Introduction (KLH Service Manager)

[KLHSvcMgr]

Hi Folks...

Was just advised that this forum exists for only KLH folks.

I was the National Service Manager for KLH from 1971 thru 1978 when KLH was then sold to Kyrocera, the original, good KLH's death knell. I replaced Reed Parrish, who went to Bose, and answered to David Dempsey, Manager of Marketing Services. At this time there were 2 National Service Managers, myself responsible for all service related matters and budgeting west of the Mississippi River. The other service manager was Jeff Ayres who was responsible for the service related matters east of the Mississippi.

The *Good* KLH was sold to Kyrocera, in 1978, by Eastern Air Devices, just as a new plant was about to open in Westwood, MA. Most of the qualified personnel left when the administration was transferred to Kyrocera, in Warren, NJ. That is when the product became controlled by the *Bean Counters* and we know what happened then.

I will try to be of help for the products prior to that change as much as possible, keeping in mind that as I get older (59) my mind is a tangle of cobwebs and I do have my *Senior* moments.

I currently am doing restoration of vintage audio products from the 50's thru the 70's for selected components (McIntosh, SAE, GAS, Sumo, Kenwood, Pioneer and Marantz) Sorry, folks I don't get involved with speakers or consumer audio products.

If you have questions please post them here, or write me at

wilsonl@absoundlabs.com

I am happy to have found this site and look forward to being of help as much as possible.

Mark

[tysontom]

>I was the National Service Manager for KLH from 1971 thru 1978

>when KLH was then sold to Kyrocera, the original, good KLH's

>death knell. I replaced Reed Parrish, who went to Bose, and

>answered to David Dempsey, Manager of Marketing Services. At

>this time there were 2 National Service Managers, myself

>responsible for all service related matters and budgeting west

>of the Mississippi River. The other service manager was Jeff

>Ayres who was responsible for the service related matters east

>of the Mississippi.

>If you have questions please post them here, or write me at

>

>wilsonl@absoundlabs.com

>

Mark,

Do you happen to know what happened to Dominic DeAngelis? He once worked in customer service at KLH and maintained a large supply of spare parts and subsequently provided a service from his home in Abington, MA, to repair even the earliest KLH epoxied drivers. Several years ago he moved out to California, I believe. He had a collection of original service-part cones, voice coils, grill cloths and so forth, and could repair early KLH crossovers by ripping out the cone, making the repair and then retrofitting a new cone and voice coil, just as it was done in the factory back in the sixties and early seventies. It would be nice to know if he's still doing this service, but I suspect that was a thing of the past.

--Tom Tyson

[KLHSvcMgr]

Hi Tom...

If memory serves, Dom worked at the factory in the manufacturing division and was responsible for the repair of the non-removable driver product line. As I recall he made up a procedure for the major independent servicers that showed them how to service the "epoxy" line. I will have to dig out my Service Manager's Procedure guide and see if I am correct.

As far as where he might have gone, I can't help you there. Sorry.

Mark

[JKent]

Welcome Mark!

For the benefit of other members here, I have communicated with Mark via the Yahoo! FM Tuners group. He is VERY helpful and knowledgable. And if you need any KLH repairs, he is recommended by the "Tuner Information Center."

http://www.fmtunerinfo.com/index.html#repairs

Good to see you here Mark

Kent

[Andy]

Hi Mark, Glad to see you've made it to this forum. Sounds like you were at KLH during the big transition from domestic production to Japanese Production, About 1971 should have been the end of the first generation modular systems, models 20,24 & 26. almost all of the component recievers frm the 1970's I've seen...models 50,51,52,55 & 57 are made in Japan. My question is, why was the model 50 which came with the small single Driver speakers the only receiver in this series which was made in the USA. I'm amazed at the great sound quality of the 4 inch single driver speaker in the model 50 (seems to be the same as the model 11 and 21 extension speaker.

Also, Was the end of the Cambridge, MA location a sudden thing or simply a slow death ?

Andy

[tysontom]

>Hi Tom...

>

>If memory serves, Dom worked at the factory in the

>manufacturing division and was responsible for the repair of

>the non-removable driver product line. As I recall he made up

>a procedure for the major independent servicers that showed

>them how to service the "epoxy" line. I will have to

>dig out my Service Manager's Procedure guide and see if I am

>correct.

>

>As far as where he might have gone, I can't help you there.

>Sorry.

>

>Mark

Thanks, Mark. It will be great for the KLH group to have your product expertise and experience.

--Tom Tyson

[KLHSvcMgr]

Hi Andy...

