Moose1963 Posted April 5, 2021 Share Posted April 5, 2021 I'm running a lot of power through my Klipsch 6000Fs and want to protect the tweeters from possibly blowing. What type of inline fuse should I use on the speaker wire? Thanks! Quote Link to comment Share on other sites More sharing options...
Peter P. Posted April 5, 2021 Share Posted April 5, 2021 Assuming the tweeter is 8 ohms nominal as the speaker itself is, I calculated a 4A fuse should be sufficient, if not a bit safe as I used the 125W continuous spec for my calculations vs. the 500W peak spec. Remove the binding post bridging straps, and run separate wires to the tweeter input terminals. A standard AGC tubular tubular fuse should be fine. Someone please correct me if I'm wrong. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted April 5, 2021 Share Posted April 5, 2021 Well, you always want to consider whether you are damaging your hearing by listening that loud !!! My own view is that fuses are great for protecting woofers but not very good for protecting tweeters. Several techniques are possible. One is to use back-to-back diodes (this was done on the type AA crossovers). Another is to incorporate an auto bulb protector. Search the threads by DJK for the schematic (it is a simple circuit). Quote Link to comment Share on other sites More sharing options...
babadono Posted April 5, 2021 Share Posted April 5, 2021 4 amps to a tweeter? HA HA HA HA HA Not fer long HA HA HA Sorry just struck me as a very funny as Fr. Guido Sarducci says. Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted April 5, 2021 Share Posted April 5, 2021 6 minutes ago, PrestonTom said: Well, you always want to consider whether you are damaging your hearing by listening that loud !!! My own view is that fuses are great for protecting woofers but not very good for protecting tweeters. Several techniques are possible. One is to use back-to-back diodes (this was done on the type AA crossovers). Another is to incorporate an auto bulb protector. Search the threads by DJK for the schematic (it is a simple circuit). Looks like a bulb and a parallel 10 w resistor Quote Link to comment Share on other sites More sharing options...
Wirrunna Posted April 6, 2021 Share Posted April 6, 2021 (edited) I recommend a polyswitch - https://www.parts-express.com/electronic-parts/Fuses-Fuse-Holders/polyswitch-resettable-fuses At around 60c , buy a few pairs in increasing amperage, put the lowest in circuit and try it, if it cuts out too often then move up to the next value. Auto bulbs are going LED, which don't work as well due to much lower wattage. Edit: Good description of how they work here - https://www.jaycar.com.au/rxe075-ptc-fuses-speaker-protection/p/RN3460 Edited April 6, 2021 by Wirrunna Added link to description Quote Link to comment Share on other sites More sharing options...
Peter P. Posted April 6, 2021 Share Posted April 6, 2021 11 hours ago, babadono said: 4 amps to a tweeter? HA HA HA HA HA Not fer long HA HA HA Sorry just struck me as a very funny as Fr. Guido Sarducci says. Well, if it's wrong, offer a correction and show my math was incorrect. Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 6, 2021 Share Posted April 6, 2021 Many companies have used a lamp for tweeter protection, although most has been in PA systems. IIRC, Community had them located where they cound be seen through the grill so the sound many could see when they were being overdriven. https://www.simplyspeakers.com/jbl-speaker-protection-bulb-sk3.html?gclid=CjwKCAjwjbCDBhAwEiwAiudBywc10gHPNWxRWoGBZiw5qzO1fsNgHp82VsKGB1otmt2RsoAOY0xTWxoCQWgQAvD_BwE Quote Link to comment Share on other sites More sharing options...
babadono Posted April 6, 2021 Share Posted April 6, 2021 4 hours ago, Peter P. said: Well, if it's wrong, offer a correction and show my math was incorrect. A 4 amp fuse would allow 128 watts to be delivered to a 8 ohm load. P = I^2 x R. For a WHOLE speaker rated for 125 watts this is probably OK. But just to the tweeter? If enough of the energy is of a high enough frequency that the crossover directs it to the tweeter you will have a blown tweeter. Ask me how I know Quote Link to comment Share on other sites More sharing options...
Peter P. Posted April 7, 2021 Share Posted April 7, 2021 My calculations are correct then, because I used 8 ohms and 125 watts in crunching the numbers. Unless the speakers are bi-wired so the tweeter can be fused separately you have no choice but to fuse the entire speaker. Without knowing the max current draw on the tweeter, we're just guessing on how it should be fused. The owner's manual offers no information on which terminals connect to the tweeter! The only other option is to remove the bridging straps and run the speaker cables to the tweeter binding posts directly. Connect a voltmeter in series and measure the max current, or use a peak hold feature on the voltmeter and take a voltage reading, then do the calculations. Quote Link to comment Share on other sites More sharing options...
