The resistor came out of a Vandersteen 3A crossover (see attached pictures). I got the color code off it, but I don't know what value it is. It's bigger than the 3W resistors I have, but 2Mohm 5W resistor turns up no axial parts on Mouser, so I wondered if maybe I was barking up the wrong tree. I've posted on the Vandersteen forums, but if they don't come back with an answer, is there any way to figure out the appropriate value?
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Various brands of power resistors will vary in size for the same power. You'd have to know the
brand to be sure of the power rating. It's probably 3W or more. Of course it has been derated.
Just install the largest one that will fit, for the brand you choose.
brand to be sure of the power rating. It's probably 3W or more. Of course it has been derated.
Just install the largest one that will fit, for the brand you choose.
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Looks like I'll have to make a tipi with two 1M resistors then. Which means I can pair two 3W and probably be fine. That's what I'll do if I don't get a useful reply from Vandersteen.
It's very unlikely there's been a 1M resistor in any loudspeaker crossover ever made.
Believe that's a 1.0 Ohm resistor.
Believe that's a 1.0 Ohm resistor.
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Ok, in that photo the stripe looks red instead of brown, but it's not gonna be 2M,
which would have no function in any loudspeaker crossover.
Since the third stripe is gone, it's probably either 2.0R (red black gold)
or 20R (red black black). I would check the other speaker of the pair and see.
which would have no function in any loudspeaker crossover.
Since the third stripe is gone, it's probably either 2.0R (red black gold)
or 20R (red black black). I would check the other speaker of the pair and see.
Hmm… have a hard time believing that third ring isn’t green. It’s clearly *something*, not burn and not the background blue. And it doesn’t look brown or orange to me.
(This failure caused the tweeter to drop out) I clipped in a couple resistors I had with leads to experiment. 2.6M made the tweeter a bit quieter than correct. Two 1M in series sounded about right (well, considering my tweeter is sitting on the table next to me). That makes me think I’m in the right ballpark. If 2.6M was close and 2M was pretty good, how could 1 or 20 be right?
(This failure caused the tweeter to drop out) I clipped in a couple resistors I had with leads to experiment. 2.6M made the tweeter a bit quieter than correct. Two 1M in series sounded about right (well, considering my tweeter is sitting on the table next to me). That makes me think I’m in the right ballpark. If 2.6M was close and 2M was pretty good, how could 1 or 20 be right?
People knee jerk answer questions in DIY Audio without even analyzing them.
NO WAY there is a 2M or even 1M resistors in a speaker cabinet passive crossover.
NO WAY there is enough voltage to burn one of them EVEN IF any is present.
So this should have been the FIRST answer, even before arguing different substitutions or dissipation.
Just sayin´
NO WAY there is a 2M or even 1M resistors in a speaker cabinet passive crossover.
NO WAY there is enough voltage to burn one of them EVEN IF any is present.
So this should have been the FIRST answer, even before arguing different substitutions or dissipation.
Just sayin´
In the smaller detail at top left, it looks to me like red-black-gold...brown?
red-black-gold would indicate 20x0.1 or 2 ohms., gold as a 3rd band is a 0.1 multiplier.
The last band is probably brown as a +/-1% tolerance band. I was a bit hesitant about calling the brown brown, but I can't convince myself of a different color, and a different color wouldn't make a lot of sense in the multiplier position.
The toasted one isn't really readable, but I assumed the full circuit photo with a resistor at top left was it (or another of the same type). There's no mistaking THAT resistor's gold sparkle, which tells me the 4th band can't be gold, so brown (1%) was my only remaining option.
Why I looked at the resistor on the board I am not sure...assumed you showed it for a reason.
Jeez...now the upper left resistor looks like BROWN is the first band. There are other values with gold multiplier, and one or two with a gold tolerance band.
So what I assumed was a red first band was not the damaged resistor.
Do such small resistances function in setting corner frequencies, or adjust the Q of an inductor or an LC pair?
red-black-gold would indicate 20x0.1 or 2 ohms., gold as a 3rd band is a 0.1 multiplier.
The last band is probably brown as a +/-1% tolerance band. I was a bit hesitant about calling the brown brown, but I can't convince myself of a different color, and a different color wouldn't make a lot of sense in the multiplier position.
The toasted one isn't really readable, but I assumed the full circuit photo with a resistor at top left was it (or another of the same type). There's no mistaking THAT resistor's gold sparkle, which tells me the 4th band can't be gold, so brown (1%) was my only remaining option.
Why I looked at the resistor on the board I am not sure...assumed you showed it for a reason.
Jeez...now the upper left resistor looks like BROWN is the first band. There are other values with gold multiplier, and one or two with a gold tolerance band.
So what I assumed was a red first band was not the damaged resistor.
Do such small resistances function in setting corner frequencies, or adjust the Q of an inductor or an LC pair?
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Look in your other one so you can read the color code accurately.
First, why did this fail? You can replace it ( the Dayton ones are pretty good) but something caused it to fail. Looks like a 2 W, but any higher wattage will be fine
First, why did this fail? You can replace it ( the Dayton ones are pretty good) but something caused it to fail. Looks like a 2 W, but any higher wattage will be fine
multi-volt: That's for actually digging in and trying to help me ID this thing instead of just saying I'm wrong with no other useful info 🙂
tvrgeek: I was testing a preamp which had a very loud "pop" when throwing the "tone-in" switch. I believe that is when it happened. At least, that is the most likely scenario I can come up with.
