Changing resistors and capacitors
SilverDove,
Changing the resistors and capacitors may make an audible difference in the sound of your SX series receivers. Whether or not you will hear a difference will depend on a number of factors. First, if an existing component has drifted off value, failed, or become leaky (capacitor) new components could fix a problem that may not be obvious. i.e. The unit still plays but is not quite right. Second, how keen your hearing is and how sensitive you are to small changes in sound quality will determine if you hear the differences. Some AudioKarma members seem to be much more sensitive to changing components within a unit than do others.
I recently replaced all the electrolytic capacitors in the signal path and power supply of my H H Scott Stereomaster 342 (circa 1969). In addition, I replaced with modified value closely matched components the equalization resistors and capacitors in the RIAA section. This improved the accuracy and channel balance and in that critical signal path. In the process of changing the coupling capacitors in the tone control and amplifier section, I doubled all the capacitance values. This added an octave to the low frequency bandwidth of the amplifier. I found that these changes to be worthwhile and I am now enjoying the 342 more than ever.
Since there are a lot of components in a Pioneer SX series receiver, I would recommend the following procedure. First, replace the components in the phonograph section. Since this section adds gain and noise not found in the other inputs it will be most sensitive to any changes you make. Second, listen to the results. If you do not hear improvements stop right there and save yourself a lot of trouble. If you do hear worthwhile improvements then proceed to the preamp section, replace and listen again.
BlackGate or Panasonic capacitors? I would try both listening carefully to see if I could hear the difference. If I could hear the difference and felt that it was significant enough then I would spend the extra money for the BlackGates. If I could not hear significant differences then why pay more? Your ears will tell you if these changes are worthwhile. Good luck and good listening.
tcdriver