How to purchase new woofers for 1987 Klipschorns

[KT88]

2 hours ago, Deang said:

Try not to over-think it. You’ll go nuts. I mean, look what happened to @John Warren

 

https://northreadingeng.com/Klipschorn_model/basshorn_model.htm

I'm impressed and I think it's cool what energy and expertise people like John Warren put into his research and testing. Because it's very refreshing that there are people who get to the bottom of things physically without getting lost in numbers and ignoring the emotional and personal hearing. I find that remarkable. 
In the case of this Sq. vs. Rd. magnet comparison, I have to be honest and say that I think it's very likely that I would enjoy both types of K33.

[DeanG Crossovers]

At the bottom of the page, after all of the analysis, John states:

 

“A comparison between the round magnet frequency response simulation and square magnet is shown for L_cec =0.1mH.  The model predicts that the low frequency response of the horn is extended by using the SQ magnet driver and, given the difference measured in the compliance between the two drivers, a result that should not come as a surprise.  As the suspension compliance of the RD magnet driver increases over time by use (i.e. the so-called break in), the low frequency response should improve.   It may also suggest that the factory response plot shown above was taken with a new, high compliance, RD magnet K33E.”

[DeanG Crossovers]

1 hour ago, RickD said:

Gave them a call. They said they don't need serial numbers. They buy the woofers from Klipsch, which contradicts what Klipsch told me. The woofer for my 1987 model was no longer available.

Start getting names from that group. 
 

‘They’ also tell people there is no repair service for the old networks - which means they don’t know about Jim or me. They routinely send people to partsexpress when they don’t know what to do. There is some real irony here, but I am going to let it go.

[RickD]

2 hours ago, Deang said:

At the bottom of the page, after all of the analysis, John states:

 

“A comparison between the round magnet frequency response simulation and square magnet is shown for L_cec =0.1mH.  The model predicts that the low frequency response of the horn is extended by using the SQ magnet driver and, given the difference measured in the compliance between the two drivers, a result that should not come as a surprise.  As the suspension compliance of the RD magnet driver increases over time by use (i.e. the so-called break in), the low frequency response should improve.   It may also suggest that the factory response plot show

Thanks for your advice DeanG. I've decided to take my woofer to Northwest Speakers and have them re cone the speakers. They are about 40 minutes drive from my house and quoted me a price $80 to $100 per woofer. If that doesn't work out I'll consider other options, staying with the original woofers sounds like the most reasonable route to go.

[RickD]

Update on my woofer issue. I removed the panel to prepare for the removal of the woofer. I put my ohm meter across the woofer and it measured 5 ohms. Here comes the good part, the wire that was connected between the fuse holder and banana plug socket was disconnected. It looked black on the end . I am proficient at soldering so I know the solder connection was done correctly. The last time I had the bass bin panel open was a few years ago when I rewired the bass bin. The wire from the fuse holder to the input was 12 awg .and completely saturated with solder. What happened and why did it happen this week?

[RickD]

Problem solved

[KT88]

40 minutes ago, RickD said:

Update on my woofer issue. I removed the panel to prepare for the removal of the woofer. I put my ohm meter across the woofer and it measured 5 ohms. Here comes the good part, the wire that was connected between the fuse holder and banana plug socket was disconnected. It looked black on the end . I am proficient at soldering so I know the solder connection was done correctly. The last time I had the bass bin panel open was a few years ago when I rewired the bass bin. The wire from the fuse holder to the input was 12 awg .and completely saturated with solder. What happened and why did it happen this week?

That is a pleasant discovery. I would also measure the DC resistance of the other woofer to make sure that everything is ok. I don't know what woofers were installed in 1987. But I would have expected you to measure approx. 3.3 ohm DC with an impedance of 4 ohm provided that the xover is not connected. But the good thing is that you obviously don't have to replace or repair anything.

[the real Duke Spinner]

5 hours ago, Deang said:

At the bottom of the page, after all of the analysis, John states:

 

“A comparison between the round magnet frequency response simulation and square magnet is shown for L_cec =0.1mH.  The model predicts that the low frequency response of the horn is extended by using the SQ magnet driver and, given the difference measured in the compliance between the two drivers, a result that should not come as a surprise.  As the suspension compliance of the RD magnet driver increases over time by use (i.e. the so-called break in), the low frequency response should improve.   It may also suggest that the factory response plot shown above was taken with a new, high compliance, RD magnet K33E.”

