SDA-2A Crossover Upgrade

2

Comments

  • Disc Jockey
    Disc Jockey Posts: 1,013
    edited March 2009
    NJPOLKER wrote: »
    Nobody knows more than the guys around here.

    LOL

    The bypass cap is supposed to help provide some airiness and spaciousness to the sound. General consensus around here is that it is not needed with new, higher quality caps and is, in fact, detrimental. I didn't really notice anything but good sound when I did my 2A's, but I don't miss not having it on my 2B's either.You can order them and try for yourself if you're curious.

    FWIW, I asked someone at Polk (Ken maybe) about the really low value of that original bypass cap and he said it was so low, it probably didn't do much anyway.
    "The secret of happiness is freedom. The secret of freedom is courage." Thucydides
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  • Systems
    Systems Posts: 14,873
    edited March 2009
    NJPOLKER wrote: »
    If you plan on going with the Solen 270uF's you better hurry. They only have 2 left at that price, I just bought the 2 for my 2a's.
    Thanks again GV
    Your welcome.
    Wow you didn't waste any time.I didn't notice the stock level was so low when I posted it.
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  • ben62670
    ben62670 Posts: 15,969
    edited March 2009
    The 270 is just fine. That cap is actually in series. Not shunt. It is used to prevent the bass signal from being canceled out by the SDA IC. It's kinda hard to fallow in the diagram, but that is the way they did it with the blade/blade SDA's.
    http://www.polkaudio.com/forums/showthread.php?t=55888
    The signal passes from the positive of the of the right to the negative of the left, and vis versa. If the cap was not there it would cancel out the bass also.
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • bcline
    bcline Posts: 59
    edited March 2009
    Yes, thanks GV for the link. I hopefully got in my order in time to get a couple. They are actually cheaper than that. The price is $34.00 Canadian which is about $27.00 U.S. Really nice deal.

    Thank you all for entertaining my questions on this thread. I've really learned a lot and now that I've ordered the Solens, I think I know what I will do with the rest of the crossover upgrade. This forum is great and your opinions are very much appreciated!
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  • Systems
    Systems Posts: 14,873
    edited March 2009
    bcline wrote: »
    Yes, thanks GV for the link. I hopefully got in my order in time to get a couple. They are actually cheaper than that. The price is $34.00 Canadian which is about $27.00 U.S. Really nice deal.
    Your welcome,yes $27 for a film cap that big is a good deal.

    Good luck with your upgrades.
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  • bcline
    bcline Posts: 59
    edited March 2009
    I just saw NJPOLKER's post on his 270 ufd Solen caps... see link. Good lord it's the size a beer can! Suggestions on how I'm going to install this... Do I need to mount it on a separate board in the speaker and solder wires from it to the circuit board? I knew they would be large but holy cow these things are huge! Mine have not arrived yet, but now I won't be so shocked.

    http://www.polkaudio.com/forums/showthread.php?t=80514
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  • ben62670
    ben62670 Posts: 15,969
    edited March 2009
    Just use some wire and mount it off board. It will not hurt performance:)
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • Systems
    Systems Posts: 14,873
    edited March 2009
    NJ will likely have a better method, but you could use a piece of masonite or peg board and secure the cap to it with wire ties and hot glue (or silicone).Then silicone or glue the finished board to the bottom of the cabinet.Solder in some leads with MonsterCable:) and your good to go.
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  • bcline
    bcline Posts: 59
    edited March 2009
    I have completed the first stage of my upgrade. On the primary crossover I decided to go with Sonicaps for the high pass filter and Daytons for the 20uF shunt caps on the low pass. I'm still waiting for the Solen 270 uF monster caps I ordered and will upgrade the dimensional crossover with those and 20uF Daytons for the shunts on it. I used Cardas solder as well.

    I've posted a before and after pic for the left channel speaker. Strangely, the low pass shunt cap on this speaker was different than the one on the right which was a standard blue electroytic cap. Anyone have any idea why two different shunt caps? Would that have been done in the factory or did a previous owner of this set change out one?

    Everything went in fine and the only disappointment is that I didn't make the hot glue go on as neatly as I would have liked...:o not that anyone will be seeing them from now on. The speakers sound great and are getting better by the hour as the caps break in. I did go ahead and order a set of RD0194-1 tweeters to replace the SL2000s. Also waiting for them to show up.

