After reading the article on capacitor linearity, I decided to purchase vintage new old stock paper and oil capacitors from Nebraska surplus sales and replace the ceramics from Goff professional. I replaced the vibrato line box with polystyrene (these sound very close to paper and oil) because I couldn't find the correct value in paper and oil. I used Gudeman paper and oil for the tone generator and the sound was improved immensely compared to ceramics or even the polypropylene capacitors they produce today. There is clear definition yet with smooth creamy sound throughout the entire range of tones. It is not muddy on the low end or harsh on the high end. I also replaced the paper and wax capacitors in the AO-28 with Sprague vitamin q's with the same value and voltages.
There are articles on the internet where "experts" tell you not to use vintage capacitors stating they are unreliable, poor tolerance, etc. I have found that the capacitors I purchased are very high quality well made pieces made in a by gone era (many are unused military surplus). Their tolerances were within a few percent if not exactly the value printed on them (much closer than the ten percent they are rated).
-You do not need perfectly matching capacitors for the tone generator, you will not be able to hear the difference. However, because the organ was calibrated with the old paper and wax the tolerances will not be the same and some tones may be louder than others. I do not recommend recalibrating the entire tone generator (you could do more damage than its worth) only the few tones that may be significantly too loud/soft. If you decide to recalibrate the entire generator, at least, take voltage measurements before making adjustments, that way you can go back to them if your new settings are unsatisfactory. I found that the original calibration works perfectly fine
with the replacement pio's (only one tone is a little
louder than the rest and its not worth the bother of loosening the magnet and pulling it back
). It is possible these capacitors will degrade in sound like the paper and wax sometime in the future, but I will probably be dead by then.
+You do not need perfectly matching capacitors for the tone generator, you will not be able to hear the difference. However, because the organ was calibrated with the old paper and wax the tolerances will not be the same and some tones may be louder than others. I do not recommend recalibrating the entire tone generator (you could do more damage than its worth) only the few tones that may be significantly too loud/soft. If you decide to recalibrate the entire generator, at least, take voltage measurements before making adjustments, that way you can go back to them if your new settings are unsatisfactory. I found that the original calibration works perfect
with the replacement pio's.
(No notes were softer/
louder after recap with this particular organ
). It is possible these capacitors will degrade in sound like the paper and wax sometime in the future, but I will probably be dead by then.
* Note** Newly manufactured paper and wax and paper and oil made for high end stereo such as Ampohm, Jensen, Jupiter, etc. should not be used in any of these circuits. I tried them in the AO-28 before and I could hear generator noise because these types of caps are very detailed and are not designed for filter circuits. When I realized the mistake I made I put in the vintage vitamin q's and solved the problem. The manufacturer's actually tell you this in their spec sheets but I ignored their warning and wasted $100 bucks on four capacitors.
My Leslie 122A also received paper and oil caps replacing the polypropylene it came with (I did wait till the warranty expired, not that that really matters) and this improved the sound of the Leslie.
