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A hello, and another S45 overhaul

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Ian
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Ian Posted: Tue, Apr 21 2020 9:23 PM

Greetings all!

Longtime (over a decade!) lurker, and with the state of the world being what it is, tacking a project I've long had on my mind.

 

Bit of an intro and background about me and my love affair with B&O—

Some years ago, I moved across the country for college, and of course, the first thing I did was swing by the local Goodwill for housewares and the like. In the basement cluttered in a sad heap was, to 18-year old me, an unexpected grail: Beomaster 1900 in rosewood with matching S45 speakers, and a slightly newer and rougher Beogram 2000.

"$20.Doesn't work" stickered on it. I flipped it over and saw the fuse was missing, and what luck, there was a RadioShack across the street.. A quick trip over and back, and a sawbuck later, I was lugging the whole thing onto the subway (and then onto the used record store). 

The setup definitely looked rough, but kept me entertained through college and the years since—at one point I shared an apartment with two other audiophiles, and it kept up with the vintage Marantz and Harman/Kardon rigs we had around the place. Some people had ragers on the weekend; we had Trader Joes wine-and-listening parties. 

In the intervening years, I've upgraded when I can. The 1900 started smoking one evening, and while I don't remember the fate of the carcass, it was replaced with an estate-sale BM2000 to match the turntable. The Beogram got a little creaky and was retired for an SL1200, another fortuitous garage-sale find, but is still in storage somewhere. 

And that left those trusty Beovox S45s. Cabinets could use some love, and the grille cloth definitely seen better days, but the drivers and surrounds were solid, and just about perfect for my tiny living room.

Then, of course, disaster struck again. I went on an extended trip and my ex, who offered to watch the place, didn't do the best job... Among other things, one, just one, of the speakers was destroyed. The grille was torn off the fret, there was a small hole punched into the phase link driver, and, for reasons still left for the ages, the whole damn thing leaning up against a wall heater. 

Thankfully the place didn't burn down, the cat was still alive, and there wasn't much else damaged, but the molded resin back was warped beyond belief, curving so much it split the MDF lip. That was about five years ago, and I just couldn't bear to bin them after 15 years. They've done a passable job hooked up to the television, and left my headphones for critical listening. 

 

Now I'm a real grown-up in my 30s, and can afford to start from scratch with a whole new setup, and some of the tiny boutique components at my local dealer are tempting. But after poking around here for the last few weeks and seeing how much love there is for these models, I figured it's worth seeing how far I get performing surgery.

 

So on to the project:

This particular pair are the earlier model 6302, angled resin back, with 6 mounting points for horizontal/vertical/angled permutations. Apparently some in this series had two hanging hooks, and still others threaded inserts for the later S45-2 stands. I've heard some disparaging reports that the -2 models were pretty flimsy cabinets owing to the MDF back, but I can say that's not true here.

 

Before anything else, I needed to tackle the back panel just to see if this was even feasible before I thought of buying new components. Thankfully the main structure of the cabinet is more or less intact, and nothing is too scorched. I wasn't sure what specific resin these are constructed of, thermoplastic, or thermoset, but we'll soon find out...

(excuse the awful cell photos. Would you believe I'm a professional photographer?)

Home Depot is still open, and I made a quick trip over for a cheap heat gun, which, strangely, lists creme brûlée as an ideal use, along with paint stripping...nothing about 50 year old speakers!

Ove Gloves on and the range hood cranked, and I started blasting it. Woof. Not a great smell. It didn't occur to me to take the drivers and batting out. 

Biohazard. Uck. Smells like burning hair.

Some small semblance of success! The trick was to evenly heat up the warped section, but not to the point of it becoming tacky. I made that mistake, and my glove made an imprint, as you can see on the left. The bubbles weren't from this procedure, but blistering from the original heater incident.

It's still lumpy, rather than the crisp angular profile befitting Beosystem, but I am going to give it another go using some scrap sheet and metal bar to form it back, and sand smooth. If you look closely, theres a sag right in the middle up front, and a bit of a bulge further back on the left. The challenge is to gently shape that down while keeping the side from bulging out. 

