Polk Audio SDA SRS 2 sound scratchy now
BarryShatswell
Posts: 7
Hi, I'm the original owner of a pair of SDA SRS 2 purchased in 1986. I drive them with a Carver Preamplifier and A-500x since about 1995 at moderate to low levels. Today, I power up the system and both speakers sound scratchy. Both channels. I tried swapping out amplifiers to three others, 2 vintage and one new and while they sound different, the same scratchiness is there when the drivers are anything about a very, very low level. About 10 years ago, I replaced the 4 main drivers in each unit with the same kind directly from Polk.
What could be the problem? I have the original tweeters and crossovers, is that the problem?
Any advice is appreciated.
What could be the problem? I have the original tweeters and crossovers, is that the problem?
Any advice is appreciated.
Answers
-
Usually distortion is caused by defective tweeters or midrange drivers. Which components are making the scratching sound?
-
I have just done some testing. The right channel lower end through mid is causing the distortion. On overall balance, the right channel is louder than the left on the high end.
-
Not the SDA pair, the main drivers on the right sound buzzy
-
Slowly push in on the driver around the outside of the dust cap evenly with 3-4 fingers. See if you feel scratchy feeling, if so STOP. It it feels hard to push in STOP you may have a shifted magnet that is either touching the voice coil or impeding it (locked up.
-
You were right. I have two on the right that are scratchy and one on the left. Can I unshift them or should they be replaced?
-
You can do both, it may not be something you may be comfortable doing. What are the midwoofer numbers? Back of the magnet will be a MW65xx number that number will determine the ease of getting another driver.
-
Looks like they are all MW6511.
-
Interesting. I pulled all three of them to examine them. I could not see anything wrong, but their movement was obviously constricted with some rubbing inside. I played with them a while and tried to see if the rubbing would occur as I turned the drivers around. I found that they hardly rubbed at all in one position. I put them back in the cabinet with the new up position and now they don't rattle as much. I know, it's probably a temporary fix. I wonder if there is a more permanent fix or replacement option. A quick search on eBay didn't show anything currently for sale of MW6511s. I need a minimum of three. Is there a third-party site for these or do you think Polk still carries them? Or, even better would be a way to fix these drivers.
-
Brian
One-owner Polk Audio RTA 15TL speakers refreshed w/ Sonicap, Vishay/Mills and Cardas components by "pitdogg2," "xschop" billet tweeter plates and BH5 | Stereo REL Acoustics T/5x subwoofers w/ Bassline Blue cables | Rogue Audio Cronus Magnum III integrated tube amp | Technics SL-1210G turntable w/ Ortofon 2M Black LVB 250 MM cart | Sony CDP-508ESD CD player (as a transport) | LampizatOr Baltic 4 tube DAC | Nordost & DH Labs cables/interconnects | APC H15 Power Conditioner | GIK Acoustics room treatments | Degritter RCM -
Thank you. I read through it and think I would prefer to buy new ones. I'll call Polk on Monday and hope they have some in the warehouse.
-
BarryShatswell wrote: »Thank you. I read through it and think I would prefer to buy new ones. I'll call Polk on Monday and hope they have some in the warehouse.
Nope. Not for many years. Your only options are a saved search on eBay and/or repair the ones you have. It may seem intimidating at first but many here have done successfully.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
In case you're on a mobil device and can't see it, @lawdogg (author of that post I linked you to) offers to fix shifted magnets in his signature. That would be the route I would go.
Brian
One-owner Polk Audio RTA 15TL speakers refreshed w/ Sonicap, Vishay/Mills and Cardas components by "pitdogg2," "xschop" billet tweeter plates and BH5 | Stereo REL Acoustics T/5x subwoofers w/ Bassline Blue cables | Rogue Audio Cronus Magnum III integrated tube amp | Technics SL-1210G turntable w/ Ortofon 2M Black LVB 250 MM cart | Sony CDP-508ESD CD player (as a transport) | LampizatOr Baltic 4 tube DAC | Nordost & DH Labs cables/interconnects | APC H15 Power Conditioner | GIK Acoustics room treatments | Degritter RCM -
If you've not JB weld epoxied your drivers yet I suggest you get to doing the ones that are not affected yet. Tedious but needs done, take your time.
-
^ What pit dog said.
I wouldn’t play the speakers with that shift. Means the contact cement they used has broken loose.
Playing them can and will damage you voice coils. If that happens you’re looking at a problem much worse than having the magnets re-centered.
There’s some folks who who’ve done the fix and you may get lawdogg to offer his services to repair them.
I recommend that approach as you know what you have vs someone else’s drivers.
