KP-301 (3.0B) Crossover - What is this?

[geoff.]

[geoff.]

Is this it? This little tiny capacitor looking disc paralleled with the resistor? (Yes, the crossover in the picture is from the KP-320, but it is the same part according to the respective schematics.)

 

Is it “necessary” and can something else be substituted? 

 

Is this what is referred to as a polyswitch?

 

 

[Marvel]

It's a polyswitch, used to protect the tweeter from overvoltage. You can remove it if you want... just don't overdo it on the power.

[geoff.]

Thanks!

 

That is great news, one of the ones on the 301 crossover is scorched.

 

Do I leave the parallel 200 ohm resistor in place or does it come out too?

 

 

[captainbeefheart]

You need to take the resistor out if you are going to take the polyswitch fuse out.

 

The polyswitch is of very low resistance when at it's normal operating currents, when a fault is detected by increase in current the polyswitch increases it's resistance to reduce current and protect the tweeter. When the polyswitch is at normal current and normal operating conditions of low resistance it being in parallel to the 200 ohm resistor will pass almost all of the normal operating current. If you just remove the polyswitch you will have 200 ohms in series with the tweeter seriously reducing it's output to almost nothing.

Edited November 8, 2021 by captainbeefheart

[OO1]

38 minutes ago, captainbeefheart said:

You need to take the resistor out if you are going to take the polyswitch fuse out.

 

The polyswitch is of very low resistance when at it's normal operating currents, when a fault is detected by increase in current the polyswitch increases it's resistance to reduce current and protect the tweeter. When the polyswitch is at normal current and normal operating conditions of low resistance it being in parallel to the 200 ohm resistor will pass almost all of the normal operating current. If you just remove the polyswitch you will have 200 ohms in series with the tweeter seriously reducing it's output to almost nothing.

 

 

5 hours ago, geoff. said:

Do I leave the parallel 200 ohm resistor in place or does it come out too?

I would replace the faulty RD050  Polyswitch or both the Polyswitches ,(peanuts in terms of cost   could be 1$  https://www.digikey.ca/ )  to restore the Protection circuit of the network  

[Blvdre]

or you can just clip it out, leaving as much of the leads as possible. Form a couple of j-hooks, connect and solder, and you're done. No need to move the 200 ohm resistor of you go this route.

[Dave A]

What you need to do is replace the polyswitch and leave the resistor in there. Blvdre is giving you the right way to do this.

[geoff.]

First off, thanks for all of the replies!

 

Where would I get a polyswitch? From Klipsch?

 

 

[OO1]

any place that sells capacitors would have polyswitches , 

[Dave A]

This should work.

 

https://www.erseaudio.com/Products/Polyswitches/R60-050-L

[OO1]

I believe @geoff. is Canadian -no point in paying customs- duties - taxes -shipping for about 50 cents Can$  of polyswitches he can buy locally in Ontario-

[geoff.]

@RandyH, have you been going through my mail? Lol.

 

I just recently received my Canadian citizenship in the mail!

 

Until then I was a landed immigrant. Moments away from deportation, NOT, the Canadian economy would collapse without my tax contribution, lmao. 

 

Fitting story on Remembrance Day here.

 

My father was in the USAF and my mother in the RCAF when they met at a dance in France, for real. Fell in love, got married and moved back to the States. 

 

I was born on a USAFB to a Canadian mother while my dad was an air traffic controller in Viet Nam.

 

A few years after his second tour was over we all moved up here to be closer to my mom’s family.

 

My father was the proudest American I have ever met.

 

 

 

 

[OO1]

On 11/11/2021 at 10:37 PM, geoff. said:

@RandyH, have you been going through my mail? Lol.

 

 ........