Working with this stuff softened is a weird texture. A bit like bread dough. If you've worked with molten glass or steel, very similar.

Then there's the mounting hooks. Gruesome. Once I have access to a metal shop again, I plan on building some S45-2 style stands, per dimensions found on past threads. McMaster-Carr has plastic-specific rivet nuts that will do nicely. I've got time to maybe devise a more aesthetically interesting stand and a more elegant pivoting bracket. Putting that architecture degree to use...

Then there's the slight problem of the missing MDF. A small piece of pine trim wood should slot in here. Glue suggestions once I'm finished? I'm loathe to use Gorilla Glue for the mess, so I'm thinking a bit of silicone to damp and standard wood glue.

Inside, there's really not too much warping and no heat damage. That's some thick material. I don't think this will affect it acoustically; it'll just look ugly as sin on the back. But you can hide the back, right?

 

Er...

Both cabs need a good cosmetic refinishing, pronto. The rest of my furniture is period-appropriate modern, but these are the embarrassments in the living room. I'd like to say they were like this when I got them (and they definitely had seen better days), but I wasn't always the best at packing for moves...

__

On to the drivers.

 

Tweeters look good. Philips mylar domes. Nothing to see here.

Onto the phase link.

 

I wish I'd taken a before photo, but it looked gruesome. A good inch-long rip from the surround inward. Ever since architecture school, I keep a bottle of Aileen's handy—everything Gorilla Glue wishes it was—and that's just the prescription, going on past wisdom. Applied perhaps a bit too heavy with a toothpick, but it's holding without extra reinforcement. It looks like it's applied a lot thicker than it is. I hope this doesn't color the sound too much, but these drivers seem to be fairly plentiful on eBay if it doesn't work out.

Excuse the decade of cat hair. These are still sticky. The other half of the pair is still relatively clean.

Now, how about those woofers?

As I said before...woof. And it gets worse.

It's been said on here that the butyl surrounds are relatively trouble-free. Apparently not always. From what I can gather, the brackets weren't located properly at the edges and bit into the surrounds, and cracks have worked their way around. Some Capt. Tolleys Creeping Crack Cure, quite possibly the other wonder glue in my drawer, is holding them relatively steady until I can work up the nerve to re-foam them. 

Unfortunately, both drivers fell to this fate.

Putting them back together will be a challenge to avoid the same problem. The existing hole can probably be epoxied just to be safe, and the proper screw location will be well far behind it—about where the indentation from the old bracket is, if you can see it.

Magnets epoxied top and bottom (and just a teeny bit of overspill, but nothing on the cones!). Amazingly didn't come loose after a 3000-mile truck ride.

 

Next step: get into the guts. The entirety of the weekend was spent researching and compiling parts for the electronics.

Down the rabbit hole of capacitor and resistor discussions. Trying to determine the discrepancy between the service manual (15µF caps) and whats actually inside mine and a few others' (16µF). Trying to find reasonably priced 16s. Trying to remember high school physics to figure out if this matters. 

In the end, I decided to go with 15µF Clarity Cap PXs. It's a close match with 10% tolerance, and 16s seemingly only come in cheap electrolytic or very expensive varieties. Parts Express doesn't have the middle-ground Solens in stock (at least as many as I need for both speakers), and won't for a while.

Perhaps someone more knowledgeable of B&O history, and experienced with crossover design, can explain the discrepancy and the expected end result. 

I figure in for a penny, in for a pound, and since some of the resistors look a bit crispy, those are going, too. Madisound's website isn't the easiest to navigate if you're looking for a specific component value, but I was able to get sets of Mundorf metal-oxide resistors for all of them at a very reasonable cost. 

 

Now the fun part is going to be rewiring these birdsnest boards with new giant caps, especially that 7-way junction on the common ground. Has anyone given a shot at optimizing the layout on a new board? I feel like at the very least, a terminal strip might help in reassembly.

