Problem with SDA-1C

SpeedyFE
SpeedyFE Posts: 143
edited February 2008 in Troubleshooting
Hello, new to the forum here. I have a question. I just purchased a beautiful pair of SDA-1C speakers from the original owner. I am running a Sony TA-1000 Digital Processing Control Amplifier to a Sony TA-N80ES Spontaneous Twin Drive Stereo Power Amplifier to my POLK's. The problem is that when I have the volume up about 2/3's of the way up, after about a minute to two minutes the tweaters cut out. Now I know that this is supposed to happen, as that is the thermal protection, but my question is WHY? Any help would be great. Thanks. Below are the specs on my AMP:

THANKS!

Continuous RMS Output Power:

2x 270W (4Ohm, 20Hz...20kHz, THD 0,006%)
2x 230W (6Ohm, 20Hz...20kHz, THD 0,005%)
2x 200W (8Ohm, 20Hz...20kHz, THD 0,004%)

1x 610W (8Ohm, mono, 20Hz...20kHz, THD 0,004%)
1x 580W (8Ohm, mono, 20Hz...20kHz, THD 0,004%)

Dynamic Output Power:

660W (1Ohm)
800W (2Ohm)
520W (4Ohm)
370W (6Ohm)
300W (8Ohm)

Power Bandwidth:

10Hz...100kHz (4Ohm, THD 0,02%)
10Hz...100kHz (8Ohm, THD 0,02%)

Dynamic Headroom:

2,8dB (4Ohm)
1,8dB (8Ohm)

Total Harmonic Distortion:

0,004% (10W/4Ohm)
0,003% (10W/6Ohm)
0,0018% (10W/8Ohm)

IM:

0,006% (4Ohm at rated output)
0,005% (6Ohm at rated output)
0,004% (8Ohm at rated output)

Frequency Response:

1Hz...200kHz (+0/-3dB)
Post edited by SpeedyFE on
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Comments

  • danger boy
    danger boy Posts: 15,722
    edited February 2008
    just how loud are you playing them exactly? It takes a good amount of volume to make the tweeter cut in and out..
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • dorokusai
    dorokusai Posts: 25,577
    edited February 2008
    I would call Polk Audio, get some new polyfuses and replace them on the current xover.

    You'll need basic soldering skills.

    If you have the same problem, we'll move on.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited February 2008
    Do you mean the ta-e1000esd? If so, I used to have the same problem with mine. The polyswitches may help for a while but you normally don't want to turn the volume past 12 o'clock on any pre-amp or receiver to prevent damage to the speakers, amp or receiver.
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  • SpeedyFE
    SpeedyFE Posts: 143
    edited February 2008
    I would first like to thank everyone for their advice. To reply to candy, yes this is the preamp that I have. I know that in general, you do not want to go past the 12 position, but with this preamp I always thought that it was safe to go beyond 12 because you can adjust the input level, but I will certainly keep this in mind now.

    Second, I read on the forums here that it may be a good idea to upgrade the x-over and tweeters, but while some people felt this was a great idea, others felt that the original equipment was best. Can anyone offer any concrete suggestions on what to do? These speakers are in near mint condition and I plan on keeping them for a while.

    Finally, I think that one of my tweeters is blown, it sounds scratchy sometimes. If this is the case, is there a repair for this or is a used tweeter or perhaps an upgrade in order?

    Thank you all again.

    Just some background, my family has owned SDA 2s, RTA 11s and now I stumbled across these SDA 1cs and I would really love to get them tip-top.
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  • dorokusai
    dorokusai Posts: 25,577
    edited February 2008
    You use the input level adjustment to compensate between channels. You should have them maxed out unless you have an actual volume issue between the L&R channels.

    If you do, you should get the bias checked and it wouldn't be out of the oridinary for that series of Sony. You can do that yourself, but you'll need a service manual or at least the board level spec's.

    It's certainly possible in this world to repair a tweeter....replace it and move on.

    If your happy with the sound, don't change a thing, end of story.

    If you want to tweak? There are a host of things you can do, some cheap, some expensive but everything is based on a 20+ year old loudspeaker and the only return on your investment is basically on THIS user forum. Keep it in perspective, have fun, mod away.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • SpeedyFE
    SpeedyFE Posts: 143
    edited February 2008
    Thank you,

    The input that I was referring to was on the preamp and not the input on the amp itself (the little knob that is under the front cover at the bottom of the preamp). So the amp is limiting my volume and not the speaker, right? They are rated to 500, how powerful of an amp do people generally use to power speakers like these?

