LOVE the bobbin holders and the detail of mounting them at 90 degrees from each other.
Shows Koss excellent design and implementation.
Shows Koss excellent design and implementation.
Other than advising to replace them, nothing.
I'm speculating but my understanding was that in addition to owning multiple pairs of these speakers, he purchased whatever examples he became aware of and in whatever condition. Many just for parts which are/were made available to those who contacted him with questions or looking for info. My guess is that him noticing scorched crossover resistors was not uncommon.
More speculation but I think that a good number who bought large speakers like these when new, belonged to the "Loud Crowd" - big boxes & lots of drivers. Which could explain encountering abused resistors.
I can cite the headbanger acquaintance mentioned in my first post. Huge speakers with a decrepit overload reset switch and brown, discolored resistors of the kind I was asking about.
And that is my plan, the resistors stay.
Capacitors were ordered this morning. US to Canada via post so who knows how long to get here.
There happens to be three switches in each cabinet about which I read repeatedly of their tendancy to break. The replacements I bought also came from the US but not direct, it was through a vendor and had to be special ordered. That took two months.
Capacitors were ordered this morning. US to Canada via post so who knows how long to get here.
There happens to be three switches in each cabinet about which I read repeatedly of their tendancy to break. The replacements I bought also came from the US but not direct, it was through a vendor and had to be special ordered. That took two months.
Metal film is a type of resistor, aka thin film.
Film capacitors refers to the dielectric being a polymer film of some sort, as opposed to ceramic disc or multilayer ceramic or electrolytic. Film capacitors come in metallized and foil types, where the conducting layers are sputtered/VFD metallization or an actual foil. Perhaps you mean the latter?
For high current (as in a crossover) film+foil is probably the best choice of capacitor as metallization hasn't the same current handling being much thinner, but this can be overkill for a small speaker crossover - the datasheets can have ripple current ratings at various frequencies which helps determine suitability.
Yes, I should have been more specific.
What I have coming are "Aluminum Metalized Polypropylene". Ordered from ERSE, series Pulse X - 250V.
Depends what you mean by "quality". As noted above, changing them to film types will almost certainly alter the sound. Mind you, new 'lytics might too! And while he's in there questioning the the resistors makes sense.
All is good. I am quite happy to ignore the prospect of tring to find appropriate resistors that would be difficult if not impossible to find. Especially since there are eight per crossover.
The purpose of my asking the initial question was because, although my electronic component "dabbling" is casual, I had the notion these types of resistors were, to some degree, "immortal". But on the other hand, there were two instances where I have seen heat affected examples and one happened to be in a crossover network and to the eye, obviously abused.
The individual who's suggestion it was to change the resistors is focused/devoted to this particular series of loudspeakers. Perhaps he had just cause for the suggestion based on the examples that came into his posession.
I was looking for other opinions about my idea that if the original resistors looked OK, as in no heat scorching, then they probably are.
The input received has bolstered my confidence that this assumption is more or less correct.
The purpose of my asking the initial question was because, although my electronic component "dabbling" is casual, I had the notion these types of resistors were, to some degree, "immortal". But on the other hand, there were two instances where I have seen heat affected examples and one happened to be in a crossover network and to the eye, obviously abused.
The individual who's suggestion it was to change the resistors is focused/devoted to this particular series of loudspeakers. Perhaps he had just cause for the suggestion based on the examples that came into his posession.
I was looking for other opinions about my idea that if the original resistors looked OK, as in no heat scorching, then they probably are.
The input received has bolstered my confidence that this assumption is more or less correct.
Your source is correct to be cautious, not just re the possibility of overheating.
When trawling the net, I came across cases of corrosion of the legs of the ceramic resistors in this model.
Some of these speakers obviously spent time in humid climates!
Fortunately, your resistors have not suffered this fate.
When trawling the net, I came across cases of corrosion of the legs of the ceramic resistors in this model.
Some of these speakers obviously spent time in humid climates!
Fortunately, your resistors have not suffered this fate.
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Those WW resistors, if not blown open due to over-powering them, will last just about forever. They don't appreciably degrade with time; they either work or they don't. I'd test those caps in the crossover to be sure everyone is home and happy.
That is what I was led to believe concerning those resistors. And new caps were ordered yesterday.
During my own info gathering, I too found references about disintegrated component leads. I was expectiong to see that actually but there was none.
According to the info I was sent, there was an "old" version and a "new" version. Those I have are the "new".
I thought perhaps the disintegrating lead phenomena may have been confined to the "old" version.
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Fully agreed!! Wire wound resistors last practically forever. They are so simple and extremely reliable.