I have a 2 questions about my tweeters.
Earlier this week I commenced a speaker crossover project to redo the components and wiring in my speakers that I constructed in 2018.
When I examined the tweeter crossover I found that the shunt resistor had burned up and fused itself. The resistor was a 5W Mills 10R. The tweeter is a Hiquphon OW-1. The tweeter appears to be just fine, or at least it looks undamaged. But when I test across the terminals on the back of the disconnected tweeter, there is no reading on the DMM.
I am thinking that this tweeter is not good and not now working.
So I checked the tweeter on the other speaker, that I have yet to disassemble. When I test the tweeter while connected, I get a reading of 4R, but not the 10R of the shunt resistor. And when I disconnect the tweeter, I get a reading showing a small resistance, but not 0R. So I am thinking this tweeter may not be blown, but maybe not quite right.
Question 1 - Are my tweeters blown?
Question 2 - Why would the shunt resistor get burned up and fused?
It is easy to buy a new pair of tweeters. But I need to have an idea of how to prevent, if possible, a repeat of this situation with the burned shunt resistor and apparently blown tweeter.
Thanks in advance for any ideas and advise.
Earlier this week I commenced a speaker crossover project to redo the components and wiring in my speakers that I constructed in 2018.
When I examined the tweeter crossover I found that the shunt resistor had burned up and fused itself. The resistor was a 5W Mills 10R. The tweeter is a Hiquphon OW-1. The tweeter appears to be just fine, or at least it looks undamaged. But when I test across the terminals on the back of the disconnected tweeter, there is no reading on the DMM.
I am thinking that this tweeter is not good and not now working.
So I checked the tweeter on the other speaker, that I have yet to disassemble. When I test the tweeter while connected, I get a reading of 4R, but not the 10R of the shunt resistor. And when I disconnect the tweeter, I get a reading showing a small resistance, but not 0R. So I am thinking this tweeter may not be blown, but maybe not quite right.
Question 1 - Are my tweeters blown?
Question 2 - Why would the shunt resistor get burned up and fused?
It is easy to buy a new pair of tweeters. But I need to have an idea of how to prevent, if possible, a repeat of this situation with the burned shunt resistor and apparently blown tweeter.
Thanks in advance for any ideas and advise.
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Could you mean a series resistor?
https://willys-hifi.com/products/hiquphon-ow1-92-tweeter
https://www.hiquphon.eu/ow_i_technical_data_and_features.html
Post a photo of the crossover.
https://willys-hifi.com/products/hiquphon-ow1-92-tweeter
https://www.hiquphon.eu/ow_i_technical_data_and_features.html
Post a photo of the crossover.
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If your shunt resistor is burnt out, it was dissipating quite a bit more than 5W, average, over a lengthly period of time. Your tweeter was likely dissipating nearly double what the resistor was because of its lower impedance. As voice coil heat. It's very likely that fragile little voice coil has been damaged in the process. This was likely caused by a crossover frequency that is too low, or seriously excessive playback levels, think drunken party. It's the only time I've ever damaged a tweeter. I would not drop a pair of new tweeters into those speakers unless my latter answer above is the cause of your damaged tweeters.
To your questions:
A1 - Very likely
A2 - That's an odd failure mode for a wire wound resistor. In my >30 years of component level electronics repair I've seen many wire wound resistors blown open and a handful that have had a significant value shift. Never one that has gone dead short.
Some pictures and a schematic of the crossover would help find the root cause of your problems.
To your questions:
A1 - Very likely
A2 - That's an odd failure mode for a wire wound resistor. In my >30 years of component level electronics repair I've seen many wire wound resistors blown open and a handful that have had a significant value shift. Never one that has gone dead short.
Some pictures and a schematic of the crossover would help find the root cause of your problems.
You might find some interesting info here:
https://techtalk.parts-express.com/forum/tech-talk-forum/1314919-hiquphon-autopsy
https://techtalk.parts-express.com/forum/tech-talk-forum/1314919-hiquphon-autopsy
Thanks for these quick replies. I do not have any pics. I will try to post a schematic later.
