Soprano signature??? What are these?

[JKent]

Just goo.

Finished the patch but I used a stain pen on it and it came out too red. Better than the chunk that was there before but not perfect.

 

 

[JKent]

Finished except for the grille cloth.  I set them up temporarily in the rec room for a listen and I think they sound good. Listening was done with the grille frames on, like the speaker on the right, with that double layer of cloth over the tweeter. I also used a 4 ohm resistor in series with each tweeter. Played a variety of music from my iPod using the Lepai T-amp that's on top of the left speaker (so not exactly audiophile but this allowed pretty good placement and listening position).

[ChrisM]

After the sorry state you got them in, I'm sure the owners will be very pleased. Good job!

[JKent]

Thanks Chris.

Here they are. Grille cloth is a bit lighter than original. I added Velcro strips for easy grille removal.

[ChrisM]

Any feedback from the owners yet?

[JKent]

Yes. I had dropped them off at my tech's because he was also working on their McIntosh pre & amp. Shortly afterward I received a nice email:

"Thank you. They are wired up and sound really nice. And look good. Maybe part of it is a rare feeling of cheating time. We bought them from my wife's boss the day before our daughter was born. She is now 35."

Nice note. Made it worthwhile.

[ChrisM]

Kent, take a look at this:

https://audiokarma.org/forums/index.php?threads/european-holophone-systems-soprano.915874/

[JKent]

You da man Chris. You're the only one who showed any interest in these and now you've uncovered more info! Thanks.

Followed links in the AK thread and found this info. They are The European Holophone Systems Soprano loudspeakers from the early '70s, made in Belgium. Here's a little more: https://6moons.com/industryfeatures/gotaway1/gotaway.html

The article incorrectly identifies the woofers as 6" Peerless. Maybe 5" Peerless?

Kent

[ChrisM]

The woofers being Peerless explains why I didn't recognise them (not British). I think a lot of people made their own versions of the KEF B110. It is also interesting that the ones you worked on had the big Audax tweeter and the 6moons review ones had the 1" dome Seas tweeter. The Seas units are very good tweeters and were used in a number of commercial speakers one example being the Boston Acoustics A200. Those tweeters do sound nice. I know because I have a pair. Mine are currently sitting on the shelf but I have plans for them.

[b_sdaddy]

Hi.

There was a link from my thread on Audiokarma, so I thought I'd add to this too!

Picked mine up last week. A round-trip of 50km and they were FREE. The seller was the daughter of the original owner. They were apparently very, very wealthy people.

I had suggested on email, that they looked DIY. She was NOT amused. It was those wooden dowels and banana plugs that got me thinking...as well as that god-awful caulk everywhere!

Actually I couldn't have been more wrong: The cabinets were hand-made by a Belgium violin manufacturer. The Grilles were never meant to come off.

I've managed to get an original sales invoice from 1983. They cost 75,000 Belgium Francs when new. I asked one of my older colleagues at work, what he earned back in 1983, as a general worker in a factory: 20,000BF.

So a few months pay. And google suggests that would be upto €4000/$4000 now. A significant purchase.

 

Aware that they're 4ohm, if someone can direct me to info. on how to protect from use with a 6-8 ohm amp.

Currently one is completely dismantled ready for a 100% renovation job.

 

btw. They used several different types of tweeter, as every model they produced had a "signature" version.

Have tracked down the original sales brochure (in french), from a Dutch guy. Hopefully he'll be able to send copies for my wife to translate.

 

Cheers.

 

[b_sdaddy]

Question;

Why would you parallel a 0,33Uf (+/- 10%) onto a 6,0uF (+/- 5%)?

0,3 is 5% of 6,0. Did they add the 0,33 to "compensate" for the tolerances in the 6,0uF cap?

Or with my limited knowledge, am I missing something?

This re-cap isn't going to break the bank, and prior to reading this, I was going to opt for just a 6,0.

 

Any advice greatly appreciated.

[ChrisM]

Well......

Your picture of the sad looking crossover is interesting because the larger(6uF) cap looks like an electrolytic. It looks like metal end caps which to me says electrolytic but it might be a paper in oil. The one in Kent's picture definitely looked like a Mylar or polypropylene. The simplest answer to the parallel cap question is that they wanted a 6.3uF cap. If these were really that fancy a speaker, they would have measured the caps for exact value. Having said that, it is also true that a 6db per octave series crossover isn't that critical of values. This isn't an LS3/5a crossover where values really are critical. Some people are also big believers in using super high quality small value caps to bypass larger caps. I am not one of them. So not only did they use different tweeters but different caps.

