write up. And yes, I lay the small inductor over to avoid interference. Very fun speaker to tweek and easy to work on.
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  • ZLTFUL
    ZLTFUL Posts: 5,648
    edited February 2013
    What do you think of the foil inductors cincy?

    I plan on tracking down a couple more sets of terminal cups and making some variations. Foils inductors is one of the things I want to try.
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
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  • SDA1C
    SDA1C Posts: 2,072
    edited April 2013
    Decato,

    Is this still your preferred or current list of upgrade components for the 15tl?

    2 x 13.5 uF (2 x 12 uF + 2 x 1.5 uF) caps
    2 x 12 uF caps
    2 x 10 uF caps
    2 x 1.75 mH, 16 awg inductors
    2 x 0.22 mH, 19 awg inductors
    2 x 2.7 ohm resistors
    2 x 0.5 ohm resistors


    Thanks, 1c
    Too much **** to list....
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  • decato
    decato Posts: 186
    edited April 2013
    SDA1C wrote: »
    Decato,

    Is this still your preferred or current list of upgrade components for the 15tl?

    2 x 13.5 uF (2 x 12 uF + 2 x 1.5 uF) caps
    2 x 12 uF caps
    2 x 10 uF caps
    2 x 1.75 mH, 16 awg inductors
    2 x 0.22 mH, 19 awg inductors
    2 x 2.7 ohm resistors
    2 x 0.5 ohm resistors


    Thanks, 1c

    Yes, I still have the same parts in my 15TLs.
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  • SDA1C
    SDA1C Posts: 2,072
    edited April 2013
    Thanks a bunch.
    Too much **** to list....
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  • robio_d
    robio_d Posts: 7
    edited May 2013
    Hi been reading and studying this page for almost 2 years and have taken the plunge and ordered the parts. I am a bit of a electronics noob, but I'm now confident I can wire up the crossovers (will probably end up squealing for help right here!).

    My RTA's have even starred on these very pages, I bought them off RX7Rotary. Real awesome cabinet job on the sides but he had not performed any mods.

    Quick question before I start. I intended on replacing the internal wiring at the same time as doing to xover/tweeters work and started to trace how these had been wired. Mark had obviously rewired as the clip connectors were not present and had been soldered direct to the drives. On tracing it looks like the woofers have been wired in parallel. All + connected and all - connected - with 8ohm drivers a 2ohm load. If I am reading the schematics uploaded for the RTA-15TL's from this site I read it as having the woofers connected in a series/parallel configuration, with 8ohm drivers an 8ohm load. Can anyone advise on the correct wiring?

    thanks

    Rob.
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  • F1nut
    F1nut Posts: 50,537
    edited May 2013
    The woofers connected in a series/parallel configuration is correct.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • robio_d
    robio_d Posts: 7
    edited May 2013
    Thanks F1nut, that means these have been wired wrong for quite some time! Erk. Be interesting to see how this alters the performance, particularly with amping. Time to pull them apart and start work. Might do this so I can reference what they should be like before modding.

    Any tips on which way the factory connected the drivers, i.e. parallel the bottom pair, parallel the top pair and series connect top and bottom, or does it not matter as they are identical drivers?

    As well as the xover rebuild, total rewiring, replacing binding posts (they are mistmatched at the mo) and fixing damage to the base of the cabinet so I can fit spikes, I've just noticed that 2 of the woofers have voice coil rubbing. Wish I had noticed that before I placed my order with Helen at polk :(. Shipping to NZ can start adding up. I can get them repaired locally by my local electronics shop who are excellent but a little slow, but might see how much new replacements might be. Then I can take time in getting the extras repaired and have some spares.
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  • F1nut
    F1nut Posts: 50,537
    edited May 2013
    robio_d, looking at my schematic, which is probably the same one you found here, it doesn't indicate the driver positions, but they are all the same MW6503 drivers.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • robio_d
    robio_d Posts: 7
    edited May 2013
    Thanks for checking, think I've worked out the wiring order from the LF wiring schematic, translated the loom to speakers and positions. Should be a parallel of the bottom pair and a parallel of the top pair with the two pairs in series. Very handy having the wiring loom schematics to work from.
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  • robio_d
    robio_d Posts: 7
    edited November 2013
    Hi, been a bit late with this update but I finished the xover and RTA repair job approx 5 months ago.

    Ended up keeping to Brian's exact specs for the build, including xover parts (solens,madisound etc) and damping material, even had a go at adding felt to the baffle. Thought if I'm going to try the mods I would like to try and get a close to the designers specs :)

    Ended up only putting one sheet of extra material behind the woofers and removed some from the radiators for more bass levels, might not be quite as clean but got more volume, with all of the extra damping just felt a little lacking in oompf. I did wrap the cross bracing that is directly behind the 2 woofers tho as it seemed like they would directly reflect those rear firing waves

    I originally made up a felt surround for the tweets and I have to say the imaging was awesome, what I did find though was if anyone was sat out of the "perfect zone" the imagine was too precise and you got one speaker or the other so ended up removing it.