WMcD Posted April 7, 2021 Share Posted April 7, 2021 The T-35 (K-77) tweeter is rated at 5 watts long term and IMHO that can be assumed for other tweeters as a ballpark figure. Therefore long term current is about 0.8 amps. Obviously the tweeter is the most delicate part of the system. WMcD 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted April 7, 2021 Share Posted April 7, 2021 10 hours ago, WMcD said: The T-35 (K-77) tweeter is rated at 5 watts long term and IMHO that can be assumed for other tweeters as a ballpark figure. Therefore long term current is about 0.8 amps. Obviously the tweeter is the most delicate part of the system. WMcD Yes and I and many others with Klipsch speakers have proved it 1 Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted April 7, 2021 Share Posted April 7, 2021 On 4/6/2021 at 6:39 AM, Marvel said: Many companies have used a lamp for tweeter protection, although most has been in PA systems. IIRC, Community had them located where they cound be seen through the grill so the sound many could see when they were being overdriven. https://www.simplyspeakers.com/jbl-speaker-protection-bulb-sk3.html?gclid=CjwKCAjwjbCDBhAwEiwAiudBywc10gHPNWxRWoGBZiw5qzO1fsNgHp82VsKGB1otmt2RsoAOY0xTWxoCQWgQAvD_BwE How do you wire this in the circuit? Just add it to the positive of the tweeter? The DHA diagram above has a resistor parallel to the tweeter, is this for the circuit or part of the protection? Quote Link to comment Share on other sites More sharing options...
WMcD Posted April 7, 2021 Share Posted April 7, 2021 I don't know. Maybe it allows the lamp to light after you've blown out your tweeter. !!! I suppose there is some sense to this because some people might assume the tweeter is still good and continue to crank the power. Though I'll admit it seems like the resister will not allow much current. BTW, incandescent bulbs have a low resistance when not getting hot enough (current) to illuminate. Then when there is sufficient current, i.e. temperature, to glow the resistance increases and thus supply some protection to the tweeter by current reduction. 1 Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted April 7, 2021 Share Posted April 7, 2021 32 minutes ago, WMcD said: I don't know. Maybe it allows the lamp to light after you've blown out your tweeter. !!! I suppose there is some sense to this because some people might assume the tweeter is still good and continue to crank the power. Though I'll admit it seems like the resister will not allow much current. BTW, incandescent bulbs have a low resistance when not getting hot enough (current) to illuminate. Then when there is sufficient current, i.e. temperature, to glow the resistance increases and thus supply some protection to the tweeter by current reduction. Here is another schematic that I have without the tweeter protection It looks like the 65 ohm resistor is for the protection circuit, maybe to maintain 8 ohms as parallel 65 and 8 ohms = 7.2, maybe add 0.8 ohms or so for the bulb and you are back at 8 ohms. Quote Link to comment Share on other sites More sharing options...
Peter P. Posted April 7, 2021 Share Posted April 7, 2021 6 hours ago, tigerwoodKhorns said: How do you wire this in the circuit? In the OP's case, the speaker wire connects to the woofer terminal positive, and the fuse bulb replaces the bridging strap to the tweeter terminal positive. It's easy, and easy to access and observe to see if it's illuminating. I'd put shrink tubing over the exposed wire, but leave the bulb visible. Quote Link to comment Share on other sites More sharing options...
babadono Posted April 7, 2021 Share Posted April 7, 2021 Ok..someone correct me if I'm full of it.......when power is applied at low levels the cold filament of the bulb acts as a low resistance allowing most of the power to go to the tweeter. As power is cranked up the filament starts to glow increasing its resistance, limiting the current and absorbing some of the power. That's why this works? or helps? Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted April 7, 2021 Share Posted April 7, 2021 1 hour ago, Peter P. said: In the OP's case, the speaker wire connects to the woofer terminal positive, and the fuse bulb replaces the bridging strap to the tweeter terminal positive. It's easy, and easy to access and observe to see if it's illuminating. I'd put shrink tubing over the exposed wire, but leave the bulb visible. OK, so in other words, it goes in the positive to the tweeter. The schematics that I posted seem to also require a 65 ohm parallel resistor. Quote Link to comment Share on other sites More sharing options...
WMcD Posted April 8, 2021 Share Posted April 8, 2021 7 minutes ago, babadono said: Ok..someone correct me if I'm full of it.......when power is applied at low levels the cold filament of the bulb acts as a low resistance allowing most of the power to go to the tweeter. As power is cranked up the filament starts to glow increasing its resistance, limiting the current and absorbing some of the power. That's why this works? or helps? In my view that is how it works, to the extent it works. I've never seen a Klipsch design with this technique BTW. WMcD 1 1 Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 8, 2021 Share Posted April 8, 2021 UREI used bulbs in some of their monitors, as has JBL, Radio Shack and others. They will work as a compressor, limiting the current to the tweeters. If you want to dig enough (I don't), you can figure it out. @JohnA John can probably explain. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.