So I went ahead and bought some used 50’s Sprague Bumblebee caps (.022) off eBay just to see if I could hear a difference. Supposedly, they were measured to be within range and since I don’t have a way of measuring them, I took a gamble. Didn’t pay a huge sum (I think they were like $30.00 for the pair), fired up the soldering iron and installed in a matter of seconds. My basis for comparison were the Gibson fake bees, RS PIO “guitar caps” and the Mojotone Vitamin Ts. I thought the RS PIOs sounded a bit better than the Vitamin Ts; Vitamin Ts had a better taper than the fake bees. Not a huge difference among all of them, but since I had them I could choose. So it was the the vintage bees vs. the RS PIOs. All of this going into an R8 with good pots/wiring, 50’s wiring, played though a high quality short cable into 3 amps (tested separately): Fender DRRI, Swart STR Tweed and Supro 1616T. Not exactly scientific, but good enough for me. To be honest, I was skeptical. There’s the rational part of me that understands the logic that every engineer will offer: a capacitor does the same thing whether it’s PIO, ceramic or Mylar, as long as the values are the same. You should not hear a difference. There’s also a part of me that believes that some things defy logic. All I can offer is that I’m told I have a pretty good ear and I can usually hear things if they’re there. The vintage bees sound a little “smoother” than the RS caps. I notice a difference in the taper; the range of usable tones now seems to be “wider”. It’s now from 8 1/2 to about 5 on the guitar’s tone control when comparing the bees to the RS PIOs, which was more like 8 to 6. This probably means the cap has veered off .022. Which could/would happen anyway if the caps were still inside a guitar from the 50s. What I thought was interesting was that the tone knob has a little less noticeable effect on the volume (as 50s wiring typically does) than before. I’m not sure this sounds better, but I can hear a difference. Not a huge difference, but it’s there. Would anyone hear any of this at stage volume or f’ing care? Hell no. How the tubes in my amp are reacting to the temperature will probabaly have more noticeable effect on my live tone that these caps ever will. It’s all corksniffing. But I’ll live with these bees for a while to see how I feel. Anyone else care to share their Bumblebee cap experiences?