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Buzz/crackle from kg4 driver


Subtle Sam

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52 minutes ago, Subtle Sam said:

Yeah I’m half way up Vancouver Island so that would be great. I will try to figure out how to dm Islander. Is he a repair guy? You are all so helpful and great. What a wonderful experience joining this forum has been!

    @Islander  is an experienced member , as well as @billybob  , Welcome to the Forum -

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I dug this out in case you have to find a full replacement. Info from some of the old timers here.

 

The old K8K specs below

 

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      On 11/11/2013 at 11:43 AM, billybob said:

    No KG-4 schematric here, but alot of some others.

    I thought I had it, but evidently I don't. But I do have T-S specs for the K-8-K woofer used in the KG 4:

    Nomz=  4.00 Ohms   Qms= 5.900  Fs= 27.99 Hz   Cms= 1268.0000uM/N
    
    Revc=  7.00 Ohms   Qes= 0.405  Fi=27.01 Hz    Mms= 25.5000Grams
    
    Levc=  1.00mH      Qts= 0.379  BL=8.80 TM     Pmx= 100.0000Watts
    
    Splo=  88.62 db    no=  0.40 %  Sb=  0.0220sqM = 34.1000sqIn
    
    SPLi=  88.00db    ni=  0.74 %  Vas= 0.0870cuM  =3.0724cuFT
    
    SPLi=88.58db  @  Vg= 2.00V Xmax= 4.0000mm....= 0.1575 In
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Hello KG4 fans - greetings from Minneapolis -

Eight KG4's here, I've blown a couple over 15 years, fuzzy-buzzy bass. I found replacements online, saved the fuzzies just in case.

These are 30 watt 8Ω woofers, wired in parallel, 3.8Ω DCR at the terminals!  Difficult load for marginal amplifiers!  When they clip

the flat-topping square wave DC pulses overheat the voice coil.  Sometimes they get unglued and rattle around in the magnet gap.

My solution was simple: turn down Bass -6dB (1/4 power) on the KG4 amplifier, turn UP the gain on a SUB-12 crossed at 40 Hz!

Amazing difference in dynamic headroom, and I haven't smoked a woofer in 12 years!  Try it, you'll like it!

 

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Rolled over and remembered the KG-2 speaker comes with the k8k woofer in the lightcream color and the baby blue cones.

Pretty sure but confirm.

Also, a couple more links, info.

There are replacements now recall on Craigslist but dark in color. Would compare them to the k8k parameters. Also some more links.

 

 

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Thanks for the info and links. I’ve been working on replacement options last night and today. So far the best I’ve come up with is this driver from Midwest. Michael Crites suggested it but he hasn’t actually heard it yet. Any first hand info on this driver appreciated. I may start a new thread with this question. 
 

https://www.midwestspeakerrepair.com/shop/home-audio/woofers/klipsch-1/mw-audio-mw-5082-8-woofer/

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14 minutes ago, Subtle Sam said:

Thanks for the info and links. I’ve been working on replacement options last night and today. So far the best I’ve come up with is this driver from Midwest. Michael Crites suggested it but he hasn’t actually heard it yet. Any first hand info on this driver appreciated. I may start a new thread with this question. 
 

https://www.midwestspeakerrepair.com/shop/home-audio/woofers/klipsch-1/mw-audio-mw-5082-8-woofer/

See that same link posted in that other thread at the top.

Good hunting...

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1 hour ago, billybob said:

See that same link posted in that other thread at the top.

Good hunting...


Yes, what might have changed is that OEM replacements seem to be getting harder to find (makes sense), and the two companies who are listed as able to repair have told me they are not able to work on these drivers. I also checked out a pioneer driver that was listed in that or another similar thread, but the specs don’t line up that well. 
 

So to my eyes it looks like these Midwest K8K clones might be the best and most readily available options. 

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36 minutes ago, Subtle Sam said:


Yes, what might have changed is that OEM replacements seem to be getting harder to find (makes sense), and the two companies who are listed as able to repair have told me they are not able to work on these drivers. I also checked out a pioneer driver that was listed in that or another similar thread, but the specs don’t line up that well. 
 

So to my eyes it looks like these Midwest K8K clones might be the best and most readily available options. 

Go ahead if you want to and start that new topic. Someone may see it here that has used it for replacement.

Compare notes on the specs that are on the Midwest link with numbers on the previous page that @Max2 left on the k8k.

Saw the one your thinking of as 75 watts rating versus 65 on the k8k. To me this means maybe more solid, less fragile, etc...

Also need feedback about the 4 or 8 ohm version. Thinking 4 but yes, feedback.

Actually on this page.

Edited by billybob
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18 minutes ago, RandyH000 said:

So you would buy a pair

 

Yes and here lies the dilemma. In fact two dilemma's. First is the $$$:  I bought the speakers for $300 USD equiv. To purchase, ship and pay duties on the new MW Audio drivers (I would want two, one for each cabinet) will be another $300 USD. Ouch.

 

Dilemma two is that I'm an OEM guy. My first car was a 1969 TBird and I wouldn't dare put anything in there from a Cougar or a Lincoln, even though it might work. One of the pleasures of owning older (vintage?) gear is that it still works and is unique.

 

Time to do some thinking...maybe I'm better off to just keep an eye out for a nice pair of Forte's or Heresy's?

