Model 5 recap

[Guest jcmjrt]

I just got a pair of Model 5's yesterday and they are my first. I got them to go with a fisher 500C that I'm restoring and needed some "tube" speakers. Anyway,I know that the switches on the back don't work. I'm not sure why yet. I need to pull the crossover and troubleshoot it. I was wondering if I should just go ahead and order caps and recap the speaker as a matter of course? There are many different caps - types, qualities, etc - and I was wondering if anyone had played with recapping these speakers and had some recommendations? Anybody do anything other than just replace caps....like cascading caps or putting in a high quality bypass cap...or...?? I'm a crossover newbie but I've been doing a little reading on the subject...and there's a lot of science as well as art...

Also, anyplace to get the logos from? new grill cloth that looks like what's on there now? The speakers are in pretty good shape but the grill cloth on one speaker has a wear point and the logos are missing.

I'm looking forward to making them sing!!

[Guest Bret]

>Components for this type of power supply weren't nearly as reliable 40 odd years ago as they are today.<

I know nothing about this model speaker. Nothing.

Over in the AR forum there has been ongoing debate about replacing capacitors. I didn't want to do it, but once I did it I found that there is ample reason to re-cap them.

Apparently these old capacitors really do deteriorate. If their capacitance tests "good" they most likely still suffer from increased ESR and dissapation factor and they might even leak.

The problem, to which I haven't found a solution, is in order not to change anything about the way the crossover was originally designed to function, you really need to match the ESR of the original capacitor *when it was new.*

Trouble is, that information is not generally available because manufacturers have been bought, gone out of business, long ago quit making that cap, etc.

The alternative would be to know what value for ESR the designer put into his sliderule by finding documents with that level of detail. Good luck.

My experience has been that even cheap capacitors will bring the crossover points back to where they should be, more or less, but are definitely an improvement over listening to the speaker with a rotten capacitor in it.

The ones that I have replaced have been billed as "Low ESR" but what was low for 1970 and what is low for 2005 MAY be two different things, but you can't know that with great certainty.

A friend of mine and I have used three different kinds of capacitors thus-far. El-cheapo non-polar electrolytics from a local supply store, el-cheapo non-polar electrolytics from Parts Express, and expensive Solen poly caps.

We do not scientifically know if the differences we hear are a result of capacitor types or if something else is at work.

Based on what we have heard we have both decided that our "next round" of experiements with capacitors will be to "by-pass" (parallel) different types of capacitors rather than cascading (parallelling in a specific manner as described at http://wwww.northcreekmusic.com).

But we're cheap. If money were no object, I'd like to try cascading, but money is an object so I'll "by-passing" next.

I personally found the Solens to be quite grainy, harsh, shrill, and awful for tens and tens of hours while they "formed." If I had the understanding and wherewithall to do it, I would "form" them outside the speaker in the way that has already been suggested.

I cannot recommend that you "by-pass" because I haven't done it myself yet. All I can do is tell you that based on my experience doing it the other way, by-passing will be what I do next, but that I will always, always replace any electrolytic capacitor more than 7 or 8 years old from now on.

Bret

[RoyC]

There is crossover info in this website's information section including an interesting Model 5 restoration project. While I'm not convinced of the benefits of expensive caps in our classics, I would recommend replacing them all in your 5. The caps in the old KLH models are notorious for going kaput. As to what to replace them with, my opinion is whatever makes you (and your wallet) sleep better at night. I've restored several KLH models with a combination of electrolytics and mylars with very nice results. Check out Ebay for emblems.

Roy

[Guest jcmjrt]

...and the concensus so far is recap. That's not hard to believe. I've read that section on northcreekmusic and I was intrigued by cascading and bypassing. Wish I knew a 1/10 of what guy does about crossovers. I've been considering building one of his kits for some home theatre speakers. I'll have to take a look at caps. I can't see going highline - auricaps or something of that ilk- as I think that I'd have to be prepared to rebuild the entire crossover to get the most out of that but some decent - definitely not the cheapest - caps would seem to be in order. If anybody has a favorite distributor of midquality caps then please feel free to chime in

and of course, I'd still like to find a good source for the logos and cloth.... )

[RoyC]

Parts Express and Madisound are good places to shop...(Madisound carries mylars, which were a favorite of mine for a long time). Between the two websites you will find a decent mainstream selection as well as high end choices.

