Hi all. I am looking for wiring diagrams that show how to properly wire zener diodes into a 2 way and a 3 way speaker crossover to limit the voltage to the tweeter. The speakers with the 2 way are Canadian Sound Dynamic's speakers from the 80's. They have great horn tweeters and they use the same diaphragms as Klipsch Heresy II's. I want to add zener diodes to the crossovers to limit the voltage to the tweeters. The crossovers are very simple. There are 2 inductors, one 10 watt resistor and one 3.3uF film cap. I am not sure how to wire the zeners into the circuit. I am aware that 2 diodes are needed per crossover but not sure how to properly wire them into the circuit. Any help or diagrams would be greatly appreciated..Thanks..
Limiting voltage is the wrong thing to do for a tweeter You are trying to limit excursion and power dissipation, while allowing high frequency transients
A normal signal for the tweeter contains high peaks (~50W), while the average power is low (~1W). Tweeters usually fail because the average power is too high. Zener diodes limit the peak voltage that can reach the tweeter. If you choose to limit the voltage at 50W, then the diodes offer absolutely no protection against a clipping amplifier. If you limit it at 1W, then the protection already kicks in at moderate listening levels.
I understand this, but I still don't understand why thats bad. I would use 5.1v 10 watt Zeners. I have them in my Klipsch Heresy I's. They come in the Industrial Heresy's from the factory so I figured I'd put them in my Heresy's. Since they were installed, I have not blown a tweeter. I like to crank my music at times. I have a Crown XTI2000 amp that puts out 500W or so per/ch. There's no doubt I over powered them. I don't hear any difference in the high end since they were put in so I don't get why putting them in is bad..
I have the zeners. 1N3996. They are not big at all unless you're comparing them to a half watt resistor.
Are the zeners still functional? I assume they're both connected parallel to the tweeter. Since there's no current limiting resistor between the power amp and the zener circuit, I would expect them to blow the first time you crank up the volume, as they essentially short the filter circuit. And all that while the HF-driver is probably still fine...
I have never used it, but I read that some use a light bulb in the tweeter line to protect against overloading.
I guess it works much like a Mains Bulb Tester, in that it remains at low resistance when "power" input is low and then suddenly increases in resistance if the sustained current through the filament heats it up.
The only difficult part is getting a bulb with the right resistance and voltage capability to suit the tweeter.
I guess it works much like a Mains Bulb Tester, in that it remains at low resistance when "power" input is low and then suddenly increases in resistance if the sustained current through the filament heats it up.
The only difficult part is getting a bulb with the right resistance and voltage capability to suit the tweeter.
Infinity used to put zeners to protect the Emit tweeters.
I wish they used them also in my old RS4001 because I blowed one 🙄
I wish they used them also in my old RS4001 because I blowed one 🙄
OP: Check out some XO schamatics for Infinity speakers. As Pico... pointed out, they used zeners in some of their designs. The Schematics will show you how to wire them in.
The only sure way I know of to protect your tweeters is to limit you playing volumn.
The only sure way I know of to protect your tweeters is to limit you playing volumn.
the best quality sounding protection comes from using a light bulb (auto bulb) in series with the tweeter. Works like a limiter sounds good. Poly switch will eat up sound quality. That has been my experience. The bulb pretty much makes your tweeter bullet proof you do have to select the correct value bulb. Hope this is of some interest. Best regards Moray James.
If one was to use Zener diodes as a limiter one needs to wire them back to back and with a series resistor equal to the nominal impedance of the tweeter. A 10 watt wire wound resistor should suffice as tweeter music transients are very brief.
This simple limiter circuit needs to be wired across the tweeter connection at the X'over network, this would maintain the integrity of its connection.
C.M
This simple limiter circuit needs to be wired across the tweeter connection at the X'over network, this would maintain the integrity of its connection.
C.M
And you would sink the excess current back to the amplifier? What would happen to the impedance curve?
The problem with using a light bulb in series is its series resistance (even when cold) as this will attenuate the level of high frequencies for the tweeter, and as the light bulb filament has a positive temperature coefficient this resistance will rise with an increase in temperature.
C.M
The zeners are connected in series, cathode-to-cathode, then in parallel with the tweeter.
The capacitors in the network act as a reactive ballast, no additional resistors needed.
A reactive ballast does not dissipate any heat, unlike a resistor in that application.
The capacitors in the network act as a reactive ballast, no additional resistors needed.
A reactive ballast does not dissipate any heat, unlike a resistor in that application.
A 12V/5W car tail light bulb is about right for a 8R tweeter. A couple of Ohms cold, ~30 Ohms hot and if it blows it's cheap
For 4R a 12V/21W bulb is better
For 4R a 12V/21W bulb is better
If I put this bulb between power amp and tweeter (direct connection, active crossover bi amp configuration),
will it prevent damage from DC or low frequency leakage?
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