Jumping in the water again... Polk RTA-12Bs...
Comments
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dang that's a chunk o change.. I never knew the RTA12's had such beefy X-overs... guess that's why so sound so damn good
post pics when you can.. we rarely see anyone do RTA x-over rebuilds.PolkFest 2012, who's going>?
Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin: -
danger boy wrote: »post pics when you can.. we rarely see anyone do RTA x-over rebuilds.
+1!!!"He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche -
i think the RTA-12Cs have one of the most complex crossovers. There are nine caps on each speaker...
Jon,
Two comments. First, there are indeed 9 caps but you don't need to buy the 750 pf caps. They are not necessary with the polyproplyene caps.
Next, there are a pair of caps in parallel, a 4.4 mylar and a 55 electrolytic. I'd discuss this with someone more knowledgable than yours truely, because that is kind of a weird setup in my experience (I don't know what Polk was accomplishing there). Perhaps they were just using up inventory. Anyway, a single 60 uf cap will probably be what you need here,
Now you are down to 6 caps. Still expensive but perhaps simpler.The world is full of answers, some are right and some are wrong. - Neil Young -
I sent an email to Soniccraft with the schematics for the crossover for the speakers. After getting no response for several days, i ordered the components as specified on the schematic. I am not going to use the 750pf caps as F1Nut mentioned they are not needed.
I got a response from Soniccraft after I had placed my order (the sender mentioned he was out on personal leave for several days so that's why no earlier response). He also mentioned the 60uf option but the parts were already on it's way...
Anyhow, that's the present situation. I am hoping to work on the crossover this weekend and that will also resolve the dead tweeter. Speaking of which, I also ordered a pair of RDO194s to replace the SL2000 about two weeks ago. I have not heard yet whether they have shipped or not (they may be out of stock again). -
Jon, I always prefer to call when placing an order, just seems to work out better.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 -
I normally send them what I have (a schematic) and look at their response. I then call them up for the orders and other questions... did not have a problem until the guy was out...
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bummer, just found out that the RDO194s I order two weeks ago are backordered again (someone apparently made a big order or something (Ok, who was it??))... I am hoping that the Sonicaps come in before the weekend at least...
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All right... the Sonicaps came in and I am upgrading the RTA-12Cs crossover. All these Sonicaps cost me a pretty penny. I ended up getting 4 4.3-uf and 8 27-uf caps, 2 2-ohm and 2 7.5 ohm Mills resistors just for the tweeter crossovers. That comes around to about $440. I will have to do the LF crossover later (that's gonna be another $150) My replacement RDO194 tweeters are on its way and should be here next Thursday. They were $48 each plus $44 shipping to Hawaii (Polk does not ship free to Hawaii, with the high cost of shipping due to fuel costs, I do not expect to see free shipping anymore in the CONUS either).
Anyway, here are some shots of the upgrade....
1. crossover before the upgrade...
2. All the pretty little Sonicaps
3. planning where to position the caps
4. picture of the bad crossover... I think I found out the why the tweeter did not work after jumping the polyswitch, the 4.4 cap was cold-soldered (the lower right corner)... -
The easiest way was to remove the tweeter assembly from the crossover board. After removing the two bolts and disconnecting the leads, the the rest was easy.
I used new weatherstripping to replace the old crumbling ones underneath the caps. Since the crossover is sitting on top of the speaker, I felt that hot glue was not needed since the original did not have any. Another slight issue is that the new caps block some of the standoffs so the PCB board sits a bit uneven. I also removed the bypass caps and did not replace them. there was no room for them anyway as the larger caps covered the areas where the bypass caps resided.
Now the bummer part. I hurt my back a couple of days ago and i cannot even sit or lie down without pain. carrying anything as heavy as the speakers is out of the question right now so I cannot even test or try out the speakers until I get better.
1. picture of the Jantzen crosscap in comparison with the Sonicap
2. picture of the crossover PCB with all the components removed
3. finished one of the crossovers next to the unfinished. -
Thank you for the pictures.
