Woofer woes on 1 of 2 KLH Model Thirty-threes

[Scott]

I have 'inherited' a pair of KLH Model Thirty-three speakers. They sound quite nice.... except that there is nothing coming out of the woofer of one of them. Nothing at all.

I saw nothing damaged or broken during a superficial visual inspection of the wiring and soldering (once I unscrewed the woofer from the cabinet). Could you help me diagnose the problem, verify the diagnosis, and fix it?  I can imagine two obvious potential issues: 1. the woofer is bad and needs to be repaired or replaced; 2. the caps are so old (or at least one is so old) that  it/they form(s) a break in the circuitry. Are there any other potential issues I should be looking for?

What is the best way to confirm or reject either issue above?

I could use a Volt/Ohm/Amp-meter to measure between the two contacts on the woofer, while playing something (the amp is an old British great: a Creek 4040S2). Could I tell from the readings I get if the problem is with the woofer or with what is wending its way to the woofer on the wires? (sorry, couldn't resist :)).

Similarly, could i measure something on each capacitor in place to determine if that cap is a break in the circuit?

Would it make sense to disconnect the woofer in the 'bad' speaker and connect it in parallel (or perhaps in place of) the woofer in the good speaker. If i do that and the woofer from the bad speaker is still silent -- does that prove that I should just throw it away, or is it possible that it can be repaired? If it can't be repaired, would someone be able to recommend a source for a replacement? WIll I need to buy a pair  if I'm replacing one?

If there is a better way to diagnose the problem, and/or some other likely cause than the two i could think of, please enlighten me, As far as I could see from these pages, the only (non-cosmetic, functional) repair one normally needs to do is to replace the caps. Are there other things I should check?

Thank you for your noob-friendliness, truly THANKS!

--scott

UPDATE/EDIT: The woofers are connected to the wiring by simple wire-nuts, so it was very easy to swap them. When I did this, I discovered two things, neither good: 1. the woofer that had been silent continued to be silent, and the woofer that had previously worked continued to work. However,it seems that the midrange/tweeter in the formerly "good" speaker wasn't working after all (while the one in the enclosure that originally housed the 'bad' woofer continued to work fine). The end result of this swap, therefore, is that I have one speaker which seems to work just fine, and one that is completely silent. There's nothing obviously physically wrong it.... but both cones make no sound. If i can do anything which might correct this, I am very open to suggestions, THANKS!

[JKent]

Welcome to the CSP Scott.

I had a pair of 33s at one time. Unusual for KLH because they are ported--sort of like the Dynaco "aperiodic" design, I think. A copy of the manual is attached.

Those black/red Callins caps are notorious and should be replaced, but to check the "bad" tweeter you could just run your music source at a low level through the tweeter alone and see if you get sound. You can do the same for the dead woofer but it seems that the woofer is truly bad. Best bet there is probably to watch ebay for the correct 10" 8 ohm woofer.

-Kent

KLH_Model33_manual.pdf

[Scott]

Thank you for the reply ( and the manual). Please allow me two follow-on questions -- I apologize in advance if (more like when) you wince at the ignorance that drips from the second one:

1a. I take it that there's no hope to find the problem and fix it for either dead tweeter or woofer. I'm sure it's silly to say this, but they both just look so... undamaged. 

1b. > watch ebay for the correct 10" 8 ohm woofer

   Well according to http://www.aphenos.net/electronics/speakers/klh/all_klh.htm, the woofer is found on both the  model 17 and the model 20, and the tweeter is found on models 6("late style"), 17, 20, and 20+.  So is finding one of these models the only way to find the "correct" woofer? Or is there something like a part number or spec etc that would allow me to know the "correct" when I'm presented with one?

2. As you can see in the photo above, the black/red caps are taped to a brown rectangular box of the roughly the same length and width as the cylindrical piece. I've certainly read elsewhere here about what caps to buy -- but do I replace ONLY the black/red cylinder, or is the brown box also a part of the capacitor, so I need to replace the box+cylinder pair with a new capacitor. (and just for my education, if the answer is that i replace only the black/red cylinder, what is the brown box? )

Again, thanks very much for your noob-tolerance.

