After the modifications I posted a while back (Black Gate input coupling cap, Hyperfred rectifying bridge, bypassed volume pot, Cree SiC Schottky switching diodes, upgraded binding posts and RCA jack) I did one final mod - replacing the output coupling cap (.68uF stacked film) with a .68uF Multicap metallized polypropylene (after some prodding by GBB - thanks!). I reported initially that the modded Moles were more forward in the treble than the stock, and that was true, until I changed the output coupling cap. Now they are just about perfectly balanced to my ears - the last upgrade brought out significantly more bass than I was hearing before, and the Moles now sound pretty much perfectly balanced to me. My hypothesis is that the other upgrades improved the higher frequencies and the bass equally, but the inferior output coupling cap did not let the improved bass through to the speakers. I think the upgraded cap has opened the door and let the bass come out as well as the higher frequencies, resulting in a more balanced presentation.
Bottom line: I'm thrilled with how these little wonders sound now with my Zu Druids - so much so that I'm now contemplating upgrading the preamp and source. I guess it never ends once you get a taste of really good sound!
