Klipsch and Capacitors

If the capacitors no electrolitic , no make sence ,  enjoy keeping

Probably not on that model as the only electrolytic cap is on the woofer.

I'd play them for 200-300 hours and then consider updating the tweeter diaphragm's (Titanium?) if more clarity/less bite is desired.

After that maybe the crossovers starting with air-core inductors.

DeKay

Leave the speakers alone. Some playing time to loosen up the drivers is all you need.

Thanks for the advice! 

+1 for only electrolytic caps are likely to wear over time.  

There's a large cap on the woofer.  If that's electrolytic you should be careful replacing it with a modern as the difference in ESR may be significant.  

For the tweeter caps I might suggest you try an Audyn 0.1uF TruCopper bypass.  About $20 each.  

@maprik ,  I have to ask.  How did a pair of KG4s go unused for 40 years?  I have 2 pairs BTW.

If it was me ALL the old stuff inside would be replaced with modern components.

Crossover

Terminals

Wire

Add additional dampening if needed.  But heck, that's the way I am.

Hello maprik!  Almost every company uses cheap parts in their crossovers. Replace just about everything in the crossovers, except maybe the board their on, with high quality parts.  Avoid ferrous metals anywhere in the signal path, including the connectors on the speaker wires. Test everything with a magnet, even the nuts and washers on the binding posts. It may sound exteme, but you will be pleasantly suprized if you do it. Be prepared to spend $100 or so for each of the left and rignt speakers. (If you have a surround sound system, do 'em all as finances allow.)  I recently upgraded all the steely bits in a four way system and was stunned at the improvement. Enjoy the music!

An old UNUSED speaker in a box for 40 years, wow...

if you are handy, i would replace the Caps with Mundorf with the same value

and might as well replace the resistors too (Dale) and listen.

But as others have recommended. Listen to it First for at least 24 hours and notice if there is distortion or any anomalies in the sound. once that is Good to go, then do the parts replacement.

just my 02cents 

@audiostick Apparently the owner owned 2 pair. His son who is a good friend recalls KG4s being in their living room for as long as he can remember. His father passed away and in preparation for the Estate sale he found the unopened KG4s in the attic. Im considering purchasing them. 

Buy them  - they are fun.

I had a thrift shop pair maybe 20 years ago and they sounded good with my  Bottlehead 3 watt amps as well as an old NAD 20 watt receiver.

I didn't have low stands so I put small blocks under the fronts to angle them up (probably not ideal, but they sure filled the living room with sound).

DeKay

I probably will just for the investment but I don't think the KG line is going to increase in value like the Heritage...

At the very least, any electrolytics should be replaced.

Even unused, they age and will no longer meet tolerance. Not to mention, that electrolytic caps just don't sound good.  

But, as one who has upgraded more vintage, and not so vintage speakers over a couple of decades, I can state with near certainty, that caps do make a difference in sound quality. 

A friend and I used to have a part time, cottage business upgrading and fixing vintage speakers here in the L.A. area, and upgrading caps always made an improvement. 

This Ebay seller has a pretty decent recap kit available. Better than what came stock for sure. 

Recap Kit for Klipsch KG4 Speaker Crossovers 

But you could do better with even better caps, buying them on your own from 

Madisound

Oh!

Not sure who this slipped my mind, but this speaker company has prebuilt replacement crossovers, ready to go, in 3 different levels of improvement. 

But even the lowest level (Copper level) is better than the Ebay kit. 

Crites Klipsch Crossovers