Why do the resistors of my 3 way crossovers get very hot on high volumes?

[Verdinut]

I rather not mention any brand or model names. I have a high end 2005 receiver, its almost 50 pounds in weight, $2000 brand new, amazing low freqs it produces. I was lucky to find it lightly used 2 years ago on internet for almost $400 including delivery.

The stats on my receiver is 120 watts x 7 (840 watts-not 500 watts as I stated before), 8 ohms, also using a seperate EQ, have 2 speaker boxes, per speaker box includes all 8 ohms- 1- 15" bass subwoofer 600 watt, 1- 8" midrange 300 watts each, 1- 3.75" tweeter 300 watts, not sure of other info.

The crossovers I bought 4 months ago (over heating resistors started 4 or so days ago), are generic and handles 1000 watts each at 8 ohms. The resistors had to go due to them getting too hot to the point of smelling like over heated plastic or ceramic only when playing at very loud volumes for an hour. They would of eventually burned or damaged the circuit board. Will either solder a wire or 20 watt resistors, may order a solder gun today or tomorrow. At least with a solder gun you don't have to use a 2nd hand to hold the solder, you just use 1 hand and press the lever and place melted solder at a precise spot.

The crossovers I had before I bought the new crossovers lasted 15 years and they never had resistors. The midrange (not the tweeter) sounded too loud on those older crossovers (as well as the new ones) and I all I need to do is lower the highs on my EQ's to give me the exact sound I want.

I totally agree with TLS Guy's reply in post#12 above about the crossover which you are using. It is not appropriate with your speaker drivers.

Also, your 7 channel receiver has a rated power output per channel of 120 watts. But the total power output per channel would be reduced if you used the All Channel Stereo playback setting, as its power supply is not adequate to produce 120 watts on all channels simultaneously. IMO, no AVR on the market is designed to produce the full rated power on that setting. Your AVR will likely output 90 watts/ch at the most with all channels driven.

 

[lovinthehd]

I totally agree with TLS Guy's reply in post#12 above about the crossover which you are using. It is not appropriate with your speaker drivers.

Also, your 7 channel receiver has a rated power output per channel of 120 watts. But the total power output per channel would be reduced if you used the All Channel Stereo playback setting, as its power supply is not adequate to produce 120 watts on all channels simultaneously. IMO, no AVR on the market is designed to produce the full rated power on that setting. Your AVR will likely output 90 watts/ch at the most with all channels driven.

Not that you'll likely ever need simultaneous max power from each channel either....

 

[highfigh]

I rather not mention any brand or model names. I have a high end 2005 receiver, its almost 50 pounds in weight, $2000 brand new, amazing low freqs it produces. I was lucky to find it lightly used 2 years ago on internet for almost $400 including delivery.

The stats on my receiver is 120 watts x 7 (840 watts-not 500 watts as I stated before), 8 ohms, also using a seperate EQ, have 2 speaker boxes, per speaker box includes all 8 ohms- 1- 15" bass subwoofer 600 watt, 1- 8" midrange 300 watts each, 1- 3.75" tweeter 300 watts, not sure of other info.

The crossovers I bought 4 months ago (over heating resistors started 4 or so days ago), are generic and handles 1000 watts each at 8 ohms. The resistors had to go due to them getting too hot to the point of smelling like over heated plastic or ceramic only when playing at very loud volumes for an hour. They would of eventually burned or damaged the circuit board. Will either solder a wire or 20 watt resistors, may order a solder gun today or tomorrow. At least with a solder gun you don't have to use a 2nd hand to hold the solder, you just use 1 hand and press the lever and place melted solder at a precise spot.

The crossovers I had before I bought the new crossovers lasted 15 years and they never had resistors. The midrange (not the tweeter) sounded too loud on those older crossovers (as well as the new ones) and I all I need to do is lower the highs on my EQ's to give me the exact sound I want.

Don't care about cost, weight, amazing low frequencies- they don't matter, but without knowing what you're using, it's impossible for us to make any kind of educated assessment. The receiver should produce all frequencies equally well.

You need to look at the crossovers and, really, you should provide a clear photo that would allow us to see the component values- there's no way to know what is needed or why the resistors are overheating without seeing what's on the boards.

How much equalization are you using and what is the volume control setting when you operate the system? If you jacked the EQ and volume controls, it's likely that your receiver is clipping and that can cause all kinds of problems.