    So if I replace the tweeter, should I upgrade or get used? I guess what I am asking is does the replacement tweeter sound better than original?

    Finally, if I did want to modify the speakers, where can I get the info on what to do and how to do it?

    Thank you again.
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited February 2008
    Yes that pre has a input level control. I used to set mine at -10db because my input was a digital toslink so I thought I could turn the volume to 3/4 (3 o'clock) but I think it's safer to leave the input level straight up at 0 and then never turn the volume past 12 o'clock.
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  • avguytx
    avguytx Posts: 1,628
    edited February 2008
    I vote to change out those little poly thermal switches first as they are culprit to "tripping" sooner as the years go by. My SRS II's did the same thing with the meters on the Carver M-1.0t barely bouncing into the 2nd and 3rd level. Some will eliminate the PT switches altogether (like I did) or replace them with new ones. YMMV.
    Richard? Who's your favorite Little Rascal? Alfalfa? Or is it........................Spanky?.................................Sinner.
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  • george daniel
    george daniel Posts: 12,096
    edited February 2008
    yep,, the older they get and the more they "trip",the easier it is to trip them,,a new set can usually be had from Polk,,ask nicely,,good luck and careful with the volume.;)
    JC approves....he told me so. (F-1 nut)
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  • shadowofnight
    shadowofnight Posts: 2,735
    edited February 2008
    All you have to do is ask....Polk has excellent customer service. PM Kenneth Swauger and he sends them out no charge.
    The first rule of Fight Club is you don't talk about Fight Club
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  • SpeedyFE
    SpeedyFE Posts: 143
    edited February 2008
    Thank you for the great input. In addition to calling customer service for the polyswitches, would they also steer me in the right direction for crossovers?

    Finally, does anyone have any input on my combination pre-amp, amp for these speakers that I posted in the first post? Is this a good combo, or does anyone have any suggestions on a better amp (am i underpowered)?

    Thanks again to everyone!

    Paul
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  • danger boy
    danger boy Posts: 15,722
    edited February 2008
    the crossovers you have to upgrade yourself.. but you also may want to update/upgrade those tweeters.. esp if one is blown. replace BOTH, not just one.. even if only one is blown. you want the sound to match in both speakers.
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • avguytx
    avguytx Posts: 1,628
    edited February 2008
    I may have some of those newer PT switches here myself that I didn't use. PM me your address and I'd be glad to mail you a pair.
    Richard? Who's your favorite Little Rascal? Alfalfa? Or is it........................Spanky?.................................Sinner.
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited February 2008
    If you basically like the way your current tweeters sound and wanna save a good $150, you can just put $3 caps on your existing tweeters and buy a used sl2000 for $20-$30 shipped from here or ebay.

    http://www.polkaudio.com/forums/attachment.php?&attachmentid=30823

    http://www.polkaudio.com/forums/attachment.php?attachmentid=31246

    http://www.polkaudio.com/forums/showthread.php?t=63676
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  • SpeedyFE
    SpeedyFE Posts: 143
    edited February 2008
    I do like my tweeters for the most part, except the one that seems like it may be blown. So I am going to just get the same one and follow your plan to use the caps. I still have to read that thread. Should I just order the tweeter from POLK directly, or you mentioned that someone here may have a pair for sale? Thanks.

    Paul
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  • danger boy
    danger boy Posts: 15,722
    edited February 2008
    Sl2000 is the silver coil dome tweeter that was used for many years on vintage polk speakers.. Polk no longer carries the SL2000 tweeter. to find one.. you should check on EBay. they pop up there all the time.
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • avguytx
    avguytx Posts: 1,628
    edited February 2008
    The SL2000's are the tweeters, and being someone that's been in this business since 1979, I would NOT be putting in a cap on the tweeter like that. All is does is jack with the crossover. But that's just 29 years of experience talking...take it for what it's worth. That is NOT something that is normally done.

    The PT switches will be mailed out to you tomorrow. I tried to send you an email back but it kicked back on me.
    Richard? Who's your favorite Little Rascal? Alfalfa? Or is it........................Spanky?.................................Sinner.
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited February 2008
    Your sda 1c speakers have the sl2000 tweeters in them. They don't make them anymore but you can buy a used one on here in the WTB section or on ebay.

