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How To: Test & Replace a Heresy-II Driver


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There are always a number of questions from new members that sorta' go like this: "I have a pair of Heresy's that I just got off eBay and they don't sound right. Seems like the midrange is out on one of them. What do I do?....". Usually everyone steps up to the plate, so to speak, and gives them advice, etc. Then it usually degenerates into the "while you're at it... change the caps, change this, change that, etc." Which is a good thing for the most part, but sometimes confuses the issue posed by the new guy's original question.....

So.... I got up this morning, turned on NPR on amp #2 with the Heresy's in the man cave (real early in the morning only thing I can deal with is coffee and news over the Heresy's... at low volume....). Amp turns on, sound comes out... but the right Heresy sounds "real funny like". For the second time in my entire life, a Klipsch speaker driver fails to work!!!! (First time was a couple years ago on a K-33 woofer in my first pair of K'horns... Whata' weird panic that caused.....). No midrange...

Well.... I had to take my son to soccer, so I made coffee, turned on the Klipschorns and assembled my tools, etc. drank the coffee, grabbed Michael, and headed to the game.... Half-time and the kids are running amok, so I called HarryO and told him of this unusual occurrence (for me...) and we laughed, etc. and concluded that as likely as not there was probably a loose wire since I had never "opened up" this pair. But, we had an idea.... since we see alot of questions like this from first time owners of vintage Heritage owners, why not go through the whole drill, take pictures and make a "how to" thread.

So.... How to: Find Out Why the Speaker Does Not Make Sound and Replace the Offending Driver......

  • First thing to do is make sure it's that speaker and NOT the amp or speaker wires, connections, etc..
  • Disconnect the speaker wire leads, and put the left wires on the right speaker and see if it "follows the speaker"
  • If it follows... It's the speaker...
  • If it does not follow the speaker, check the speaker wires and make sure the terminals are clean on the amp and the speakers.
  • Same problem? then there is something wrong with the amp and that's another problem altogether.....

So since the problem followed the speaker..... What do we do?

First... TURN OFF the amp and disconnect the speaker wires at the terminals on the speakers. NEVER mess around with the speaker with the wires connected or the amp turned on......

Second.... Assemble your tools....

  • For newbies, go to Walmart or your local automotive parts store and buy a multimeter. It's a critical piece of equipment in maintaining and testing your Heritage drivers....
  • You should have an battery screwdriver or drill with adjustable torque settings
  • Have painters tape to mark the leads from the cossovers to the drivers
  • Leatherman (or Gerber, etc.) multipurpose tool
  • Pencil with an eraser (more on that later)
  • Magic marker (to mark the tape and/or the driver terminal...)
  • Normal phillips-head screwdriver (required for K-53 midrange work
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This is the most difficult part.

  • First, carefully turn the driver so that one "spine" edge of the horn is in the cutout slot next to the woofer, and the driver is next to the round cutout next to the tweeter.
  • Use the painters tape to mark the yellow (+) lead.
  • Disconnect the leads and lift the driver out at the angle shown in the photograph. It will ONLY come out at that angle shown....

Don't worry about the gasket still on the motor board. More on that later.

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Take the driver to a work bench, dining room table, etc. Connect the "multimeter" with the switch set to the "omega" or ohms, or resistance setting. Usually these meters have a number of settings, so select the setting that reads from 0 to 20 ohms, etc. Better idea... Read the instruction manual.....

In this case the driver measures 11.6 ohms, or for sake of simplicity it's 12 ohms. A K-53 should read between 11.2 and 11.8, and this can vary because of how you connected the meter leads, the meter's peculiarity, etc. If it's not in this range, then there is a problem with the diaphragm, and you need to replace (a) the driver itself (call Klipsch Parts), or (B) the diaphragm itself (call Klipsch Parts or contact Bob Crites - BEC on the Forum) if you are very good with a soldering iron...

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In this case as we saw, the driver was good, and the problem was actually due to a loose connection, but let's assume that the driver was not ok....

So.... From Klipsch Parts here are 2 brand new K-53 drivers. You can see the part number. Whenever I obtain new (or used drivers), I always label them with the date I tested them and the part number with the magic marker. Saves time later when determining the last time you tested a spare driver.....

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So we are ready to go. First thing I do (optional...) is trim the gasket where those "cutouts" are on the motor board. You don't have to, but when you reinstall that driver and horn, it WILL catch on the gasket sticking out, drag it down into the cabinet, or even worse, pinch and tear it.... Murphy's Law. Or just consider the Clint Eastwood Rule... "Do you feel lucky?...."

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Let's look at the K-53. The driver is connected to the K-701 horn by those 4 screws. Why, we ask ourselves, do we need a phillips head screwdriver when we have that nifty drill...? Well, two reasons... First, drills and electric screwdrivers don't fit under the horn, and second, when installing the horn back on a new driver, you really want to do it very carefully and not overtorque the screws, etc.

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Here's what it looks like, unscrewed... NOTE. When you unscrew the screws...., not only will the horn come off, but the driver will separate into the coil and the magnet assembly. If you are not extremely careful re-inserting the coil into the magnet assembly you will desotroy the coil/diaphragm. BE CAREFUL......

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New vs old. NO difference. New ones are shipped with an adaptor (most of the time... depending on which stock they grab - older stock does not have that adaptor) to allow them to screwed on metal K-whatever horns. Since we are using the plastic K-701 horn, we simply unscrew the "screw-on" adaptor. Yes, you could screw one on yout K-400 horn on your Klipschorn i you wanted to. But that's another tale!!!

Notice the small paint pen mark on the hot lead.....

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We now screw on the horns to the drivers. Only use a phillips head screwdriver. DON'T try to do it with a drill, etc. You can damage the horn, strip the threads in the magnet retention plate, crack the horn flange,etc. In this photo I needed to assemble another pair for Heresy's under refurb in the garage, so that's why there are 3 of them.....

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