I can not hear difference as finite as such.... WTH. I would throw an Altec 418 in there

And be happy. 🙂

[RickD]

1 hour ago, KT88 said:

That is a pleasant discovery. I would also measure the DC resistance of the other woofer to make sure that everything is ok. I don't know what woofers were installed in 1987. But I would have expected you to measure approx. 3.3 ohm DC with an impedance of 4 ohm provided that the xover is not connected. But the good thing is that you obviously don't have to replace or repair anything.

I'm thinking corrosion might have caused the internal break. My multi meter is a Klein and it's been accurate when measuring resistors.

[KT88]

30 minutes ago, RickD said:

I'm thinking corrosion might have caused the internal break. My multi meter is a Klein and it's been accurate when measuring resistors.

Because it is accurate I would compare the DC resistance of both woofers, measuring the woofers without connection to the xover. Others are the experts but a 4 ohms Z of a woofer should measure below 4 ohms DC resistance if the voice coil is ok.

[the real Duke Spinner]

21 hours ago, RickD said:

Thanks for your advice DeanG. I've decided to take my woofer to Northwest Speakers and have them re cone the speakers. They are about 40 minutes drive from my house and quoted me a price $80 to $100 per woofer. If that doesn't work out I'll consider other options, staying with the original woofers sounds like the most reasonable route to go.

I have never been happy with ReCones

Especially with JBL and Altec

They never sound the same emwith an aftermarket Cone/VC. 🙄

[the real Duke Spinner]

16 hours ago, RickD said:

I'm thinking corrosion might have caused the internal break. My multi meter is a Klein and it's been accurate when measuring resistors.

That's a Sparky Tool. 😀

[RickD]

5 hours ago, the real Duke Spinner said:

That's a Sparky Tool. 😀

The jumper from the fuse holder was completely turned to dust. It was toast.

 I wasn't able to remove the jumper from the fuse holder to the positive speaker terminal because the nuts on the banana plug terminal were soldered together during manufacturing. One end of the jumper was broken off. After removing the insulation, I found no metal inside, only copper oxide. So the fix is new fuse holders and banana plug sockets. I'll have to see if I can cut the old old sockets off with my dremel tool I suspect I'll need to address both speakers.

[RickD]

22 hours ago, KT88 said:

Because it is accurate I would compare the DC resistance of both woofers, measuring the woofers without connection to the xover. Others are the experts but a 4 ohms Z of a woofer should measure below 4 ohms DC resistance if the voice coil is ok.

Because of the corrosion found, I'll have to address both speakers. From the factory the banana plug nuts were soldered from the factory so I did not replace the wire from the fuse holder to the Positive banana plug. I thought "What could possibly go wrong" I'll open the other speaker and check the resistance on the coil and install some new banana plug sockets.

[Khornukopia]

On 6/20/2024 at 4:24 PM, RickD said:

The jumper from the fuse holder was completely turned to dust.

 

Very unusual to hear about any corrosion inside a Klipschorn woofer enclosure. Can you share pictures?

[RickD]

On 6/20/2024 at 8:57 PM, Khornukopia said:

 

Very unusual to hear about any corrosion inside a Klipschorn woofer enclosure. Can you share pctures?

Too late for the photos. When I changed the crossover networks the speakers were wire with a Monster cable type wiring. Since the insulation was clear I could see green for the first half inch of cable so I replace all the wire except for the jumpers to the fuse holders since they were soldered to the banana plugs. The new cable I installed I soldered to the end of the banana plug. During this repair I cut the cables off and replaced with new banana plug receptacles and eliminated the fuse holders and used those holes to install an additional set of banana plug receptables. Since I don't play the speakers very loud I see no reason for fuses. As I said in a previous post the jumper  from one of the fuse holders was completely corroded to the point where there was no solid copper left. Just powdered oxide. One woofer measured 4.3 ohms and the other measured 4.7. The resistance may be a bit high but I'll put them to the test and see how they sound. If they don't perform, I'll replace or re-cone the woofers.

[babadono]

Yep good ol' circa '70s '80s Monster cable garbage. Don't you know wires are supposed to be green it's more ecological.

[Khornukopia]

On 6/20/2024 at 5:57 PM, Khornukopia said:

 

Very unusual to hear about any corrosion inside a Klipschorn woofer enclosure. Can you share pictures?

 

On 7/1/2024 at 11:42 AM, RickD said:

Too late for the photos ...

 

Oh, I was under the impression that you just recently discovered the corrosion as the cause of the problem.