Roy

[Guest jcmjrt]

Well, I ordered the caps today from parts express. I'm going to try the Dayton caps - mostly metallic polypro - but will be bypassing the tweeter caps with a small Dayton foil cap. They weren't in stock on the whole order so it'll be longer than I wish it would be to get the material to start..but hopefully, it will be sweet when I'm done!

[Carlspeak]

Check out the KLH section of the Classic Speaker pages. At the bottom of the middle section there a file called "crossover information for the KLH MOdel 5" download and unzip it. There's a photo of an upgrade job I did regarding new caps. There's also a schematic and parts layout drawing for your referernce. I did basically the same as you but didn't bother with the bypassing. That's a very subtle improvement most noticed with very high end systems. Changing from the old electrolytics to the metalizzed PP or mylar film caps will make the biggest improvement in soundstage and clarity. You'll actually hear more detail with the new caps and want to listen to all your old favorite tunes once again.

Enjoy!

Carl Richard

Carl's Custom

[Guest KLHmodel5parts]

I have at least one logo and maybe two. Let me know if you are interested.

[Guest jcmjrt]

I'm interested in the KLH logos for my Model 5. Give me a jingle at jcmjrt@yahoo.com

[Guest jcmjrt]

It took a while to get the caps and then I was just busy so the first speaker just got recapped. I decided to recap each speaker one at a time so I could A B the speakers and see how much difference the recap was and whether it was worth it or not. I recapped with Dayton metal polypro caps and bypassed the tweeter and mid caps with a small, high voltage Dayton film and foil. I used Kester solder and cleaned contacts with Deoxit. Let me tell you that the difference is night and day! There is nothing subtle about it. The two speakers could hardly be more different. The recapped speaker sounds clean and clear and the other speaker is absolutely muddy! If you've been thinking about recapping, Go For It!!

I didn't think that the recap was too difficult. The hardest part was figuring out a good way to get the much larger caps into place on the board. Mostly I just made a bundle of the 4uF and 3uF caps along with their bypass caps and stacked them all in place.

Next I'm going to try resealing the woofer and A B for that change. I'll let you know what I think.

[Carlspeak]

......... Let me tell you that the difference is night and day!

>There is nothing subtle about it. The two speakers could

>hardly be more different. The recapped speaker sounds clean

>and clear and the other speaker is absolutely muddy! If you've

>been thinking about recapping, Go For It!!

>

See, what did I tell you! There will always be the proponents of the "original sound" or "voicing" as it's been referred to by some. However, I believe hearing more of the detail in the original recording far surpases the "original sound" and brings more enjoyment to the listener. Someone who posts at this site has it right:"Don't forget the music"

Carlspeak

Carl's Custom Loudspeakers

http://www.classicloudspeakerservices.com

[Guest Bret]

>The recapped speaker sounds clean and clear and the other speaker is absolutely muddy!<

That's been my experience, too. The thing I do not yet understand is exactly why. If it is just that the crossover points are being shifted back to their original design parameters, that makes a lot of sense; we aren't asking drivers to play way out of their designed frequency areas.

But then, why would it be that the old capacitors might still be in spec (therefore crossover points have not shifted) and nevertheless sound muddy?

If it were something else, like just lowering the ESR so you had "more" tweeter (for instance), you'd think that you could compensate by turning the tweeter down on the repaired speaker to make it match the unrepaired. But you can't. Something in the old capacitor is creating "mud."

Being cautious with assertions, I'm still not entirely convinced that it isn't "more" tweeter. These capacitors have an operating range. At the low-end they act like an inductor and at the high end they act like a dead-short. There must be a curve to that behavior. If you change the curve, surely you must also change the sound. I would think it would take very little of that to change the original "voice" of the speaker system.

I suppose that's really academic. After break-in I never heard a changed capacitor that I didn't like. Some I couldn't tell a difference in, sure. But none that I disliked.

Time to experiment some more!

Bret