As for your back, I know where you're coming from, feel better."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche -
Looking good. Hope your back feels better quickly!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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Excellent Job.... So, is the Jantzen 27uf much larger than the stock cap? I am surprised at the size difference between the Jantzen and the sonicaps...Mains.............Polk LSi15 (Cherry)
Center............Polk LSiC (Crossover upgraded)
Surrounds.......Polk LSi7 (Gloss Black - wood sides removed and crossovers upgraded)
Subwoofers.....SVS 25-31 CS+ and PC+ (both 20hz tune)
Pre\Pro...........NAD T163 (Modded with LM4562 opamps)
Amplifier.........Cinepro 3k6 (6-channel, 500wpc@4ohms) -
Excellent Job.... So, is the Jantzen 27uf much larger than the stock cap? I am surprised at the size difference between the Jantzen and the sonicaps...
If you think the Sonicaps are big, the Jantzen Silver Series Z-caps are twice as big as the shown Jantzen crosscap at roughly 1.75 x 4 inches. According to the cap reviews online, the Silver caps are supposedly even better than the Sonicaps. But at $150 for a 27-uf value and $60 for a 4.4-uf value, you are looking at a whopping $1700 per speaker. That's really at the point of diminishing returns to me...
A good comparison can be found here comparing the V-Cap, the Sonicap and Mundorf Silver-oil caps. the conclusion was while the Mundorf was the best performing cap, the differences between the Mundorf and the Sonicap could only be detected in a direct comparison. -
You indicate otherwise......
I'm telling you that, "sometimes it sounding like the music was in a reverb or echo chamber" is not normal for SDA speakers and they do not compromise the fidelity one little bit. Therefore, based on your own comments, something was wrong with your ex-SDA's.
SDA's reveal so well many people make such a comment. If engineers "mixed" with a set of SDA's they would use less of a given effect. SDA's don't compromise fidelity that's for sure but they do reveal more. I often hear an excess of an effect then disconnect the interconnect and it's very tame in comparison. There are recordings that sound worse when using the "effect" (interconnect) like "Owner of a Lonely Heart" by Yes. Way overproduced with excess reverb on the vocals. Also listen to Patricia Barber's "Cafe Blue" vocals with and without. Another case of excess reverb that makes the vocal track worse with SDA.Also Beatles and other early stereo where everything is either L or R with a greatly diminished center image. Don't get me wrong I'm SDA all the way but clearly this is an issue. Also make a CD or tape with L to R pans and notice that it moves in a linear fashion except from the L speaker to near L center and then again from near R center to the R speaker. It's like there is a hole there. This is also very noticeable on Kimbers demo SACD where the choir members call out there names from right to left. It is linear except in those positions I mentioned between the speakers and center image. Also too many engineers think stereo has three locations only; L,C,R. I wish they would place things all across the spectrum using the nuance of pan pots. OK that's my rant. Oh room treatments are even more needed IMO w/SDA. I have a lot now and SDA has never sounded better! I just treated the apex of my cathedral ceiling with incredible affect to the center mono image and greatly improved coherence between L,C,R noticed especially during pans. I used Jon Risch's DIY recipe. Here is a pic:
sorry they are so small
ET
System: MF Trivista SACD > Placette passive> CJ passive horizontal bi-amp> MF 2500A(LF) MF2100(HF) > 1.2TL's
Other: Speltz silver Eichmann IC's & speaker wire, Econotweaks Detail Magnifiers, PS Audio P-300(source), R. Gray 600, Al Sekala's AC R/C filters, R. Gray HT PC's, Oyaide R-1's,WPC-Z , M-1, Herbie's & DIY Isolation
Room: Qty 7 - 4' tall 18" diam. bass traps, Qty 4 - 4' X 2' X 4" panels. All DIY - man my wife is tolerant! -
With the help of my son, i was able to connect the RTA-12Cs up to the amp. The crossover with the blown polyswitch also had a blown SL2000 driver. Odd, it does show continuity on an ohm meter but no sound, but I digress. I was able to jury rig my leftover SL1000s from my Model 10Bs and everything worked okay.
After a couple of hours of listening, this is what I noted...