    For $12, it's worth trying the caps. They can't harm your speakers in any way. The techs haven't figured out how or why they work but I've been using them for over a year with great results.
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  • SpeedyFE
    SpeedyFE Posts: 143
    edited February 2008
    Ok, sounds good. I have been reading a lot and I am trying to decide whether to upgrade the crossovers and the tweeters. I am usually a "keep them as they came person", just for originality, but swapping parts is usually OK by me as long as I could put it back to "stock" so to speak if I ever wanted to.

    AVGUYTX--thanks for mailing the switches, I am not sure why the email came back, I will look into that.
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  • F1nut
    F1nut Posts: 50,557
    edited February 2008
    Do not put a cap on your tweeters, it totally changes the crossover points and creates a suck out in the frequency response.

    CL, you need to STOP giving out bad advice.
    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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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited February 2008
    The caps are plug and play if you can find the right terminals. If not, I can mail you some connecting terminals. If you don't like the way the caps sound, unplug them and you're back to stock. No soldering and unsoldering.

    http://www.polkaudio.com/forums/attachment.php?&attachmentid=30823

    http://www.polkaudio.com/forums/attachment.php?attachmentid=31246
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  • avguytx
    avguytx Posts: 1,628
    edited February 2008
    Again....do NOT put the caps inline on the tweeters. I have yet to see any documents that supports this idiotic idea. You are totally changing the crossover characteristics.
    Richard? Who's your favorite Little Rascal? Alfalfa? Or is it........................Spanky?.................................Sinner.
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited February 2008
    I'm listening to my sda 2b's with sl2000wc's (with caps) right now and they sound marvelous.

    Auditions available on request.
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  • avguytx
    avguytx Posts: 1,628
    edited February 2008
    You just don't get it and it's not worth pursuing this any further. You are giving out totally wrong advice based on some idiotic notion which is proven by speaker designers (no less). You are more a troll than a help here.

    It's like the Pioneer ad years ago of a fat, hairy guy wearing a thong standing on a diving board that read, "Just because it fits, doesn't mean it looks right".
    Richard? Who's your favorite Little Rascal? Alfalfa? Or is it........................Spanky?.................................Sinner.
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited February 2008
    Not everything is finite and can be explained. You have to try it to hear the results.

    Do you think Matt Polk or Bob Carver used a textbook when they were designing their speakers and amps? I'll bet a lot of it was trial and error. Where do you think the phrase came from.

    If you're afraid of failure, you'll never accomplish anything.
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  • SpeedyFE
    SpeedyFE Posts: 143
    edited February 2008
    I would hate to get in the middle of this, but I really appreciate the information. It seems though that "tweaking" the x-over seems to be a safe thing to do. Does anyone have schematics on this or more info?

    Paul
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  • avguytx
    avguytx Posts: 1,628
    edited February 2008
    candyliquor35m wrote: »
    Not everything is finite and can be explained. You have to try it to hear the results.

    Do you think Matt Polk or Bob Carver used a textbook when they were designing their speakers and amps? I'll bet a lot of it was trial and error. Where do you think the phrase came from.

    If you're afraid of failure, you'll never accomplish anything.

    Yeah, but they have EE degrees so they would know not to do something idiotic. I'm not afraid of failure...I'm quite successful actually. Crossover design is a science. Not sticking something in and "seeing if this works". Well, maybe you do that...but not the real world.

    Hey, here's one for you. Pull the cap out and put in an inductor and get back with us and tell us how good that sounds.
    Richard? Who's your favorite Little Rascal? Alfalfa? Or is it........................Spanky?.................................Sinner.
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  • SpeedyFE
    SpeedyFE Posts: 143
    edited February 2008
    What is the tweeter that came after the SL3000s?
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited February 2008
    One of my favorite phrases is "When you think you know everything there is to know about the business you're in, it's time to get out of that business.".

    Why? Because such an attitude stifles your innovative and creative capabilities and your competitor will come along and try something that's never been tried before and run you out of business.

    I'll bet Matt and Bob would be some pretty depressed guys if they didn't let their mind wander into new and uncharted waters. This isn't that different and just because you've never heard of it or tried it, you are discounting it without even trying it.

    When I hear of something new to try and it's not dangerous or expensive, I can't wait to try it.
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  • candyliquor35m
    candyliquor35m Posts: 2,267
    edited February 2008
    SpeedyFE wrote: »
    What is the tweeter that came after the SL3000s?

    SL2000WC
    SL3000WC I haven't tested yet but since the sl3000 isn't my favorite tweeter, I'm not in a hurry to test it with caps.
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