Old Thread; New Member!
As everyone has already replied, "mfd" = "uF" = "microFarad" which means the value has an exponent of 10 raised to the -6 or 1/1000000. In engineering documents, they use the symbol mu (see
https://en.wikipedia.org/wiki/Micro-) which is a greek letter that looks like a little M with long sweeping legs. Since traditional documentation doesn't support the greek alphabet, they use "mfd" as a short notation for "microfarad" and "uF" to indicate the "head of the mu" and F to indicate "Farad". (I realize nobody cares... but wanted to provide some basis for feeling "comfortable" with the disconcerting notations! No different really than if you were looking up pipe notations for your household plumbing).
ANYWAY... the REAL reason I'm replying here is to say THANK YOU to all of you contributors for leaving your experiences here! I'm leaving a few thoughts and comments of my own while I restore my T-300s -- as I've been lucky enough to be the single owner and I'm only interested in "refreshing" my basically already excellent condition speakers.
I found Erse yesterday while scouting out CAPS just before finding this site ... and they have 5% tolerance CAPS that are peer-priced with the PartsExpress 10% electrolytics (which others have measured the PartsExpress CAPS at +11% tolerance). But "why electrolytics" you ask? If you search the web you'll see that there's discussion that, if you don't know the detail to which the original designers used to create their cross-over networks, the equivalent circuits of other technologies like the Metalized Polypropylene CAPS may shift or off-center your passbands. While that may not matter on the T-300's due to the Lpads that allow you to vary the passband, and the given benefits (longevity; tighter tolerance) of the Metalized Ploypropylene -- it does raise the question: who's done a juxtaposed test after burn-in of new "different technology" CAPS to determine if the extra costs merit the audible rewards? You're almost certainly going to need to update the foams in another 10-20 years... how much beyond renewal is hype and reward? I'm hoping that some smart and tenacious consumer will follow that path for the rest-of-us!
Anyway... this post is not to ridicule anything or anybody.. because without the questions, suggestions and lessons-learned shared by everyone else on here -- people like myself, engineer or not, are at best "bumbling fools."
Respectfully Yours,
jj
