SDA-1A Still Howling - HAD ENOUGH!!!
altecman
Posts: 52
As per previous post about the pair of SDA-1A speakers I picked up, there is still a very louding beeping/howling sound coming dfrom the speakers when I connect the interconnect cable. I replaced the VTL tube amp for an Australian built ME 750 (SS amplifier). This amp can play down to 1 ohm loads and has a 2KVA double c core transformer, 120 wpc into 8 ohms, 500 wpc into 1 ohm and is common grounded. I made up a cannon plug /cable for the 1-A's and after all of this I have had enough!!!!!!. Any ideas as I am at the point where I will throw this speakers into the skip.
Post edited by altecman on
Comments
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although not a current model speaker by Polk.. call Ken in customer service... he is the guy who can help you out better than any of us.
good luck. I have never heard of a speaker "howling" before. That in itself is odd.PolkFest 2012, who's going>?
Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin: -
danger boy,
The sound from the speakers is like something is out of phase causing a loud sounding medium to high frequency oscillating sound, that why I called it a beeping sound. You think if the interconnect cable is wired incorrectly the amp or speakers would short out. I was wondering if there was something in the xover that could cause this. -
Ok, seems like it's time to open up the speakers and have a poke around. Check that the polarity is correct from the IC connection to the crossover and then from the crossover to the drivers. Blue and black are positive. White and green are negative. Positive is marked on the drivers by a small red dot.
Can you take some nice close up photos of the crossovers and the IC connection inside the speakers?
Don't give up yet, we'll try our best to help.
There is also an SDA troubleshooting guide that is available. I think I have a copy that I could scan and email to you. I just have to find it, which may be easier said than done....LOLPolitical 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 -
F1nut,
Found SDA trouble shooting guide on the Net, took measurements and are all within specification. Made sure that Left & Right SDA connections are out of phase. Hooked up interconnect cable and still I get this very loud howling noise (no music) coming through the speakers irrespective of what level the volume control is set at.
I am at my wits end, anyone got a match!!!! -
I blew some SDA drivers up with a non common ground setup (Adcom 555II in mono mode). It sounded just like you described. If they are playing with out the interconnect in then either the cable is bad or the amp has a problem with common ground. Can you try another amp? The speaker don't break down right away.
Good luck,
engtazengtaz
I love how music can brighten up a bad day. -
my guess is the amp is the problem too.. to me everything should begin there for trying to solve this problem. Yeah if you have another amp, that you know is common ground.. swap that out. even if you have a receiver, that might help isolate the problem.PolkFest 2012, who's going>?
Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin: -
No doubt its the amp which is not common ground. I had a similar problem with the Adcom 5400 amp I bought which is not common ground and when I fired it up I heard an awful sound similar to what you described except worse. Adcom told me to run a wire across the black terminals on the back of the amp and it was fixed.
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Another vote for the amp as the culpritThe first rule of Fight Club is you don't talk about Fight Club
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No doubt its the amp which is not common ground. I had a similar problem with the Adcom 5400 amp I bought which is not common ground and when I fired it up I heard an awful sound similar to what you described except worse. Adcom told me to run a wire across the black terminals on the back of the amp and it was fixed.
that's odd, i never had your problem with my Adcom 5400.. i did blow a fuse in the amp one time though.. it just didn't have the balls for my SRS's. the yellow warning light kept flickering..PolkFest 2012, who's going>?
Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin: -
Thats kinda odd you did'nt have that problem because I sure did. The guys at Adcom were real helpful too and knew just how to solve the problem.
I am also thinking I need more power but will save that for another thread. -
danger boy wrote: »that's odd, i never had your problem with my Adcom 5400.. i did blow a fuse in the amp one time though.. it just didn't have the balls for my SRS's. the yellow warning light kept flickering..
Off topic, that's because it's a non-common ground amp. That amp should have had plenty of balls for the SRS's. I remember when you had trouble with that amp AL. Had you tied the negative terminals together I bet the yellow light would never have flickered unless you were playing it stupid loud. The fuse probably blew for the same reason (non-common ground).
To the OP, it sounds like it's amp related, but if your sure the amp is common ground I've heard of a couple cases where the pre-amp was the issue. I'd check all the connections inside and outside the speaker and if you can, make a second "test" SDA cable to rule the cable out.
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul! -
heiney9,
How could the preamp be an issue, at the moment I am using a home made passive preamp. When people talk about connecting the negative terminals of the amp's speaker terminals together is there any ill effect of this. I don't need to make another SDA cable as the one I made is of a good standard using military grade 3 pin cannon plugs and sockets and tested fine by a multimeter. -
heiney9,
How could the preamp be an issue, at the moment I am using a home made passive preamp. When people talk about connecting the negative terminals of the amp's speaker terminals together is there any ill effect of this. I don't need to make another SDA cable as the one I made is of a good standard using military grade 3 pin cannon plugs and sockets and tested fine by a multimeter.
I wouldn't tie the negative terminals together unless you contact the manufacturer first. Some non-common ground designs can do this other scan't depending on the internal architecture.
A completely passive pre isn't going to have an issue and if you are sure the cable is good then the best thing to do is call Ken on Monday. He is great, easy to talk to and extremely knowledgeable. If he can't give you an answer he will talk to Matt himself or one of the other big guns to get your situation figured out.
Polk customer service is second to none.
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul! -
Guys, he's in Australia.
Altecman, test your replacement amp to see if it really is common ground.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 -
The Polks are finally working OK. Talked to the amp manufacturer and he said that by tying the negative terminals together won't damage the amp. When I got home from work I put a jumper lead between the 2 negative terminals and low and behold all works fine now. There is only a slight buzz from the SDA tweeters when you put your head near them but that doesn't matter as I will remove a lead from the terminals as detailed in a previous thread as this will prevent the phasy sound that sometimes happens with certain types of music.
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Actually, it sounds like the speakers were working as advertised all the time and that you didn't have your ducks in a row vice the amplification. Glad that everything seems to be working.
BDTI plan for the future. - F1Nut -
You probably roasted that tweeter.
Congrats on finding the problem,
engtazengtaz
I love how music can brighten up a bad day. -
I'm glad the problem has been resolved.
A slight buzz with your ears a few inches away from the tweeters is normal.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 -
Throw them in the skip. I like that idea.Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