BTW- you don't place solder, you heat the board's trace and the wire to a component and let it flow toward the hot area. 'Placing' a blob of solder results in cold (bad) solder joints.

 

[highfigh]

Not that you'll likely ever need simultaneous max power from each channel either....

Unless it's in Party Mode.

 

[lovinthehd]

Unless it's in Party Mode.

Yeah am just thinking of normal surround, haven't been any parties lately.....

 

[slipperybidness]

I rather not mention any brand or model names. I have a high end 2005 receiver, its almost 50 pounds in weight, $2000 brand new, amazing low freqs it produces. I was lucky to find it lightly used 2 years ago on internet for almost $400 including delivery.

The stats on my receiver is 120 watts x 7 (840 watts-not 500 watts as I stated before), 8 ohms, also using a seperate EQ, have 2 speaker boxes, per speaker box includes all 8 ohms- 1- 15" bass subwoofer 600 watt, 1- 8" midrange 300 watts each, 1- 3.75" tweeter 300 watts, not sure of other info.

The crossovers I bought 4 months ago (over heating resistors started 4 or so days ago), are generic and handles 1000 watts each at 8 ohms. The resistors had to go due to them getting too hot to the point of smelling like over heated plastic or ceramic only when playing at very loud volumes for an hour. They would of eventually burned or damaged the circuit board. Will either solder a wire or 20 watt resistors, may order a solder gun today or tomorrow. At least with a solder gun you don't have to use a 2nd hand to hold the solder, you just use 1 hand and press the lever and place melted solder at a precise spot.

The crossovers I had before I bought the new crossovers lasted 15 years and they never had resistors. The midrange (not the tweeter) sounded too loud on those older crossovers (as well as the new ones) and I all I need to do is lower the highs on my EQ's to give me the exact sound I want.

The various specs that you have provided are largely useless!

Before you say the resistors are "too hot", exactly how hot did they get? This is where an IR thermometer comes in quite handy!

Why would you think a 20W resistor would be less hot? The heat comes from the power that the resistor is dissipating. A 20W resistor can dissipate more heat before it burns out, but the heat that is dissipated will be the same if all other variables are held the same.

The bottom line here-- From the info that you have given, and the ideas that you have presented, it is very clear that you are in way over your head here! You have come to the right place to start learning, and every expert today was a novice at some point, so I'm not trying to discourage your learning experience. But, as others have said, if you really want the best help, then accurate descriptions with actual make/model and detailed pics is the best path to getting the best help.

Note-- It would seem that those crossovers can't handle 1000W each, as you are certainly not hitting them with that much power and they are "over-heating", maybe. Furthermore, the 8ohms rating on that power handling doesn't really make much sense.

 

[highfigh]

Note-- It would seem that those crossovers can't handle 1000W each, as you are certainly not hitting them with that much power and they are "over-heating", maybe. Furthermore, the 8ohms rating on that power handling doesn't really make much sense.

I worked with someone at a stereo shop who was a bit of a smart-ass and when people would ask if an inexpensive speaker would handle 100 Watts, he would say "Yeah, sure...A hundred Watts? Yeah, it'll handle 100 Watts....once.".

 

[highfigh]

Sorry for this stupid question: Could a resistor be considered a mini "step down transformer" in a circuit?

No- it will reduce voltage/current, but it wastes a lot of energy in the process and that heat can damage other nearby components. A transformer uses a magnetic field to couple the input (primary) winding(s) with the output (secondary) winding(s)- if more voltage is desired, the ratio of 'turns' between the primary and secondary will be expressed as something like 40:1 and if less voltage is desired, it would be something like 1:40.

Resistors are a good way to drop voltage, but they do waste energy and in extreme cases, the excessive heat can damage combustible materials in the area, which means they can burn.

 

[highfigh]

I asked the seller around 5 hours ago if I were to remove the resistors would I need to replace it with a wire running across if I don't replace with a better resistor and he didn't respond yet. I asked him yesterday would removing the resistors cause an affect or difference to the crossovers and he replied yesterday and said exactly this, "Nope, the white stand-offs just allow the crossover to sit up a bit, other than that no function." and then he also replied, "The resistors in the crossover help it maintain a constant 8 ohms to your amplifier".