 

scott 

 

[JKent]

No wincing--I promise.

I don't know if the drivers can be repaired. Maybe Roy or some other knowledgeable person will comment. If the woofer CAN be repaired, you could send it to CSP member RoyC or to Bill LeGall of Millersound in PA. The thing is, it may not be worth the cost. Tweeters are hard to fix but there are spares available. First check it as I described. It may just be the caps (or the switch).

Don't believe everything you read in that spreadsheet. The Models 17 and 20 are identical EXCEPT for the fact that the 20 has a 4 ohm woofer. You want 8 ohms. You'll need to watch the auction site. 

Another thing to consider: The 33 woofers had that "hot cross buns" pattern on the cone, so a 17 woofer (for example) still won't be a perfect match. One solution would be if you found a PAIR of 10" KLH woofers. There is a pair of Model 20 woofs on the auction site now and you could install both but that would make your speakers 4 ohm and you need an amp that can handle that (lower nominal impedances are harder to drive).

There is a KLH Model 38 woofer on ebay now and that "looks" right. The seller is well-known and I would think willing to answer questions. Does your woofer have a square magnet or round? The 38 is square and I suspect the 33 is too (I have no photos of mine) but the Model Six woofer has a round magnet. The 33 has been described as a ported version of the Six, with the same drivers, but I'm skeptical.

The brown rectangular boxes are wirewound resistors and they don't usually go bad. They are marked with something like 4 ohm 5w (Greek letter Omega = Ohm). I have seen problems with 5 watt resistors and I do prefer 10w but most folks here will say the 5w is fine. Just cut the masking tape and pull the capacitor off. It does not have to be taped to the resistor.

A word of caution: That aluminum plate conducts electricity so be sure no bare wires touch it.

Ask all the questions you want and keep us posted.

Kent

PS: Here is a thread I posted when I finished my 33s 

 

[Scott]

Yes, I had noticed myself both the impedance difference and the missing 'hot-cross-bun'. Thank you for your post; it contained all the answers I needed (both the ones I knew I needed and the ones I didn't realize I needed until I read them :)). The magnets of the woofers of these 33's are square.

As far as sourcing a replacement is concerned -- with all the talk of how unusual and rare the ported design is, I rather assumed I would not see components very often at all. But in fact someone is advertising a pair of Model Thirty-three speakers on Craigslist near my mother for $35, and claims that they're in great shape. Hmm, so I could buy a woofer that 'looks right' for $28.50, or buy two complete speakers for $35. Of course. if I buy a pair I'll have three; I guess the one I was going to fix up seems like it's going to undergo a magic transformation into a "source of future spare parts."

The only problem is that the pair of speakers is close to NYC... and I now live in London (UK) ( work relocation). But i'll be back visiting at the end of December, so I'm hoping to convince a friend to pick them up for me now. I promise to report back once the I have the components and start the actual work. It's possible that will only be in a few weeks.

Just out of curiosity about those resistors: I can always just do a quick check to see if they perform in line with their spec. Suppose I **DO** need to replace one of the resistors, can I replace just the bad one(s)?  Or if I replace one should I replace them all?

Thanks for all the help; I'll post just as soon as I've made some progress,

 

Scott

 

[JKent]

I think your idea of buying another pair at that price makes perfect sense. You can take the best parts of the 4 speakers and make one good pair, then sell the remaining good parts. Maybe even save the spare cabinets for a future DIY project--they're nice cabs.

Regarding the resistors, you can replace just 1 or as many as are needed. The reason I don't like the 5w resistors is I have seen scorched and/or broken ones in at least 2 KLH speakers, so I usually replace with 10w. The wirewound resistors cost less than $1 each, so why not? http://www.parts-express.com/Search.aspx?keyword=wirewound resistors&sitesearch=true

Keep us posted!

-Kent

[Scott]

The first two emails I sent to the lady from Craigslist got no reply; the third email  caused the ad to be removed from Craigslist. So I guess I was too slow from the beginning for that. Well now that my friend has offered to pick up a craigslist purchase for me, I can be faster on the mark next time....

