Crossover overheated and broke, Why? *pics*

[Karkov]

Ran the DMM across some speakers and I *think* I fried some voice coils on some mids and highs.

2 tweets and 1 6.5"

sucks

[Wicks]

The white blocks are 10-25W power resistors. They can take a beating.

If it were a freak failure then you wouldn't have melted plastic.

That's a sign of excessive heat.

I don't see any discoloration which would be a sign of long term overheating.

That cracking appears stress related.

My guess would be that the resistor was overpowered recently.

Either the crossover was overpowered (unlikely) or your amp started failing with some DC bias to the speaker outputs.

Connect your DMM on that amp output and set it to DC volts.

Play a test tone at moderate to high volume (don't have any speakers connected).

See if the DMM registers a significant DC voltage level.

Depending on your crossover, I would expect it to be able to filter any DC signals so your speakers wouldn't get hurt but it sounds like they may have.

[Karkov]

The white blocks are 10-25W power resistors. They can take a beating.

If it were a freak failure then you wouldn't have melted plastic.

That's a sign of excessive heat.

I don't see any discoloration which would be a sign of long term overheating.

That cracking appears stress related.

My guess would be that the resistor was overpowered recently.

Either the crossover was overpowered (unlikely) or your amp started failing with some DC bias to the speaker outputs.

Connect your DMM on that amp output and set it to DC volts.

Play a test tone at moderate to high volume (don't have any speakers connected).

See if the DMM registers a significant DC voltage level.

Depending on your crossover, I would expect it to be able to filter any DC signals so your speakers wouldn't get hurt but it sounds like they may have.

What would a significant DC level be? What number would I be looking for and what number wouls be out of place?

[MrSkippyJ]

Ran the DMM across some speakers and I *think* I fried some voice coils on some mids and highs.

2 tweets and 1 6.5"

sucks

Check whatever crossover that other tweet was hooked up to also.

[Wicks]

The white blocks are 10-25W power resistors. They can take a beating.

If it were a freak failure then you wouldn't have melted plastic.

That's a sign of excessive heat.

I don't see any discoloration which would be a sign of long term overheating.

That cracking appears stress related.

My guess would be that the resistor was overpowered recently.

Either the crossover was overpowered (unlikely) or your amp started failing with some DC bias to the speaker outputs.

Connect your DMM on that amp output and set it to DC volts.

Play a test tone at moderate to high volume (don't have any speakers connected).

See if the DMM registers a significant DC voltage level.

Depending on your crossover, I would expect it to be able to filter any DC signals so your speakers wouldn't get hurt but it sounds like they may have.

What would a significant DC level be? What number would I be looking for and what number wouls be out of place?

If the meter is staying in the milli-volt range then its probably fine.

You're looking for something in the volt range (over 1V).

Your amp is basically a frequency variant AC inverter. It converts DC to AC so you should be seeing absolutely no DC bias from the outputs at all.

Speaker voice coils are dead short circuits at DC so its imperative that your amp has no DC bias on the outputs.

[Karkov]

Gotcha, will do some testing when I have time. Thanks so much for the interest guys!

[_paralyzed_]

Ouch man, those are some spendy components to fry. Now you have time to work on my system!