SO is there still a chance if I were to remove the resistors and not solder a wire back, will the bass, mid and tweeter all work or will any of them not work until I solder a wire or other resistor back? I'm kind of an amateur and would rather not solder at all for fear I may damage the crossover, can I use a tool to remove the resistors or is melting the silver solder the only option?

FINAL question, if I decide to buy a new 3 way crossover now or in the furture, can I buy a 3 way crossover with NO resistors? Do they make 3 way crossovers with no resistors or do all of them have them?

Don't worry about whether a crossover has resistors- they perform a specific task, which is to balance the output volume of the speaker components, but the issue here is: were these crossovers just something this seller buys or makes, or were they designed specifically for your speaker components? If they're generic, being what your speakers need is a pipe dream and if they were designed specifically for your components, he blew it, or you're cranking the receiver past its limits of clean power and the amount of boost you're using with your equalizer is causing so much distortion that the resistors are being treated like farm animals.

As far as these crossovers handling 1000 Watts, I seriously doubt they would. You have been the victim of faulty information- if it was a small difference between the description and reality, it could be said that the specs are optimistic and if there's not a small chance of these handling 1000 Watts, it was a lie.

Just in case you might want to know, the difference between the voltage at 100W and 1000W is- 100W going to 8 Ohm speaker impedance would be 28.3V and for 1000 Watts, it would be 89.4V and if you look at the parts with numbers on the crossover, you should see voltage ratings, especially on the capacitors (the tubular parts with a wire coming out of each end). These would need to be rated for at least 150V and it would be shown as 150WVDC. If they show 50WVDC, they're designed for 100 Watts, not 1000 Watts. That rating is used to prevent component failure and if the capacitors fail, you won't hear anything from the midrange and/or tweeter and it may make some sound of its own when it fails, as well as possibly adding some odor.

 

[slipperybidness]

or you're cranking the receiver past its limits of clean power and the amount of boost you're using with your equalizer is cause so much distortion that the resistors are being treated like farm animals.

I didn't pick up on that equalizer info at first.

My $ says you nailed it right here!

@nickless exactly HOW are you using your outboard equalizer??? Are you using it to cut certain freqs? Or to boost certain freqs? How much boost and what freqs?

 

[nickless]

Also, your 7 channel receiver has a rated power output per channel of 120 watts. But the total power output per channel would be reduced if you used the All Channel Stereo playback setting, as its power supply is not adequate to produce 120 watts on all channels simultaneously. IMO, no AVR on the market is designed to produce the full rated power on that setting. Your AVR will likely output 90 watts/ch at the most with all channels driven.

My receiver is a 7.1 surround sound type. I only use 2 speaker boxes (not 7), and the 2 channels that im using are receiving equal wattage as all 7 channels as this type of receiver is known to provide that. That means 120 watts x 7 channels=840 watts total. For 2 channels that would be 420 watts per channel, if im correct. The specs also state they may be 100 watts per channel (or 120 watts per channel), not sure which one. If theyre 100 wattts per channel that means thats 350 watts per channel when using the stereo output instead of surround sound. I was never a fan of surround sound where you have to place 6 or 7 speakers all around the room. WT?? Although i know people prefer that when watching a movie but surround sound is not at all good when playing CDS.

 

[highfigh]

My receiver is a 7.1 surround sound type. I only use 2 speaker boxes (not 7), and the 2 channels that im using are receiving equal wattage as all 7 channels as this type of receiver is known to provide that. That means 120 watts x 7 channels=840 watts total. For 2 channels that would be 420 watts per channel, if im correct. The specs also state they may be 100 watts per channel (or 120 watts per channel), not sure which one. If theyre 100 wattts per channel that means thats 350 watts per channel when using the stereo output instead of surround sound. I was never a fan of surround sound where you have to place 6 or 7 speakers all around the room. WT?? Although i know people prefer that when watching a movie but surround sound is not at all good when playing CDS.

AV receivers don't send all of the power from all channels to one pair of outputs because each channel has its own amplifier, so no- you're not going to have 350W coming from one pair of terminals. If it did, you would have the same situation as using a powerful stereo amplifier and a speaker selector with level controls and that's not how these work.

Again, you really need to provide more info because someone hasn't been telling you the truth about this stuff.