    Thanks for all your help guys... this project was not nearly as tough as I first thought it might be.

    before.jpg


    after.jpg
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  • NJPOLKER
    NJPOLKER Posts: 3,474
    edited March 2009
    It looks like you decided to leave the original poly switches alone?
    If they are the originals you may want to order two new ones from Polk CS, I think no charge.
    Some say to bypass the poly switch with a jumper. I have not because of the potential for someone being reckless with the power. I have alot of clean power but ya never know what could happen :o
    This is a good start for you and you'll find the low pass a little more tricky but not too tricky for you now :)
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  • bcline
    bcline Posts: 59
    edited March 2009
    Is this switch just to protect the speaker from being overdriven or does it serve some other purpose? Why do you need to change them out, do they go bad or do they just make a better one now?
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  • fbm211
    fbm211 Posts: 1,488
    edited March 2009
    It is to protect the tweeters.It shuts off then comes back on after a few moments..They do go bad over time.Some suggest a bypass as it will improve the SQ of the highs
    SDA-2BTL with custom IC
    Adcom 565 monoblocks--Monarchy Audio M-10 preamp
    Theta Data Basic Transport--Stello DA100 Signature DAC--Camelot Dragon Pro2 MK III
    Harman Kardon T-55c TT
    DH Labs Q-10 Signature Speaker Cables With Furez silver plated copper bananas
    Revelation Audio Labs Prophecy Cryo-Silver Reference AES/EBU
    Revelation Audio Labs Prophecy Cryo-Silver i2s digital cable
    4 Furutech FP-314Ag with FI-11cu Plugs/FI-11AG IECs--- Power Cords
    DH LABS REVELATIONS ICs-amps
    Revelation Audio Labs Paradise cryo-silver ICs-Source to pre
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  • bcline
    bcline Posts: 59
    edited March 2009
    So, if I bypass it, what do I need to be careful about doing... or not doing to keep from blowing the tweeters?
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  • fbm211
    fbm211 Posts: 1,488
    edited March 2009
    First good clean power.NO CLIPPING...Second dont crank it up too much.
    SDA-2BTL with custom IC
    Adcom 565 monoblocks--Monarchy Audio M-10 preamp
    Theta Data Basic Transport--Stello DA100 Signature DAC--Camelot Dragon Pro2 MK III
    Harman Kardon T-55c TT
    DH Labs Q-10 Signature Speaker Cables With Furez silver plated copper bananas
    Revelation Audio Labs Prophecy Cryo-Silver Reference AES/EBU
    Revelation Audio Labs Prophecy Cryo-Silver i2s digital cable
    4 Furutech FP-314Ag with FI-11cu Plugs/FI-11AG IECs--- Power Cords
    DH LABS REVELATIONS ICs-amps
    Revelation Audio Labs Paradise cryo-silver ICs-Source to pre
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  • Face
    Face Posts: 14,340
    edited March 2009
    What are you driving them with? If it's a receiver, leave them in.
    "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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  • bcline
    bcline Posts: 59
    edited March 2009
    It's a receiver... Onkyo TX-SR806... I tend not to overpower as my old ears can't handle it like they used to no matter how clean it is. Now as my kids get older and enter their teen years... that could be a different story.
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  • bcline
    bcline Posts: 59
    edited March 2009
    After reading other posts on this subject, it would seem that I would have to be turning up the volume to a rediculous point where it would be so distorted I might rather find more enjoyment running bamboo shoots up my fingernails. I do not listen to my music that way nor will I ever allow my kids to do that either... not in this house at least. :) So, I think I will go ahead an take them out...
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  • fbm211
    fbm211 Posts: 1,488
    edited March 2009
    Does that reciever have pre outs.You could get a nice used amp to power them with and Im sure you would enjoy the better SQ you would get.AudiogoN has good deals on used ones.High current like adcom,rotel,marsh etc is the way to go for SDAs IMO
    SDA-2BTL with custom IC
    Adcom 565 monoblocks--Monarchy Audio M-10 preamp
    Theta Data Basic Transport--Stello DA100 Signature DAC--Camelot Dragon Pro2 MK III
    Harman Kardon T-55c TT
    DH Labs Q-10 Signature Speaker Cables With Furez silver plated copper bananas
    Revelation Audio Labs Prophecy Cryo-Silver Reference AES/EBU
    Revelation Audio Labs Prophecy Cryo-Silver i2s digital cable
    4 Furutech FP-314Ag with FI-11cu Plugs/FI-11AG IECs--- Power Cords
    DH LABS REVELATIONS ICs-amps
    Revelation Audio Labs Paradise cryo-silver ICs-Source to pre
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  • bikerboy
    bikerboy Posts: 1,211
    edited March 2009
    Hi,
    I have been following this thread with the idea of doing the same. The polyswitch is the blue thing next to the square resisters? I will jumper mine but the dimensional xover (top one in the photo) is where I will need the 270 uf cap to replace the 3 blue ones? Bcline, any word on the sound of the changes?
    Main system: Lyngdorf TDAI 2170 w/ Pioneer 42" plazma-> Polk LSiM 703 w/Tivo, Marantz tuner, BRPTT: Nothingham Spacedeck-> Pioneer PL L1000 linear arm-> Soundsmith DL 103R-> SUT->Bottlehead ErosDigital: I3 PC w/ Jriver playing flac -> Sonore Ultrarendu -> Twisted Pair Audio ESS 9028 w/ Mercury IVY Vinyl rips: ESI Juli@24/192-> i3 PC server
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  • NJPOLKER
    NJPOLKER Posts: 3,474
    edited March 2009
    Your polyswitch is in the high pass/lower x-over in pic next to the resistors mustard colored
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  • NJPOLKER
    NJPOLKER Posts: 3,474
    edited March 2009
    You will need the 270uF to replace the two 130uF caps which are tied together. You will need a separate cap to replace the 20uF cap. When installing the new caps put the 20uF over the 270uF there are pictures posted by yours truly in another thread.
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  • bcline
    bcline Posts: 59
    edited March 2009
    bikerboy wrote: »
    Hi,
    I have been following this thread with the idea of doing the same. The polyswitch is the blue thing next to the square resisters? I will jumper mine but the dimensional xover (top one in the photo) is where I will need the 270 uf cap to replace the 3 blue ones? Bcline, any word on the sound of the changes?