Both the 50 and the 51 used outsourced parts obtained from an overseas vendor but were partially(50) and completely(51) assembled here in the US. The 54 was totally USA made. The 52 and the 52A were 100% screened in Cambridge. Someone mentioned that the 52A was a quad receiver. I am not aware of the 52A as a quad unit but using a modified IF section. It also was sold with an outboard Quasi-Quad adapter, if memory serves me correctly, but was basically a 2 channel receiver. If someone has a n in-board quad 52A, I would love to see it. The only Quad I am aware of was the 54 and the prototype 40Q.

The driver used in the 11, 11W, 21 and the 703 was called the 12.5 driver and was made in Cambridge. It was also used in the 5, 12, 14, 15, and 19 in serial numbers above 93000.

The dying of the *Cambridge* era started with the sale to Kyrocera. KLH was in the process of building a factory/administration facility in Westwood Ma, prior to the sale because sales were high enough that the Cambridge facility couldn't keep up. The new facility was almost completed when KLH was sold. Kyrocera moved everything to Warren, NJ and thus, their driving the name into the ground. When Kyrocera bought KLH from Eastern Air Devices, most of the upper management bailed out, including the chief design engineer, Daniel Von Recklinghausen. The last *Original* KLH product was the CBx, 3xx and the SCX-x series speakers and the Burwin 1201A.

Mark

>Hi Mark, Glad to see you've made it to this forum. Sounds

>like you were at KLH during the big transition from domestic

>production to Japanese Production, About 1971 should have been

>the end of the first generation modular systems, models 20,24

>& 26. almost all of the component recievers frm the 1970's

>I've seen...models 50,51,52,55 & 57 are made in Japan. My

>question is, why was the model 50 which came with the small

>single Driver speakers the only receiver in this series which

>was made in the USA. I'm amazed at the great sound quality of

>the 4 inch single driver speaker in the model 50 (seems to be

>the same as the model 11 and 21 extension speaker.

>

>Also, Was the end of the Cambridge, MA location a sudden thing

>or simply a slow death ?

>

>Andy

[KLHSvcMgr]

Hi Kent...

Did you get your unit working properly?

Mark

>Welcome Mark!

>For the benefit of other members here, I have communicated

>with Mark via the Yahoo! FM Tuners group. He is VERY helpful

>and knowledgable. And if you need any KLH repairs, he is

>recommended by the "Tuner Information Center."

>http://www.fmtunerinfo.com/index.html#repairs

>

>Good to see you here Mark

>Kent

[dynaco_dan]

>The driver used in the 11, 11W, 21 and the 703 was called the

>12.5 driver and was made in Cambridge. It was also used in the

>5, 12, 14, 15, and 19 in serial numbers above 93000.

Hi Andy;

Welcome aboard.

Would this also be referred to as the full-range driver's for the extention speakers?

Is this also the mids of the Five's and Twelve's?

[KLHSvcMgr]

Hi Vern...

The 12.5 was a full range driver and was used in the extension speaker stand-alone (Model 703) and also in the speakers with several of the systems as well.

The 12.5 was also used as a mid-range driver in the Model 5 with serial numbers starting at 93,000.

Mark

[KLHSvcMgr]

Vern...

Oops....forgot the 12 also starting at serial number 93,000.

Mark

[dynaco_dan]

Hi Mark;

Thank you, Mark.

What might the Fives and Twelves mids look like below serial number 93,000?

That is if we can see a physical difference.

[JKent]

No--still working on it. I emailed the schematic to a friend who is an electronics/computer engineer. Trying to trace the bad ground. Grounding lug 1 or 3 on the volume pot did not fix it. Checked DC voltage on Q2--OK. Maybe a break somewhere inside the pot. Does it make sense to crack that open?

(for the benefit of other members--this is a volume glitch in a KLH Model 21 radio, "2nd generation" Mark has been helping with)

[KLHSvcMgr]

Kent...

If the control is intermittent and/or open caused by a fracture there is not much you can do about that since the conductive surface is deposited carbon. If the cause is from a loose binding between the carbon and the lug, you might try to crimp it a bit. But be careful as the bakelite material is probably brittle.

Mark

[soundminded]

Mark;

Thank you for contributing to this site. I'm sure your advice and experience will be very welcome to many of us.

I have two pairs of KLH 6s. One is a very early production model with epoxied drivers and non removable grill cloths. They were serviced at the factory many years ago so the operation of their tweeters is not an issue. I am wondering about your advice for resealing the woofer surrounds. Is there a product you have found best for this task? Orange County Speaker Company has a product called XL49 which it recommends. I'm reluctant to try anything without expert advice I can count on. Any opinion on this or any other product? Any advice on how to apply it without sacrificing the grill cloth? I have considered cutting it away and replacing it with one mounted on masonite and velcro attachments. Any suggestions for testing the woofers to determine whether or not it is even necessary? I admit that at the time I purchased them (used) in 1964 my expectations of bass response were much more modest than they are today, especially once owning a pair of AR9s (an almost impossible act to follow by anyone.) Bass response still seems to be satisfactory though even after all these years. I do not push them hard for fear of damaging them. As I recall they were only rated to handle 40 watts which was a lot of power by 1964 standards. They are among my most prized audio equipment possessions.

