sda 1c

transamz

just became polk man purchased a pair of sda1cs for 275.00 from an older man who said they were purchased by his son who got married and moved away.they are beutiful speakers and the sound is magic .i have a little problem ,they seem to shut down or the sound gets muffled at high volumes or 12:00 on the receiver which is hk avr 45.when i turn it down to 9:00 they sound perfect, what gives newwbie.thanks

jdhdiggs

In my limited experience, it sounds like an amp issue. Do you have any other electronics to test out the speakers on?

transamz

i have a vintage jbl sa600 rated at 40 watts per channel and i get the same problem. i think i need more power.help!!!!

VR3

Sounds like the tweeter protection circuit ---

The highs shut off right?

Yeah, protection switch thing I believe

transamz

i cant tell if tweeters stop because i turn every thing off quickly ,i dont want to damage any thing prematurely.the soud just goes muffled and volume decreases rapidly.ill let it play a little longer and listen to the tweets.

transamz

vr3 you were right tweeter in left speaker shutn down right plays fine but it effects overall sound, what is the fix for this any help would be greatrly appreciated.

VR3

Call Ken at CS -- he has a fix I believe, but it involves soldering - not sure, call Ken at CS

Emlyn

I remember the days I used to damage equipment by abusing it, but that was fortunately a long time ago and I was abusing crappy gear as a teenager anyway. If your speakers didn't have an abuse protection device you may have blown the tweeters, maybe the mid-woofers, and maybe the damaged the crossovers before realizing what was happening. The speakers may or may not be damaged now, because it sounds like you've experienced the shut down more than once. Stop what you're doing and get a more powerful amplifier. The JBL was worse than your receiver.

Until you do get more power, keep the volume level down. On the bright side, if the speakers are damaged, you can buy replacement drivers from Polk through this Web site, but it defeats the purpose of getting a good deal on some great vintage speakers if you have to replace the parts with non-original parts. The tweeters are no longer manufactured, but they may be available used, or similar replacements are available from Polk.

The AVR45 is rated 65 watts per channel in stereo mode. The AVR45 is rated to power speakers with 8 ohm nominal impedance minimum. Damage to audio equipment is almost always caused by underpowering speakers and demanding too much of an amplifier.

On any receiver with the old style volume control knob, turning the volume up to the 12 o'clock position should be considered the maximum safe volume level for that piece of equipment to be used, even though the knob will keep turning to the right. 9 o'clock is usually moderate level.

By running the receiver at high volume you were causing the receiver's amplifier to clip, sending a distorted signal to the speakers that caused the tweeters to overheat and causing the thermal protection device to trip. Do a search on the word "clipping" in the forum for much more information.

The SDA 1C is a 6 ohm speaker with MINIMUM power requirements of 50 watts per channel. The suggested amplification range is 50 to 500 watts per channel. You'll need a minimum of 100 watts per channel in real world use. 200 watts per channel seems like it would be a better match for your listening habits. A two channel used Adcom amp is usually a good starting point. Figure on spending around $500 to get suitable gear (preamp plus amp) to use the 1Cs decently.

Good luck.

dorokusai

It may in fact be the polyfuse protection circuit. It will create the condition you are hearing if it is tripped.

I presume that if you turn the volume down, or turn the stereo off then on....that all is well?

They get more sensitive over time when pushed into protection mode. Contact Polk Customer Care for more information on the replacement.

kswauger@polkaudio.com

It could also be the amp, just letting you know some more information.

transamz

thanks all who responded to my problem, i think its the polyswitch at low volume every thing is just fine. i will email ken to try to get the switch,just wondering if this a beginner fix or should i let the pros make the replacement of the switch.thanks all once again im glad to be a polk man, im hooked!!!!!

dorokusai

It is a very easy part to replace, just basic soldering involved. Ken will square you away with all the information you require for replacement.

F1nut

While I agree that you need to change the polyswitches in both speakers, Emyln has hit the nail on the head, you are overdriving the receiver. I would say that the 10 o'clock to MAYBE the 11 o'clock position is as high as you should turn it up. Even if you do get a 200 wpc amp with a pre amp you can not just keep turning it up without regard to clipping, which will still occur around the 11 to 12 o'clock position. You have great speakers and it's your duty to respect them.

madmax

Originally posted by F1nut
You have great speakers and it's your duty to respect them.

F1 speaks the truth. Keep the following in mind while you play with these. The SDA 1C speakers were sold for around $1500 (I cannot remember the exact price right now) but in my opinion could have sold for a LOT more. It is one of my favorite SDA speakers. You are driving them with a fairly cheap receiver that cannot make them sound anything like they should. I'm talking about quality and volume. I would go ahead and replace the polyswitch and keep the volume down until your system grows. The 1C's will take you as far as you want to go until you hit the top of the audio system food chain. Although I hate to associate a price with audio components I will anyway just to give you a feel for what you have. The 1C's are very at home with a $5000 system and will keep up with you beyond $20K with the best amplifiers, preamplifiers, CD players and turntables. They are NOT a $275 set of speakers. Even with the highest class components you will find that to replace them you would have to spend more than $5K. In my opinion you have about the best speakers you can ever hope to have. I hope you feed them well with equal quality equipment in the future.

madmax