Except that I might not need to be at all. Because I have fixed the woofer :). Faced with no replacement on the horizon, I remembered how undamaged the silent woofer had looked, and I thought I'd give it one last really good look. I attach some pics of what I saw: the wire leads  which are glued onto the paper of the cone itself seemed a bit frayed. So I put on an endless loop .wav file (just to have sound continuously playing, and lo! when I put my fat finger right on the spot which seemed frayed, the speaker played. Unfortunately, I'm a horrible solderer, and it took me a good hour to get a serviceable gob of solder to connect the wires that are glued to the cone, leading to the voicecoil and the wire leading away from the cone back  out to the electronics of the speakers. I don't include a pic of the finished job because it looks terrible and I'm not at all proud of it. But the two woofers seem to output identical sound now. 

Question: Is there some REASON that the wires are in fact glued to the woofer cone itself?  Is it just so that they aren't loose and won't buzz, or is  there some electrical property that is important for the speaker operation that is the result of the wires being glued to the cone.

Alas, a quick look at the silent tweeter didn't reveal any leads; I will test them tomorrow. But if I understand your post above, Kent, the silent tweeter might be fixed by replacing the caps. So i'll do that next, and won't consider replacing the silent tweeter until I've done that.

Question: does one normally remove the electronics from the speaker cabinet and replace the capacitors (and perhaps resistors) outside the cabinet, and then put the finished/restored/repaired electronics into the cabinet? Or is it better/simpler just to replace them in situ, without removing anything from the cabinet but the items to be replaced.

Question: I'm pretty sure that I'm going to want to replace the foam surrounds as well. Do I need to spend all that money on ebay to buy new foam surrounds, or can I just cut out my own from a similar piece of foam rubber. Can I use some thing sheets of ordinary foam rubber, or does it need to be the same 'plastic-y' thin sort. (and if so, does that sort of foam have a name that I can ask for? Just hoping to save some more pennies. )

I'll post about the tweeters once the caps are done.

The attached pics show what I could see by visual inspection. And the uploaded video shows how I can reconnect the broken connection with my finger. You can hear the sound creaking when the connection isn't great.

VID_20161204_125506.mp4

[JKent]

Hi Scott

Congratulations! It's always more satisfying to fix one of these yourself than toss it IMHO.

A few comments, in no particular order:

1. These woofers have cloth surrounds and they should not be replaced. But judging by your question, I suspect a jargon "language barrier". If you mean the foam gasket between the tweeter or woofer and the front baffle then yes. Those gaskets get squished to the point of being useless. You can buy very nice foam gasket in a roll from Parts Express. http://www.parts-express.com/parts-express-speaker-gasketing-tape-1-8-x-3-8-x-50-ft-roll--260-540 Other options would be to buy sheets of Creatology foam from Michael's Craft Shop and cut out gaskets https://www.michaels.com/M10390268.html?dwvar_M10390268_color=Black or you may be able to find thin foam gasket tape intended for insulating windows and the like. Like this but maybe narrower http://www.homedepot.com/p/Frost-King-E-O-3-4-in-x-3-16-in-17-ft-Brown-Vinyl-Foam-Weather-Seal-Self-Stick-Tape-V449BH/100118458
2. There is no "normal" for working on the crossovers but it is usually more practical to work on them in situ as you say. btw--crimp connectors and wire nuts work well if you are unsure of your soldering skill.
3. Don't have an informed answer on the wires glued to the cone. My guess is it's just to hold them in place but someone with more knowledge may give a more accurate answer.

Keep up the good work!

Kent

[RoyC]

10 hours ago, JKent said:

Don't have an informed answer on the wires glued to the cone. My guess is it's just to hold them in place but someone with more knowledge may give a more accurate answer.
 

Keep up the good work!

Kent

I agree with all of Kent's points. Just to clarify regarding the leads on the cone...The small wires are the voice coil leads, which extend from the top of the coil in the magnet gap to the cone. They are glued to the cone to stabilize them to prevent breakage and distortion. The flexible "tinsel" leads connect the voice coil leads to the woofer's terminals.