[mrdb]

A non-invasive way to check the woofers is to measure the system bass resonance. If you have or can borrow an audio sine wave generator and either an AC voltmeter or oscilloscope you can easily make the measurement. Most audio generators have 600-ohm output impedances, so just hook the generator to the speaker and hook the oscilloscope or voltmeter across the speaker, also. Next, sweep the generator from 30 to 70 Hz or so while monitoring the voltage on the scope or meter. You are looking for a voltage maximum. The actual value is not important, and will depend on the generator output amplitude. Just make sure the generator output is sufficient to give a reliable reading. You will not damage the speaker with this setup because the generator is only capable of supplying some tens of milliwatts, well below any danger level. (Besides, you'll be listening, anyway.) I have my Audio Magazine collection in storage, so I can't verify the published system resonance of the model Six, but I'm guessing it is somewhere in the high 40s to low 50s.

This method works because the impedance of the speaker rises to a maximum at resonance and its impedance in shunt and the generator's output resistance in series form a simple voltage divider. An inexpensive digital meter will have sufficient bandwidth to make the measurement, but generally cannot be relied on much beyond a couple of hundred Hz. The better meters (Fluke,etc) have much wider bandwidth, but again, for bass resonance there should be no problem.

Bob

[KLHSvcMgr]

Hi Soundminded...

Generally speaking we didn't experience a large volume of low frequency driver failures, but the most common of those was from operation at amplifier clipping causing the voice coil to burnup. They were rated, as I recall at around 40 watts as you indicate, however, I don't have any spec sheet for them.

I am not familiar with the Orange County product, although I have heard that their parts are pretty decent.

If your speaker was serviced at KLH, then the grill should have been replaced with a grill that was fastened with small brads. The original type, was attached into a small grove using a putty knife. This grill was removed with a sharp razor blade cut about an inch from the lip and then pulling the cloth from the grove.

As far as testing the speaker, the method described by MrDB should work ok. Manufacturing swept the speakers within our anechoic chamber. Most of the speaker servicing was done by Manufacturing so I wasn't heavily involved in the day to day functioning of that operation. The service department did mostly electronic, building/repairing crossovers from manufacturing and those little *special* projects for those higher up, if you know what I mean. We also handled parts, RA's and all the administrative functions, warranty, relations and sales support, hardware wise.

Mark

[tysontom]

>A non-invasive way to check the woofers is to measure the

>system bass resonance. If you have or can borrow an audio sine

>wave generator and either an AC voltmeter or oscilloscope you

>can easily make the measurement. Most audio generators have

>600-ohm output impedances, so just hook the generator to the

>speaker and hook the oscilloscope or voltmeter across the

>speaker, also. Next, sweep the generator from 30 to 70 Hz or

>so while monitoring the voltage on the scope or meter. You are

>looking for a voltage maximum. The actual value is not

>important, and will depend on the generator output amplitude.

>Just make sure the generator output is sufficient to give a

>reliable reading. You will not damage the speaker with this

>setup because the generator is only capable of supplying some

>tens of milliwatts, well below any danger level. (Besides,

>you'll be listening, anyway.) I have my Audio Magazine

>collection in storage, so I can't verify the published system

>resonance of the model Six, but I'm guessing it is somewhere

>in the high 40s to low 50s.

>This method works because the impedance of the speaker rises

>to a maximum at resonance and its impedance in shunt and the

>generator's output resistance in series form a simple voltage

>divider. An inexpensive digital meter will have sufficient

>bandwidth to make the measurement, but generally cannot be

>relied on much beyond a couple of hundred Hz. The better

>meters (Fluke,etc) have much wider bandwidth, but again, for

>bass resonance there should be no problem.

>

>Bob

Bob,

I don’t think that measuring the system resonance, as you indicate, will necessarily determine if the woofer surround is leaking *unless* the surround is completely porous; otherwise, the resonance will stay pretty much where it was originally. In any event, measuring the way you describe -- although it will probably work with the proper audio oscillator -- is not a precise way to do it in any event. Some of the older high-quality oscillators with relatively high-output voltage, such as Hewlett-Packard’s model 200, can probably override to some extent the impedance mismatch, and a small voltage peak could be measured. A better way to measure resonance (aside from acoustical measurements) is to use a voltage divider to determine the impedance peak.

I also don’t believe that KLH ever published the system resonance of the KLH Six, but I believe it was in the range of 53-54 Hz., slightly lower than the AR-2ax. If the surround of the woofer is leaking, therefore, damping (speaker “Q”) and harmonic distortion are affected more than anything else. Remember, too, that the speaker is not hermetically sealed; it is acoustically sealed.

--Tom Tyson