 

Finally, since I'm already tearing these apart, I went ahead and ordered new hookup and interconnection wire, batting, and 5-way terminal cups. 

Hope you're still with me. Big project for my inaugural post, and I'm going all out. They're not in the worst shape I've seen here (see: burnt S75s, that S45, so hopefully they'll be good as new once I'm through. 

In researching this, I've seen plenty of posts on re-foaming, re-capping, re-wiring, and refinishing as individual projects. Not a lot of complete overhauls covering all of the above! Between the damaged cone and resin, I've been wondering if this whole project was an exercise in throwing good money after bad. A few older posts I've come across have called the mighty S45 'a dime a dozen,' in their ubiquity, and yet at least in 2020, I'm not seeing them up for sale often. 

Right now, I see a pair of 6302s in good, all-original shape, and even a single one sans-fret for about the same price; with tax and shipping, they come out to over $200—almost double what I'm spending on this project. And I'd still want to perform the same upgrades, so I'd be spending more on top of it. Fixing the resin is just a small part of a bigger project, and it makes me feel less guilty cutting holes for stands and terminals, anyway!

And besides, find me a new set of speakers with comparable clarity and presence, not to mention good looks for under $200. They're perfect for my little living room—bigger than bookshelves, smaller than towers, match my furniture (most important thing, of course)..

Any advice or tips are appreciated, of course. I'll leave you with one last photo of future projects—sprucing up the BM2000, and giving a little love to a CD3300 local record store gave me for free to take off their hands.

Beomaster 2000 (1980s), Beogram CD 3300 (1987), Technics SL1200mkII (1984) + Ortofon 2m Bronze, Beovox S45 (1970s)

In progress: custom stands for the Beovox

On deck: Beogram 5000, SoundSmith SMMC4

Ian
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Ian replied on Fri, Apr 24 2020 9:36 AM

A few packages came in today! One from Amazon (inexplicably shipped FedEx Next Day Air; I'll never figure out their logistics algorithm), another from eBay, and the 'big one' from Madisound.

But first, some progress on cabinets:

I hit the scratches with some 600 grit sandpaper I had left over from a different refinishing project. The water damage and scuffs are out, miraculously! These probably won't need as much work as I thought. 

 

From the first two packages: parts to make some new cable. I picked up a single 15-foot, 14ga speaker cable pre-assembled with banana jacks and wrapped in a woven sheath. Then I cut it in half. That gives me enough room to cover the distance at my long wall with plenty left over, and a lot less slack to deal with than the OEM cables. 

From eBay, a pair of male screw-terminal DIN connectors. They look a little chintzy, but I couldn't find much else. After much effort spent tinning the bare wire, I couldn't fit them into the little receptacles, so they were chopped off and started again, and very carefully cut and inserted flush, with attention to stray strands. The whole assembly was potted in silicone, and I slipped shrink-wrap over the whole thing (before inserting into the terminals! Forgot this step the first time around) to keep the sheath attached to the strain relief. 

Onto the crossovers.

Starting to lay things out, and oh dear. I had some idea how big the capacitors would be and knew they'd have to hang off the board, but the 10W resistors threw me for a loop. They're significantly longer, with proportionally shorter leads. There's no way I'd be able to swap them out like-for-like sticking straight up, since I'd both run out of vertical clearance and run out of lead to reach back to the board. Time to lay it out just a little differently. Note the hand-written markings just to keep myself sane.

A quick clearance check, taken sticking my phone into the phase-link driver hole. 

One of the challenges with this particular speaker is the space constraints. The crossover board sits on standoffs at an diagonal angle, so there's little room for a bigger board, and not a lot of height before it hits the speaker,  and batting has to go in here somewhere. That precludes my idea of building from scratch on a bigger board, unfortunately, but saves me from trying to unglue the inductors and re-arranging them.

I considered standing the caps on-end and threading wire through the spare mounting holes, but that likely would get me in trouble. it looks like if I mount them on the edge of the board with zip ties/silicone, I should be fine. 

 

More or less the final layout, cleaned up severely from the original. 