 

[slipperybidness]

My receiver is a 7.1 surround sound type. I only use 2 speaker boxes (not 7), and the 2 channels that im using are receiving equal wattage as all 7 channels as this type of receiver is known to provide that. That means 120 watts x 7 channels=840 watts total. For 2 channels that would be 420 watts per channel, if im correct. The specs also state they may be 100 watts per channel (or 120 watts per channel), not sure which one. If theyre 100 wattts per channel that means thats 350 watts per channel when using the stereo output instead of surround sound. I was never a fan of surround sound where you have to place 6 or 7 speakers all around the room. WT?? Although i know people prefer that when watching a movie but surround sound is not at all good when playing CDS.

Well your ability for providing useless information is surpassed by very few around these parts.

 

[Truthslayer]

My receiver is a 7.1 surround sound type. I only use 2 speaker boxes (not 7), and the 2 channels that im using are receiving equal wattage as all 7 channels as this type of receiver is known to provide that. That means 120 watts x 7 channels=840 watts total. For 2 channels that would be 420 watts per channel, if im correct. The specs also state they may be 100 watts per channel (or 120 watts per channel), not sure which one. If theyre 100 wattts per channel that means thats 350 watts per channel when using the stereo output instead of surround sound. I was never a fan of surround sound where you have to place 6 or 7 speakers all around the room. WT?? Although i know people prefer that when watching a movie but surround sound is not at all good when playing CDS.

Nope- Your still only getting 120 watts in stereo mode. You've been given a lot of valuable info in this thread.
Your expecting more from your receiver than it can deliver. Mostly likely you are over driving the receiver, hence sending distortion. Thus causing this heating issue in the resistors which seems to be bothering you.

In your situation and the limited info you wish to supply, you should have only removed the resistors if you were going to replace them better quality and equal value. But to just remove the resistors and use a straight wire, is asking for trouble. Your going to be sorry you didn't heed all all the advice you've been given.

 

[Verdinut]

My receiver is a 7.1 surround sound type. I only use 2 speaker boxes (not 7), and the 2 channels that im using are receiving equal wattage as all 7 channels as this type of receiver is known to provide that. That means 120 watts x 7 channels=840 watts total. For 2 channels that would be 420 watts per channel, if im correct. The specs also state they may be 100 watts per channel (or 120 watts per channel), not sure which one. If theyre 100 wattts per channel that means thats 350 watts per channel when using the stereo output instead of surround sound. I was never a fan of surround sound where you have to place 6 or 7 speakers all around the room. WT?? Although i know people prefer that when watching a movie but surround sound is not at all good when playing CDS.

If each amplifier has a rated output of 100 watts, in stereo it does not become more powerful. In stereo, you would still get 100 watts coming out of each channel.

You would need to read books on audio amplifiers to learn about the real facts on electronics and audio playback.

 

[lovinthehd]

Well it's about the method of rating to an extent, too. If conservatively rated (not likely these days more and more) the two channel spec might bench test significantly better than it's rating.....but how 420wpc comes out of using multiple channels is a concept even the marketers aren't using

 

[NINaudio]

Well it's about the method of rating to an extent, too. If conservatively rated (not likely these days more and more) the two channel spec might bench test significantly better than it's rating.....but how 420wpc comes out of using multiple channels is a concept even the marketers aren't using

Maybe he's tried bridging it?

 

[highfigh]

Well it's about the method of rating to an extent, too. If conservatively rated (not likely these days more and more) the two channel spec might bench test significantly better than it's rating.....but how 420wpc comes out of using multiple channels is a concept even the marketers aren't using

Maybe FM is involved (not Frequency Modulation).

 

[Kvn_Walker]

This is one of those priceless threads where someone asks for help but really doesn't want to be helped.

"I want you to fix my problem, but I won't tell you what my equipment is or how it's set up."

 

[ryanosaur]

This is one of those priceless threads where someone asks for help but really doesn't want to be helped.

"I want you to fix my problem, but I won't tell you what my equipment is or how it's set up."

Remind us of anything?

Would wiring 4 super tweeters per speaker box increase life of tweeters?

I bought 8 super bullet 3" tweeters at 8 ohms each and have a 500 watt receiver. I want to wire 4 tweeters to each 3 way crossover per speaker box.(2- 3 way crossovers, 2 speaker boxes[per each box- 1 15" woofer,1 mid range,plus 4 tweeters]). Through the years i always wired just 1 tweeter to a...

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