    HUGE difference with the woofers being wired correctly in amplification needed to drive the polk's - funny that. Dropping the loom back to spec and putting the stack back at 8ohms approx meant that my amps no longer had to struggle to get decent volume 32w can now crank as much as 100-150w did previously.

    Hardest bit of all of the process was repairing the base, mainly due to my many failed finishing attempts! Ended up attaching a 20mm piece of MDF to the base, recessed at the side to not detract from the veneer. Actually really happy with the results and means I can now have the speakers on spikes. Also had an added benefit of increasing the mass and rigidity of the speakers.

    Ended up building the crossovers from scratch and was actually the easiest bit of the whole process. Mounted them on a mdf plinth with some carpet underlay underneath, thought it might help with vibrations.

    After everything was put back together, WOW is all I can say. Immediately everything was better, most notably the warmish nature had been replaced with lush non fatiguing detail and for the first time the soundstage seemed to extend past my ears with one Boards of Canada track leaving me very bemused as the sounds were appearing from just behind my ears :)

    I would say the mods have put these speakers on par to some NZD$4000 speakers I auditioned.

    Thanks to all who have posted and helped, and also thanks to VR3 mods for stopping responding to my emails when I was going to purchase a kit, because without that kit I would not have learned so much.

    But mainly huge thanks to Brian/Decato for kindly putting this info up for use. You have improved my system overall by a huge measure :)

    Because I had so much fun doing this I am thinking about making another set of xovers using "premium" bits (clarity caps esa/mundorf supremes/solen perfect lays). I know that the improvement will be nowhere near the first, but am I curious to see how higher cost parts will perform. As I will make new boards I can swap both xovers in and out for testing. The new xovers won't be cheap, but still way cheaper than normal cable or rare NOS tube upgrades, so worth a shot :)
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  • decato
    decato Posts: 186
    edited November 2013
    robio_d wrote: »
    But mainly huge thanks to Brian/Decato for kindly putting this info up for use. You have improved my system overall by a huge measure :)

    Because I had so much fun doing this I am thinking about making another set of xovers using "premium" bits (clarity caps esa/mundorf supremes/solen perfect lays). I know that the improvement will be nowhere near the first, but am I curious to see how higher cost parts will perform. As I will make new boards I can swap both xovers in and out for testing. The new xovers won't be cheap, but still way cheaper than normal cable or rare NOS tube upgrades, so worth a shot :)

    Excellent! I am so glad to hear that the mods worked out well for you. If you do go through with purchasing "premium" components, please post your results. I still have my RTA 15TLs and use them all the time, but I never bothered to install higher-end components. I did use Clarity Cap SAs in my 1.2 TLs, but I can tell you they did not measure as well as the Solens. The Clarity Caps I received had higher ESR and looser tolerances (12.23 uf vs Solens 12.00 uf).
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  • robio_d
    robio_d Posts: 7
    edited November 2013
    If I do I will certainly post the bits used and impressions. The difference between the solen's/madisounds and other costliers caps/parts is one part hoping to get a wee bit more out of the polks, but also to test if more $'s does in fact = better, and I'm willing to find out that they might just not!
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  • Leosangeet
    Leosangeet Posts: 19
    edited November 2013
    RTA 15T.jpg
    IMG_0034.jpg
    IMG_0035.jpg
    IMG_0036.jpg
    IMG_0037.jpg


    My compliments to you for this excellent thread. I'm new to this but recently purchased an RTA 15T (not TL). This comes with SL3000. Here is what I have for you :-

    I have decided to upgrade based on your recommendations. I have already ordered RD0198 from polk. I opened my Xover and noticed that It is slightly different from what you have shown. Please see attached sketch (circuit diagram). Everything looks same except there is one more small capacitor on the tweeter side of the circuit. The capacitor does not have a value but it says -090 910S.

    So should I continue with the same suggestion that you have made ??
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  • cincycat13
    cincycat13 Posts: 882
    edited November 2013
    Welcome to the upgrade fever Leosangeet. The "extra capacitor" you are seeing on the tweeter side is the polyswitch that was used to help keep people from damaging the tweeters. You are fine to proceed without if you are using sufficient amplification and don't abuse the volume knob. It is not a value. You can search the forums and find some suitable polyswitches if you choose.

