Blown tweeter in a Henry 8x8?

[reverendrally]

Hi all, a buddy has lent me his SWR henry 8x8. It's an early Pre-fender. It did something weird the first day I had it and I think it's blown the tweeter. I was wondering if someone has the factory impedances for the tweeter so I could test it and see if its burnt out?

[coreyfyfe]

This is from the SWR website and should help you to test if the tweeter is indeed broken:

Q: I think I may have blown the tweeter in my SWR speaker enclosure. How can I verify this and where can I find a replacement?
A: To test the tweeter, first, without plugging in an instrument, connect your amplifier to your speaker cabinet as you would normally, then turn the amplifier's power switch to the "On" position. Rotate the treble and master volume controls to maximum, at which point a loud hiss from the tweeter should be audible. Rotate the tweeter attenuator control back and forth and listen for increase (clockwise) and decrease (counter-clockwise) in volume of the hiss.

If you don't hear any change as you sweep the attenuator control, you may have either a blown tweeter diaphragm or a fried attenuator "L-Pad." A blown tweeter diaphragm is more likely, so you should order either a replacement diaphragm for the horn or a replacement piezo tweeter depending on the model of SWR speaker enclosure that you own. Please contact your local SWR retailer or any Authorized FMIC Service Center to order replacement parts.

It's a piezo tweeter, so it has a very high impedance and I'm not sure how it would measure out. I think it's supposed to be like 1000 ohms but that's just from googling around. Good news it that it's pretty cheap if you have to replace...
SWR TWEETER FOR HENRY - Thomann UK Cyberstore

[markkoelsch]

Unless you have a bridge, and most do not, you cannot actually measure impedance. You could measure resistance, but I am not sure what the nominal value would be.

It could be blown. Luckily, they are not very pricey. Do you have access to a cab you could borrow a horn/tweeter out of to test with?

[reverendrally]

no. could I measure the resistance with a multimeter?

[Bassmec]

Originally Posted by reverendrally

no. could I measure the resistance with a multimeter?

Just take it out of circuit and connect it across the output of a music player or hi fi, it either works or it don't.

[will33]

Piezo's are cheap, like 2-3$. It should have a resistor in front of it, like another 1-2$. If it's hooked up to an adjustable l-pad (attenuator), it should have an 8ohm resistor across the terminals, assuming an 8ohm l-pad. Basically another 1-2$ resistor and l-pad's are about 10$ last I checked. Basically saying, you could replace the whole works and probably have change out of a 20....well, with shipping maybe no change but you get the idea.

Piezo's don't have a voice coil, they work off of a crystal. Testing resistance doesn't do much good. Remove the piezo, less resistors and all that so it's just the tweet. Hook it up to a radio tuned in between stations so it's static, turn the volume up just a little. If it makes noise, it's good, if it doesn't, it's not.

Typical piezo... Goldwood GT-1005 Wide Dispersion Piezo Tweeter 270-011

Piezo mounted on a bigger horn, loads lower to meet where a typical bass speaker starts to roll off in the highs. May not be necessary with 8's, depending on how their voiced. With a Henry, probably not.... Goldwood 3" x 7" Wide Dispersion Piezo Horn Mid/Tweeter 280-062

[reverendrally]

Thanks. That makes me feel a lot better. He lent it to me for 2 weeks. I want to make sure I have a solution to whatever is broken when he gets back from OS.