KLH Model 6 woofer frequency range.

[RoSu_30]

It's possible you have a short from the voice coil to the frame of the speaker that could overload your amp. Gently and slowly push the cone down, and listen for any rubbing noise as the cone travels up and down.

I do have a rubbing sound on the right speaker - the one that has a lot of static-after he repairs the amp he's going to test the caps, speaker resistance and the VC. I appreciate your reply very much-these really are good speakers and I intend to keep them-I keep the Sherwood because of the Geranium output transistors that give it a very "warm" sound-together they make a quality system-+ a so so turntable-

 

[FluxT]

The term Voice Coil keeps coming up-I do get a "rubbing sound" from the speaker that has the most static-The amp just got dropped off for repairs-When It's done both speakers will have their resistance, caps and VC checked-Hopefully that will answer a lot of unknowns-thank you-

"Voice coil rub" would be what you're hearing. The speaker itself is a paper cone that rides along an electrically charged rod (the voice coil), and is attached to a soft suspension known as a spider. Feed it electricity, and the cone moves back and forth. When the speaker gets overdriven, the voice coil gets too hot and deforms (because it's metal), or the cone can get too old and sag onto to the coil. In either case, when it tries to move along the coil, it scrapes and causes the static noise you're hearing. You've got a shot at fixing this by simply turning the speakers upside down for a few weeks (the cone will sag back into place), or getting a replacement pair of KLH Model Six woofers.

FWIW, a good friend of mine has a similar Yamaha receiver, and I've tried it with my Sixes. It was a good clean combo, worth a shot if the Sherwood is toast. Sixes aren't the pickiest about amplifiers, but they respond well to clean power.

 

[RoSu_30]

"Voice coil rub" would be what you're hearing. The speaker itself is a paper cone that rides along an electrically charged rod (the voice coil), and is attached to a soft suspension known as a spider. Feed it electricity, and the cone moves back and forth. When the speaker gets overdriven, the voice coil gets too hot and deforms (because it's metal), or the cone can get too old and sag onto to the coil. In either case, when it tries to move along the coil, it scrapes and causes the static noise you're hearing. You've got a shot at fixing this by simply turning the speakers upside down for a few weeks (the cone will sag back into place), or getting a replacement pair of KLH Model Six woofers.

FWIW, a good friend of mine has a similar Yamaha receiver, and I've tried it with my Sixes. It was a good clean combo, worth a shot if the Sherwood is toast. Sixes aren't the pickiest about amplifiers, but they respond well to clean power.

Wow, the posts keep getting better and better (more helpful). I think finding replacement speakers will not be an easy task - no way to test them. So while I'm looking into that I will turn the one that rubs upside down and see if that helps-Someone told me to get the serial number of the speaker and do a Google search-but I didn't see a number anywhere on the speaker. Most of the ebay KLH speakers are for Model 17- The only serial number I have is on back of the cabinet..

The person who has the Sherwood for repairs used the term "dirty juice" and recommended getting a quality surge protector, which I haven't had for a few years. He thinks that may have contributed to the static from the Sherwood. Have a good day and thanks. Rob

 

[swechsler]

The nice thing about purchasing from eBay is that eBay has your back - if a seller describes their item as tested and working, and when you receive said item, you determine that's not the case, the seller has to take it back, and pay return shipping (so the only loss is your time). So after ensuring that everything in the cabinet is working OK, buy the replacement woofer and test it in the cabinet.

 

[RoSu_30]

The nice thing about purchasing from eBay is that eBay has your back - if a seller describes their item as tested and working, and when you receive said item, you determine that's not the case, the seller has to take it back, and pay return shipping (so the only loss is your time). So after ensuring that everything in the cabinet is working OK, buy the replacement woofer and test it in the cabinet.

Yes, that is true about eBay. And it is probably the most likely place to find and purchase a replacement. Good that you pointed that out. It's probably best to wait until I find out if the woofer(s) actually need replaced. And that won't be for a week or two. I decided to get the receiver repaired first. Which may or may not the reason I think at least one woofer might be bad.

I started my thread to find out what the resistance range of the woofer should be (I used the term impedance by mistake) and got a slew of well intended and helpful replies. That, opened up posts that included asking for pics and referring to speakers, surrounds, amps, and voice coils. I got overwhelmed.

So, I simplified it- 1)repair the receiver 2)have the speakers checked before deciding what to do and 3) I figured out because they are 8 Ohm speakers the resistance should probably be somewhere between 6 and 8 Ohms. But had I figured that out before joining AK I would have not had such a great time getting educated.

Thank you.
Rob

 

[toxcrusadr]

This may be helpful.



There are several reasons why the voice coil can rub. The cone is suspended mostly by the spider, but is also kept centered by the surround. The voice coil and its former (which is like a section of hollow tube) is suspended in the magnet gap (usually just called the gap). 1. The whole assembly can sag over time due to gravity and that can often be fixed by rotating the woofer 180degrees so it can sag the other way for a few years. 2. If the previous owner put on new surrounds, they may have mounted one off center which will lead to immediate rubbing and probably can't be fixed without removing the surround. Some people cut out the dust cap and insert shims (thin strips of plastic or paper) around the voice coil to keep it centered while the surround glue dries. Some people don't shim and this can lead to rubbing. 3. Finally, if a speaker is overdriven, the bottom end of the voice coil former can slap against the back of the magnet assy ('bottom plate" in the drawing), crushing it up a bit, and the wrinkled end how hits the magnet as it goes in and out.

If the previous owner did indeed replace the surrounds, I'd suspect a lack of centering first. Usually requires detaching the surround from the basket, re-centering and re-gluing.

 

[RoSu_30]

toxcrusadr:

It's extremely helpful-it's always good to know what things are called-

The voice coil info is also helpful-but perhaps a bit out of my skills level-

I wrote to Vintage AR on ebay he confirmed that my surrounds are paper and they appear to be in excellent condition.
One of them- I'm, sure- has voice coil thump-or as I would have called it back in my car days "piston slap"

First the repaired Sherwood-2nd is the piston slap-and to insure I go about it the right way I'm gonna cut and past your information and put it in a safe place so I have it when I get to that step-It is really appreciated-

The wealth of knowledge and the willingness to share on AK is very reassuring-

Have a good day-
Rob

 

[Tim D]

????? "I wrote to Vintage AR on ebay he confirmed that my surrounds are paper" ?????

Paper? Do you mean cloth?

 

[RoSu_30]

My apologies-thank u for pointing that out-incorrect terms make things confusing-
They are cloth surrounds-