Amp Protection Kicks In Intermittently, But Only With SDA Cable Attached
Moofy
Posts: 102
OK, I'm stumped (but that's not hard to do).
I have a Luxman R-117 and two pairs of speakers, some VR3-modded Polk SDA 2s and Atlantic Technology AT-1s.
The Lux and AT-1s play great together.
When I unplug the speaker wires from the AT-1s and plug them into the SDAs, the Lux's protection circuit kicks in intermittently (i.e., the red light on the volume knob goes dark). I just retrieved the Polks from Speakerlab, and the tech there said he played them for half a day with no problems (although using another of my receivers, a Denon).
Before I took the SDAs to Speakerlab, they were tripping the protection on the Lux and the Denon within a few seconds of getting signal. Speakerlab found a bad tweeter in the Polks, which they replaced.
When I got the speakers home, they exhibited the same problem as previously, although sometimes they will play for minutes at time (rather than seconds) with no problem.
A little history: I modded the Polks back in December with the help of a great local Polkie. The speakers worked great for about four months. Then I got the itch for better amplification, the ordered a Teac integrated online. I was DUMB! I didn't check to see if the Teac was common ground (which it isn't!). That's when the problem started.
As I said, Speakerlab found nothing wrong other then the bad tweeter, which we replaced. And the problem only occurs when the SDA cable is attached.
I'm stumped. I hope some of you big-brained Polkies may have some hints or suggestions. Thanks.
Seth:sad:
I have a Luxman R-117 and two pairs of speakers, some VR3-modded Polk SDA 2s and Atlantic Technology AT-1s.
The Lux and AT-1s play great together.
When I unplug the speaker wires from the AT-1s and plug them into the SDAs, the Lux's protection circuit kicks in intermittently (i.e., the red light on the volume knob goes dark). I just retrieved the Polks from Speakerlab, and the tech there said he played them for half a day with no problems (although using another of my receivers, a Denon).
Before I took the SDAs to Speakerlab, they were tripping the protection on the Lux and the Denon within a few seconds of getting signal. Speakerlab found a bad tweeter in the Polks, which they replaced.
When I got the speakers home, they exhibited the same problem as previously, although sometimes they will play for minutes at time (rather than seconds) with no problem.
A little history: I modded the Polks back in December with the help of a great local Polkie. The speakers worked great for about four months. Then I got the itch for better amplification, the ordered a Teac integrated online. I was DUMB! I didn't check to see if the Teac was common ground (which it isn't!). That's when the problem started.
As I said, Speakerlab found nothing wrong other then the bad tweeter, which we replaced. And the problem only occurs when the SDA cable is attached.
I'm stumped. I hope some of you big-brained Polkies may have some hints or suggestions. Thanks.
Seth:sad:
Post edited by Moofy on
Comments
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Did the tech use the SDA cable when testing?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 -
Yes. I asked him several times.
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I see. I'm thinking you've got a shorting issue on one of the crossover boards. It could be as simple as a cold solder joint. I'd pull both boards and retouch every solder joint including the Molex blocks and the connections on the binding post plate. I would also check for loose wires/connections and for frayed/damaged cable jackets, that includes inspecting the wiring of the inductors. Be sure to confirm that polarity is correct from the binding posts (red + is on the left) to the board and then to all drivers. Black and blue wires are positive, white and green are negative.
I should add that when the non-common ground amp was used it could have easily sent enough juice into the speakers to cause solder joints and wire to melt. After all, it did take out a tweeter.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 -
Is the sda cable homemade or the one that came with it when they were new? Also when you modded you Polks is it did you re connect the wires correctly to the sda connector inside the speaker? Does it use a blade blade connector by chance if so I have seen people wire both speakers the same way and if you look at the print for the crossover pins A and B are flipped on the left vs the right cab. Just a thought.Absolute corruption empowers absolutely.
Lg 55LW5600 TV
Onkyo PR-SC 5508
Legacy Audio Focus SE
Legacy Audio Silverscreen HD center
Polk F/X500i Rears
Parasound HCA-3500
Sunfire Grand Cinema
Behringer iNUKE NU6000DSP
Pair of CraigSUB SS-18.1 -
The SDA cable is a custom one from Trey at VR3 Mods.
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Is the sda cable homemade or the one that came with it when they were new? Also when you modded you Polks is it did you re connect the wires correctly to the sda connector inside the speaker? Does it use a blade blade connector by chance if so I have seen people wire both speakers the same way and if you look at the print for the crossover pins A and B are flipped on the left vs the right cab. Just a thought.
A good thought at that.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 -
I would check the wall wiring and see if something is goofy seeing as your Denon played them for a half a day at speaker lab, but will only play for minutes at your place.
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I am talking about the with wiring inside the speakers. The SDA connector on the back of the speaker has 2 wires the left uses a black and a white one the black wire needs to be connected to small blade and the white to the larger. However the Right speaker is wired to where the white wire is connected to the small blade and the blue is connected to the large blade.
Trust me take a look at both and make sure this is done correctly. My friend took his in to be repaired and what they did was work on one at a time but they used one speaker to look at where everything was wired and the white wires ended up being placed both on the small blade and the black and blue on the large blade it caused the same issue your having.
Good luck.Absolute corruption empowers absolutely.
Lg 55LW5600 TV
Onkyo PR-SC 5508
Legacy Audio Focus SE
Legacy Audio Silverscreen HD center
Polk F/X500i Rears
Parasound HCA-3500
Sunfire Grand Cinema
Behringer iNUKE NU6000DSP
Pair of CraigSUB SS-18.1 -
Any progess?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 -
Even though this was a DIY kit you can ship them here and we will fix them under warranty...- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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Thanks to everyone for your advice. I'm in heaven right now, listening to my SDAs! Jake, the Polk magician who helped me with the mod, came over last night to help with troubleshooting, and found and fixed the problem. The SDA circuit in the right speaker was not backward, as specified in the schematic. What we can't figure out is why the speakers worked for 5 months with this condition, and how the TEAC non-common ground amp seems to have triggered the symptoms. At the moment, ours is not to reason why, but to listen to SDA hi-fi...bad poetry, sincere intent. The Polk community comes through again: you guys rock...and Jake is a true wizard. Cheers.
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That's great news, glad you got it resolved.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 -
Glad we got it fixed, and I'm still questioning what the speaker tech did with those speakers as nothing he said adds up. I enjoyed the short listening session with them last night and the upgrades you've put into those 2As sound great!
