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Electrovoice T35 tweeter: did I kill it?

Patrice B

Patrice B

Super Member
Electrovoice TW35 tweeter: did I kill it?

Hi,

I just bought a big pair of speakers containing SP12 woofers and T35 tweeters. One of the the tweeter didn't made any sound so, nothing to loose, why don't I open it?

So I did and obviously, the tiny wires going to the terminals (+ and -) were broken during the process. Anyway, the problem was elsewhere as the lead was also cut just inside the dome, thus the no sounding problem.

I tried to repair but I'm not sure I did it neatly:

I managed to unwrap a small section of the coil (on top, do not worry) to restore the broken connection. It was kind of successful but... I was thinking the gasket was factory glued with the diaphragm (it stayed on the dome in the dismantling process, probably dued to 40 years in this state).

Then, I put some Super glue between the gasket and the dome after the resoldering process. Until I saw this: http://www.critesspeakers.com/rebuild_k-77_alnico_tweeter.html

I read that the gasket isn't supposed to be glued... Yikes. Will it change the sonics? I also did worse (I think) by putting Super glue on the coil itself (it was disformed, like a detended spring, not what it is supposed to look I assume).

So far, doing a test with a buzz tone on my analog voltmeter, there's a continuity between neg. and pos. It also emits sound when doing the same test resting on the magnet. I then assume it somewhat works. But will the sound be ok?

I also noticed that when putting the red probe on one side, the diaphragm goes up so I guess this is the + side. If the red probe is on the other side, no movement, so negative side?

BTW, I ordered a replacement T35 dome and coil but was in a hurry to hear these wonderful drivers.

It leads me to another question: could I build myself a replacement gasket (cardboard of the same thickness) when I'll receive the replacement part cause I'm afraid it'll be hard to restore the original gasket in its original condition (Super glue!!!)?

Thanks.

Patrice
 
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by unwinding the voice coil, you changed the parameters of the driver. i believe bob crites has rebuild kits for these.
 
Oh my God...

The replacement part I ordered is for T35 but I have a TW35 (Wolverine).

I hope it's enough similar that the diaphragm will fit.
 
Celt said:
I think I'd be following up with them on that one.
Click to expand...

Sorry to ask (my main language is french):

Do you mean it'll be ok?

Thanks.

Patrice

**If you mean to ask them about the possible issues. I already wrote to the seller. Now awaiting an answer.
 
Looking at what Bob Crites is offering and the diaphragm I bought (pictures only). They look exactly the same.

Maybe I'll ask Mr Crites directly...
 
BTW, the old diaphragm didn't fit in the speaker after the repair...

I also tried today a no name diaphragm/voice coil I've found in a surplus store: dome was a little higher than the original EV. The sound was really really weak.

I just have to wait and be patient.

**I also mailed Mr Crites about the interchangeability, just to be double sure...
 
gugusse said:
BTW, the old diaphragm didn't fit in the speaker after the repair...

...I just have to wait and be patient.

**I also mailed Mr Crites about the interchangeability, just to be double sure...
Click to expand...

i've tried the same trick on tweeters in the past. though i have been able to get some to produce sound, they are never the same. if the diaphrams do not work, those tw-35's come up frequently on that auction site, and aren't extremely pricey.
 
Mr Crites confirmed that the diaphragm is supposed to fit in the TW-35.

However, he told me that it is sometime really hard to center the diaphragm properly on some old EV's.

Patrice
 
Well, things evolved in the last hours:

I've found someone here in Montréal refoaming and repairing speakers... and specialized in vintage drivers.

I've bring the tweeter at 5:30 pm and it was ready 45 minutes later with a new diaphragm and a new gasket. I stayed and looked at the repair. He used a test tone, an oscilloscope and tweaked the screws until he decided this was the right tone...

If I had done the repair myself, I would surely have tightened the screws without knowing that it's not as simple. He even tried a first diaphragm and declared that it wasn't playing well with my driver. So, he put another one. Really professional and friendly and now, I have a wonderful pair of SP12B's and TW35's!!!

I'll keep the diaphragm I ordered as a future spare.

Patrice
 
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Question again: the woofer's and tweeters are 8 ohms, connected to a CR-35 crossover. Do I have to hook them to the 4ohms tap of my HKA500?

I guess I could measure resistance of the main wires coming from the speaker...
 
Well, I answered my own question I think!:D

Resistance is around 6.5 ohms so it depends where it sounds better.

More power to the 8ohms tap I decided so here it goes...

BTW, no "loudness contour" needed with those beasts, it's way too boomy!!!
 
Here's how looks the finished product:

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IMGP1252.jpg


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IMGP1251.jpg


I had to remove some kind of vinyl imitation (two layers: orange and brown fake wood), clean the remaining goo, sand a little bit and varnish.

The back panels were painted black and I was too lazy to remove the paint so I opted for some applicable imitation of plain wood.

As for the grilles, there was again two layers (hmmm... good for the sound isn't it?): the old original fabric and a new black cloth, stapled directly on the front.

Unfortunately, even as I liked the look of the old original fabric, there were two big holes made for the woofers so I bought some guitar amp fabric to replace it.

As you can see in the 2nd pic, I put a preventive protection on the woofers (I can - and already did on three sets of speakers - punch easily some holes right in the paper cones... Don't ask me how I did it, it's... ahem... embarassing! :D): some kind of metal grille specifically engineered against yours truly and his son...

I even pushed the detail and scanned the logo on the brochure I got with the speakers. Then, I put it on sticker labels.

Sure, not a professional aesthetic job (as I'm some kind of "professional butcher" when it comes to restore speakers or tube amps...) but it looks fine.

It sure does sounds fine too!

Patrice
 
Impressive: I don't need any tone compensation for these speakers to sound good. The bass and treble of my Harman Kardon A500 are at "flat" level. In fact, adding bass make the sound boomy and adding treble make it too harsh...

Not the case for my Monitor Audio Bronze 2 (little treble emphasis on a Scott LK-72 + loudness compensation switched on), Wharfedale's Denton (bass and treble maxed on an Heathkit AA-32), Goodmans's Minister SL (bass and treble maxed on Clairtone S-601), Realistic MC-2001 (bass and treble maxed on an Heathkit AA-100) and Wharfedale's Diamond 8.2 (little emphasis on bass and treble on a Fisher X-100A).

And I don't even talk about all my others tube amps, mainly consoles, where the bass and treble are also at max.

Patrice
 
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