As you can see up top, I cut a few more notches to be able to run the resistors lengthwise across the board and keep them secure. I moved things around to give a bit more breathing room, rather than have everything crowded around the common terminal, as it was before. I wonder if these crossovers were assembled freehand, and then sort of crammed onto the board in final assembly. Trying to translate the schematic to a physical layout has my brain hurting.

 

A few notes on this:

1- in assembly, the capacitor/resistor combo coming off the tweeter's positive terminal were reversed compared to the schematic; I saw another post somewhere on here where someone ran into the same problem. I'm leaving it for the time being. That was the way it was built, and my brain isn't up to remembering how R-C networks work for the time being. Besides, swapping them throws off my beautiful layout.

2- As I mentioned, the original caps were specced at 16µF and I bought 15s. Measured with a multimeter, they're all on the high end of tolerance and end up closer to 16, and I'm sated by this.

3- I'm an idiot, and forgot to order 1Ω resistors. hence reusing the old ones... Another shipment placed....

4- This layout is 90% finished. There's a few jumpers I need to add once my order with wire comes in tomorrow. Notably, rather than have every negative terminal soldered together in a big mess, of a common ground, I separated them out by each speaker; they'll be tied together on the backside of the board. That yellow lead on the left is the positive common relocated from the middle of the board, and will be tied to the two loose capacitors, plus the positive input terminal. I thought of adding some terminal strips to look all professional-like, but there isn't much real estate left for that.

Tomorrow, when my brain is firing on all cylinders, I'll check the setup against the schematic and the other crossover board. Don't want anything frying.

 

The next big shipment comes in tomorrow, with terminal cups, speaker wire, batting, and grille cloth. I preemptively ordered new butyl surrounds from Speakerworks just down south in Eugene, and have those, the remaining resistors, and some hardware from McMaster-Carr arriving next week.

 

In the meantime, I'm digging some KLH bookshelf speakers (another great find—a past housemate left them after moving out) out of storage tomorrow. I never realized how bad the speakers in my television sounded...

Beomaster 2000 (1980s), Beogram CD 3300 (1987), Technics SL1200mkII (1984) + Ortofon 2m Bronze, Beovox S45 (1970s)

In progress: custom stands for the Beovox

On deck: Beogram 5000, SoundSmith SMMC4

Dillen
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Dillen replied on Fri, Apr 24 2020 1:35 PM

I wouldn't replace the original resistors with 10W types. They will never burn if the speaker gets overloaded,-  instead the drivers will.
Actually, I woudn't replace the original resistors in the first place. There's no reason unless burned or broken and in that case I would choose same ratings as the original.

The old capacitors will measure high in value as the die. That's normal.
Replacing 16uF with 15uF is perfectly fine. It's well within the components own tolerances and most schematics show 15uF anyways.
But those blue caps are complete and utter overkill if you ask me.
You won't be able to tell the difference from fresh electrolytics to those bulky things. Not in S45s.

Martin

Ian
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Ian replied on Fri, Apr 24 2020 5:54 PM

Martin,

Thanks for chiming in—the wisdom is much appreciated!

Regarding the resistors, I think I had read a few too many threads of S75s burning up, and since a few of the existing ones looked a bit brown and crispy, thought it to be safe based on lots of reading on the DIY Audio boards. It also didn't help that I couldn't find a single vendor for all of the necessary values in a lower wattage, and shipping costs would quickly grow exponentially... Madisound had everything in stock.

I see now that there's several schools of thought on sizing resistors, and regardless if overdriven, something—driver or resistor—is going to go boom. I'm less worried knowing the BM2000 is only 30w and never cranked past 50% volume. 

As for capacitors, well, at least I'm not the first to put some giant ones in there...

https://archivedforum.beoworld.org/forums/t/5584.aspx

They certainly are a bit overkill, but the price was reasonable. Same story as the resistors: that was the cheapest the same vendor had; others didn't have enough in stock.

Of course now I know you're the Martin everyone speaks about for recap kits, and that would have solved these sourcing problems! Oh well. Lesson learned now. 

