My AP Centuries have a resistor in the high-mid cross-over section which have suffered from over-heating. In one speaker it seems to be fine but everything around is brown. In the other speaker it is worst, and the resistor is disconnected, the soldering melted. These resistors are soldered in parallel and over a 4.7 ohms - 5 watts ceramic resistor.
I want to replace both resistors but I need help to identify them, type and value.
Also these resistors seems to have different values in every speaker, (1st. and 2nd. band seems to have different colors) Is that so ? Why would it be ?
I am attaching pictures.
Finally, Where could I find the AP Avanti Centuries' cross-over diagrams ?
Thank you
I want to replace both resistors but I need help to identify them, type and value.
Also these resistors seems to have different values in every speaker, (1st. and 2nd. band seems to have different colors) Is that so ? Why would it be ?
I am attaching pictures.
Finally, Where could I find the AP Avanti Centuries' cross-over diagrams ?
Thank you
Attachments
This looks like it should be in the multi-way forum.
Are you sure they're not just different because one has been heated more than the other? I'd try working out the resistance value from the bands, and then use a DMM if they're not open circuit, to see if the band value and measured value are close. That is, if you can't find a schematic.
There's a chance these were used to tune the crossover to a particular response curve (for example to pad down the tweeter by finer adjustment of the resistance over the ceramic) so they might not be the same in every speaker, although this implies quite bespoke manufacture (=$) and it's more likely they are all the same for that speaker series. This would also imply their resistance is quite a bit lower than the 5w as it is probably just for lowering the overall resistance across that point a tad, as would be required to adjust the response. This would also sit with them burning (as they'd carry more current, having lower resistance than the 5w) although their lower power rating is also an issue here.
As for wattage, they look like 3 watt rated, but that's only based on size. I'd use a 5 watt resistor if you can get one in the value required, but they probably didn't for that reason - because it's an intermediate value not available in the 5w series.
I hope that might give you some ideas.
Are you sure they're not just different because one has been heated more than the other? I'd try working out the resistance value from the bands, and then use a DMM if they're not open circuit, to see if the band value and measured value are close. That is, if you can't find a schematic.
There's a chance these were used to tune the crossover to a particular response curve (for example to pad down the tweeter by finer adjustment of the resistance over the ceramic) so they might not be the same in every speaker, although this implies quite bespoke manufacture (=$) and it's more likely they are all the same for that speaker series. This would also imply their resistance is quite a bit lower than the 5w as it is probably just for lowering the overall resistance across that point a tad, as would be required to adjust the response. This would also sit with them burning (as they'd carry more current, having lower resistance than the 5w) although their lower power rating is also an issue here.
As for wattage, they look like 3 watt rated, but that's only based on size. I'd use a 5 watt resistor if you can get one in the value required, but they probably didn't for that reason - because it's an intermediate value not available in the 5w series.
I hope that might give you some ideas.
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the white things on that carbon resistor looks like a glue 
and both resistor looks like in different value.company might did it for fine tune imo..but im not sure about the meltdown..
still wonder why the resistor can disconnected physically instead of burned out if it's really overheated
and both resistor looks like in different value.company might did it for fine tune imo..but im not sure about the meltdown..
still wonder why the resistor can disconnected physically instead of burned out if it's really overheated
Thank you Stuey,
I removed the resistors, one measure 8.5 and the other one 8.9 ohms, so I think they used to be same value resistors, the overheating altered the colors and a little the value ????
I happen to have on hand a pair of 3.7 ohms 10 watts Duelund resistors, Would it be okey to replace the paralell connected resistors ( 5 ohm - 5 watts and ~8.7 ohm ) for this Duelund ?
The resistor is connected in series with the mid range unit.
Thank you again.
I removed the resistors, one measure 8.5 and the other one 8.9 ohms, so I think they used to be same value resistors, the overheating altered the colors and a little the value ????
I happen to have on hand a pair of 3.7 ohms 10 watts Duelund resistors, Would it be okey to replace the paralell connected resistors ( 5 ohm - 5 watts and ~8.7 ohm ) for this Duelund ?
The resistor is connected in series with the mid range unit.
Thank you again.
Thank you Ishiru,
General question, for crossover fine tunning, would it make any difference a 3.2 or 3.7 ohms resistor in the midrange driver ?
Thank you
General question, for crossover fine tunning, would it make any difference a 3.2 or 3.7 ohms resistor in the midrange driver ?
Thank you
and now it is It is certainly worth a try. The value difference may be too small to hear. You may also hear a difference for the better. You are however potentially losing the whole point of the perfectly dialed in resistance if that is the purpose of that configuration. I would try it..
Hi,
3.7R is a little higher than the previous combination
so it will work fine, the change in mid is unlikely to
be that noticeable, and may be better or worse.
rgds, sreten.
Adding a further parallel 22R is a tuning option, (or 10R or 15R).
3.7R is a little higher than the previous combination
so it will work fine, the change in mid is unlikely to
be that noticeable, and may be better or worse.
rgds, sreten.
Adding a further parallel 22R is a tuning option, (or 10R or 15R).
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I'd guess those resistors would be specified at the same value originally, probably orignal spec being 8.2 ohms. Depending on tolerance value, they may still be in spec.
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