Sonicaps/Solens Installed in SDA 2B's
Stew
Posts: 645
I completed the crossover upgrade on my SDA 2B's last night. I used Sonicaps for the high pass filter (12 uF GenI) and associated bypass (0.1 uF GenII), Solens for the shunts in the low pass filters (20 uF and 39 uF), and Mills MRA-5 2.7 ohm resistors. Thanks to DarqueKnight for the schematics and to BlueMDPicker for the excellent step-by-step instructions in the thread "SDA 2B Studio Crossover Upgrade" (http://www.polkaudio.com/forums/showthread.php?t=28959&highlight=sda+crossover+upgrade).
I immediately noticed a subtle but definite improvement. They sound smoother and cleaner from top to bottom, more open and detailed mids and highs, more realistic vocals, more precise imaging, and larger soundstage. These changes are not dramatic individually but the combination makes a difference. The biggest difference I noticed is that there is no longer any listener fatigue associated with the highs even though there is more detail. It's hard to completely describe the overall difference but it's a little easier to forget you're listening to speakers and they're simply more enjoyable to listen to.
There has been some discussion about using all Solens or all Sonicaps versus Sonicaps for the high pass and associated bypass and Solens for the low pass filters. I can't say how much if any difference there would be using all Sonicaps but I definitely don't hear any negative results from the combination.
On a side note, there are three different schematics for the 2B crossovers (1987-bb, 1987-pb, and 1989). Mine have the 1987-pb (pin-blade) crossover. The only difference between 1987-pb and 1989 is the polyswitch. 1987-pb uses RDE050A and 1989 uses RDE090A. I've never had any problems with them but am curious if anyone knows the difference between these two and why Polk changed them.
I immediately noticed a subtle but definite improvement. They sound smoother and cleaner from top to bottom, more open and detailed mids and highs, more realistic vocals, more precise imaging, and larger soundstage. These changes are not dramatic individually but the combination makes a difference. The biggest difference I noticed is that there is no longer any listener fatigue associated with the highs even though there is more detail. It's hard to completely describe the overall difference but it's a little easier to forget you're listening to speakers and they're simply more enjoyable to listen to.
There has been some discussion about using all Solens or all Sonicaps versus Sonicaps for the high pass and associated bypass and Solens for the low pass filters. I can't say how much if any difference there would be using all Sonicaps but I definitely don't hear any negative results from the combination.
On a side note, there are three different schematics for the 2B crossovers (1987-bb, 1987-pb, and 1989). Mine have the 1987-pb (pin-blade) crossover. The only difference between 1987-pb and 1989 is the polyswitch. 1987-pb uses RDE050A and 1989 uses RDE090A. I've never had any problems with them but am curious if anyone knows the difference between these two and why Polk changed them.
SDA 2B-TL (Sonicap/Solen/Mills, Erse Super Q, Rings, Spikes, No-Rez)
1000VA Dreadnought
Dared SL-2000a (Siemens & Halske TM 12AT7WA's, Brimar 5Z4G)
Jolida JD-100a (Sylvania BP TM Gold Brand 5751's), NAD C275BEE, Blue Jeans
RTiA3, Onkyo TX-SR605
1000VA Dreadnought
Dared SL-2000a (Siemens & Halske TM 12AT7WA's, Brimar 5Z4G)
Jolida JD-100a (Sylvania BP TM Gold Brand 5751's), NAD C275BEE, Blue Jeans
RTiA3, Onkyo TX-SR605
Post edited by Stew on
Comments
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Congrats on the upgrade, Stew! I believe you'll notice some other subtle improvements after running them a few hours.
I don't have the schematics in front of me, but I recall that Polk began using the Xover for the CRS as well (which I believe originally had two tweeters per cabinet). The difference in polyswitches may have been to protect a higher current potential? -
It'll only get better as they burn in. As Mike alluded to, Polk went with a higher value poly as the previous poly's tripped a little too easily.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 -
Congratulations Stew! Glad you saw an improvement with the upgrade. Like Jesse said, you should notice some additional refinement in sound as the caps burn in. Jeff at Sonic Craft told me 50 hours for the most change, total burn in at 100 hours. I notice with all Sonicaps the sound got smoother and even more detail. Happy listening! Did you get to eat any turkey while you were engaged in this work?
Carl -
I stayed up late Wednesday night to do the upgrade so I wouldn't miss the Turkey! They already sound better than they ever have. If they get even better, that will be gravy (pun intended). As for the polyswitches, these have rarely, if ever, tripped. I assume previous advice to leave them alone unless they're causing a problem still applies.SDA 2B-TL (Sonicap/Solen/Mills, Erse Super Q, Rings, Spikes, No-Rez)
1000VA Dreadnought
Dared SL-2000a (Siemens & Halske TM 12AT7WA's, Brimar 5Z4G)
Jolida JD-100a (Sylvania BP TM Gold Brand 5751's), NAD C275BEE, Blue Jeans
RTiA3, Onkyo TX-SR605 -
I left the stock polys in my 2Bs and SRS. I've had no issues with the 2Bs, but the SRS tripped once a few weeks ago (first time ever since owning) and will now trip regularly if driven hard. Ken (Polk CS) sent me a couple of replacements already. I just need to get busy and install them.
