Quote Originally Posted by johnsonad View Post
A comment on another thread lead me to starting this one. As most people feel their original inductors superior to after market versions I thought it would be interesting to list out measured values as a comparison for the archive.

These are the measurements from one of my stock crossovers and of the replacements. Stock were measured with a BK 875A and BK 2890A. Replacement with a bridge meter by North Creek and the BK 2890A for resistance.

Stock:
L1, 0.18 mH, 0.04 ohms
L2, 2.43 mH, 0.37 ohms
L3, 0.61 mH, 0.12 ohms

Replacement (North Creek Music 8awg air core)
L1, 0.30mH, 0.07 ohm
L2, 2.62mH, 0.28 ohm
L3, 0.77mH, 0.14 ohm

Stock total resistance: 0.53 ohm
Replacement: 0.49 ohm

The total difference in inductor resistance is trivial. As a mentor of mine expressed, you can always add resistance.

As far as the total crossover goes, it makes sense to have closely matched values vs. the 20% deviation as one member stated that Altec might have used. My goal is 1% matching between parts on the externals I'm building. Once finished and burned in for a while I'll post some listening impressions.

WRT to 20% tolerances is WRT the Model 19 Crossover which was from the mid seventies early eighties I'm sure that improved as the components got better Capacitors,inductors,etc...

Personally I prefer iron core to air core is there any difference in sound "Who Knows" but to my ears I think there is, they just sound better to me IMHO.As other members have noted that when they replaced their inductors with air cores sound changed.When the old Altec Iron Cores replaced it also brought back the Altec Sound !! The rule of thumb here is go with what sounds best to you.As music is nothing more than personal preference you can't get any more Individual than that IMHO. :2thumbsup:


Best Regards !