Alternatives to EV T35 Tweeters

[TN Allen]

I recently reconnected an updated Dynaco ST70 and EV 12TRXB speakers I used for years before building newer systems. I used my cell phone as a source directly into the ST70 using the phone's volume control and the equalizer for tone control. I am pleasantly surprised with the quality of the sound, it compares very well to the newer components. These are a combination of Peerless Corundum tweeters in waveguides and NE series woofers. The cabinets are T/L designs.

I have a few more T/L cabinets started and have the Peerless NE woofers, and had intended to use more of the Corundum tweeters, but these are not available except in large orders. Consequently, I'd like to find high frequency drivers similar to the 12TRXB T35 horns to mount to waveguides. Here is a link to an article describing the T35 tweeters:

https://audioxpress.com/article/remembering-the-electro-voice-t35-super-tweeter

I've tried various dome and radiator ring tweeters, but prefer the Corundum domes, also the TB inverse dome PE sold a few years ago, also no longer available in small quantities. I've also considered ceramic and Beryllium dome tweeters, but given the cost of these would like to find something less expensive.

I'm not certain the T35 is a compression driver, if it is though, perhaps someone with experience with compression drivers and waveguides can recommend some possibilities. I can mill or turn waveguides to match drivers.

Thank you in advance for suggestions.

[billfitzmaurice]

There's no need to go with separate drivers and horns, and I do mean horns. This is pretty close to the T35: https://www.parts-express.com/Eminen...IaAiI5EALw_wcB

The main difference is that it's a CD horn, so it's placed horizontally, as opposed to the T35 diffraction horn that's placed vertically.

[devnull]

The T35 and all it's variations are compression drivers with integral horn assemblies. Off the top of my head they were 95 x 65 degree horns, about 105 dB, 3500 minimum crossover. EV crossovers were spec'd for 16 ohm woofers so you'll probably have to roll your own vs using what they published.

I've got some data sheets and xover diagrams some place, let me know if you'd like me to dig them up and post them.

[TN Allen]

Thank you, I've ordered a pair.
Thank you for the generous offer of data, I'll need to start with the new components' data though.

[DrewsBrews]

In case you are interested. Paudio PHT-409. Knockoff of the tweeters used in the previous few generations of the (lower end?) heritage speakers. Has a phenolic diaphragm. They appear to be b-52 buyouts still available on the usual auction website.

Here are some of my measurements:





(Distortion) Black=THD, Red=2nd orfer, Orange=3rd order, etc.

[TN Allen]

Thank you for all of the above information.
The APT-150 drivers arrived. I've connected one quickly and the sound is very similar to the T35 and Corundum tweeters. That is, inso far as I can tell, given my hearing is compromised.

I've also ordered a pair of the PHT-409 horns to compare.

Taking this inquiry one step further, are there high compliance woofers currently manufactured that may compare favorably with the EV12TRXB woofer?

[billfitzmaurice]

https://www.parts-express.com/Eminence-KL3012CX-8-12-High-Power-Coaxial-Woofer-8-Ohm-290-5642?quantity=1

[DrewsBrews]

Not sure what is meant by "High compliance"

For tweaking the PHT-409s I'd suggest setting up a cheap LIMP box for ARTA freeware. I ran a constant test on the impedance while I tried the diaphragm in different orientations. Once I found the best orientation just screw the horn down to lock it in place. Of a few pair that I got, one of them needed opening up the indexing holes a bit on the diaphragm so I could move it around more.to find the sweet spot in the gap.

[billfitzmaurice]

"Not sure what is meant by "High compliance"

My assumption is long xmax. Since there are no T/S specs available for the 12TRXB one can't say what it has for xmax. If one doesn't need the 7.47mm of the KL3012CX the Beta 12CX is a much more affordable alternative.

[TN Allen]

Not sure what is meant by "High compliance"

For tweaking the PHT-409s I'd suggest setting up a cheap LIMP box for ARTA freeware. I ran a constant test on the impedance while I tried the diaphragm in different orientations. Once I found the best orientation just screw the horn down to lock it in place. Of a few pair that I got, one of them needed opening up the indexing holes a bit on the diaphragm so I could move it around more.to find the sweet spot in the gap.

The PHT-409 tweeters arrived, they seem good, particularly at ~$45/pair, and compare favorably so far to the Corundum and Eminence APT 150 horns. This is through listening.

I think I understand correctly that you loosened the 3 hex head screws in order to adjust the diaphragm/voice coil location relative to the magnet. I'll need to reacquaint myself with ARTA.