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Yet another 4x saga


K6cdxkms

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Happy holidays folks,

over the last two weeks I have been working on my pare of 4x speakers

to start from the beginning I have had these speakers for ~ 20 years and only used them for about 4 hours.

I got them from a "frend that needed some beer money and thought ,due to the condition of the cabnets they could not be in that bad of shape as they worked but not for long. So after using them the bottom speaker lost base in one cabnet .

Since the cabnets were in such good condition I threw then in storage with a bunch of other stuff .

To make a long tail longer ,Last month my Kenwood 9600 receiver lost a channel , As a Christmas gift to my self I am having it repaired and since I nolonger need the pare of larger spekers that I have been using I thought that I would reserect the old AR's.

To start I pulled them out of storage and checked each out to see which box had the bad speaker..

Pictures to follow.

Like I said the Wood is probably as good as it gets ,

more photos to follow

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This is how I removed the cloth and covers.

I used the knives as a leaver to pry the inserts up from the glue .

Tap on the covers untill you find a loose area , insert the knife between the woof and fabric as if you were cutting the fabric away from the wood and lightly pry the whole knife , you will here the glue seperating from the cover. work each side like this and the cover will pop up .

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Now that the fabric covers are off this is what the speakers looked like.

I had done some work on the inside before taking pictures .

I had removed the glue spots on each corner and the middle of each long side , also did a little sanding before taking pictures.

Just trying to document the procedure as it should have been done.

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There were cut white foam gaskets under the speakers ,

No picture of them.

Pulled the fiberglass out and placed each box in separate bag to weigh at later date.

Note :

I have been in the construction industry since the mid "70's. The fiberglass smelled of formaldehyde .

These boxes stink and will have to air out for a couple of days outside.

Do not !!!!!!!!!!!! reuse old fiberglass due to impregnated formaldehyde gases.

This stuff is really bad for you.

Make shure you wash your hands and clothes after working with the old FG.

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This is box 398018.

The *" speaker is blown, , scratchy, 0 ohms of resistance.

Date on speaker is June 26,1972

Magnet assembly is totally enclosed by glued on metal plates.

The speaker box that this speaker was in has a MDF front.

Unit 399821 front material is Particle board/ glue plus sawdust, actually quite fragile. I may have to reinforce this box , do not know as yet.

The resonance is different between the boxes.

Do not know how to correct that problem.

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Here is the replacement speaker that I got on "e-S".

This speaker has tape over the magnet to close off the air from the back side.

No date on speaker.

Question ?

When redoing these speakers do leave the tape on the speaker magnet or do I open it up so air can move through the speaker?

Pictures follow.

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So this is where I stand today .

I already had the solvents on hand so all I had to buy was some Danish wood oil, sand paper and I will have to get some stain to repair one small area.

By the way, when using Acetone , wear protective gloves , Acetone penetrates the skin and goes straight to the liver. NOT GOOD

thinner dries out your skin to the point where it will crack along the fold lines in your hand and are hard to heal.

I will be starting wood refinish this week and front paint as well.

This is it for me this week.

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Had a little time tonight to do some explotory work on the cross over system.

Here are the results so far.

Cab 399821 -- L ohms = 1.2ohm Based on drawing No.102014 this Coil should have an ohm reading of 0.40 ohms, 200 % high

Cap = 21.98ufmd - high by 9.9%

Cab 398018-- L ohm = 1.2 ohm Based upon drawing No. 102014 this coil should also have an ohm reading of 0.40 ohms , 200% high

Cap = 22.81ufmd - high by 14.05%

Tweeter values are as follows

Tweeter 1 = 4.7ohm

Tweeter 2 = 4.9 ohm

Woofer values are as follows

Original woofer = 6.1 ohm

Replacement woofer = 4.7 ohm

From the results as presented it looks as though :

1. The tweeters are good - so far

2. Caps are off 9.9% and 14.05% on the high side respectively-- These are to be replaced since they are high and probably will go higher

,

2. The woofers - 6.1 ohm and 4.7 ohm respectively, I just do not know-- any ideas out there?

3. The Coils - ohms are way off the specs for the coils- in the range of 200%

Due to the high ohm reading on the coils I guess that now I need to remove and weigh the coils to see if they are the correct weight and go from there. Wherever there is.

Pots have been removed but not deconstructed as yet for cleaning.

I am open to ideas/knowledge/etc. on this.

Thank you,

Ken

PS. This site is great, I have learned so much from the posts of all.

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Had a little time tonight to do some explotory work on the cross over system.

Here are the results so far.

