I bought a pair of S40s for next to nothing because of foam rot of the woofers.  In addition to replacing the foam surrounds on the woofer, I'll probably also replace the caps in the crossover and possibly rewire them.  I had very nice results recapping (thanks Martin!) and rewiring a pair of S45-2s, so I thought I'd do the same with these S40s.

A previous owner of these S40s had disconnected the lead/input wires from the "B&O" plug, drilled a hole in the back, and stuck the bare wire ends through the hole.  So someone before me has been inside these cabinets.

Well, below is a picture of one crossover.  Is this thing wired right?

Brown wire was an input (Positive?)

Gray was also an input (Negative?)

Red was woofer +

Black was woofer -

White was tweeter +

Purple was tweeter -

Well, it looks like I've figured out posting photos - sorry about what that first post used to look like.

I'm now 80% through refoaming the woofers.  This is not rocket science.  I know - I have a BSE in aerospace engineering (Michigan, '00).    Photos posted when both are set.

Lessons learned (so far):

1) There is definitely a learning curve.  I would say my technique was at least 50% better on the second woofer (so far), if not 75%.  I think by a fourth woofer, technique would be fairly accomplished.

2) Shimming, and therefore replacing a dust cap, has got to be done.  I don't know how you can consider refoaming without shimming.  No offense intended to those who don't/haven't in the past.

3) Woofer Repair part number 8A618 with 2.75" dust cap definitely fits the S40 woofer.

Photos and more commentary to come.

So priority one was refoaming the woofers.  If that doesn't work, what's the point of doing anything else?

Here are both S40 woofers a few days after I adopted them.  

And here's the second one refoamed.  It actually looks better in the photo than it does in real life.  I'm not going to bother posting a photo of the first one I did.  See learning curve comment in post #2.

If you look at the surround, you may notice what looks like eight small bumps spaced equally around the woofer.  That's where there are small holes (screw?) in the metal basket.  (You can see said holes in the photo above.)  I could have avoided this by trimming 3 mm all the way around the surround (which would have also "matched" the original), but that would have left only 3-4 mm of contact area.  I guess I could have made cutouts for the (screw?) holes.  Another lesson learned.

The new dust cap is an almost felt-like paper, a bit different and certainly more mass than the original which was a slightly translucent, stiff, I don't know, cloth maybe?  But it was easy off for shimming, and easy back on and looks fine.

Neither refoamed woofer will win a beauty contest, but both woofers are done.    Took about 4 hours, but that was taking care of my kids and hosting an exterminator for awhile.  Actual work was maybe an hour, most of the time you're waiting for adhesive to set.  I will let the adhesive set overnight then do some listening to them tomorrow to see if I should proceed with the rest of the project.

I know there will likely be a break-in period, so I won't trash them if they don't sound pleasing right away.

Next report after listening.

Both woofers pass a quick and dirty Do I Still Work? test.  I hooked them up one at a time to my desk top system and played some white noise, pink noise, test tones, and music.  They both appear to work as expected.  It's amazing how little low end is heard before mounting in a box.  Speaking of which, next test will be remounting into cabinet number 2 (which still has an intact crossover) and more listening to determine if the project is to continue.  So far, so good.

The photo is of woofer 2 during "testing."

Nice job - well done for having a go.

Thanks, Peter.

Woofer 2 has been remounted in Cabinet 2.  All is well in S40Land.  Listened to some mono Zeppelin (both electric and acoustic), and it sounds like a loudspeaker.  Need to put S40 1 back together and do some stereo listening as a pair.  But it looks like this project continues to be a go.

I have three more questions for Greater Beoworld (question 1 was whether the crossover is wired correctly).

2) What can be done to tone down the ugliness of the gouge on the top of this cabinet?

3) The back cabinet wall is a molded plastic.  Anyone have any experience cutting this material with a jig saw?  Since a previous owner pulled out the cables from the DIN plug I thought I'd Americanize the cabinet and put a banana plug terminal cap in them.  (Did the same to my S45-2s with excellent results, but the back cabinet wall of the S45-2 is particle board or MDF.  Oops - there I go horrifying most everyone and revealing myself to be a "modder" and not a "restorer.")