We will need some pictures of your rebuild so we can learn more about these speakers and to cheer you on.

 

[JKent]

hey b_sdaddy

I was glad ChrisM found your threads, just wish we'd known about them sooner. Very interesting speakers as it turns out.

A couple of thoughts:

1. The 0.33uF is probably a "bypass cap." Some audiophiles think that putting a small value cap, often of higher voltage, in parallel with the main cap "improves" the sound. I'm skeptical. In the ones I worked on the arrangement was sort of the opposite of yours. The big cap was a yellow mylar and the small one was metallic green. Maybe PIO as Chris suggests. I don't think either one was marked in my case but I had to replace one pair because of a broken lead and I measured the big cap at 6.2uF, small one at 0.33 so I replaced them with 1.5 + 1.5 + 0.33.
2. Are you sure these are 4 ohm nominal? The woofers in mine were totally shot and had no markings. DCR readings were all over the map IIRC. But the tweeters were Audax HD13D34H, which are 8 ohm. I think your tweets are SEAS though. That 6moons article is interesting but not 100% accurate. It says the woofers are 6" Peerless and they are really 5". And as Chris noted they sort of "look" British.

Keep us posted.

Kent

[b_sdaddy]

So then,

the sad picture was due to fact that they had glued the panel to the cabinet. Chipboard was always going to break. Will fashion a new plinth.

Should I be exact both in values and type of capacitors? A readily available single 6,2uF surely would suffice?

Running a thread over on Audiokarma, but I'll post the first batch on here also!

 

So it's a full strip-down 100% restoration:

Cabinets are 9/10 already, but damage to some corners. Will fill, veneer and make good.

The wooden dowels have already been sanded away. To be replaced with plastic pegs.

All drivers working perfectly, but as you can see, there's four small bolts missing on one of the tweeters. Have taken two off of the other one for now, but will obviously source replacements.

The crossover's a simple job. Just deciding on what "exactly" to replace the old caps with.

As with my Leak Sandwiches (see photo), I'm going to have too 'modernize' the aesthetics: The front panel is 8mm mdf. Everything else, real wood veneer that will come up beautifully after a weekend's work.

They're keepers, so I'm not interested in maintaining the "period" look.  Some things I do, example my Lenco L70 with existing arm and bakelite headshell, and this time, no.

The mdf panel with be filled and sanded, and then sprayed satin back. There will the nice detail of a 5mm frame of real wood still.

This panel was never meant to be seen. Coupled with half a litre of caulk that they used, it's not nice to look at.

I'm going to fashion foam gaskets instead. I'm also going to replace the period brown grill cloth with black.

Started with one today, getting it back to the shell.......

 

[ChrisM]

13 minutes ago, JKent said:

Are you sure these are 4 ohm nominal?

Probably. two 8ohms in parallel. Back when, most of the drivers were 8ohms. I know Mr. Kloss made some 4ohm ones but the vast majority of commercially available ones were 8. In Paleolithic times, 16ohm drivers ruled the land. 16ohms makes tube amps happy.

[b_sdaddy]

17 minutes ago, JKent said:

hey b_sdaddy

I was glad ChrisM found your threads, just wish we'd known about them sooner. Very interesting speakers as it turns out.

A couple of thoughts:

1. The 0.33uF is probably a "bypass cap." Some audiophiles think that putting a small value cap, often of higher voltage, in parallel with the main cap "improves" the sound. I'm skeptical. In the ones I worked on the arrangement was sort of the opposite of yours. The big cap was a yellow mylar and the small one was metallic green. Maybe PIO as Chris suggests. I don't think either one was marked in my case but I had to replace one pair because of a broken lead and I measured the big cap at 6.2uF, small one at 0.33 so I replaced them with 1.5 + 1.5 + 0.33.
2. Are you sure these are 4 ohm nominal? The woofers in mine were totally shot and had no markings. DCR readings were all over the map IIRC. But the tweeters were Audax HD13D34H, which are 8 ohm. I think your tweets are SEAS though. That 6moons article is interesting but not 100% accurate. It says the woofers are 6" Peerless and they are really 5". And as Chris noted they sort of "look" British.

Keep us posted.

Kent

Got the 4 ohm from that article! Did also check with MM and from the inputs got 3,8ohm?

Just as a benchmark, switching between the Leaks and these, and with a constant , non adjusted volume, the Sopranos were 50% louder. Rarely go more than 3 oclock anyway.