FWIW, the speakers are 6 years old. The design itself is 20 years old and was designed by the late Rick Craig in 2003 as a custom design for me. I built this set of speakers after I moved to Australia some time ago and did not move the originals with me.
It is quite possible that I played music too loud, briefly at times in the past.
Also, the burned shunt resistor reading was like 2Million ohms.
FWIW, the speakers are 6 years old. The design itself is 20 years old and was designed by the late Rick Craig in 2003 as a custom design for me. I built this set of speakers after I moved to Australia some time ago and did not move the originals with me.
It is quite possible that I played music too loud, briefly at times in the past.
Also, the burned shunt resistor reading was like 2Million ohms.
I just read the specs and it mentions DC resistance to be 5.8R. Would that be the same as measuring across the terminals when tweeter is disconnected?
The image below is not from my speaker. It is from a older Troels speaker, but it does use similar drivers that I use, Seas Excel W18E and OW-1.
The tweeter network is very close to what I have. There is NO R1011 resistor. C1021 is 8.2uf. C1041 is 15uf. R1061 is 2R. L1031 is 0.2mH. And I have a shunt resistor of 10R across the tweeter terminals. In my construction I have the shunt resistor attached at the end of R1061 that goes to the + terminal, and the other end of the shunt attaches at the end of the coil L1031 that attaches from the - terminal wire.
The tweeter network is very close to what I have. There is NO R1011 resistor. C1021 is 8.2uf. C1041 is 15uf. R1061 is 2R. L1031 is 0.2mH. And I have a shunt resistor of 10R across the tweeter terminals. In my construction I have the shunt resistor attached at the end of R1061 that goes to the + terminal, and the other end of the shunt attaches at the end of the coil L1031 that attaches from the - terminal wire.
Attachments
So, it seems that I have one good tweeter and one bad tweeter.
Thanks for all the help.
Tweeters get blown when amplifiers clip. You may want a higher power amplifier to avoid clipping if that is happening.
The crossover software Xsim has a power calculation for every component. So you could load your crossover in that and plot the power going to the blown resistor and tweeter to see what it takes to blow them up.
You may be a good candidate for a pair of Hypex Fusion plate amps with DSP crossovers built in. You can create a bullet proof system with these. First you can easily put in 4th order crossovers with ease. The woofer and tweeter have separate amplifiers, so clipping the bass doesn't blow the tweeter. Lastly these amplifiers have a power limiting feature on each individual amplifier. So you can limit the power going to the tweeter to be 80% of it's specified long term power handling figure and it will never send it more power than that. So it will make your system party proof.
You might also look at crossovers that add a light bulb in series with the tweeter to limit the power.
https://www.hypex.nl/products/amplifier-families/fusion-amplifier-family/fusionamp-fa122
The crossover software Xsim has a power calculation for every component. So you could load your crossover in that and plot the power going to the blown resistor and tweeter to see what it takes to blow them up.
You may be a good candidate for a pair of Hypex Fusion plate amps with DSP crossovers built in. You can create a bullet proof system with these. First you can easily put in 4th order crossovers with ease. The woofer and tweeter have separate amplifiers, so clipping the bass doesn't blow the tweeter. Lastly these amplifiers have a power limiting feature on each individual amplifier. So you can limit the power going to the tweeter to be 80% of it's specified long term power handling figure and it will never send it more power than that. So it will make your system party proof.
You might also look at crossovers that add a light bulb in series with the tweeter to limit the power.
https://www.hypex.nl/products/amplifier-families/fusion-amplifier-family/fusionamp-fa122
I have given a few things some thought, and I think I have a likely understanding of what may have happened.
I am older and mostly listen to classical music, and mostly by myself. So, no loud drunken parties.
I also have had poor hearing for most of my life. Thus, my music listening has generally been at a louder level than that for many others with better hearing.
I recently got hearing aids, which have helped tremendously!!!!!
