Need help identifying parts for crossover

[mustang guy]

I am reverse engineering the KP-201 type KP-2.0A network. Attached is what I have done so far, but I cannot identify with certainty 2 of the parts. One is a small ceramic cap, and the other is an air core inductor. Any and all help would be appreciated. The attachment is the current diagram, the photos are to help ID the parts.

Here is the cap. Is this a 5pF?:

Here is the inductor. I can only guess it's inductance:

Here are some misc pictures of the whole network:

edit: The attached schematic is WRONG. Having this incorrect schematic is pertinent to the understanding of this thread.

Edited April 26, 2014 by mustang guy

[Axz Hout]

x

[WMcD]

Mach 1 beat me to it.

I don't know about the inductor value but the attached schematic should help. [Edit, see my later post attaching the correct file. Grr.]

Also, the schematic with the mystery component is almost certainly wrong in topology for the tweeter circuit. Again the attached schematic helps.

We have a third-order high pass filter for the tweeter. There is that poly switch in parallel with a 200 ohm resistor. I believe it is arranged like that so that when the polyswitch opens, there is still a resistive load on the crossover (200 ohms plus the tweeter) and the tweeter is getting much less current.

Maintaining the resistive load prevents the crossover from otherwise forming an L-C series circuit to ground, which will be a short circuit at some frequency.

WMcD

KP-262.pdf

Edited April 26, 2014 by William F. Gil McDermott

[Axz Hout]

x

[WMcD]

This time for sure, Rocky.

Sorry.

WMcD

KP 201 Crossover Schematic (Thanks to Michael Colter).pdf

[mustang guy]

OK, there is some erroneous information between my network and the schematic you all provided. Also, I still don't know what an RDE 050's capacitance is, and I'm not sure what the specs are on the #3504 are other than that it attenuates down 10db on the center tap.

Look at where the negative ties into the positive at the tweeter after the air inductor on my schematic. This is the way the thing is hard wired on my crossover.

Check out the ground strap end on the far right of the picture.

It is going to the positive terminal of the tweeter:

Edited April 26, 2014 by mustang guy

[mustang guy]

Here is what I think is the corrected schematic.

edit: I just found out that in the provided schematic (PDF), the RDE050 is refering to a varistor. The 200 Ohm, 25 watt resistor it is paralleled with is a wirewound type.

second edit: I just went back over mach-1's post above, and he is refering to the RDE050 as a polyswitch. The pdf schematic is refering to it as a varistor. Very confusing...

Here is the actual text from the document describing this circuit:

KLIP Circuit

The new Klipsch Limiter Protection (KLIP) circuit automatically protects the high-frequency section from being overdriven. The KLIP curcuit uses a semiconductor to monitor input to the tweeter. When input exceeds the safe power-handling limit, the KLIP circuit reduces the level to the tweeter by 10db. As soon as the input level decreases to a safe level, output returns to normal. The KLIP circuit allows the speaker to deliver all of its usable output on musical peaks and does not degrade sound quality.

Edited April 26, 2014 by mustang guy

[Axz Hout]

x

[mustang guy]

You show a wire shorting out parts in the tweeter (+) circuit.

The yellow/orange blop is not a cap, similar to this from PE http://www.parts-express.com/raychem-te-connectivity-rxe050-050a-polyswitch--071-254

Thank you for clarifying about the polyswitch.

I realize the short. That is the way it is wired. Please read post #6 carefully and look at the pictures.

[Axz Hout]

x

[mustang guy]

Can anybody explain why the positive terminal of the tweeter is connected directly to the negative input from the source as shown in post #6? It does not match the Colter schematic, and has me scratching my head...

[mustang guy]

The H II shows the same crossover without protection circuit, and tweeter polarity reversed. How much power are you feeding these?

Your diagram in post 7 would not feed the tweeter (-) ?

Sorry was typing at same time as you.

That is the way this network is wired. What the heck does it mean?? I am going to go to the shop and see if the other KP2.0A's are wired this way.

[mustang guy]

I know what it is. It's reversed polarity on the tweeter. I should have guessed that. I thought there was something dreadfully wrong.

My schematic matched the Heresy II and adds the KLIP protection circuit.

The Colter does not represent my crossover.