Jury's still out on what cap(s). 40 years on, the range is immeasurable to what it was. If I 'just' went with a 6,2uF, surely only measuring equipment could record any audible differences.

6,2uF @ 1% now must be within tolerances of 6,0uF (+/- 10%) & 0,33uF (+/- 5%) 40 years ago.?

 

Or do I mix as they did, and go for the small 0,33uF, and two 3,0uF @ 1% (6,0uF are like hens teeth!)

 

Cheers

 

 

[ChrisM]

7 minutes ago, b_sdaddy said:

Should I be exact both in values and type of capacitors? A readily available single 6,2uF surely would suffice?

Since you're not doing a "purist" restoration, I'd say just use one high quality cap. Solen makes a 6.2uF for about $5.

 

32 minutes ago, JKent said:

Are you sure these are 4 ohm nominal?

I forgot. In that previous post when we were discussing the crossover, I mentioned it was about 3KHz. I got that number from assuming an 8ohm tweeter and a 4ohm woofer system. The coil would have to be more like .4 something uF for 3KHZ with an 8ohm woofer system.

[JKent]

DUH. Totally forgot the woofers were in parallel 😕

[b_sdaddy]

It's only 'non-purist' aesthetically.

And as for the original caps, if the designers opted for the small cap. in parallel, why shouldn't I go with the same, or as close as availability allows?

My usual supplier has;

5,6uF @ 1%  & 0,65uF @ 5%

(or is 0,65 too high to be regarded as a bypass?)

And the original specs under the magnifying glass: ERO MKT1813  6uF 250v (+/-5%)    and    ERO1813 Film Cap 0,33uF 250v (+/-10%)

[ChrisM]

15 minutes ago, b_sdaddy said:

It's only 'non-purist' aesthetically.

And as for the original caps, if the designers opted for the small cap. in parallel, why shouldn't I go with the same, or as close as availability allows?

My usual supplier has;

5,6uF @ 1%  & 0,65uF @ 5%

 

And the original specs under the magnifying glass: ERO MKT1813  6uF 250v (+/-5%)    and    ERO1813 Film Cap 0,33uF 250v (+/-10%)

Sure go for it. As I said, I'm not a member of the "bypass" church but it won't hurt and it's sort of authentic.

It looks like the originals were both polyester so either that or polypropylene for an upgrade.

[b_sdaddy]

Gotta love the internet!

 

Just found a supplier of the ERO MKT1813 6,0uF (+/-5%) caps!  UK based and as you can imagine, not going to break the bank.

Getting the smaller 0,33uF's is no problem.

 

Sorted, as the younger generation say.

[b_sdaddy]

So after a week, one is complete!
Stripped cabinets, repaired, stained & varnished.
Recovered grilles.
Rebuilt crossover with Mundorf M-Caps: 6,2uF & 0,1uF
Rewired everything.
Spent hours removing all of that caulk!
Resprayed/touched-up drivers.
Made foam gaskets, replacing the caulk, as now with the grilles removed, you'll see everything.

Initial listening suggests recapping was necessary.

Now onto the second one......
 

[JKent]

That looks great! Wish I'd had your project to serve as guidance before I did mine. Great work!

Kent

[b_sdaddy]

Thanks for the compliment.

Going to start on the second one now.  And for the foreseeable future, they're staying.

 

Stephen

 

 

 

 

[ChrisM]

That first one does look very nice and no doubt the second one will be just like it.

I would like to caution you though about something I just noticed. Kent's woofers had no markings on them and your photos show none so we don't actually know which Peerless woofers they are. I was admiring the photos of your finished one when I noticed that the surrounds appear to be shiny and smooth. I then went back and looked at your earlier photos of the woofers.

It is quite possible that these Peerless woofers have surrounds made of PVC. If they do, it is imperative that you keep the grill covers on. There is a lot of evidence that sunlight causes the PVC surrounds to degrade. At first their parameters start changing but it is so gradual people don't notice any changes in the sound. Eventually they shrink up and lose their shape thus wrecking the driver. They also lose their shiny "plasticy" look. Once this happens, that's it. So far no replacements for PVC surrounds have been found so repair isn't possible. Heat and humidity may also affect them but the main factor appears to be sunlight. This also affects neoprene surrounds to a much lesser degree and butyl rubber the least.

It is somewhat ironic that people who spent more money to get higher end speakers back in the 70's and 80's left the grills off to admire the drivers and because in general they sounded better with them off and now their surrounds are bad. Obviously the Soprano's were voiced with the grills on since they glued them so there should be no sound penalty to leaving them on.