The 12s have a slightly deeper bass which not as boomy as the 10Bs. It is however at a lower sound level than the 10Bs, I guess the boominess is in part to blame. There is a slight improvement in depth and focus over the 10Bs, but the 10Bs display a wee bit more ambiance and "air" to the sound. Also, the 10Bs have a bit better balance in overall sound imaging. The 12s shows some compression in ensembles where everything is a bit more veiled and not open. I did notice that I have to crank up the amp a bit more than I did with the 10Bs. At louder volumes, the 12s do require more power than the 10s as the amp starts to run out of power quicker.
Accuracy suffers a bit, some instruments sound more colored with the 12s than with the 10Bs, most notably the piano. A grand piano does not sound quite as grand as it should be, missing some of the resonances I'd expected.
Anyway, I will wait for the RDO194s which should be in next week and make another analysis of the system later And since I still have the bypass 750pf Relcaps, I will probably add them in after breakin and see what kind of differences a bypass cap does to the sound. I still need to break in the caps for awhile to see how the sound improves or not, and I think I will have to dig up a more powerful amp to see if that improves the compressed soundstage.... we shall see. -
Jon, you can't possibly judge the sound until those caps have at least 200 hours, 400 is even better, on them. Anything you're hearing now will not be like that 200-400 hours later. That's not to mention the mis-matched tweeters you're running.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 -
I realize that...
I replaced both SL2000s with the SL1000s. -
Ok Jon, just checking.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 -
thanks for your concerns... I do occasionally make stupid judgments...
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Hooray!! I just got the replacement RDO194-1 HD drivers for my Polk RTA-12Cs... i will be installing them later this week and testing out the speakers.
If all goes well, my next item on the agenda is to remove the vinyl covering and putting on real wood veneer. I am debating whether I should remove the black vinyl from the front baffle and veneer that as well... It would look something like this pre-production RTA-12As shown below. I will probably remove the plastic grille guides and drill them out. Replace them with magnets, veneer over the magnets and insert matching magnets in the grille itself to give it a smoother look without the grilles...
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what about see-thru grill cloth. That might be fun to experiment with.
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candyliquor35m wrote: »what about see-thru grill cloth. That might be fun to experiment with.
Now that is just weird...
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IMO, I would stick with the black grill cloth but remove the vinyl like you were saying. I also dig on the custom magnet grill work that would look great and would give it a nice touch.
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If you think the Sonicaps are big, the Jantzen Silver Series Z-caps are twice as big as the shown Jantzen crosscap at roughly 1.75 x 4 inches. According to the cap reviews online, the Silver caps are supposedly even better than the Sonicaps. But at $150 for a 27-uf value and $60 for a 4.4-uf value, you are looking at a whopping $1700 per speaker. That's really at the point of diminishing returns to me...
A good comparison can be found here comparing the V-Cap, the Sonicap and Mundorf Silver-oil caps. the conclusion was while the Mundorf was the best performing cap, the differences between the Mundorf and the Sonicap could only be detected in a direct comparison.
$1700 per speaker? how do you arrive at that? what did I miss?PolkFest 2012, who's going>?
Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin: -
the pricing is as follows....
to replace the 4 4.4-uf caps you will need 8 2.2-uf @ $29 = $232.00
to replace the 8 27-uf caps you will need 8 22uf caps @ $115 = $920 and 8 5-uf caps @ $37 = $296 (there is no 27-uf value so I had to sum them up)
to replace the 2 55-uf caps, you will need 4 22-uf @ $115 = $460 and 2 10-uf caps @ $67 = $134
so $232 + $920 + $296 + $460 + $134 = $2042...
a bit higher than I thot... -
that's insane of course.. but there must be a less, much less expensive route I'm sure.PolkFest 2012, who's going>?
Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin: -
Well, anyone considering the Jantzen Silver caps for upgrades has to be crazy anyway... i can see them only to upgrade some JBLs which have only two caps per speaker...
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I still would love to try Mundorf Silver in Oil caps in my Tannoys."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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My 2 cents:
I put Solens in my monitor 10's and they sound MUCH improved over stock. I put Sonicaps in my SDA-1C's and they also sound great. Both the monitors and SDA's have RD-0 tweeters. I have not upgraded my RTA-12C's yet, but based on the capacitor count, I'd probably lean toward Solens.
I was somewhat of a crossover upgrade/capacitor skeptic until I put the Solens in my Monitor 10's. The improvement in dynamics was quite obvious in both the SDAs and the monitors.