Cab 399821 -- L ohms = 1.2ohm Based on drawing No.102014 this Coil should have an ohm reading of 0.40 ohms, 200 % high

Cap = 21.98ufmd - high by 9.9%

Cab 398018-- L ohm = 1.2 ohm Based upon drawing No. 102014 this coil should also have an ohm reading of 0.40 ohms , 200% high

Cap = 22.81ufmd - high by 14.05%

Tweeter values are as follows

Tweeter 1 = 4.7ohm

Tweeter 2 = 4.9 ohm

Woofer values are as follows

Original woofer = 6.1 ohm

Replacement woofer = 4.7 ohm

From the results as presented it looks as though :

1. The tweeters are good - so far

2. Caps are off 9.9% and 14.05% on the high side respectively-- These are to be replaced since they are high and probably will go higher

,

2. The woofers - 6.1 ohm and 4.7 ohm respectively, I just do not know-- any ideas out there?

3. The Coils - ohms are way off the specs for the coils- in the range of 200%

Due to the high ohm reading on the coils I guess that now I need to remove and weigh the coils to see if they are the correct weight and go from there. Wherever there is.

Pots have been removed but not deconstructed as yet for cleaning.

I am open to ideas/knowledge/etc. on this.

Thank you,

Ken

PS. This site is great, I have learned so much from the posts of all.

Ken,

I seriously doubt your inductors are both measuring 1.2 ohms. Those are AR #5 coils which should measure 1.2mh (not ohms). Double check your measuring method. What are you using for a meter? Given the tolerances of typical meters, your Sprague capacitors are also likely to be still quite usable, though it can never hurt to replace the caps.

Whatever formaldehyde was in that fiberglass out-gassed a long time ago. There may be reasons to prefer new stuffing, but that isn't one of them. The fiberglass in your cabinets is actually the preferred type compared to the earlier type used by AR. The cabinet material (MDF and/or plywood) also had formaldehyde in it....and is usually the cause of these types of odors. Relax, at this point the hazards are much greater in any solvents you are handling.

The masking tape is supposed to be on your woofer magnet, so don't remove it.

Now that you have two woofers and working tweeters, you could simply deal with the level controls and have a fully functioning pair of 4x's if you wanted to try them out.

Roy

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This is box 398018.

The *" speaker is blown, , scratchy, 0 ohms of resistance.

Date on speaker is June 26,1972

Magnet assembly is totally enclosed by glued on metal plates.

The speaker box that this speaker was in has a MDF front.

Unit 399821 front material is Particle board/ glue plus sawdust, actually quite fragile. I may have to reinforce this box , do not know as yet.

The resonance is different between the boxes.

Do not know how to correct that problem.

Haven't seen a magnet like that on any AR driver before. The 4x woofers usually seen have cloth surrounds and ventilated voice coils using a screened dust cap and screens on the side of the magnet pole piece.

Curious where the short might be on that voice coil. If you pull the spider it should be obvious.

I'm sure RoyC is correct, these will sound fine once any issues with the pots are addressed.

Roger

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I had some time today to redo the X-O's and do some initial priming on the fronts.

X-O caps are 19.91 and 20.01 , 0.45% and 0.05%

Cannot get any better than that without getting a package of caps and taking the closest out.

Left to do:

1. sand primer

2. fill small holes around the speaker edge.

3. Re-prime

4. Re-sand

5. Paint fronts with black

6. Redo exterior wood

7. Install speakers

8. Pop a top on some beer and relax to the music.

Still a lot to do before #8.

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  • 4 weeks later...

I have not forgotten this site, I have been on Temporary Duty Assignment away from my normal work site.

This is where I stand on the wooden cabinets.

I have sanded the exteriors , stained them with a Mahogany stain then re-sanded with 400 wet or dry sand paper so only about 10-15% 0f the stain is left at best.

Taken one cabinet and put Danish oil on and sanded with 400 grit wet with Danish oil, Done this 2 times while waiting 72hrs between coats to allow to dry.

Same cabinet two coats of Danish oil wet sanded with 600 grit.

Same cabinet two coats Danish oil wet sanded with 800 grit.

Last coats of oil will be done when the other cabinet is finished to the same 800 grit level as the first cabinet.

Then 2 coats of Danish oil with 1200 grit wet or dry.

Final coat of oil will be done by hand with a drop of oil placed and rubbed with palm of hand using no more than necessary so as not to have to sand final coat.

I know this seams excessive but the finish will look like a fine English shot gun stock with all of the pores filled.

The wood on these cabinets is worth the time.

I will try to get pictures of the 1st cabinet with 800 grit level of sanding , later today. Interior shots of the wood do not bring out the character of the wood as an outside photo.

We jut got hammered with ice yesterday and last night.

The hardest part of this is the time it takes for the Danish wood oil to dry so to fill the pores of the wood.

I try to do two coats every time I am home , at work 5 days off 3-4 then go back on duty 5 days.

Scheduled to go back out Tuesday so I should be able to get at least one coat on the other cabinet today or tomorrow and will be ready for the next coat when I get back.

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Looking forward to pictures. I noticed your logos are the rather rare type with recessed lettering filled with red paint. Nice. Those will clean up nicely.

Ice huh? Hate that. We're having blizzard conditions here in the Appalachian mountains of northern NJ.

-Kent

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post-178141-0-10968700-1453645357_thumb.Yea, we got about 2" 0f sleet, /1/" of freezing rain then ~1/2" of snow .

Most of the roads are clear now and power was on at least for me through out down here in the Sandhills of N.C.

We do not get that much bad weather but when it hits it has a tendency of breaking these pine trees and killing power.

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