    I have not installed my 270 caps yet. I just received them yesterday afternoon and probably won't be able to get to them until this weekend at the earliest.
    I will say that the upgrade of the high main crossover with the Sonicaps and Daytons has resulted in better detail in the sound. I'm hearing things I did not hear before especially with subtle notes and background licks in the music. Overall, the sound is brighter and seems more natural than it was before. I still have not removed the polyswitches yet... again I will do that when I get around to upgrading the dimensional crossover (that's the upper crossover in your pic).

    NJ's thread is here.
    http://www.polkaudio.com/forums/showthread.php?t=80514
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  • bcline
    bcline Posts: 59
    edited March 2009
    fbm211 wrote: »
    Does that reciever have pre outs.You could get a nice used amp to power them with and Im sure you would enjoy the better SQ you would get.AudiogoN has good deals on used ones.High current like adcom,rotel,marsh etc is the way to go for SDAs IMO

    I do have preamp outputs (called a 2nd room output on the receiver). However, I don't think I have the money at this time to be going the route of the an audiophile grade dedicated amp. I do know what they can bring as I have a good friend who is in the business of super high end audio and home theater. He is the exclusive Martin-Logan dealer in Wichita right now. I've heard his stuff and have been blown away by it. However, I am a teacher and that brings it's limits and besides that, my wife has entertained my hobby this far, I don't want to push it. :) We will go with baby steps. ;)
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  • NJPOLKER
    NJPOLKER Posts: 3,474
    edited March 2009
    Good for you. You know if you enjoy it what more can you ask for. I think you should leave the polyswitches in the x-over. You will not hear the difference and will give you some protection in case the unexpected happens, which happens too often :eek::eek:
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  • Face
    Face Posts: 14,340
    edited March 2009
    I would replace the poly switches with new ones. I believe they're free from Polk.
    "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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  • NJPOLKER
    NJPOLKER Posts: 3,474
    edited March 2009
    Damn guy from L.I. is correct :D even a blind squirrel finds a nut :p:p
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  • bcline
    bcline Posts: 59
    edited April 2009
    For those of you who have sat on the fence about changing your SL2000 tweeters to the RD0194 tweets. Quit sitting. I got mine yesterday and installed them and if I didn't know better, I would have said that I was listening to an entirely new set of speakers. I didn't realize how harsh the SL2000s were until I heard the change. I even have slight hearing loss at the high end, but I could sure hear what everybody had been talking about. The new xo components improved things... this upgrade just made all the difference.

    BTW... I realize my Onkyo is not up to par with some of the integrated amps and monoblocks you are all talking about, but I get the feeling that some of you think it must be a fairly unimpressive Best Buy special too. If you look at the specs on the 806 it is not that bad and I beg to differ with some of you that I probably will not hear a difference when I make a change. This system is plenty clean enough to hear very subtle changes and as a musician myself, I have a pretty good ear for things. I know it ain't no McIntosh, but after owning some pretty dirty sounding recievers in the past, this one is leaps and bounds above many. Put it in direct sound mode and it essentially shuts down all extra functions and becomes a simple amp. It has 0.08% THD values, ample wattage and more importantly ample current flow. It has had no problem powering these SDAs and with the volume at 0db, I have it all the loudness I care to handle. Someday, I would like to own the real deal when I win the lottery or inherit a huge estate. For now this will do.
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  • Face
    Face Posts: 14,340
    edited April 2009
    If you replace the poly switches and they start to kick in again, you know why. If they don't, then enjoy.
    "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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  • NJPOLKER
    NJPOLKER Posts: 3,474
    edited April 2009
    I think you nailed it when you stated "ample current flow" which is critical.
    Its awesome you are enjoying your speakers and the upgrades.
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  • Face
    Face Posts: 14,340
    edited April 2009
    Why receivers generally suck: http://www.polkaudio.com/forums/showthread.php?t=81136
    "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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