Repairing the tweeters of the Klipsch RB-35

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You can’t miss the golden reflection of a Klipsch speaker. I got myself a pair of RB-35 back in 2005 and now after 13 years with a few years unused I decided to put them back in service. Surprise the sound of the tweeters is just completely dull and asymmetrical between left and right. One of them is barely audible.

Investigation and repairing

I have seen on a forum that the tweeter them self could be disassembled and cleaned. Since I couldn’t possibly use the speakers in that state I decide to try and to take the risk.

First 8 torx srews TX15 for the front panel. No need to remove the back panel exept if you want to check the crossover circuit.

Then 3 Philips screws holding the tweeter on the front panel.

Repairing the tweeters of the Klipsch RB-35

The connectors are easy to unplug and there size act as Poka Yoke.

With the ohmmeter no issue the tweeter is between 2 and 4 ohms.

To continue the disassembly process it is required to remove the yellow glue. That can be done with the help of a knife breaking the glue part by part.

From there the magnet gets out after apply some pulling force. 

There is indeed a fluid inside the magnet’s trench but it seems extremely thick and seems loaded with metallic particules.

There is no way the solenoid could correctly move.

To clean the trench I used some printer paper and then I used a breadboard cable on which the contact pin fits exactly the size of the trench. 

On the second tweeter the fluid didn’t seem to be loaded with particules but was pretty thick any way. That explains why it sounded louder but faded.

Obviously I cleaned both the tweeters to ensure symmetry. 

To reassemble the magnet is automatically aligning with the tweeter body and hold on it with the remaining glue. For now I’m testing without added new glue and will see if it holds with time. 


Repairing the tweeters of the Klipsch RB-35

Replacing the tweeters

The original K-130-DN aren’t produced anymore and where replaced by the K-137 from the synergy series which were also replaced by the K-138.

Despite the technical differences Klipsh seems to have announced the K-138 as the official replacement part without any need of modification. 

On forums there are discussion about the impedance différence from 3 to 8 ohms which impacts the crossover cut frequency. But the ones who tried said they sounded ok. 

Quick summary (I can’t guarantee the correctness of these info since I don’t possess all of them)

  • K-130-DN: Titanium dome, 3 ohm, no heatsink, plastic base is black
  • K-137: Aluminium dome, 8ohm, with heatsink, plastic base is black
  • K-138: Aluminium dome, 8ohm, with heatsink, plastic base is transparent

Risks of cleaning

Removing the fluid comes with a risk since it is supposed to enhance thermal conductivity. Additionally the K-130-DN is not equipped with a heatsink so that definitely a worse case. In case the solenoid would melt then I would still be able to buy a pair of K-138.

Results

I’m blown away by how good the tweeters sound now. I’m might be wrong but it is possible that it’s even better than when they were new. 

Link

Forum canuckaudiomart (Where the disassembly was mentioned)



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