I have an original pair of Polk SDA SRS speakers (the ones with eight 6503 dirvers per cabinet.) The dates on the crossovers are 10/29/86 and 1/22/87 respectively. Unfortunately, the pair I have consisted of two left speakers and Ken kindly supplied me with the wiring schematic so I could convert one of the left speakers to a right speaker.
I performed the change out and have the following issues:
1) The balance only seems to work on one side with respect to the SDA drivers. Basically, when I turn the balance all the way to the left the left speaker plays normally and the right speaker's SDA drivers play less loudly. When I turn it all the way to the right, the right speaker plays normally, but there's hardly a peep from the left side. I'm guessing that it's a crossover issue in the right speaker but what to do?
2) When I have the volume up, there is a slight, but noticable hum coming from the right speaker without any music being played. No such thing on the left side. Any ideas? They still sound good when music is played.
3) The lowest tweeter on the right speaker is blown or it's yet another crossover issue. I haven't tested it against another tweeter. The other three in the same cabinet appear to be just fine.
As a final note, the wiring diagram calls for the interconnect cable plug to be modified as follows: the left channel should have pin 1 connected to the oututs of the 130 microfarad capacitors (green wire and broad blade?) and pin two connected to 2.75 mH coil (black wire and thin blade?). The right speaker sound be the mirror image. I had to do this work during the conversion. I'm guessing that this has little to do with the problem, but perhaps I'm sadly mistaken. Honestly, which pin is 1 and which one is 2?
Finally, I noticed that the drawing was revised in 2/87 and a 92 microfarad capacitor was added in parallel to a 2.7 ohm resistor. Any thoughts why? Is it worth doing the modification? Are there any other upgrades that are worth doing to these speakers?
I'd really like some help because I'm stumped! Any assistance would be greatly appreciated!