In 2022 I changed amplifiers, to an Orchard Audio Starkrimson Ultra amplifier. This amp has a current overprotection circuit. And in the first few months I tripped that protection circuit a few times. And the tripped module was always the same one. And that is the module that powered the speaker with the now blown tweeter.
The protection circuit tripped only when I had the music a bit on the loud side. The larger story here is that the new amp had a much lower input impedance than my old amp, Class A/B lateral mosfet amplifier. New amp had an input impedance lower than the impedance setting on my LDR volume control. I found I was often having the volume setting up close to maximum, just to get a suitable loudness level. And remember, much classical music is recorded at a much lower level than other musics, for dynamic range purposes. And the sacd recordings I favor are on labels that feature low recording levels and high dynamic range.
With the previous amplifier, and it's higher impedance level, I never had the volume control setting near as high as with the Starkrimson.
FWIW, Starkrimson input impedance is 47k. Old amp input impedance is 75k. Tortuga default impedance setting is 50k with LDR's and 60k with the discrete resistor module. I was using the discrete resistor module at the time I bought the Starkrimson. And I have noticed that when I got the discrete resistor module I had to turn the volume up quite a bit to get the same level as when I used the LDR module. I even wrote to Mort about this.
Then about a year ago I made a change in the LDR volume control. I changed out the discrete resistor module for the LDR module and was able to take advantage of the Tortuga adjustable impedance settings. I lowered the impedance setting to 10k significantly lower than the Starkrimson input impedance.
This change made a very significant difference in the volume control level setting. And I have not tripped the current overprotection circuit a single time since making this correction in the volume control.
And then when I got the hearing aids a few months ago, I could turn the volume level down another significant level again.
This all is my best understanding and best explanation of what might have blown my tweeter.
Thanks again to all who replied so quickly to my post. This is a great and very helpful audio forum!!!!!!!!
I am older and mostly listen to classical music, and mostly by myself. So, no loud drunken parties.
I also have had poor hearing for most of my life. Thus, my music listening has generally been at a louder level than that for many others with better hearing.
I recently got hearing aids, which have helped tremendously!!!!!
In 2022 I changed amplifiers, to an Orchard Audio Starkrimson Ultra amplifier. This amp has a current overprotection circuit. And in the first few months I tripped that protection circuit a few times. And the tripped module was always the same one. And that is the module that powered the speaker with the now blown tweeter.
The protection circuit tripped only when I had the music a bit on the loud side. The larger story here is that the new amp had a much lower input impedance than my old amp, Class A/B lateral mosfet amplifier. New amp had an input impedance lower than the impedance setting on my LDR volume control. I found I was often having the volume setting up close to maximum, just to get a suitable loudness level. And remember, much classical music is recorded at a much lower level than other musics, for dynamic range purposes. And the sacd recordings I favor are on labels that feature low recording levels and high dynamic range.
With the previous amplifier, and it's higher impedance level, I never had the volume control setting near as high as with the Starkrimson.
FWIW, Starkrimson input impedance is 47k. Old amp input impedance is 75k. Tortuga default impedance setting is 50k with LDR's and 60k with the discrete resistor module. I was using the discrete resistor module at the time I bought the Starkrimson. And I have noticed that when I got the discrete resistor module I had to turn the volume up quite a bit to get the same level as when I used the LDR module. I even wrote to Mort about this.
Then about a year ago I made a change in the LDR volume control. I changed out the discrete resistor module for the LDR module and was able to take advantage of the Tortuga adjustable impedance settings. I lowered the impedance setting to 10k significantly lower than the Starkrimson input impedance.
This change made a very significant difference in the volume control level setting. And I have not tripped the current overprotection circuit a single time since making this correction in the volume control.
And then when I got the hearing aids a few months ago, I could turn the volume level down another significant level again.
This all is my best understanding and best explanation of what might have blown my tweeter.
Thanks again to all who replied so quickly to my post. This is a great and very helpful audio forum!!!!!!!!
I fear your amp is oscillating. With such a powerful amp running out of current on decent audio signal is unlikely (your woofers would have suffered massively). So probably something went wrong. Does the amp have decent input and output HF filters?