Edited April 26, 2014 by mustang guy

[Axz Hout]

v

[Axz Hout]

c

[mustang guy]

OK, I dig it now. I went ahead and posted my schematic on the Klipsch Crossovers thread.

BTW, I could not find the KP-201 crossover anywhere. That is why I started this. I am glad I did, since the correct way is reversed tweet wiring.

I corrected the #7 post. You might have a look to see if there is anything else I missed...

Edited April 26, 2014 by mustang guy

[Deang]

Late to the game.

A polyswitch has .5 ohms of resistance.

[WMcD]

I'm pleased to present the schematic. I can't explain why a given hardware crossover doesn't match as far a topology. Except for wiring the tweeter out of phase.

 

We are mostly concerned with the phase of the acoustic output of the squaker and tweeter relative to each other at the crossover frequency. There are three influences.

 

One is the phase induced in the electrical filters as they roll off and up. We also have to recognize that the electrical schematic of the crossover fails to show the inductance of the driver coil. But it is there. We see it in measurements of the input impedance of any driver. At some point it is going up.

 

The second is the effect of the mass of the diaphragm- voice coil unit. In an electrical analogy it has a value of a cap or inductor -- but these are tricky to model.

 

The third is the acoustic offset of the drivers which is to say, delay. Just ballpark math, but I think at 7000 Hz, the wavelength in air though the horns is about 1 inch. So if they're offset is 1 inch or 2 inch or 3 inches inch, the effect is a multiple of 360 degrees. So they come into phase despite or because of the delay. But if the offset is 1.5 or 2.5 or 3.5 inches, then they are 180 degrees out of phase.

 

In the later case, there is going to be a dip in acoustic output. At least on axis.

 

What to do? You can reverse the electrical signal feeding the tweeter to solve the problem (at the crossover freq) and move them back into phase, so there is no dip.

 

WMcD

Edited October 3, 2014 by William F. Gil McDermott

[mustang guy]

Thank you everyone for the help.

I'm pleased to present the schematic. I can't explain why a given hardware crossover doesn't match as far a topology. Except for wiring the tweeter out of phase.

We are mostly concerned with the phase of the acoustic output of the squaker and tweeter relative to each other at the crossover frequency. There are three influences.

One is the phase induced in the electrical filters as they roll off and up. We also have to recognize that the electrical schematic of the crossover fails to show the inductance of the driver coil. But it is there. We see it in measurements of the input impedance of any driver. At some point it is going up.

The second is the effect of the mass of the diaphragm- voice coil unit. In an electrical analogy it has a value of a cap or inductor -- but these are tricky to model.

The third is the acoustic offset of the drivers which is to say, delay. Just ballpark math, but I think at 7000 Hz, the wavelength in air though the horns is about 1 inch. So if they're offset is 1 inch or 2 inch or 3 inches inch, the effect is a multiple of 360 degrees. So they come into phase despite or because of the delay. But if the offset is 1.5 or 2.5 or 3.5 inches, then they are 180 degrees out of phase.

In the later case, there is going to be a dip in acoustic output. At least on axis.

What to do? You can reverse the electrical signal feeding the tweeter to solve the problem (at the crossover freq) and move them back into phase, so there is no dip.

WMcD

Note that

That makes good sense. I have looked at the response curve of this speaker, and it is nice. It is good to 50HZ, but really flat from about 70, so I think a sub high/low crossed at that frequency would probably work best. I cross my LaScalas at 65, for best results.

Late to the game.

A polyswitch has .5 ohms of resistance.

Are you sure? The reason I asked is that I thought I had figured out that the 050 meant 0.5 amp hold current. I found several polyswitches with .5 amp hold and 72VDC max current, and they all had 1.17 Ohms resistance.

It would be nice to include the specifics of the polyswitch in my diagram.

edit: I found a post referring to a replacement part number to an RDE050A changed to RXE050. If that is correct, the resistance is indeed 1.17 Ohms.

Edited April 26, 2014 by mustang guy

[Deang]

I can only tell you what I've found by measuring with a DVM. Many want those out of their tweeter circuits, and to remove them, I have to substitute a resistor. When I first started doing this, I bought a couple dozen, and the handful I measured were right a half an ohm. I called Bob about an hour ago, and he said an old one will measure much higher than a new one. I also wonder if some are measuring these things without zeroing their meters first. Bob says .3, I have it at .5