Epos ES11 tweeter noise

[carlosfm]

Today I was listening to some good music LOUD and for the first time I noticed on one of the speakers a noise coming from the tweeter.
Like a rattle.
It was only apparent with very few musics, mainly some that had a loud piano.
I detected this with a Linn demo SACD/(HD)CD hybrid disc.
I thought to myself: this is it, I have a bad tweeter on my beloved speakers.
I have never opened them, I didn't know how to, looking at them you really scratch your head.
But this time I had to.
So I oppened the bad speaker.
It's not that difficult: you remove the rubber thing that holds the grilles and behind that there's a screw.
It's 4 big screws, one at each corner of the speaker, that brace the front to the back panel.
Opened it, and I was impressed.
Double cabinet.
No wonder this speaker has no resonances, absolutely no box sound.
As it was opened, I saw that the wiring was not so good as I thought. After all, it was not the (later model) DNM Reson, but some other cheap wire.
I stripped some spare Kimber 4TC and used single conductor wires for the tweeter and double for the woofer.
While re-wiring I saw the problem.
The original tweeter wires has so much solder that it was in contact with the magnet.
Thinking of it, the short was not permanent, it was effective only when a large current passed through it.
The speakers have never been opened before (or so it looked like), so this is a manufacturing fault.
I open this thread so that anyone that has these speakers and this problem finds the solution.
As I am at it, I'm changing the Bennic 1.5uf film cap for something better, let's see what comes out of this.
Now excuse me, time to re-wire and re-cap the other speaker.

[coredump]

Carlos,

the ES11 was developed primarily for a Naim context, using Naim amplification; as such the earlier models' inner cabling is just multi stranded copper, similar to NACA4/5.

The synergistic attributes of DNM/Reson LSC was 'detected' at a later date.

When putting it back together, make sure there's no stuffing blocking the ports.

Best regards,

Oliver

[Salas]

The original cap is not that good as a part but some people I know had to return back to it after substituting with other much dearer and proven caps. Thing is that it sounds synergistic to the particular tweeter. So be sure you dont lose it.
A cap that sounded good and synergistic is Mundorf supreme silver oil. Worth its money.
Also if in the end you have a slightly bad tweeter, the only guys who keep old Epos parts are: www.lockwoodaudio.com
I would suggest you get a spare for the future since Epos 11 is a classic that will never be repeated.

[carlosfm]

Originally posted by coredump
Carlos,
the ES11 was developed primarily for a Naim context, using Naim amplification; as such the earlier models' inner cabling is just multi stranded copper, similar to NACA4/5.

Hi Oliver,
The inner cabling really looks like PSU cable.
Those cables that you see on transformers.
It says: "Mayflex 18Awg - 1 mm2 105ºC 600V".
Worth replacing.

Originally posted by salas
The original cap is not that good as a part but some people I know had to return back to it after substituting with other much dearer and proven caps. Thing is that it sounds synergistic to the particular tweeter. So be sure you dont lose it.

You are so right, Salas...
I changed the original Bennic film caps for some "good" Siemens film caps and the speaker sounds like cheap.
That magical midband and treble is no more.
I'm gonna let them -in until tomorrow. If the speaker sounds the same to me (like crap), I'll put the Bennics in again.

Originally posted by salas
A cap that sounded good and synergistic is Mundorf supreme silver oil. Worth its money.

Let's see how this story ends.
The Bennics aboard again should return the magical sound of this speaker, and the better cabling should make it's job too.
Or not?
I still have the original cables...

Originally posted by salas
Also if in the end you have a slightly bad tweeter, the only guys who keep old Epos parts are: www.lockwoodaudio.com

No, the tweeter is fine now, really.
I played the same track again at loud volume and no problem at all.

Originally posted by salas
I would suggest you get a spare for the future since Epos 11 is a classic that will never be repeated.

Indeed.
I just love them.

[coredump]

Carlos,

Originally posted by carlosfm
[B]The inner cabling really looks like PSU cable.
Those cables that you see on transformers.
It says: "Mayflex 18Awg - 1 mm2 105ºC 600V".
Worth replacing.

that's what Naim speaker cable basically is - mains cable. Naim amps don't like speaker cables with huge capacitance, hence this approach works pretty well for them.

Originally posted by carlosfm
You are so right, Salas...
I changed the original Bennic film caps for some "good" Siemens film caps and the speaker sounds like cheap.
That magical midband and treble is no more.
I'm gonna let them -in until tomorrow. If the speaker sounds the same to me (like crap), I'll put the Bennics in again.

as I wrote elsewhere, check the caps' ESR before; if it proves to be different to the Bennics', use a resistor to restore the balance.

MCap Supreme work very well in this application, IMHO no need to spend twice that money.

Best regards,

Oliver

[carlosfm]

Originally posted by coredump
Carlos,
that's what Naim speaker cable basically is - mains cable. Naim amps don't like speaker cables with huge capacitance, hence this approach works pretty well for them.

Yes, they don't use zobels.
Capacitive cables can even kill Naims.

Originally posted by coredump
as I wrote elsewhere, check the caps' ESR before; if it proves to be different to the Bennics', use a resistor to restore the balance.
MCap Supreme work very well in this application, IMHO no need to spend twice that money.

The speakers still sound like crap today.
Tonight I'm gonna put the Bennics back.
Anyway, there's a 47R resistor in parallel with the tweeter and I'm sure that changing the cap this one has to be tuned too.
I just don't feel like fiddling right now.
Gonna check the price of those Mundorf caps, as I've been told several times that they are very good.
First I wanna enjoy the speakers with the Bennics back in and the new internal cables.
Maby I won't change anything more.
Oh, the amp runs er now.

[Nuuk]

Now you too can join Carlos in

hi-fi heaven !

[carlosfm]

Originally posted by Nuuk
Now you too can join Carlos in
hi-fi heaven !

142 pounds?
Maby I can get a spare pair of new ES11s cheaper, on a distributor.
I'll phone them tomorrow.
Yes, my friend has told me some months ago that they still have a pair of new ES11s, but they "seam to have a problem".
I'll ask him the minimum price, as they can't sell them.
I guess I know what's the problem.

[PB2]

The significant theoretical difference between electrolytics and film caps is that electros tend to have much higher ESR (thinner plates) and usually more ESL. This is fairly serious in bigger 50 uF and higher caps, but still the theory applies in general. So something you might want to try at some point, is to add a bit of series resistance with the film cap. For a 1.5 uF it should not be much at all probably less than .1 ohm and it could be as high as .5 for larger values above 100 uF but it depends on the constrution of the cap. Might also try a smaller value, just by 5 or 10% since electros tend to run toward the lower side of the tolerance. Less material saves the company money, more profit.

Real world capacitors, especially electrolytics are really distributed networks. The section of plate furthest away from the attachment point is connected through the inductance and resistance of the plate wind leading up to that section. This causes the effective capacitance to change with frequency and to a larger extent with electrolytics. Still, it's not much.

[PB2]

oops, saw Bennic and thought electrolytic just reread that it was a film, but 1.5 uF? sounds too low, sure it's not 15 uF for a large tweeter like that?