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12 minutes ago, Subtle Sam said:

To purchase, ship and pay duties on the new MW Audio drivers (I would want two, one for each cabinet) will be another $300 USD. Ouch.

 you need to find 1 original 8 inch kg4 woofer , place a wanted ad in the garage sale section , who knows ?

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3 minutes ago, RandyH000 said:

 you need to find 1 original 8 inch kg4 woofer , place a wanted ad in the garage sale section , who knows ?


That would be ideal. I’ve had an ad up in garage sale for a couple days with no response. Also have searches saved in eBay and Canuck Audio Mart with alerts if something comes on the market.

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that was my thread linked above. I did I buy the Midwest replacement for the single blown k8k I had. sounded nice to me. just to be balanced I went ahead and replaced the right side with another Midwest replacement (same woofer on the left). I think they sound a little better than when I bought them. but, could just be imagining that. I have been considering buying 2 more and replacing all the woofers. Why not, I already replaced the tweeters and caps? I haven't done that yet though.

 

I currently have a working k8k and a blown k8k I can let go of. and when I replace the other two, ill have two more. I plan on keeping my KG4 until I can save up the scratch for some forte or cornwall. But, that will be a long while. I really like the sound of my KG4, so I don't mind putting some more money in them. I of course will never get that money back on resale.

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46 minutes ago, jef0707 said:

that was my thread linked above. I did I buy the Midwest replacement for the single blown k8k I had. sounded nice to me. just to be balanced I went ahead and replaced the right side with another Midwest replacement (same woofer on the left). I think they sound a little better than when I bought them. but, could just be imagining that. I have been considering buying 2 more and replacing all the woofers. Why not, I already replaced the tweeters and caps? I haven't done that yet though.

 

I currently have a working k8k and a blown k8k I can let go of. and when I replace the other two, ill have two more. I plan on keeping my KG4 until I can save up the scratch for some forte or cornwall. But, that will be a long while. I really like the sound of my KG4, so I don't mind putting some more money in them. I of course will never get that money back on resale.


Good to hear the Midwest have been a good replacement! I’ll pm you and see if we can work something out for your working k8k. 

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8 minutes ago, Subtle Sam said:


Good to hear the Midwest have been a good replacement! I’ll pm you and see if we can work something out for your working k8k. 

It would be nice if the seller of the 4's to you for good money would be cool enough to either take them back or, help with speaker replacement cost.

Wow, cool that link to the recent past has shown up the OP.

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I have owned a set since the 90's and I listen to these  more in my shop that I do with with house system. 

A few observations from my non engineering background is that these cones on the K8 are very, very light and flexible.  With both drivers hitting hard with the power turned up, they were having to work overtime with that fairly stiff and heavy coned 12" passive on the back of the cab. With such hard relief due to the passive it was easy to over extend these drivers and damage the coils.  Another note is that some KG4's came out as 4 ohm speakers, which I have, yet I have seen terminal caps with KG4 printed on them that show 8 ohms.  The plot thickens possibly.  I have seen these on Craigs list and Ebay for $150 a pair, which makes it difficult to be cost effective in replacing a driver or two or even matching all 4 up when you can get a bullet proof set of old Heresy's for a little more money.   These little speakers are truly hidden gems with the money factor as long as you dont score a clicky driver with a burnt or broken voice coil which will sound great at low volume, but open it up and the coil will lose contact at a certain level of driver excursion.   But boy do these little two ways sound great and with a small package that with drop down in the upper 30 cycle region, its a well rounded speaker.  Not a huge amount of efficiency at 92db I think, but the 4 ohm versions would make up a bit of that throwing the powersource in a lower impedance offering more juice, but clipping would come much sooner. This may be the culprit of so many drivers getting damaged from AVR's and other sub par power sources getting stepped in a 4ohm load and the power of said source just cant do it and cooks the driver from a high THD dose of power.   

 

 

You can do better, but for the money, I would give these a hard look.

 

https://www.parts-express.com/dayton-audio-da215-8-8-aluminum-cone-woofer--295-332

 

 

 

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10 minutes ago, Max2 said:

I have owned a set since the 90's and I listen to these  more in my shop that I do with with house system. 

A few observations from my non engineering background is that these cones on the K8 are very, very light and flexible.  With both drivers hitting hard with the power turned up, they were having to work overtime with that fairly stiff and heavy coned 12" passive on the back of the cab. With such hard relief due to the passive it was easy to over extend these drivers and damage the coils.  Another note is that some KG4's came out as 4 ohm speakers, which I have, yet I have seen terminal caps with KG4 printed on them that show 8 ohms.  The plot thickens possibly.  I have seen these on Craigs list and Ebay for $150 a pair, which makes it difficult to be cost effective in replacing a driver or two or even matching all 4 up when you can get a bullet proof set of old Heresy's for a little more money.   These little speakers are truly hidden gems with the money factor as long as you dont score a clicky driver with a burnt or broken voice coil which will sound great at low volume, but open it up and the coil will lose contact at a certain level of driver excursion.   But boy do these little two ways sound great and with a small package that with drop down in the upper 30 cycle region, its a well rounded speaker.  Not a huge amount of efficiency at 92db I think, but the 4 ohm versions would make up a bit of that throwing the powersource in a lower impedance offering more juice, but clipping would come much sooner. This may be the culprit of so many drivers getting damaged from AVR's and other sub par power sources getting stepped in a 4ohm load and the power of said source just cant do it and cooks the driver from a high THD dose of power.   

Had one of each version in my pair. Round cup and rectangle.

Power is what am wanting to ask OP. Thanks!

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