4) It would appear from the back of the cabinet these were intended for wall mounting.  True?

Anyway, you should be able to see both issues below.

The reassembled S40s are pictured below in my desk top system (replacing S45-2s) taking the Whole Lotta Love Test.  They received about a B-.

I'm gonna play the heck out of them over the next few days and then report back.

New capacitors arrived today from a guy in Michigan I used to buy parts from back in the 80's when I built a few pairs of speakers.

Solen.

Dude.  They are huge.

Made some more progress on the S40s today.  Pulled everything out of each cabinet and made cutouts for the new terminal cups.

The rear of the S40 cabinet is 3/8" thick thermoplastic, likely PVC.  As it is a thermoplastic, I had an interesting experience making the cutouts.  As the cut was made (with a jig saw, using a "multipurpose" blade), the heat of friction would allow both sides of the cut to rebond. 

On the first cabinet, I made the cut in one circular pass, only to find at the end the PVC had cooled and bonded back together!  I essentially had to cut the first cabinet three times and give it a smart rap with a hammer to free the cutout.

On the second cabinet I just cut small wedges and knocked them free before they fully cooled.

Replacing the capacitors on the crossovers and rewiring next.

The internal stuff is now done.  Yesterday I had taken both apart.  Today I started by marking one of the crossovers with a "what gets wired where key."

(For those who can't wait until the end, yes, they sound fine.  Listening to "Abbey Road" with the S40s right now.  The bass on these S40s [and my S45-2s] are just wonderful.  Won't win any loudness contests, but at low to just-above-moderate levels, WOW.  Tight, clean, musical.)

Next I desoldered (as best I could) the existing network and removed the wires and capacitors.

I replaced the old wires with some new 16 gauge mid-grade stuff (from a speaker supply outfit).  And of course I replaced the old caps with the giant Solen caps.  I resoldered.  Much easier than the 3-way S45-2s I did last month.  Lastly I put some hot glue on the sides of both caps, plus the top, connecting them.  This is the other crossover, the one I didn't mark with the what goes where key.

The giant Solen caps ended up covering one mounting screw hole, but I just moved up one set and the crossovers still fit fine.

Next I Americanized them with a new terminal cup.  Sorry if that offends.  The new terminal cup has five way binding posts and is gasketed.

Rich:

(For those who can't wait until the end, yes, they sound fine.  Listening to "Abbey Road" with the S40s right now.  The bass on these S40s [and my S45-2s] are just wonderful.  Won't win any loudness contests, but at low to just-above-moderate levels, WOW.  Tight, clean, musical.)

 

I was listening to my all original S45-2s a lot earlier today. I kept saying what you did over and over to myself, very impressive speakers. At one point I stopped what I was doing and went over to the BeoMaster, I kept pressing and pressing the Voxes, incredible all the way up to nearly 80% volume, I chickened out there . I absolutely adore them.

Great job Rich, way to go!

Thanks, Evan.  I let them play at moderate level for 5 hours while I was gone, and now I'm home again and listening to Beethoven's 9th on the S-40s.  Very pleased with what I've heard so far.

So then, after the Americanization of the back side, I flipped them over and soldered the new wiring to the drivers.  And then I made another minor mod - I discarded the original foam and replaced it with this stuff.  The sheet in the picture is exactly twice as much as is needed, so I simply cut it in half and used one half in one speaker and the other half in the other.

I did the same mod in the S-45-2s.  This step is probably completely unnecessary, but I gotta tell ya - I hate the Beovox foam I've seen so far.

I remounted the tweeter (with new screws, 3/4" #6), then slid the new foam sheet into the cabinet through the woofer opening.  I pulled the foam up to the top of the cabinet with one hand while sort of shielding the crossover network with my other hand.  There is just enough extra length on the foam sheet that it folds at the bottom of the cabinet to cover the bottom side.

And finally, I remounted the woofer, again with new screws (also 3/4" #6, but I think 1" will be better with those plastic spacers).

