What do I have?
irishjim
Posts: 2
Bought what I was told were Polk SDA 1C's that were supposedly original except for one tweeter being replaced. I was extremely happy with the pair I received. I have been a member here for quite some time. Although they sound good my plan was to rebuild the crossovers ASAP. I removed the first radiator to take inventory and what I saw didn't match the schematic for a SDA 1C. I remove the speakers and found each had a SDA SRS2 label.
Comments
-
Well first off we need more clear pictures of the drivers. It looks like from the blurry picture you provided it apyto be a mw6509. Those drivers were used in two models, SDA 1b and the first SDA SRS 2. If all the drivers are mw6509 and you have a blade/Blade interconnect socket then you have a SDA 1b. It appears to have a RD-0194-1 tweeter which is a good thing as the sl2000 tweeters are not highly prized. The RD-0194 is a better tweeter.
Also if your crossover is two boards then that also would point to the SDA 1b. -
That top tweeter "looks" like a SL2000 that someone painted black. Pretty low resolution photos so hard to zoom in and see what's what. That one driver looks like an MW6503 which was indeed used as the stereo driver in the SDA2B (the SDA driver was MW6511, MW6510, and MW6501 depending upon 2B, 2A, or 2). The 1C is supposed to have 2 x MW6511 stereo drivers and 2 x MW6510 SDA drivers.
What are the other drivers in your speakers? You only showed us the one. Is there anything else you see that you think is wrong or is it just that one driver?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 -
Those are 1B's with some sort of messed up 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 -
The srs 2 and 1c crossover are the same basically if I recall correctly, very minor differences if any- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
-
Yep main difference is the sda inductor- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
-
The srs 2 and 1c crossover are the same basically if I recall correctly, very minor differences if any
Yes but there are two incarnations of the SRS 2. One was built on the SDA 1b the other SDA 1c. Two different critters with two different sets of drivers. -
Agreed, we successfully converted a 86 srs 2 to an 87 with great results- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
-
Yep. I agree must be a SDA1B as others have said. And MW6509 (not MW6503). Looking at the pictures in the SDA Handbook, the driver spacings are different in the 1B vs 1C and the bottom panels are different. That's a 4 ohm impedance speaker so make sure you have good amplification that is compatible.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 -
Thank you to each and everyone of you that helped me recognize that these were in fact SDA 1B's. I acquired all of the parts to rebuild the crossovers and have in fact rebuilt the portion of the rebuild for the MW6509 drivers and MW6509 SDA drivers. I haven't acquired the Tweeter replacements yet and have held off on rebuilding that portion of the crossover. The diver portion sounds great. My dilemma is since my original tweeters test OK and sound very good. Is there a sound advantage to rebuilding the tweeter portion at this time. Film caps seldom degrade over time and the 750Pf's likewise continue to read as new. I have the parts but wasn't sure I had much to gain until I acquire new tweeters?
-
Rebuild crossovers there's a big difference
-
Not all "film caps" are created equal. Polyester (mylar) caps are smaller and have higher dissipation factor and dielectric constant than polypropylene caps. Polk used the mylar ones in the high frequency crossover circuit.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 -
Order the RD0194-1 tweeters today. Then order the rest of the caps and resistors. Do not use Dayton, Bennic or Solen caps. Vishay-Mills resistors are a good choice.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