Well, it is a Class D amplifier.....
Woofers are fine.
It is impossible to know when I burnt the shunt resistor, etc.
But after I corrected the impedance imbalance issue, no further issues with the amp.
Woofers are fine.
It is impossible to know when I burnt the shunt resistor, etc.
But after I corrected the impedance imbalance issue, no further issues with the amp.
I missed that... Your impedance analysis could be right, but (at least in theory) transmission can be fine with input and output impedance in the same range. Oscillating won't have happened, HF (audio band) components in the audio signal because of the chain setup might. And you likely will not have heard that (most of us don't hear 18kHz at full power). I'd measure the chain with a scope or with my measuring gear.
I just went back and measured the tweeters again. This time I disconnected both wire leads and measured each tweeter out of the box.
The suspected bad tweeter still shows NO reading whatsoever. The reading across the wires reads 10R with the newly installed replacement resistor.
The suspected good tweeter measures 6.4 ohms now. The reading across the wires reads 10.2 ohms. Thus, that tweeter is all good.
I do not have a scope so cannot measure the amp. The modules were new and fully tested by Leo when I bought them. And the protection circuit performed as designed. Perhaps it should have kicked in sooner than it did, hard to know.
Again, after correcting the impedance issue, all has been well.
I am fairly confident now that I can install a new tweeter and be okay.
The suspected bad tweeter still shows NO reading whatsoever. The reading across the wires reads 10R with the newly installed replacement resistor.
The suspected good tweeter measures 6.4 ohms now. The reading across the wires reads 10.2 ohms. Thus, that tweeter is all good.
I do not have a scope so cannot measure the amp. The modules were new and fully tested by Leo when I bought them. And the protection circuit performed as designed. Perhaps it should have kicked in sooner than it did, hard to know.
Again, after correcting the impedance issue, all has been well.
I am fairly confident now that I can install a new tweeter and be okay.
So, good to know how to do parallel resistance/impedance math. For any two devices in parallel the impedance will NEVER be higher than the smallest one. So if you have 10 and 8, you are guaranteed the final result will be less than ten, and probably closer to 4. The calculation is something like this:
1 / ( (1/10) + (1/8))
1 / ( (1/10) + (1/8))
I think I may know what happened to my tweeter. Some memory kicked in this morning, and I remembered something from 3+ years ago.
Well before I went with the Starkrimson amp, my amp designer friends from Melbourne came to visit, listen and evaluate a new amp prototype.
And I remember that there was a connection issue with the speaker cable spades and small binding posts on one of the amp channels. I did not know the amp was actually ON, something touched, and there was a loud POP.
Eventually everything got sorted out with the connections, after the amp got turned OFF. But on the side that had popped, there was no sound. It was a definite worst-case scenario. When I reconnected my own amplifier to the speaker, there was sound. So, I thought at least I had not blown up my speaker.
And when my friends returned home, there was no damage to the amplifier. So, all seemed okay.
But now that I have remembered this incident, it could well have been what blew up the shunt resistor and tweeter voice coil. It certainly makes more sense that the overcurrent protection not tripping fast enough.
And after this I decided to change from spade ends on the cable to bananas for the amp connection.
Well before I went with the Starkrimson amp, my amp designer friends from Melbourne came to visit, listen and evaluate a new amp prototype.
And I remember that there was a connection issue with the speaker cable spades and small binding posts on one of the amp channels. I did not know the amp was actually ON, something touched, and there was a loud POP.
Eventually everything got sorted out with the connections, after the amp got turned OFF. But on the side that had popped, there was no sound. It was a definite worst-case scenario. When I reconnected my own amplifier to the speaker, there was sound. So, I thought at least I had not blown up my speaker.
And when my friends returned home, there was no damage to the amplifier. So, all seemed okay.
But now that I have remembered this incident, it could well have been what blew up the shunt resistor and tweeter voice coil. It certainly makes more sense that the overcurrent protection not tripping fast enough.
And after this I decided to change from spade ends on the cable to bananas for the amp connection.