Roy

[Scott]

My thanks to you both for the information, including the correction that my previous post referred incorrectly to the foam gaskets as "surrounds." I only needed a minute with google images to understand the difference. Apologies for my earlier confusion.

I imagine that I'll find elsewhere on this site an answer to what might prove to be my last question for this little project: what is the specification of the two kinds of fabric I need to purchase to replace the front grille panels? The thin wooden cut-out frames onto which the fabric is stapled seems to me to be in perfect shape; I doubt I need to replace those unless you tell me that the staple-holes that would be created by changing the fabric will be some sort of acoustic problem. But this seems very unlikely to me.

The fabric that is there now (which I assume is the original material) has two layers: a finely-meshed black burlap underneath a more coarsely- grained golden/beige burlap. I'd like some advice on what I need to buy if I want to renew/refresh/restore the original sound. Actually, if this presents an opportunity to **improve** on the original, I'm very open to learning how I should go about doing that.

BTW, while on this topic: I've noticed that 'everyone' seems to note to me how unusual (and perhaps unique) is the 'ported' design of the KLH Model Thirty-Three speakers.  Here is a pic of the front and back of the fabric grille, plus a close-up to show the different textures of the two fabrics. I thought some people might be interested to see that the cut-out for the speaker drivers are circles, while the cut-out for the port is a square (while the port itself is a circle, of course). I assume there is some reason; I bet, for example, that the cut-outs for their three-way speakers are three circles.

 

 

[JKent]

Hi Scott

No need to apologize--we were all learning at some point (and still are!)

There are different opinions about the grille cloth. Here's mine:

1. There is no need for 2 layers and the double layer probably interferes somewhat with acoustical transparency
2. These are not highly collectible, so use whatever cloth you think will look best for your taste and decor
3. A very good and economical choice IMHO is "Irish Linen" sold in the needlepoint department at Michael's. It's 28 count linen, now made in Poland. Color is "Tea" and it sells for about $8 a roll. Michael's always has a 40% off coupon, so about 5 bux. You'll have to check the dimensions and see if you need roll or 2.

Those boards are actually kind of thin for 1/4" staples. I use Aleene's Tacky Glue (also at Michael's). Glue the fabric on as best you can, getting it as tight as you can but don't worry too much. When it is completely dry, use a spray bottle to spritz water on it, then dry with a hair dryer. The natural linen cloth will shrink to make the finished work tight as a drum.

-Kent

[Scott]

Two steps forward, one step back  (i'm trying to be optimistic about this...)

1. So I finally swapped the two tweeters between the two speakers, as a simple way to see if the tweeters themselves or the electronics (caps etc) were causing one tweeter to be silent. And I'm sorry to say that it's the tweeter (when I swapped them, the tweeter that had been working continued to work, and the one that was silent continued to be silent. In other words, swapping the tweeters caused a swap in which speaker was defective). 

Bottom line is that I am now officially on the lookout for a tweeter to replace an original one in my KLH Model Thirty-Threes.

I note that the aphenos.net spreadsheet cited above is a bit confusing about this tweeter. It asserts that the model 33 tweeter is the same as the model six tweeter -- but it doesn't say which of the two Model 6 styles ("early" or "late") matches. (Though it does make the positive assertion that the two styles of model 6 speakers do have different style tweeters). Also, the tweeters of this type are sometimes listed as being 1-5/8" and sometimes listed as being 1.63" -- since 1-5/8 == 1.625, this is not exactly a contradiction, but it makes it harder to see which models have the "same" tweeter. In the end, I *think* that the spreadsheet seems to imply that the same 1-5/8" tweeters were used by KLH in Models 33, 30, 17 and 6 (late style). 

Do people have an opinion about whether I just need to find one good tweeter of the above type? Or do i need to replace the pair of tweeters with a pair of tweeters, once I am replacing one of them?

2. Thank you for all the suggestions about exactly where to buy the capacitors and which to buy. However, I live for the moment in the UK, , and so I am trying to buy locally. The model 33s need 2uF and 8uF capacitors -- but I'm having a slightly tricky time finding 2uF ones.  Here the caps I seem to find all are rated 2.2uF. Does this make a difference? 

