Is this capacitor worth keeping?

[cadbury8]

Originally posted by Cal Weldon
I like to use wire wound resistors, air core inductors and poly caps for the series connections and sand resistors, iron core and elec's for the by-pass.

Not sure if there's any sense in that though.

yes the crossover contains air core inductors. two of them. One small coil on a on a nice clear plastic round reel. The other is on a long square reel. The red sure is pretty.

The crossover also has two lamps on the bottom of it. I assume those were ment to protect the tweeter from overloading.

It also has a yellow thing on the bottom with a wire coming out both ends. it is labled F 4.0J MT 100V. One of the lamps is connected to this yellow thing. they are both connected in series.

anyway a couple more questions. Is there any way to test the transducers to find out what their specs are so they may be used in the future? Also what does the J stand for on the resistor? 5W 6Ohm J.

here is a dumb arze question for ya all. do you have to build a crossover for a specific voltage or wattage? meaning will a simple crossover work for 1000 watts as well as 10 watts? or does everything have to be scaled accordingly?

[cadbury8]

Originally posted by anatech
Hi Cal,
"Sand cast", or "bathtub" resistors as they were known as, are in fact wire wound.

Whether the parts are in series, or in "bypass" makes no difference. They are all in the signal path.

Hi tinitus,

The value means nothing. What is important is that they are in an AC circuit and therefore must be non-polarized types.

-Chris

tow of the 5w 6OhmJ bathtub (i like that.) sand cast resisters are in series connected to the two lamps. So it looks like this:

lamp > resister > resister > lamp > yellow thing F4.0 J MT 100V > resister bathtub sand cast 5W 3R3OhmJ > + side of tweeter. Its also picking up the small coil at the 3Ohm resister along with the cap.

[djQUAN]

the yellow thing is a film cap. not sure what type though. the markings say it's 4uF 100V

the lamps are indeed used for protecting the tweeter from overloading.


do you have pics?

[tinitus]

My point about the "small" value was, or should have been, that it dont cost much to change to something better

[MikeBettinger]

Originally posted by cadbury8


Also what does the J stand for on the resistor? 5W 6Ohm J.

here is a dumb arze question for ya all. do you have to build a crossover for a specific voltage or wattage? meaning will a simple crossover work for 1000 watts as well as 10 watts? or does everything have to be scaled accordingly?

The J on both the cap and resistor most likely means 5% tolerance. In standard practice F = 1% J =5% k = 10%.

A crossover designed to handle 1000 watts can be used for 10 watts but not the other way around. The voltage and power ratings need to reflect the signal they are processing.

One side note from experience; you might not want to use a higher voltage rated cap (than necessary) in a lower signal voltage applications.

In order for a cap to handle higher voltages, the dielectric must be made thicker. Because an electric field on one plate causes a current to flow in the other plate of the cap, the plate distance as well as the dielectric material (the normal focus with capacitors) can have an audible effect on the low level signal - because the field strength drops off rapidly with distance.

In speaker applications this causes a softening of the sound at lower levels and there appears to be a volume threshold where things sort of clear up.


Regards, Mike.

[cadbury8]

No, i dont have pics. sorry. I know it would make things easier as my explanations are kind of lacking. Two minutes with pics and you guys could draw a scematic of the thing and tell me what it is doing exactly. lol.

thanks to you all for the information.

Why would anyone use a multi-tap transformer with a switch to change between wattage in a crossover? 3.75w 7.5w 15w 30w all at 8ohms.

next question completely off topic is this:
has anyone ever soldered a new cap onto a motherboard of a computer? i had one blow on my motherboard. The side of it is brown and the top looks like the top of an expanded ballon. hehehe. It probably isnt possible.