RTi10 Towers. One speaker has no tweeter output. Swapped the tweets, still no output ?

gn2

So I have a pair of RTi10's, one of them has no output from the tweeter. So I swapped tweeters, and the one with no output still has no output ?


So, it must be the crossover ?

Can I buy a replacement crossover ? Are they repairable ?

Is there something else I'm not considering ?

pitdogg2

Most likely melted a resistor. XO is on the binding post plate. Remove the plate and take a picture to show us, maybe we can see for sure. What are you running the speakers with? Receiver, amp?

gn2

I'm running them with a little Rotel integrated amp at the moment. I'll post a pic.

pitdogg2

Tweeters are the first to go when trying to get too much output with too little power/current. When you try to get big sound out of a little piece of equipment you run the risk of sending a huge spike from the equipment clipping. If you're lucky you just toast a tweeter, in your case it seems you likely may have toasted something else.

gn2

Thanks for that opinion, but my little Rotel does better than the majority of modern receivers.

It is definitely the crossover.

treitz3

That may very well be just a cap failure. They are getting up there in age.

[EDIT:] Sorry, my manners. Welcome to Club Polk! You may want to (since you are in there) consider upgrading some of the components.

Tom

pitdogg2

Have you used a multi-meter to see if both tweeters are good or bad?

That cap is no good.
Regardless of your little Rotel (which I'm not knocking BTW) the RTi10 and RTiA 7 ( I think is comparable) are hungry for both power and high current. I would check the other XO to make sure that cap is not starting to bulge as well. There are a few things that can cause this issue. One is heat from getting too hot, two is they could be defective for one reason or another ( doubtful but it happens) The score marks are to allow it to open to keep it from exploding off the board and causing larger problems. If I was going to replace that with the same value I would move up to another cap same value with the exception that has a 105*C rating instead of the 85*c rating. It will tolerate heat better. You could also move to a film cap and take the electrolytics out of the equation all together. The film caps will be MUCH larger. You will need to get creative to keep it on the board. Since I cannot see the actual value of the cap ( 12uf, 20uf, ect) that would also be helpful to know.

gn2

Closer examination revealed one of the monolith like resistors is blown too. It has too much crud on it for me to identify exactly. I think it says "5W2.2(Ohm symbol)J " Under it on the board is printed: 2.2R .

I've done some Googling, but I can't seem to find, or understand, I guess is more accurate, what exact resistor I need to buy, nor where to buy it from ?

Thanks for the advice on the capacitor, btw. I have a hard time understanding the differences in value for components and the impact different values will have with the component in use. I don't want to change the crossover, simply restore it to working condition.

mhardy6647

You need a 2.2 ohm 5 watt power resistor.
I'll let others here chime in on the 'best' choice for a replacement.
It would be worth changing the resistors in both crossovers.
You also have what appears to be a nonpolarized electrolytic capacitor that has vented. It needs to be replaced. Again, both speakers' crossovers should be done.
You need to replace it with a capacitor of as identical a value for capacitance as possible, otherwise you'll change the electrical properties of the crossover. The working voltage of the capacitor is relatively unimportant, although it should be at least that of the capacitor you're replacing. Higher working voltage rating (or temperature rating) is OK.
The schematic of your crossover is probably available here or from one of the hardcore Polkies on this forum.

In general, the most important parameters for a speaker crossover are R, C, and L -- the resistance of resistors (and also inductors' DC resistance), the capacitance of capacitors, and the inductance of the inductors (coils, also sometimes called "chokes") in the crossover network. The type of components used will have more subtle but often audible impace, too. For example, the nonpolarized electrolytics are inexpensive, but other types of capacitors (e.g., various film types) are "better" in readily measurable (linearity or "ESR") and in more subtle ways.

pitdogg2

You need a 2.2 ohm 5 watt power resistor.

I would increase this resistor to a 10 or 12 watt 2.2 ohm from the 5 watt rating. The extra wattage value will better protect from future meltdowns with the resistors.

mhardy6647

... or make something else burn down instead

In seriousness, though, yes, it won't hurt to put a resistor rated for higher power than what was in there, and it might well help.

F1nut

Thanks for that opinion, but my little Rotel does better than the majority of modern receivers.

That may be, but your little Rotel is the reason for your cooked crossovers.

Clipdat

gn2

F1nut wrote: »

Thanks for that opinion, but my little Rotel does better than the majority of modern receivers.

That may be, but your little Rotel is the reason for your cooked crossovers.

The speakers were purchased used. The crossover was cooked by someone else.

F1nut

I stand corrected. That said, be careful as those speakers eat power.

gn2

Update, in case anyone finds this in the future. I bought replacement capacitors and a resistor. Pulled the visibly damaged pieces, replaced with new; both speakers are now working again !

Thank you to everyone who provided advice, much appreciated !

msg

Nice work.