Tweeters inoperative on new-to-me RTi12's...

BjornB17

I purchased a pair of RTi12's from a forum member and received them today. They arrived in perfect cosmetic condition and boxes look like they were handled fine during shipment.

Upon hooking up, it noticed that the tweeters on both of them do not work. Bass and midrange (the 5 drivers besides tweeters) seem to sound fine and undistorted. I checked with other RTi speakers and swapped out cables, even opened them up and found no loose cables. What is the likely suspect? Blown tweeters, or burned crossovers? Or something else?

FestYboy

Do they have the post straps?

BjornB17

FestYboy wrote: »

Do they have the post straps?

They didn't come with them but I jumped them with speaker wire like I did on my RTi10's.

Tony M

When I found out my tweeters didn't work, I took the tweeters out and touched them with a live wire at very low volume and found them to be fine.

It's probably a ceramic resistor on the crossovers. The Rti series has that one flaw. I have a pair that also has those resistors blown, I've yet to fix them but it should be very easy.

I also bought a set of Rti8s that had those blown also. If you take the crossover out ( behind the wire nut plate) , you might see the burnt one on each. I bought new cross-overs from Polk Audio. Polk doesn't have new cross-overs for the RTi12's anymore.

BjornB17

Tony M wrote: »

When I found out my tweeters didn't work, I took the tweeters out and touched them with a live wire at very low volume and found them to be fine.

It's probably a ceramic resistor on the crossovers. The Rti series has that one flaw. I have a pair that also has those resistors blown, I've yet to fix them but it should be very easy.

I also bought a set of Rti8s that had those blown also. If you take the crossover out ( behind the wire nut plate) , you might see the burnt one on each. I bought new cross-overs from Polk Audio. Polk doesn't have new cross-overs for the RTi12's anymore.

Hmm interesting. If it is the crossover I can just replace the resistor, right? Is there a resistor upgrade for this crossover that I should consider? I guess this is better than it being the tweeters (if that is the case) since polk doesn't make a color matched tweeter for the RTi12 anymore (supposedly the RTiA9 version is a slightly different shade).

My understanding is these speakers have been sitting in storage for a long time and barely used, if that would point more towards resistor failure instead of tweeter wear.

Tony M

Polk wanted 130.00 for a new tweeter for the RTi12's. It was a while back but I think I'm right.

BUT. I think anybody who's had a problem with the Rti line has had a burnt ceramic resistor.

My RTi8's cross-overs were different in that one didn't show any burnt anything. The other had a burnt one that I could easily see.

People on this forum say to just replace those things with a little larger value one that isn't so fragile.

BjornB17

Tony M wrote: »

Polk wanted 130.00 for a new tweeter for the RTi12's. It was a while back but I think I'm right.

BUT. I think anybody who's had a problem with the Rti line has had a burnt ceramic resistor.

My RTi8's cross-overs were different in that one didn't show any burnt anything. The other had a burnt one that I could easily see.

People on this forum say to just replace those things with a little larger value one that isn't so fragile.

I'll pop the crossovers off probably tomorrow and see how they look. I got a C in electrical circuits in college so I might need some guidance on "a little lager value" means. What value should be larger and about how much?

pitdogg2

a little larger value would be. it's a 4ohm 5 watt resistor replace it with a 4ohm 12 watt resistor. Buy better resistors like vashay mills or mundorf 10 or 12 watt.

what ever the resistor wattage try to double it DO NOT double the ohm value keep ohm value the same.

BjornB17

I just swapped out the tweeter with one from an FXi3, and the sound didn't change, so likely it is the crossover. Speakers are not too complicated so not much else it could be. I pulled one of the crossovers out and it looks good, though, no scorch marks that I could see. But, I'm guessing that it could fail without the burn marks?

Tony M

That's what I found out. No sign on one but it wasn't working.

The other is scorched black ( or brown. it's been a while ) I believe in the middle of a ceramic rectangular box resistor.

Hermitism

So is this an issue with RTi speakers even if you never send a clipping signal to the speakers? I ask because I have RTi speakers in my HT.

Tony M

I think it's just poor quality resistors.

Go up to your speakers and listen to the tweeters.

Hermitism

Tony M wrote: »

Go up to your speakers and listen to the tweeters.

They're still bright.

BjornB17

Ok next question, which resistor specifically is it (when looking at board) and how do I remove it and replace it?

Hermitism

Can you post a picture? I'm interested in this, as well.

tonyp063

According to this, it's the 2.5 ohm, 5 watt at R1

Tony M

I haven't opened up my RTi12's yet. You might have to remove the bottom woofer or two to gain access to it. Mark everything with tape so you know how to replace things where they came from.

Sorry I haven't removed mine to give you more help.

A few others on this forum have I know. Maybe the search function box will bring them up.

Tony M

Hermitism wrote: »

Can you post a picture? I'm interested in this, as well.

I see you have the Rti8's.

I can take pics of my RTi8 burnt cross-over for you tomorrow.

Hermitism

Tony M wrote: »

Hermitism wrote: »

Can you post a picture? I'm interested in this, as well.

I see you have the Rti8's.

I can take pics of my burnt cross-over for you tomorrow.

Oh no, I meant for the op to post a picture of his crossover to help figure out which resistor it was. Thanks for the offer though, you're awesome!

pitdogg2

Buy new 2.5ohm 10 or 12 watt if you're replacing.

http://www.soniccraft.com/product_info.php/25-ohm-vishay-mills-mra-12-p-4634

Tony M

I know over the years this problem with the Rti's tweeter resistor failing has been the topic of a few threads. People wanting schematics and input for what to replace these things with. Already have Mills resistors made as a contender.

Thanks Tony!!!

I just saw the schematic posted above that I missed while watching TV. COOL!

BjornB17

2 resistors ordered Now to figure out how to install them.

Tony M

You ordered the 10 watt version, right?

BjornB17

I ordered the 12w version in the link. That should be fine right?

Tony M

Oh, I just re-read your post and I see you ordered the MILLS resistors. I hear they're GREAT!

That's what I've read to do. I haven't ever heard of a person saying that those blew too. But I think most get a good brand. mid level or great level. Just not a cheapo replacement.

BjornB17

So do I cut the old resistor off and solder the new one on, or how does one do this?

pitdogg2

BjornB17 wrote: »

So do I cut the old resistor off and solder the new one on, or how does one do this?

no you must desolder the old one. A better question is have you ever soldered before? No offence but if you have never removed and replaced parts on boards this might be out of your skillset. I hate to see you make matters worse.

BjornB17

pitdogg2 wrote: »

BjornB17 wrote: »

So do I cut the old resistor off and solder the new one on, or how does one do this?

no you must desolder the old one. A better question is have you ever soldered before? No offence but if you have never removed and replaced parts on boards this might be out of your skillset. I hate to see you make matters worse.

I have not. Maybe I need to take the crossover to a pro

BjornB17

Looks like in have two home audio/tech stores near me that will do it 👍

BjornB17

Alternately, any issue with me replacing the crossovers with that of the RTiA9? Supposedly they are slightly better and appear to be compatible and I can source the parts.