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Model 5 recap question


jimkarl
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Pick a pair of model 5's up and want to do a basic (inexpensive) recap on them. I will probably just look on ebay or parts express as my part source. Question, the existing caps look polarized? Am i reading those incorrectly? Parts expess sells non polarized so I didn't want to get the wrong thing.  Also think that 3uf may not be too common - should I be using 3.3 or 2.7 in place? Given a 10% tolerance it may not make a difference but looking for opinions. Sanity check, I need a 25, 15 three 4's and a 3, correct? Times two of course.  Any other tips appreciated. One of the caps was dual 3uf/4uf but i'm not sure which lead was which (they both measure way out of spec now so I can't tell from the reading) Thanks for any help/advice. 

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Welcome jimkarl

I've rebuilt several of these and I'll see if I can find a parts list and/or the old threads.

No--they are not polarized. KLH used some 2-in-1 caps so the black lead was the common.

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I need a 25, 15 three 4's and a 3, correct? Times two of course.

Yes. I recommend Carli caps from Madisound. They are inexpensive and RoyC tells us their ESR is closer to the originals.

I may be the oddball here but i always replace the resistors. The originals are 5w and I've seen burned 5w resistors in Fives and Twelves. At a buck apiece it's cheap insurance.

-Kent

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From Madisound:

2 Carli MET 3.3uF mylar capacitor $1.30
6 Carli MET 3.9uF 150V mylar capacitor $1.35
2 Carli MET 15uF 150V mylar capacitor $4.10
4 Bennic 12uF 100V NPE capacitor $0.85
2 Madisound 10 Ohm 15W wirewound Resistor 0.50
4 Eagle 16 Ohm 15W wirewound Resistor $0.50
2 Madisound 5 Ohm 15W wirewound Resistor$ 0.50
2 Madisound 6 Ohm 15W wirewound Resistor $0.50

For the 25uF you could use a Carli 10uF + Carli 15uF
I used Eagle 16 Ohm resistors for the 15 Ohm. They’re on sale.

Here's a thread:

Here's another. It shows a burned resistor and a recap with monster caps

Browse through the KLH section and you'll find several threads on the Fives. Great speakers. The xo can be a little confusing with those darn double caps and such but there's lots of guidance here.

Almost forgot. You asked for other tips. I think this, from a previous post, warrants re-stating

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A final thought on the Fives: After recapping mine I was a little disappointed. They look beautiful and were "supposed" to be KLH's answer to the AR-3a. They just didn't excite me. So now I'm trying to get rid of some of the many speakers I've acquired, and found a buyer for the Fives.

Pulled them out of the corner where they've sat for over a year to inspect them before packing. Then I noticed what I had never looked for before: The cloth woofer surrounds were quite porous. So, following the Service Bulletin #60 I applied Roy's sealant to the woofer and mid surrounds, and to the woofer dust cap. Fired 'em up and WOW! Now THAT's what they should sound like! Just as good as my AR-3a's and AR-91s (now I'm sort of sorry I sold them wink.gif).

SO...Before considering esoteric caps for your Fives or other cloth-surround speakers, seal the woofer surrounds. It makes a MAJOR difference!

One more note: Although the Service Bulletin says to seal the dust cap as well, I don't think it's necessary to use Roy's non-drying sealant there. The caps are quite rigid. Aleene's Tacky glue or white glue used for foam surrounds should probably work fine.

Roy is CSP member RoyC. If your woofers need to be re-doped use ONLY his butyl-based formula. You can buy it directly from him or from ebay seller Vintage_AR.

-Kent

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Thanks for the masisound point and tips! I'm going to check that site out tomorrow. I think the only challenge left (other than the ordering waiting and working on it) is figuring out which side of the dual lead was the 3 and which was the 4 but it sounds like there is some info on that after I browse for it. Thanks!

 

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Thanks for the masisound point and tips! I'm going to check that site out tomorrow. I think the only challenge left (other than the ordering waiting and working on it) is figuring out which side of the dual lead was the 3 and which was the 4 but it sounds like there is some info on that after I browse for it. Thanks!

 

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Looking at your list, you have more caps then are in my model 5? I don't have any 12ufs in mine, nor two 15uf's (just one plus another if I want to make the 25uf which you pointed out). Am I missing something? In the noise, cost-wise, but I don't see them.Maybe your is a differebt rev of Model 5. My board doesn't look like yours. Mine is a PCB type board. 

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Hey jimkarl

As I said, the Five xo can be a little confusing. The reason for the "extra" caps:

2x12uF = 24uF to replace the single 25uF

10uF + 15uF = 25uF another way to replace the 25uF

IIRC the dual-lead caps are either 2x2uF or 2x4uF. I "think" the 3uF is a single.

The PCB is just a newer version but the same components

stripped.JPG

top.JPG

P5044054.JPG

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PS

I recently worked on some Fives and still had the old caps and they were indeed a 2x4 and a 2x2 but a single 3uF BUT I looked at the photos of the PCB one and you're right--there is a 3+4uF. If you look at the photo below, the 3+4 is between the 16uF cap and the 15ohm resistor. The 3uF side is next to the cap and the 4uF side is next to the resistor. In this case the 3uF is a 2.7 + that orange 0.22uF parallel cap.

Getting the bigger resistors in there was tricky.

old and new.JPG

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Ah the 12uf now makes sense! Is it possible to work on the board with disconnecting all wires? Also, I see you have some brown tape on some - what is that? and some white stuff on the board underneath. Some sort of glue? recommendations for a cheap solution on that?

lastly you show 4 16 ohms on your list but I only see 1 (per cab) on the schematic on mine. Is this again the different board revision?

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If you want to keep costs down, the two 12uF electrolytics will work. Madisound does not have a single 25uF 'lytic. Or use a single 22uF electrolytic in parallel with a 2.7uF Carli mylar.

9 minutes ago, jimkarl said:

Is it possible to work on the board with disconnecting all wires?

I'm guessing you mean "without" and yes but I found disconnecting easier and I just used the other board as a model.

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 I see you have some brown tape on some - what is that? and some white stuff on the board underneath. Some sort of glue? recommendations for a cheap solution on that?

The brown tape is just holding the paralleled caps together. KLH used plain Scotch tape. White stuff: 

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The caps are all attached to the board and in some cases to each other with double-faced foam tape. RTV takes too long to cure and hot-melt glue can damage film caps.

 

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