having seen the "Mission" post and having also taken apart quite a few older cross-overs when making repairs and salvaging parts from older boxes I have a query.
Would it be an advantage to mount the cross-over resistors on individual heat-sinks??
I have just picked up some industrial shelving support from a junk pile, ot is perforated and by cutting small lengths of it and using silicone as the glue i could attach the ceramic resistors in such a way as to cool said resistor more effectively.
Is there any real advantage??
Would it be an advantage to mount the cross-over resistors on individual heat-sinks??
I have just picked up some industrial shelving support from a junk pile, ot is perforated and by cutting small lengths of it and using silicone as the glue i could attach the ceramic resistors in such a way as to cool said resistor more effectively.
Is there any real advantage??
These types of resistors are designed not to need a heatsink - the body can dissipate the rated power. The problem arises simply because of a combination of any or all of:
- too much voltage applied (exceed power rating), abuse from clipping etc
- inadequate airflow given to implementation
- underspec power rating to save a few pennies
- too much voltage applied (exceed power rating), abuse from clipping etc
- inadequate airflow given to implementation
- underspec power rating to save a few pennies
It is just that I have seen so many instances where the resistor has burnt the substrate the have been attached to, either foam as in the case of my IMF's or the cheap fibre of some of the printed circuit boards.
I know in amplifier applications ceramic resistors are always mounted proud of the base/ circuit board to allow airflow but in all the crossover applications I have seen they are glued hard against the board.
It seemed like a no cost possible benefit
I know in amplifier applications ceramic resistors are always mounted proud of the base/ circuit board to allow airflow but in all the crossover applications I have seen they are glued hard against the board.
It seemed like a no cost possible benefit
You can just suspend the resistors in free air above the board - just solder them in with short leads and the wire itself will hold them up. No need to rig up anything underneath it, unless you just want to glue in a small piece of metal or other heat resistant material for looks and/or extra stability.
I was under the impression that the resistance changes with significant change in temperature, and that the signal undergoes distortion above a particular temperature for that component.
i.e. that a ceramic reisistor shouldn't get noticably hot?
Metal Oxide resistors (high cost, but good sound) can be heat sinked to handle 100 plus watts (i.e not get noticably hot under normal use), or mutiple higher valued ceramic resitors can be paralleled as necessary.
David
i.e. that a ceramic reisistor shouldn't get noticably hot?
Metal Oxide resistors (high cost, but good sound) can be heat sinked to handle 100 plus watts (i.e not get noticably hot under normal use), or mutiple higher valued ceramic resitors can be paralleled as necessary.
David
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