I think I'll put the crossovers aside for a minute and resume my search for resistors another day. Still have a lot to do on finishing the cabinet work and mocking up stands in the meantime. 

Beomaster 2000 (1980s), Beogram CD 3300 (1987), Technics SL1200mkII (1984) + Ortofon 2m Bronze, Beovox S45 (1970s)

In progress: custom stands for the Beovox

On deck: Beogram 5000, SoundSmith SMMC4

Rich
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Rich replied on Tue, Apr 28 2020 2:31 AM
Nice project - good luck with it. I have a spare phase link if you need it.


Ian
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Ian replied on Tue, Apr 28 2020 7:01 PM

Rich—

much appreciated...your restoration projects on here are what inspired me, particularly the thrift-store P45s. Lucky find. As for the phase link, mines at least functional, though now I’d wished I’d used contact cement instead of Aileens. I’ll hit you up if it turns out to be horribly out of whack. 

in other news, things are coming along—couple more packages arrived. New woofer surrounds from came from Simply Speakers down in sunny Eugene, and aside from scraping out the horrible funk of the old ones, installation went fine. Frets were recovered with minimal hitches, aside from getting the old B&O badges out  

Second batch of resistors is on the way from Madisound, and my McMaster package got held up at the local UPS center after they failed to put an address on the waybill..how that happens, I don’t know. It’ll be fun trying to get there sans car. 

but I’ve got enough on my plate for the next few days. Apparently I missed some liquid damage on the undersides of both cabs, and rather than leaving well enough alone, I’m trying to flatten the veneer out. My experience is in metalwork, not wood, and I think I’ve spent as much on adhesives and finishing supplies as I have parts. Got plenty of furniture to work on so it isn’t for waste.

I dug out the aforementioned spare bookshelf speakers—not KLH as I remembered, but some 80s Design Research boxes. Crisp and nice imaging, but not room-filling like the S45s. 

And hey, if everything goes sideways, the old cabs make great stands.

Beomaster 2000 (1980s), Beogram CD 3300 (1987), Technics SL1200mkII (1984) + Ortofon 2m Bronze, Beovox S45 (1970s)

In progress: custom stands for the Beovox

On deck: Beogram 5000, SoundSmith SMMC4

Ian
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Ian replied on Wed, May 6 2020 12:10 AM

Well folks, they're done. They look amazing. They sound amazing.

I wanted to post updates as I went along, but I've mostly been on a marathon working (with many hardware trips in between!). At 3:30 this morning, I screwed them back up, plugged them in, and put on a new copy of Candy-O by The Cars that just came in.

 

They're definitely worth the effort put in. For sure. The clarity and soundstage is wonderful with these, and perfect for my small living room. They were in such sad condition before I'd all but given up on listening without headphones for some time now.

Next project are fabricating stands: there's a fairly narrow sweet spot, and sitting on the floor does them no justice. 

But I'll get around to posting my illustrated steps, much of which was a lot of learning on the fly on crossover design, woodworking, and the ins-and-outs of adhesives. But first, to rediscover some music that's languished..

Beomaster 2000 (1980s), Beogram CD 3300 (1987), Technics SL1200mkII (1984) + Ortofon 2m Bronze, Beovox S45 (1970s)

In progress: custom stands for the Beovox

On deck: Beogram 5000, SoundSmith SMMC4

Rich
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Rich replied on Wed, May 6 2020 1:03 PM

Congratulations.  My S45-2 pair are set up in the dining room with my best B&O:  BM4000, BG4002, BC4500 and CDX.  They don't quite get the use they should, because we spend most of our time in the family room where M70s are the front speakers of the home theater.

The P45s get some use in the spare bedroom where we keep the treadmill, and my S40s are my desktop speakers in the master bedroom with computer and my best non-B&O equipment.

4 world class sets of speakers, all requiring some level of work to get them back up to snuff.  Fun projects they all were, and several years later, worth every penny of cost and every ounce of effort.


