Upgrade X-over on Monitor 12?

[plastic_avatar]

I see all kinds of X-over upgrade talk about the 10's and 7's and SDA's and everything in between... but I can't find anything on the 12's, yet :(

Can it be as simple as looking at the schematic and throwing new caps and whatnot in?

I know that's a pretty simple-minded question, but I'm new at this vintage speaker thing :D

(I bought a pair of Monitor 12's Series II for $19 at the local Salvation Army (great shape overall, but one box was missing a tweeter, and the other tweeter was 'crusty' on the edges), bought 2 replacement SL-2500's off of ebay 2 days ago for $54, and figure what-the-hell, why not see how much it would cost to re-do the X-overs *before* I get the fever and order the RD0198's.)

[ShinAce]

The cost will depend on the quality fo capacitor you go for.

Obviously, tossing the cheapest non-polarized electrolytics in the wrong place won't help. Likewise, putting foil caps everywhere will cost an arm and a leg.

Yours might or might not have the polyswitches. The switch adds a capacitor to the crossover.

The cap for the woofer won't gain anything from a good cap. This one is 16.4 uF and should be replaced since it's electrolytic(most don't age that well). Myself, I'd be on the fence about using another electrolytic since it's a small enough value(16.4uF) and low voltage(50V). If you do go better on this one, realize that the speakers will probably disintegrate before the new cap goes bad. Feels like putting a new engine in a car rusted with holes.

The tweeter has two major caps. One is 12uF and electrolytic as well. You can upgrade this to something better, but don't go overboard. The other cap on the tweeter is 12 uF and already of decent quality. Replace this with what you can afford.

All values stay the same unless there's an adjustement for the replacement tweeter that I missed. Electrolytic caps usually have a different shape. They won't be perfectly smooth cylinders(like the good caps), they have a ring depression at one or both ends. They also sometimes have NP(non-polarized) written on them. The fact that a cap has to say it's the non-polarized kind does not instill confidence ;).

p.s. Welcome to Polk.

and good luck!

[plastic_avatar]

Excellent.

Thank you for the info :)

I'm going to give everything a good cleaning/inspection this weekend, so I'll check the x-over pieces then. I guess I might as well check the innards of my 5jr's, too.

Danke, Shin!