by michaelm Sat Mar 26, 2011 12:25 pm
I went with the coupling cap replacement mod for the 1 mfd caps and the results have been very plentiful in my system. I upgraded the stock caps with Mundorf Silver and Oil, and the PAS 4 now sounds extremely open with a much darker background. I cooked the Mundorfs on a Marantz solid state amp with FM radio fuzz for 150 hours to burn them in. Some of the results I noticed right off the bat are as follows.The stage is larger and more dimensional. The bandwidth is a lot more linear. The resolution is much more accurate and detailed. There is a lot more spacial aspects to the music. My system now has a much more laid back and natural feel to it. The list goes on, but all in all the preamp just sounds even more amazing than it did before. I think this modification would help it to stand even firmer with higher priced preamps.The caps cost 95 or so dollars from Madisounds, but I can equate the sound quality gain as being just as big of an improvement as going from an entry level Movign Magnetic Cartridge to upgrading to a three hundred dollar Ortofon 2M Bronze (that I got within a couple of days of doing the modification.) I recorded the same songs' beginnings from the tape output and from the main output for my ST 120, and even though both of the outputs have different circuitry paths, I still feel that the differences are so vast that the caps are the main reason for the increase in fidelity. To further reduce any ideas that one may have on the improvements being subjective, my girlfriend that is hardly a fidelity enthusiast noted that she definitely heard an improvement with the Mundorfs. When she doesnt hear much of an improvement she usually just looks at me blankly and tells me that she cant tell a difference. Hah. I am really happy with the results minus one little road block. The Mundorf caps had larger leads coming out of them than the holes in the circuit boards would allow. I had to use a tiny file to shape them to where they would fit. I suggest replacement of the coupling caps with higher end caps for any preamp that it is possible on. Different caps have different presentations, so if you consider a mod like this, look into them for a while and research to find out what would sound best in your system. I chose the Mundorfs because a lot of the info suggested that they would help balance out my system. Music sounded a little too analytical and mechanical, before, and these caps really made it more 'musical' WHILE adding more detail. I am extremely happy with Bob's suggestion now that I have applied it.