I did some more experimenting. It seems the circuit works "fine" without that resistor in place at all. It connects to ground/neutral, so I'm thinking maybe it's an overflow for high voltage? 😕
Opening up these speakers is a royal PITA. You have to pry-off the bottom cap, then remove ~1,500,000 staples, then roll up the cloth sock, then you have to remove the mid bass driver and de-solder it, and remove enough stuffing to make Pooh Bear obese in order to get to the actual crossover.
I'll contact the manufacturer tomorrow. Probably talk to Richard Vandersteen, unless he wants to give me to someone who better remembers resistor values. If that fails, or their only recourse is to send in the crossover, I'll open up the other speaker and see what's what.
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I'm still convinced that's a green third band 😛 But multi-volti's assessment of the nearby resistors is compelling. Especially if it's the same value as the one to the upper-left of it.
tvrgeek: I was testing a preamp which had a very loud "pop" when throwing the "tone-in" switch. I believe that is when it happened. At least, that is the most likely scenario I can come up with.
I did some more experimenting. It seems the circuit works "fine" without that resistor in place at all. It connects to ground/neutral, so I'm thinking maybe it's an overflow for high voltage? 😕
Opening up these speakers is a royal PITA. You have to pry-off the bottom cap, then remove ~1,500,000 staples, then roll up the cloth sock, then you have to remove the mid bass driver and de-solder it, and remove enough stuffing to make Pooh Bear obese in order to get to the actual crossover.
I'll contact the manufacturer tomorrow. Probably talk to Richard Vandersteen, unless he wants to give me to someone who better remembers resistor values. If that fails, or their only recourse is to send in the crossover, I'll open up the other speaker and see what's what.
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I'm still convinced that's a green third band 😛 But multi-volti's assessment of the nearby resistors is compelling. Especially if it's the same value as the one to the upper-left of it.
The green band is not the third, it is the fourth. You cannot see the third band because it has burned away. The green band also is within the burnt area and has likely changed color somewhat from its original hue. I could be wrong, but that is how I see it. One has to wonder what a 2M resistor could be doing in a speaker.
So: red-black-??-"green"-gold.
Colors are notorious for changing appearance on burnt resistors. A red band makes a darn convincing brown or even black much of the time.
Overflow for high voltage? That is hard to fathom, there is no high voltage in a speaker.
DO you have another of these speakers? When you say this speaker works fine without that resistor, does it sound identical to the other speaker? I know you don't want to open up another one, but it might pay to check for the same damage.
In my estimation, a loud pop wouldn't cause that sort of damage. That resistor burnt from excess current through it for some period of time. If it is associated with the nearby L-pad, you might see if the L-pads are functioning. A typical reason might be running too much high end into the speaker for extended time.
As a service tech, when I see something like this, I expect to see the speakers mate with the same damage. Since most folks crank up the volume and/or EQ on both sides at on .
Just as a exercise, assume that was a 1 watt resistor of 2M ohms, 2,000,000 ohms. What voltage would have to be across the resistor to cause it to dissipate 1 watt? I get a little over 1400 volts, if I did it correctly.
So: red-black-??-"green"-gold.
Colors are notorious for changing appearance on burnt resistors. A red band makes a darn convincing brown or even black much of the time.
Overflow for high voltage? That is hard to fathom, there is no high voltage in a speaker.
DO you have another of these speakers? When you say this speaker works fine without that resistor, does it sound identical to the other speaker? I know you don't want to open up another one, but it might pay to check for the same damage.
In my estimation, a loud pop wouldn't cause that sort of damage. That resistor burnt from excess current through it for some period of time. If it is associated with the nearby L-pad, you might see if the L-pads are functioning. A typical reason might be running too much high end into the speaker for extended time.
As a service tech, when I see something like this, I expect to see the speakers mate with the same damage. Since most folks crank up the volume and/or EQ on both sides at on .
Just as a exercise, assume that was a 1 watt resistor of 2M ohms, 2,000,000 ohms. What voltage would have to be across the resistor to cause it to dissipate 1 watt? I get a little over 1400 volts, if I did it correctly.
Touché guys, you have provided some valuable points of education, even if you did have to clonk me over the head with them 😛
From the horses mouth, that's a 20 ohm 3W resistor. I'll check that second potentially damaged one, too. Thanks for calling that out turk.
I ran this speaker and it's mate with only the top section connected (since I have the bass woofer removed for access, not in perfect stereo, but one on each side of me at similar distances. Unscientifically, they sounded the same. I had alligator leads clipped on to the old posts, and I tried them with a 22 ohm resistor and open, without any apparent change in the sound.
From the horses mouth, that's a 20 ohm 3W resistor. I'll check that second potentially damaged one, too. Thanks for calling that out turk.
I ran this speaker and it's mate with only the top section connected (since I have the bass woofer removed for access, not in perfect stereo, but one on each side of me at similar distances. Unscientifically, they sounded the same. I had alligator leads clipped on to the old posts, and I tried them with a 22 ohm resistor and open, without any apparent change in the sound.
I think it's just flux. I was able to get some of it off with alcohol and a brush. See before/after attachments.
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I checked the other speaker, no sign of damage there. I may have only had one connected at the time of the incident. Thanks all!