RS28A-4 vs RST28A-4

[HumbleDeer]

Hey!

A while ago the RS28A-4 was discontinued, just after I ruined the tweeter on my TANGO MT speakers I built (DIY).

I looked at the graphs of the supposed replacement brother RST28A-4 and saw the curves look similar enough for me to be happy with. But what about the Fs and Re? Does the change in Re from 2.8ohms to 3ohms have any significant impact on how the crossover will function?

ANd eh.. Does the phase stuff actually make a difference either? It doesn't look majorly disruptive to me.

Cheers,
Anna

RST28-A Spec:
https://www.parts-express.com/pedocs/specs/275-131--dayton-audio-rst28a-4-specification-sheet.pdf

RS28-A Spec:
https://www.parts-express.com/pedocs/specs/275-130--dayton-audio-RS28A-4-specifications.pdf

 

[Mario Pankov]

I have not played with that tweeter but here is what I know about your issue:

- Jeff Bagby, who did a design featuring it, did post on his facebook page that the new version won`t work in place of the older so it would need a different crossover
- Parts Express changed their OEM to a new company, if I was you, I would avoid buying from the first batches. They were known to have consistency issues on all their RS28 line tweeters through the years

That being said, just look for an RS28 (so the older version), you should be able to find some. Looking at their datasheets,m the RST is significantly different, I wouldn`t expect it to work with an RS crossover either.

 

[HumbleDeer]

I have not played with that tweeter but here is what I know about your issue:

- Jeff Bagby, who did a design featuring it, did post on his facebook page that the new version won`t work in place of the older so it would need a different crossover
- Parts Express changed their OEM to a new company, if I was you, I would avoid buying from the first batches. They were known to have consistency issues on all their RS28 line tweeters through the years

That being said, just look for an RS28 (so the older version), you should be able to find some. Looking at their datasheets,m the RST is significantly different, I wouldn`t expect it to work with an RS crossover either.

Right, yes. I knew about the OEM issues. The one I ruined was actually one I tried to fix after it was misaligned from the factory. There's a couple shops locally (nation-wide) that still have the diaphrams but that's all. The motor also had some alignment issues but I was able to fix that with a screwdriver. It's sad to see they can't make a plug-and-play replacement though!

 

[HumbleDeer]

Would there be significant change required to make the RST tweeter work with the RS-designed crossover? It uses the standard design.

 

[ernperkins]

When Jeff redesigned the Continuum after the RST28A went NLA he choose the Morel CAT308 over the new RST28A. Evidently the CAT308 required fewer crossover changes than the RST28A.

 

[HumbleDeer]

When Jeff redesigned the Continuum after the RST28A went NLA he choose the Morel CAT308 over the new RST28A. Evidently the CAT308 required fewer crossover changes than the RST28A.

So if I were to apply the changes he made for the CAT308 to my crossover's Tweeter part, would that be it? I'd be worried about the crossover frequency at the woofer/tweeter point, as the Continuum uses a different woofer.

 

[Dissi]

RST28A-4 replacing RS28A-4

The RST28A-4 is a new tweeter and there's not much known about it yet. But based on the datasheet it should be possible to use it as a replacement for the RS28A-4 by adding a local Lpad to the driver consisting of 1.2 and 5.6 ohms. That's a general patch which should not only apply to the Tango speaker. The crossover does not change. Just an idea and possibly worth a try... 🙂

 

[HumbleDeer]

But it should be possible to make the Lpad changes on the crossover board, right?