Need help identifying KLH capacitors

[DaveD]

I have bought a second pair of KLH 17s. They do not have the same type of capacitor as my first pair, bought new in 1974. I believe that the second pair was made earlier, but both pairs have the black terminal panels with reverse silver printing. The rather irregular shaped yellow caps in my first pair have been identified as metallized polystyrene and are still within original specification according to the technician who tested them.

The second pair has caps that are black cylinders. The ends of the cylinders are red. The ends are not flat, but dome shaped. I am wondering what type of capacitor this is and if this type is likely to be out of spec being over 30 years old. The speakers are working but have not been tested for sound quality. I wonder if these are wax/paper capacitors.

As luck would have it, I have snatched off of eBay a pair of these crossovers with the caps I am asking about. An additional mystery about this photo is that the two 17 crossovers are not identical. One has a capacitor connected to the toggle switch and one does not. The seller claims to have removed these and to have tested them and found them working. He makes no mention of the different designs. Could there have been two versions of the crossover produced at the factory?

[JKent]

Hi Dave

Don't know if there were 2 designs but I doubt it. The caps in my 17s go to the toggle. btw--those black/red caps are really craps and MUST be replaced! Here is a photo of my "exploded" M17 caps and the rebuilt xover.

Good luck

Kent

[JKent]

PS

See John's explanation of what's wrong with those black/red caps here:

http://www.classicspeakerpages.net/IP.Boar...amp;#entry76807

[Guest rhollingsworth]

PS

See John's explanation of what's wrong with those black/red caps here:

http://www.classicspeakerpages.net/IP.Boar...amp;#entry76807

Once again, thanks for the guidance.

I got to the crossover on my "new" 17s that I am restoring, and everything looks pristine.

The speakers sound fine, and they respond to changes in the normal-increase-decrease switch.

But, I'm a believer now that I read the comments on what happens to these "craps" over time, no matter how good they look.

Since the resistors are inexpensive, I may just buy switches and build entirely new crossovers, rather than unsolder the old ones.

Regards,

RH

[JKent]

When I did my Seventeens and Twenties (same xo design) I used the old switches but replaced the resistors with Dayton wire wound resistors. There are 3 in each speaker, but I didn't make a note of the values. 3 ohm, 7.5 and another one. If I were doing it now, I'd probably go with Mills resistors from PE or Eagle (or Mundorf) from Madisound. Even these "premium" resistors are pretty cheap (Eagles are $1.20 ea for any value) and they are compact and easy to work with. And they will outlast the 5 watt originals.

I used Dayton caps from PE but if I were doing it again I'd probably go with inexpensive Carli mylars from Mad. They come in the needed 8uF value and the 2uF's can be made up with paralleled 1uF Carlis.

Kent

[Guest rhollingsworth]

When I did my Seventeens and Twenties (same xo design) I used the old switches but replaced the resistors with Dayton wire wound resistors. There are 3 in each speaker, but I didn't make a note of the values. 3 ohm, 7.5 and another one. If I were doing it now, I'd probably go with Mills resistors from PE or Eagle (or Mundorf) from Madisound. Even these "premium" resistors are pretty cheap (Eagles are $1.20 ea for any value) and they are compact and easy to work with. And they will outlast the 5 watt originals.

I used Dayton caps from PE but if I were doing it again I'd probably go with inexpensive Carli mylars from Mad. They come in the needed 8uF value and the 2uF's can be made up with paralleled 1uF Carlis.

Kent

Kent, I took your advice and got the Carli caps and Eagle resistors from Madisound in restoring my 1968 17s.

They didn't have a 7.5 ohm resistor, but they did have two values that would add to that.

In retrospect, I wouldn't recommend replacing the 7.5 resistor unless it is obviously burned because when you select the "normal" switch position, that resistor is bypassed anyway. Over the years, the "normal" position is the only setting I found satisfying.

As you said, since there is no Carli 2mfd, a pair of 1mfd caps is needed for each 2mfd value.

So, where in the original there was one dual 2mfd cap and three resistors wired to the switch, I have four 1mfd caps and four resistors.

I won't show you a picture of the engineered result, for you would surely say "OMG!" But the circuit is correct and does work.

I also really appreciate the tip on Watco Danish Oil. The previous owner of these 17s (no-good-!@%$#!) had stuck some adhesive backed material as padding on the bottoms. Chemicals weren't working, or I didn't have the patience, so sandpaper was employed. I also tried to rebuild a couple of corners with moderate success. Mid-way through this process, I was consoling myself saying it was really the listening experience that was important, not how the boxes looked. Then I applied the Watco product, and suddenly things looked a whole lot better.

Since there was a lot of light coming through the woofer surrounds, I treated those with Permatex hi-tack gasket seal.

Now my 1971 models look a little pale.

I saw Zilch's comments on stacking, but I'm not going to let him spoil my fun. :-) rh

[JKent]

Looks good! If the others look pale, you might use Howard's Restor-a-Finish in Walnut. Available at Home Depot. You apply with steel wool then wipe off. Does a great job--should really bring those pale ones back to life without harsh strippers etc.. You can then use Watco oil over it or wax it.

At least that green felt may have protected the bottoms.

Hope you enjoy them!

Now I gotta get to work on my beat up 17s

Kent

[boreas]

PS

See John's explanation of what's wrong with those black/red caps here:

http://www.classicspeakerpages.net/IP.Boar...amp;#entry76807

Thanks, Kent, for reposting that link. I'd either forgotten it or ignored it since I only recently got ahold of a pair of Seventeens. I was more or less under the impression that the caps posed a risk only to themselves when they blew up, not that they posed a risk to the tweeters while they were "working". I'll definitely recap the Seventeens now!