Ian
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Ian replied on Wed, May 13 2020 1:11 AM

Thanks Rich. you’ve got a very enviable collection, and I see how these old beauties are truly collectible. That Beomaster/CDX combo is an exercise in contrasts, for sure! I’ve got my BGCD 3300 in serviceable shape, but the champagne/taupe/brushed aluminum of that series was a very unfortunate aesthetic choice. The CDX is just gorgeous.  

You’re right in these being truly world-class.  Infinity Quantums they are not, but worlds ahead of their peers of similar size and vintage, or even today’s compact bookshelf speakers. Somewhere in my fathers basement is a pair of old Kenwoods with an absurd number of drivers, and SPL aside, they don’t hold a candle to these.

I’m incredibly impressed with the setup right now...I’d actually been considering spending a bit, relegating the setup to my workspace or bedroom and acquiring a separates system (either something lovely and vintage from Hawthorne Stereo here in Seattle, or the new Technics Premium-class...I’m an abject sucker for UV meters) for my main living space. But after running through a number of well-mastered CDs and digital streams, it’s a whole new experience that doesn’t leave much for want in a small space. 

I had some doubts on the Beomaster, but I spent some of my stimulus cash on an Ortofon 2m Bronze for the TT, and the receiver is holding its own with that very precise cart. Who needs an external preamp when you’ve got an amp from the apex of vinyl? Besides, it’s very easy to use, has a tuner (I discovered a fantastic low-power station just across the street from me), and a new cartridge leaves me with enough on my plate to tweak. 

but anyway, to the topic at hand. I’ve spent much of my time obsessively aligning my turntable and digging out long forgotten albums, but I promise to continue with the step-by step of the restoration. Next: frets and woofer surrounds.  

Beomaster 2000 (1980s), Beogram CD 3300 (1987), Technics SL1200mkII (1984) + Ortofon 2m Bronze, Beovox S45 (1970s)

In progress: custom stands for the Beovox

On deck: Beogram 5000, SoundSmith SMMC4

Ian
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Seattle
Posts 10
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Ian replied on Wed, May 13 2020 1:11 AM

Thanks Rich. you’ve got a very enviable collection, and I see how these old beauties are truly collectible. That Beomaster/CDX combo is an exercise in contrasts, for sure! I’ve got my BGCD 3300 in serviceable shape, but the champagne/taupe/brushed aluminum of that series was a very unfortunate aesthetic choice. The CDX is just gorgeous.  

You’re right in these being truly world-class.  Infinity Quantums they are not, but worlds ahead of their peers of similar size and vintage, or even today’s compact bookshelf speakers. Somewhere in my fathers basement is a pair of old Kenwoods with an absurd number of drivers, and SPL aside, they don’t hold a candle to these.

I’m incredibly impressed with the setup right now...I’d actually been considering spending a bit, relegating the setup to my workspace or bedroom and acquiring a separates system (either something lovely and vintage from Hawthorne Stereo here in Seattle, or the new Technics Premium-class...I’m an abject sucker for UV meters) for my main living space. But after running through a number of well-mastered CDs and digital streams, it’s a whole new experience that doesn’t leave much for want in a small space. 

I had some doubts on the Beomaster, but I spent some of my stimulus cash on an Ortofon 2m Bronze for the TT, and the receiver is holding its own with that very precise cart. Who needs an external preamp when you’ve got an amp from the apex of vinyl? Besides, it’s very easy to use, has a tuner (I discovered a fantastic low-power station just across the street from me), and a new cartridge leaves me with enough on my plate to tweak. 

but anyway, to the topic at hand. I’ve spent much of my time obsessively aligning my turntable and digging out long forgotten albums, but I promise to continue with the step-by step of the restoration. Next: frets and woofer surrounds.  

Beomaster 2000 (1980s), Beogram CD 3300 (1987), Technics SL1200mkII (1984) + Ortofon 2m Bronze, Beovox S45 (1970s)

In progress: custom stands for the Beovox

On deck: Beogram 5000, SoundSmith SMMC4

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