Actually, the specific ones i found are Jellyfish Audio 2.2uF 400V MKP Bipolar Audio Capacitors (the item code from Jellyfish Audio is B00H7GN1R0). Any thoughts about how appropriate or not these are? I attach a pic of the cap to this post as well.

[JKent]

Hi Scott

The 2.2uF cap will do fine, or you could put two 1.0uF caps in parallel.

There is a similar list of KLH products in our library, here http://www.classicspeakerpages.net/library/klh/  Unfortunately it's not 100% accurate but may give an idea about other suitable tweeters. KLH did use the same tweeters on many of their early models.

-Kent

[dxho]

12 hours ago, Scott said:

I note that the aphenos.net spreadsheet cited above is a bit confusing about this tweeter. It asserts that the model 33 tweeter is the same as the model six tweeter -- but it doesn't say which of the two Model 6 styles ("early" or "late") matches. (Though it does make the positive assertion that the two styles of model 6 speakers do have different style tweeters). Also, the tweeters of this type are sometimes listed as being 1-5/8" and sometimes listed as being 1.63" -- since 1-5/8 == 1.625, this is not exactly a contradiction, but it makes it harder to see which models have the "same" tweeter. In the end, I *think* that the spreadsheet seems to imply that the same 1-5/8" tweeters were used by KLH in Models 33, 30, 17 and 6 (late style). 

Do people have an opinion about whether I just need to find one good tweeter of the above type? Or do i need to replace the pair of tweeters with a pair of tweeters, once I am replacing one of them?

The 'early' Model Six had epoxied drivers (or glued in tweeters); definitely not the same style you have.

Apologies for the confusion. Aside from that, it looks like I need to clarify tweeter sizes and interchangeability.

[Scott]

If there's one principle I've learned in my career to date, it would be the principle: "if user aren't complaining about your product -- complaining **bitterly** about your product - chance are good that your product isn't very valuable to them." I hope that my whines about the spreadsheet showed very clearly just how valuable I think it is.

As it is now, the information about which drivers are the same is partly in the letter designation that you give, partly in the comments section, and partly left as an exercise for the reader to deduce logically from the letters and the comments. It would be very useful if you replaced the letters/labels and the comments about 'being the same as...' with a single new column that just gives the complete list of model numebrs that use the same driver. 

Another thing that would be wonderful (if it could be done) would be to indicate when there is a bon fide replacement part available, Perhaps there just isn't ever such  thing. But (for example) now that I'm in the market for a tweeter from a Model 33,  I probably would jump at the chance to just buy two new tweeters that while not being originals, could 'play one on TV" .I just wouldn't know where to look, and i wouldn't really know what to ask for. It would be great, for example, if i could read in the spreadsheet that part no. <foo> at PartsExpress makes an excellent prostethic tweeter to replace the on that was originally there.

[dxho]

Oh good, the table is filling a purpose :-)

There are some reasons the driver interchange isn't more detailed:

re: tweeters in question: I've only been able to determine two types (aside from
the very late Model Seventeen), and they all appear directly interchangeable in
performance. KLH is no help at all, as they didn't stamp part numbers on them.

There are no new equivalents, as far as I'm aware. Some of the regulars here,
such as J Kent or RoyC, might have more information about that. I don't have the
equipment to test all the parameters of the old drivers, or the ambition to dig
through the literally hundreds of possible candidates. The good news is that used
drivers are plentiful.

I don't or haven't owned all the models involved.

I'm lazy.

I originally compiled the AR and KLH lists because the ones I found here were
inaccurate and incomplete.

[RoyC]

Scott,

Any properly functioning KLH tweeter with the same dimensions as your dead tweeters will work fine. How's that for simplicity?  

These tweeters did have a couple of small technical and cosmetic variations, but are overall extremely similar. The primary visual difference is some have unpainted faceplates and others have black painted faceplates. They are, however, very unique compared to any non-KLH tweeter, so there are no equivalent alternatives.

Roy

[Scott]

I hope that all had a wonderful holiday, and that anyone enjoying the last day of the holiday today is doing something more enjoyable with the rest of her/his day than reading this post :). 

