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EV 15trx Speakers ... Who knows about them?

blondiebass

blondiebass

Member
Hi, wondering if anyone has any experience with Electro-Voice 15trx drivers. My research shows they were sold back in the day to fit into various cabinets as DIY projects.

My question is, are the speakers worth keeping? They sound kind of muddy. Right now they are in a monster cabinet with a Milo Badge on them. I was told from one person Dave West made them...another person told me he did not.

Either way, I would love any more info on these and would like to know how good I can make them sound.

Could these sound as good as some similar era Klipsch?

Here's a few pics for your viewing pleasure..

Thanks in advance!!
 

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They should sound crisper than muddy, maybe not up to today's standards but close. Under the bell on the back of the speaker there should be a capacitor or a pair of them for the tweeter, probably in need of replacement, hopefully that would wake up the tweeter. Or the voice coil is bad but more likely the cap.
 
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Those were used in many speaker cabs at one time. There's a Vintage Electro-Voice page on Facebook where you can find out anything you want to know about them. Several ex-EV employees are part of the group.
 
EV were used in early Klipsch systems, also Stephen Trusonic. Properly implemented that 15 full range driver will cause the hairs on your arm to stand up. The bass and midrange are world class, not sure if I would part with them if I had them. It’s the little T-35 tweeter in the center that’s letting you down. The capacitor needs to be replaced. Even then, that tweeter dies around 12k or so. The 15” is an EV SP-15b, you can look that up. Congratulations!

Biggles
 
The tweeter they are using there was sold for use above 3khz as super tweeter by EV back in the day. Pretty ambitious for a 12" driver to meet up with let alone a 15". Assuming they're working at all.
 
IME these drivers can sound pretty good. As has been mentioned check the crossover capacitors and the level control.

Back in the old days DIY hobbyists were often pretty casual about the speaker cabinets they used and the muddiness could be caused by the cabinet not being of the proper size and venting. Such a situation could cause underdamped bass and a significant bump in the bass response--muddy bass.
 
Yes indeed, keep them and replace the capacitor for the tweeter. Give them a test in your cabinets and report back. Also, pictures of the inside, outside, and dimensions may help others to make recommendations.
Good luck!
 
Once you've replaced the tweeter cap- you might also want to try putting in a 1uf cap between pins 2 and 3 of the L-pad (input and output). That will allow you to turn down the "mids" coming out of the tweeter slightly, without attenuating the output above 10KHz. That seems to help the T35 sound a bit more "open".

EDIT: In fact, the cap may only need to be 0.47uf, in some cases. I remember using that size on the 12TRX- but, the larger woofer (more efficient) of the 15TRX may well work better with the larger 1uf size.

Regards,
Gordon.
 
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Awesome, I'll get some pics and dimensions of the cabinets. You will cringe. I'm more of a (kitchen) cabinet builder than EE so I can have fun with that side of the equation. I have some new caps coming so I'll try that first and clean the attenuator. Then go from there! I'll post my progress for those who are interested.
Thanks again for the insights.
 
A friend of mine had the EV SP15 woofers with whizzer cones and the T35 tweeters, until his cats got the cones. They were in folded horn cabinets and sounded great. Depending on how your cabinets are tuned, you might just have real nice speakers there.

I still have a massive magnet from one of his destroyed woofs. It's extremely powerful.
 
You obviously have the older units and they should be reconed. As for the hoghs it could be the crossover needs a total rebuild. If it were me I would cpntact Great Plains audio for help and if that a no go, then EV for complete restoration. The Magnets probably need recharging and I know Great Plains has replacment HF diaphragms and can recharge your magnets.
 
Well, I pulled the rear bells of and found something strange. Both speakers have 2 caps. One speaker has 2.4uf 200v. (marked as 2.4mfd) and the other speaker is 6uf 100v. (marked 6mfd)
I'm guessing this is micro farads. Not Millie.

Any thoughts on the difference in the caps? And any idea what the engineers designed?

I also pulled the l-pads and found both looked like they had melted at roughly the midpoint of the dial. Gonna need new ones.

Attached are pics.

Also a picture of the cabinet. The size is roughly 40" tall, 18" deep and 30 wide. Not vented other than the cracks in the particle board seems.

I believe these were used in a bar or something based on the condition.
 

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Is one of the speakers 8 ohm and the other 16 ohm? That would explain why one cap is half the value of the other. 8 ohms would use twice the cap value, and half the inductor value, to give the same crossover response as 16 ohms.

Most of the 15TRX I have seen, have had the 6uf caps- and most of them have been that same reddish color.

Regards,
Gordon.
 
C5342798-4368-4DA7-8528-2365787762F1.jpeg Hi, I just picked up a pair of 15TRX’s this past weekend. Mine seem to be in pretty good shape and sound really good but I’d like to take a look under the bell to see what’s in there. How does one remove the bell?
 
Since the optimum cabinet size for an infinite baffle cabinet is greater than 20 cu.ft., has anyone ever tried using a cabinet of that size. How did it sound? I’m play with the ideal of trying it.
 
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