A while back I picked up a pair of Twenty-Fours to go along with the Twenty-Twos that I've had for a while. The Twenty-Fours are in pretty good shape. That nice wool tweed grille cloth is in great shape, unlike that from the Twenty-Twos that ended up on your Model Eight. (It was an Eight, right?) These should come up looking like new.

Seems like I'll have a few projects to keep me occupied now that the rains have finally arrived in the redwoods. I've also got a pair of non-KLH's (ADS L780 2) I want to refinish.

[JKent]

That nice wool tweed grille cloth is in great shape, unlike that from the Twenty-Twos that ended up on your Model Eight. (It was an Eight, right?)

Yes--It was an Eight and thank you again! I finally gave up on looking for "perfect" match grille cloth AND "original" style installation (cut just a tad bigger than the opening and pushed into the groove to hold it). Now I make mini grilles out of 1/8" Masonite and linen (or salvaged cloth from other speakers. Made one recently from Model Five cloth).

Here are some photos. Top speaker has linen, bottom has your 22 cloth.

Kent

[boreas]

Made one recently from Model Five cloth).

Here are some photos. Top speaker has linen, bottom has your 22 cloth.

Kent

They look good! I think I like the linen better since it more closely matches the color of the Model Eight face plate.

[boreas]

Hi Dave

Don't know if there were 2 designs but I doubt it. The caps in my 17s go to the toggle. btw--those black/red caps are really craps and MUST be replaced! Here is a photo of my "exploded" M17 caps and the rebuilt xover.

Good luck

Kent

Hi, Kent -

I've been studying the photos of your M17 crossovers and it looks to me like you ended up using a 2 MFD cap and then a pair of 4 MFD caps in parallel, all Daytons. Am I looking at this correctly? If not, please straighten me out. Also, it appears that the M17 used 50 volt caps but that everything available now is 150 volts and up. This is not a problem, right? The voltage in question is what the cap will handle?

Thanks,

John

[JKent]

Hi, Kent -

I've been studying the photos of your M17 crossovers and it looks to me like you ended up using a 2 MFD cap and then a pair of 4 MFD caps in parallel, all Daytons. Am I looking at this correctly? If not, please straighten me out. Also, it appears that the M17 used 50 volt caps but that everything available now is 150 volts and up. This is not a problem, right? The voltage in question is what the cap will handle?

Thanks,

John

Hi John

I'm on vacation so can't check to be sure, but am almost certain I used one 8uF and two 2uFs--not paralleled.

Kent

[boreas]

Hi John

I'm on vacation so can't check to be sure, but am almost certain I used one 8uF and two 2uFs--not paralleled.

Kent

Hmmmm... now I'm really confused. The XO's in my Seventeens each have 2 capacitors. One has 2 leads coming out of one end and none out of the other. It's marked as follows:

+ 15001262 +

52-6928

N.P.

+ 8uF-50V

I take this to be a non-polarity 8uF capacitor rated for 50 volts. Is that correct?

The other cap has 2 leads coming from one end ans one lead from the other. It's marked:

2 MFD +

50 V N.P.

+ 51-6927

Hong Kong

This would be a 2uF (MFD for micro Farad?) non-polarity cap rated for 50 volts, right?

I'm so confused!

Anyway, hope you're enjoying your vacation!

John

[Guest rhollingsworth]

Hmmmm... now I'm really confused. The XO's in my Seventeens each have 2 capacitors. One has 2 leads coming out of one end and none out of the other. It's marked as follows:

+ 15001262 +

52-6928

N.P.

+ 8uF-50V

I take this to be a non-polarity 8uF capacitor rated for 50 volts. Is that correct?

The other cap has 2 leads coming from one end ans one lead from the other. It's marked:

2 MFD +

50 V N.P.

+ 51-6927

Hong Kong

This would be a 2uF (MFD for micro Farad?) non-polarity cap rated for 50 volts, right?

I'm so confused!

Anyway, hope you're enjoying your vacation!

John

Hi, I am attaching a schematic of the 17 "crossover."

The cap with two leads at one end is actually a pair of 2mfd caps in one casing.

I never heard of such a thing until I saw this.

So there is really a total of three caps in the circuit.

RH

[boreas]

Hi, I am attaching a schematic of the 17 "crossover."

The cap with two leads at one end is actually a pair of 2mfd caps in one casing.

I never heard of such a thing until I saw this.

So there is really a total of three caps in the circuit.

RH

Ah, that would explain the markings. The marking of 2 uF is correct. They're just 2 of 'em! So two new 2 uF caps wired together at one end and then at the other end one of them connected to the increase side of the toggle and the other to the normal side - or to wherever they're connected now in the old XO.

Dayton apparently doesn't make an 8 uF cap but does make an 8.2 Would that be close enough or should I make up an 8 uF cap out of two 4 uF caps?

Thanks for the schematic! It's great!

John

[JKent]

Ah, that would explain the markings. The marking of 2 uF is correct. They're just 2 of 'em! So two new 2 uF caps wired together at one end and then at the other end one of them connected to the increase side of the toggle and the other to the normal side - or to wherever they're connected now in the old XO.

Dayton apparently doesn't make an 8 uF cap but does make an 8.2 Would that be close enough or should I make up an 8 uF cap out of two 4 uF caps?

Thanks for the schematic! It's great!

John

Hi John

Glad you got it straightened out. Yes--8.2 is fine. +/- 10% is absolutely OK.

Kent