The long-awaited components have finally all arrived, and I began to do the job, and had to stop before I could even plug in the soldering iron: the 2uF capacitors in the speakers have one black and TWO read leads. The capacitors that arrived in the mail/post have ONE lead on each side. Although previous posts already contain pictures of both the original electronics and the new 2.2uF capacitor, I'll attach (slightly better) ones to this post for convenience. (And for my education and perhaps others to, since my hand was already down there, I took a little panorama set of shots of the inside off the cabinet; I thought someone might be amused to learn what is on the other side of the port in a "ported" design.)

Returning to the matter at hand, since these are not collectors items, and I WANT MY SPEAKERS already, I'm going to note that "OBVIOUSLY" if you look at how the double-leads of the two-red-leaded capacitor are soldered to the switch there, it seems pretty clear that one of the two lead gets used when the user chooses the "normal" setting on the back, and the other is used when the user chooses the "more treble" setting on the back. I'll just solder the one lead I have to the place where the centre (center) lead on the original is soldered, and then I'll use the "normal" setting on the speaker. But if some kind soul could tell me please:

1. What kind of capacitor do I need to order, or how do I modify the regular one that i have -- to make the setup work properly (that is, with a switch at the back that emphasizes treble or bass).

2.Would it be more accurate to solder the single lead of the cap I have to the 'higher  treble' setting and then use that? That is, i assumed that the two leads on the original cap correspond to "running at the full nominal 2uF" and "running at something less than the full nominal 2uF" -- but perhaps something else is really true.

As a final comment, I note that from the pictures on can see very plainly that all four resistors have different ratings, and that indeed three out of 4 are rated higher than 5W. They seem to be pristine, so unless someone tells me that there's a reason to replace them, I'm certain they're attached by a better soldering job than what the caps are about to be attached via, and I'll leave them be.

Thanks!! almost there, i hope.

Scott

 

[RoyC]

Scott,

1-The capacitor with one black lead and two red leads is actually two 2uf capacitors with one input wire. You need two caps to replace that one item in each cabinet.

2-The resistors are rated at 5W and 7W, but the values are different. Leave them as is. They are most likely OK.

Roy

 

[JKent]

Hi Scott

Just to expand on Roy's comment; the colors of the leads make no difference so don't worry about red and black--just twist one lead from each 2uF cap together and solder that end to the lug.

Be very careful that no metal touches that aluminum (aluminium ) back plate. A stupid design IMHO. I put heat shrink tubing on the capacitor leads but electrical tape will do. If you happen to remove the speaker terminals be sure that you re-install the 8-32 machine screws with the rubber insulating washers so there is no contact there.

-Kent

[Scott]

Thanks for the explanation about the cap. A final comment and final question (famous last words, I realize):

1. Comment:

On 1/2/2017 at 2:24 PM, JKent said:

Be very careful that no metal touches that aluminum (aluminium ) back plate.

Well, if you look at the picture of the electronics that are over the back plate, you will see not one but two places where various leads are soldered to a lug which is screwed directly into the back plate itself. At one of these screws,  the double-lead from the 2uF cap is one of the things that's solder to the back plate screw. so there are plenty of wires that are touching the back plate. And yes, i've triple-checked that no wires are touching the back plate unintentionally. If i've missed something and the 'original' wiring (photographed) above is wrong, please let me know asap.

2. Question:

Is there a correct and incorrect way to re-insert the pink insulation fluffy bricks or the calico cloth back into the speaker cabinets? Now that i know that there is a conduit pipe leading to the port, I would hate to ruin  or lessen the effect it has on the sound by putting the insulation material in wrong and obstructing the flow of sound through the conduit.

 

Scott

 

[JKent]

Hi Scott

1 Those logs are not screwed directly to the plate. They pass through the plate but each has a rubber insulating washer or grommet to prevent metal-to-metal contact. So no wire should touch the plate. You might try removing those machine screws, taking note of the sequence of nuts, washers, lock washers etc. and carefully examine to make sure the rubber is not crimped or deteriorated. There can be no electrical contact from the screw to the metal plate.