    There really is not a "15T" model...the fact that it has the SL3000 it is a "TL" model and you can continue without issues. The T vs TL on the 15 model can be discussed somewhere in a thread here. Have fun!
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  • Leosangeet
    Leosangeet Posts: 19
    edited November 2013
    cincycat13 wrote: »
    Welcome to the upgrade fever Leosangeet. The "extra capacitor" you are seeing on the tweeter side is the polyswitch that was used to help keep people from damaging the tweeters. You are fine to proceed without if you are using sufficient amplification and don't abuse the volume knob. It is not a value. You can search the forums and find some suitable polyswitches if you choose.

    There really is not a "15T" model...the fact that it has the SL3000 it is a "TL" model and you can continue without issues. The T vs TL on the 15 model can be discussed somewhere in a thread here. Have fun!

    Thanks for your quick response. I have ordered all the parts.

    Yes I know what you are saying about difference between T and TL. This is discussed earlier on this thread. I also had the argument with the Polk lady earlier today. I know this is 15TL but my speaker tag and the sticker on the X-over says 15T. Please see attached.
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  • Leosangeet
    Leosangeet Posts: 19
    edited December 2013
    cincycat13 wrote: »
    Welcome to the upgrade fever Leosangeet. The "extra capacitor" you are seeing on the tweeter side is the polyswitch that was used to help keep people from damaging the tweeters. You are fine to proceed without if you are using sufficient amplification and don't abuse the volume knob. It is not a value. You can search the forums and find some suitable polyswitches if you choose.

    There really is not a "15T" model...the fact that it has the SL3000 it is a "TL" model and you can continue without issues. The T vs TL on the 15 model can be discussed somewhere in a thread here. Have fun!

    Upgrade done. Speaker sounding much better. Thanks again....
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  • decato
    decato Posts: 186
    edited December 2013
    Leosangeet wrote: »
    Upgrade done. Speaker sounding much better. Thanks again....

    Excellent! I'm happy to hear that you are pleased with the modifications.
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  • MarkTX
    MarkTX Posts: 58
    edited December 2013
    After reading this thread for the last few days I'm ordering some components from parts express and going to bring these puppies back to life. bought them off craigslist with fried inductors, shorted caps, blown tweeters, etc... poor speakers :( already ordered the new tweeters... my SRT's will have to hold me over till the new parts arrive ;) once i get the 15TL's up and running I'll post my SRT's for sale assuming i can get my post count up. on a side note, any reason why the post count must be so high for someone to post a for-sale ad? I emailed the admin but never got a response, kinda disappointing.
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  • EndersShadow
    EndersShadow Posts: 17,590
    edited December 2013
    MarkTX wrote: »
    After reading this thread for the last few days I'm ordering some components from parts express and going to bring these puppies back to life. bought them off craigslist with fried inductors, shorted caps, blown tweeters, etc... poor speakers :( already ordered the new tweeters... my SRT's will have to hold me over till the new parts arrive ;) once i get the 15TL's up and running I'll post my SRT's for sale assuming i can get my post count up. on a side note, any reason why the post count must be so high for someone to post a for-sale ad? I emailed the admin but never got a response, kinda disappointing.

    Regarding the post count, the Flea Market is for the Community members to buy and sell things at prices that are lower than they tend to sell elsewhere. Its also a protected marketplace that we only want contributing members to use.

    So no drive by sales.

    Once you've hit 100 posts we tend to have a feel for you as a person, you've become an "involved" member, etc.

    My sig line says it all
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
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  • decato
    decato Posts: 186
    edited December 2013
    MarkTX wrote: »
    my SRT's will have to hold me over till the new parts arrive ;) once i get the 15TL's up and running I'll post my SRT's for sale

    I'm curious, why would you replace the SRTs with RTA 15TLs?
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  • MarkTX
    MarkTX Posts: 58
    edited December 2013
    didn't buy the RTA's to replace the SRT's, just kinda stumbled across them on craigslist and decided to fix them properly. If i sell the SRT's i'll use the RTA's and put the $3k in the bank to be that much closer to retirement. I figured i'd chime into the polk forums to offer them to fellow polkies but it seems one has to go thru a background check to get any love on here lol. it's okay, i work with the FBI and do investigations for a living, so maybe i'll fit in ;)
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  • fossy
    fossy Posts: 1,378
    edited December 2013
    Mark , you in the Austin area? ...Ive seen a ad for some srt's here not to long ago on CL ...they must sound awesome ....
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  • decato
    decato Posts: 186
    edited December 2013
    MarkTX wrote: »
    If i sell the SRT's i'll use the RTA's and put the $3k in the bank to be that much closer to retirement.

    No problem. Good luck with the mods and best wishes for a long, happy retirement.
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  • MarkTX
    MarkTX Posts: 58
    edited December 2013
    yes, southwest austin.

    decato, disregard the PM.
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