I swapped the S-40s into my desk top system for the S-45-2s and gave them a Loser test.

So - we are happy, and we are listening to some refurbished S-40s.

Now - I've got to decide what to do with them.  Regardless of who ends up with them, I still would like to fix that gouge on the top, but I'm not sure how to proceed with that.  My brother-in-law the general contractor is coming over tomorrow, I suppose I should pick his brain.

If I decide to keep them, I'll probably change the grill cloth like I did with my S-45-2s.  If I decide to give them away, I'll just let the new owner decide if there's anything more cosmetically to be done.  If I decide to try to sell them, I guess I'll leave the grills as is and just try to cover the gouge.

Fun project.  And I learned a lot.

Rich:

Fun project.  And I learned a lot.

These threads are all very interesting and inspirational.

Once I gain the courage to try a woofer re-foaming I will do so on a very deserving pair of Realistic Optimus T-120 speakers.

Rich,

Once they are played in a little more, you will have to review the S40s against the S45-2s for us. I know I am very curious as to how pronounced that "phase link" is in the S45-2.

I had a pair of T-120s back in '85.  Those things were bullet proof.  We tried to destroy them and failed!  I had a mixing board in the audio path and someone blew a whistle into a microphone.  There was some kind of protection in those T-120s - you could see light glowing inside the cabinet through the bass reflex port when you blew the whistle!

Anyway, this past Sunday I picked up some vinyl from my Friendly Local Used Record Store:

Rolling Stones Dirty Work

Eagles Hotel California

Jethro Tull Thick as a Brick

Robert Plant Principle of Moments

All appeared near mint, and all turned out to be except the Eagles (very good instead, just a little static; but it did have a poster of the band I didn't know existed - Henley wasn't even recognizable!).

So I listened to the "new old" records on Sunday with the S45-2s and now I'm just finishing listening to the lot with this:

B&O RX-2 w/ MMC4 (rebuild by Bennie) -> NAD 7175PE -> S40 refurb

These are a very pleasing pair of speakers.

I will have to take up Evan's request for a comparison to the S45-2s.  Maybe after I finish rebuilding my Beomaster 2400 that's sitting in pieces in the garage.

Rich:

I had a pair of T-120s back in '85.  Those things were bullet proof.  We tried to destroy them and failed!  I had a mixing board in the audio path and someone blew a whistle into a microphone.  There was some kind of protection in those T-120s - you could see light glowing inside the cabinet through the bass reflex port when you blew the whistle!

Way hay!

I believe mine are from 84, spot on. They survived a direct hit from my earlier youth as they were my first Hi-Fi speakers, originally they were my father's. They were replaced by some JBL Northridge E80s once the foam rings on the woofers went. Thankfully my Dad has let me keep them for later repair, but I'm not sure for how much longer! I like them too much to part with them!

I will have to investigate this protection circuit buisiness, too.

What wonderful timing - the UPS man brought my new copy of Dark Side of the Moon today.

This is my first 180 gram LP.  These things are hefty.

Gonna play Dark Side with the S40s then swap them out for the S45-2s and play it again!

Rich,

Very nice!

The Solen caps are also my first choice for crossover rebuilds, in the budget price range. Did you choose the 450Volt version?

Remember - you can always correct your mistakes on the #1 woofer when the foam fails in another 20 years - then you won't feel so bad ;-).

To patch up dents in the B&O woodwork, I ask my friendly neighborhood carpenter for a small packet of wood dye coloring powder (Rosewood-Palisander), and mix that in to a bit of fine wood filler (from Home Depot), and couple of drops of Elmer's wood-glue (to make the mix VERY tough).

Apply it in the gouge, leveling it with a chisel, and work quickly before the glue dries hard. The colour matches great, and it won't chip!

After it's dry, sand it gently with fine Water-paper (without the water) to a shiny consistency - it will be tough because of the added glue. Apply some teak oil, and it will be indistinguishable from the surrounding area.

Menahem

The Solen caps are 400V.

Thanks so much for the procedure for fixing the gouge!