2. No special method. Try to keep from blocking the port and leave room behind the woofer. Leave no exposed wood. the cloth (should be an open weave, like crinoline) is to keep fiberglass fibers out of the woofer, so lay it over the fiberglass with a deep enough pocket to accommodate the woofer and tuck all the edges under the front baffle.

-Kent

[Scott]

Boy do I feel stupid about the back plate. The fact is that when I saw those screws, I remember thinking that it seemed very odd that the circuitry should  be connected to the plate TWICE. I also thought it made no sense for all those components to be connected to ground at all. I don't really understand electronics all that well, and it didn't occur to me that the solution to the riddles was that indeed the circuitry WASN'T connected to the back plate, nor to ground. Anyway, thank you for not beginning your item 1 of the previous post with "You idiot!!"

So the caps are finally done, and OMG WHAT A DIFFERENCE!!! It's as if the speakers were overworked and run-down tired before, and now they've had a good 10-12 hour sleep, and are bright-eyed and busy-tailed once again. If only I myself had caps that I could replace so easily to such great effect. 

I still have the grille cloths to renew, and a tweeter to swap out, but it's already clear that the improvement is dramatic. A truly heartfelt thanks to all who helped me with this.

 

scott

 

 

[JKent]

20 minutes ago, Scott said:

thank you for not beginning your item 1 of the previous post with "You idiot!!"

That would have been a very stupid comment because I (and most of us here) have been on your position before. Nice thing about this forum is the guys are not only helpful but usually quite civil. But I'm curious--did you find a short or something to account for the intermittent loss of sound?

I'm pleased and not at all surprised that you hear such a dramatic improvement. While there are "some" crossover capacitors from that era that may still be good the Callins or Temple or Whale caps that are black with red ends are notorious for leaking (or worse). Once you swap out the dead tweeter you should be able to enjoy those speakers for many many years t come.

-Kent

[Scott]

I know of other online forums where the general level of expertise and the signal-to-noise are as high as here; and I know of other online forums where the cilvility, cooperation, and helpfulness between long-standing (often expert) members and clueless noobies is as high and as deep as it is here.  But it's the combination of the two -- the great expertise and the enormous civility showed when liberally sharing the knowledge -- that make this site quite unique, at least for ,me.

>  But I'm curious--did you find a short or something to account for the intermittent loss of sound?

Why yes; I did find the cause; I tried to explain this in the post and attached pics I made on Dec. 5 above. Apologies if that I wasn't very clear there. Basically, the "voice coil lead" of the 'bad' woofer were frayed. (The voice coil lead is the wire which leads from the top of the voice coil, is glued to the woofer cone, and ends at a point on the woofer cone where it is soldered to the "tinsel" leads that go from the solder point to the woofer terminals. (Thanks to RoyC and his post of Dec. 6 above for the correct nomenclature)). In truth the voice coil lead 'wire' is a composite of several wire threads, and it had frayed to the point where the connection was broken -- but just barely, so that sometimes i would move the speaker, and knock the voice coil lead back into a connected state. I attached a video to that same post on Dec. 5 which shows how i can make and break the connection just by applying a bit of pressure with my finger to the frayed wire. I fixed this problem just by applying a bit of solder to the frayed threads to refashion the voice call lead into a solid wire.

The original confusion i had was due to the following facts about the speakers as I first received them: one of the speakers had a fully functional woofer and a dead tweeter; the other speaker had a fully functional tweeter and the mainly-non-functional-but-occasionally-working woofer. So both speakers always produced sound, but the sounds were never matching. And I couldn't really even figure out at first which speaker was 'bad', because sometimes one and sometimes the other would be louder and sound fuller, depending on whether the intermittent woofer was working or not. 

Apologies for droning on, I just think that having a truly complete description might help the next noob to keep on plugging till s/he has great speakers again. Unfortunately, I myself am not quite done, even setting aside the fact that I still need to find a tweeter -- but i'll put my newest little problem into a separate post.

My eternal gratitude to JKent, RoyC, and dhxo for the advice/help/information they/you gave so generously throughout this thread. The clarity of your posts has been transformed directly into the clarity of the sound I'm hearing as I type this; I added nothing to your posts but a soldering iron and some solder.