I have a KB-100 Keyboard amp. When I got it the tweeter and woofer were both toast. I put a JBL 2225H driver in and scrapped the tweeter. I used it as a bass amp for a while. I've got another tweeter to put in it now so I can sell it, but I don't know what crossover cap it used. I'm pretty sure it only used one cap in series with the driver. It is a piezo tweeter, like the one below. Looks like it's lower frequency spec is 3.5kHz. Does anyone know what cap would be best? Or what it used originally? The schematic doesn't show that part of the amp.
Goldwood GT-1005 Wide Dispersion Piezo Tweeter
Goldwood GT-1005 Wide Dispersion Piezo Tweeter
Post 3 in the thread below suggests that it is still better to use a simple crossover:
Piezo xo help -
Techtalk Speaker Building, Audio, Video Discussion Forum
Piezo xo help -
Techtalk Speaker Building, Audio, Video Discussion Forum
Don´t overthink it, doubly so in an amp which is being completed just to be sold, so why re-engineer it?
Wire it like Peavey did: a piezo tweeter with a series resistor, 22 or 47 ohm, 1 or 2W.
I have the parts, why not? Looks simple enough, 24ohm resistor and 4.7uf cap.
The woofer has already been upgraded to the JBL2225H.
I have the parts, why not? Looks simple enough, 24ohm resistor and 4.7uf cap.
The woofer has already been upgraded to the JBL2225H.
Something isn't quite right, I'm getting a crackling type distortion. Same result running another amp directly into the speaker.
So is it the speaker or the piezo making the noise?
The piezo
Piezo could be cracked or defective. Can you sub it into some stereo speaker you have?
The piezo is new. Maybe it doesn't like my crossover for some reason?
Open it up and have a look for anything out of place, these things are dumb simple. On another note, since Motorola stopped making these things your chances of getting a usable device(brand new) is no better than 50/50.. which is to say there is no quality control on these anymore.The piezo is new. Maybe it doesn't like my crossover for some reason?
New things can be defective, never assume.
Motorola made them for years, then CTS bought the line from them, and I forget where it went after that. But there are other people making clones of them.
If you suspect the crossover, just bypass that and use a resistor like stock. Any difference? I suggested subbing it into a different speaker system just to check the part itself.
Motorola made them for years, then CTS bought the line from them, and I forget where it went after that. But there are other people making clones of them.
If you suspect the crossover, just bypass that and use a resistor like stock. Any difference? I suggested subbing it into a different speaker system just to check the part itself.
Well, this explains it....
IMG_2503.JPG - Google Drive
I lifted the bend part back into place and tried it again. I think it is better but I'm still having the issue a bit. I'll get a better idea tomorrow when I can turn it up more. I've emailed the ebay seller.
I lifted the bend part back into place and tried it again. I think it is better but I'm still having the issue a bit. I'll get a better idea tomorrow when I can turn it up more. I've emailed the ebay seller.
It crackled a bit after I fixed the diaphragm but it isn't doing it now. And I put my musicians earplugs in and turned it up enough that the comp light came on.
I send the seller the picture and he gave me a refund. So if it continues to work I have free piezo tweeter.
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