EBS evolution proline cab tweeter

[Majid]

Hello bass lovers,

 

Happy new year 😊

I own an EBS HD350 head with EBS evolution proline 2000, 4x10, 800W with selenium st304-slf tweeter. I bought this rig second hand last year. As I was not experienced with the sound of EBS, I didn’t notice anything until I read (on the internet) about the hi-fi and special brightness/clarity of the EBS sound and also watches some videos. Then I started feeing that there is something wrong with my stuff. I recorded the amp directly and it sounded very clear and bright so no issue….Then I started looking into the cab by tweaking the high frequency selector switch on the back of the cab to boost the level of the tweeter but didn’t hear any difference. Then I opened the cab and listened to the tweeter closely but didn’t hear any sound coming out of it. I demounted the tweeter, disconnected the wires and measured the resistance. The ohm meter didn’t show anything. So, few questions:

1. Is there anyone with the same exp. here?

2. Am I guessing the issue correctly that the tweeter is faulty and need to be replaced? Or am I doing a wrong test and perhaps the issue is somewhere else?

3. Where can I find Selenium ST304-slf tweeter if the issue is with the tweeter itself?

 

Thanks and best regards,

Majid

 

 

[Bill Fitzmaurice]

It's a blown tweeter. The usual cause is a crossover inadequate to provide adequate protection and/or using distortion effects. The Selenium ST304-slf can't go lower than 3.5kHz, which IMO is way too high. If you like the way it sounds my advise is to leave it as is.

[Majid]

46 minutes ago, Bill Fitzmaurice said:

It's a blown tweeter. The usual cause is a crossover inadequate to provide adequate protection and/or using distortion effects. The Selenium ST304-slf can't go lower than 3.5kHz, which IMO is way too high. If you like the way it sounds my advise is to leave it as is.

Hi Bill,

thanks for the reply.

No, I don’t and that’s the issue. I like a clear and crispy high end (but not too thin) as I mostly slap on my 70’s jazz basses. Without a tweeter, the cab doesn’t sound the way I like. What would be the alternatives if I’m not able to find a new ST304-slf? Chatgpt suggested eminence APT80 v2 but I need to modify it to be able to mount it due to size difference.

[Bill Fitzmaurice]

The tweeter/horn that I recommend is the Eminence BGH25-8, as it's specifically designed for electric bass. It can be used as low as 2kHz, where you need it for wider dispersion than woofers can give, and rolls off above 10kHz, where there's nothing of value for bass. However, it requires a purpose built crossover for best results. You probably need that anyway, no matter what tweeter you end up with. The crossover is where many manufacturers cut corners, with blown tweeters being one result.

[Majid]

45 minutes ago, Bill Fitzmaurice said:

The tweeter/horn that I recommend is the Eminence BGH25-8, as it's specifically designed for electric bass. It can be used as low as 2kHz, where you need it for wider dispersion than woofers can give, and rolls off above 10kHz, where there's nothing of value for bass. However, it requires a purpose built crossover for best results. You probably need that anyway, no matter what tweeter you end up with. The crossover is where many manufacturers cut corners, with blown tweeters being one result.

Has the Eminence you recommended as enough clarity and presence as ST304-SLF does? And what crossover does it need? Where can I get the spec of that crossover to be specifically built?

[Bill Fitzmaurice]

It's a better tweeter than the ST-304-SLF. This is the crossover for a 4 ohm cab, which yours appears to be. Make sure, it makes a difference. The low pass (woofers) and high pass (tweeter) are on separate boards so you don't confuse the wiring. On the low pass filter the capacitor is a non-polar electrolytic (NPE), rated for at least 50 volts. The coils may be solid or air core. What’s critical is that the DCR (resistance) of the coil be less than 0.2 ohms.  On the high pass filter the capacitors are poly or mylar, rated for at least 100 volts. The coils are air core, of the smallest available wire gauge with no more than 0.5 ohms DCR. A plus/minus 10% tolerance of the component values is permissible. High pass:

 

Low pass:

Edited December 30, 2024 by Bill Fitzmaurice

[Majid]

36 minutes ago, Bill Fitzmaurice said:

It's a better tweeter than the ST-304-SLF. This is the crossover for a 4 ohm cab, which yours appears to be. Make sure, it makes a difference. The low pass (woofers) and high pass (tweeter) are on separate boards so you don't confuse the wiring. On the low pass filter the capacitor is a non-polar electrolytic (NPE), rated for at least 50 volts. The coils may be solid or air core. What’s critical is that the DCR (resistance) of the coil be less than 0.2 ohms.  On the high pass filter the capacitors are poly or mylar, rated for at least 100 volts. The coils are air core, of the smallest available wire gauge with no more than 0.5 ohms DCR. A plus/minus 10% tolerance of the component values is permissible. High pass:

 

Low pass:

Thanks a lot for the explanation and for the schematics.

Is the 0.4mH reactor/coil in the low pass circuit the same as the one in the high pass circuit?I mean do both circuits share the same coil? Because their ratings are pretty close. 

[Bill Fitzmaurice]

They're totally separate. They also have different maximum DCR, so the .4mH will probably be a larger gauge. The only commonality of the two filters are they both connect to the input jack(s) at the + and -. I recommend Jantzen coils and capacitors.

[Chienmortbb]

@stevieused to wind coils for people but with his LFSys venture I am not sure he still does. He may also advise on capacitors.

[stevie]

To design a two-way crossover, you need to measure the drivers on the baffle you'll be using. You'll need a frequency response curve, a phase response curve and an impedance curve for each driver. Unless you have that information, you're guessing - and the likelihood of a suboptimal crossover is extremely high. There is also a very real chance that the crossover will damage your amplifier.

 

Replacement diaphragms for the original tweeter are available for not much money here: https://speakerrepairshop.nl/en/diaphragms/for-selenium/g-10000060.

[Majid]

3 hours ago, stevie said:

To design a two-way crossover, you need to measure the drivers on the baffle you'll be using. You'll need a frequency response curve, a phase response curve and an impedance curve for each driver. Unless you have that information, you're guessing - and the likelihood of a suboptimal crossover is extremely high. There is also a very real chance that the crossover will damage your amplifier.

 

Replacement diaphragms for the original tweeter are available for not much money here: https://speakerrepairshop.nl/en/diaphragms/for-selenium/g-10000060.

Hi Stevie,

Thanks for the reply. 

Honestly I’m not specialised in that area so my preference would be a replacement of the faulty tweeter with the same model rather than building a new crossover and using a different tweeter.

Are you saying if I replace the original diaphragm, it would be repaired? If that’s the case then it’d be preferable.

[pete.young]

You could contact EBS directly via https://ebssweden.com , they have a pretty good record for supplying spare drivers and other cab components.

[stevie]

41 minutes ago, Majid said:

Are you saying if I replace the original diaphragm, it would be repaired? If that’s the case then it’d be preferable.

 

The diaphragm assembly is the part that contains the coil, which is what normally blows. Replacing the diaphragm will repair the unit.

[Majid]

35 minutes ago, pete.young said:

You could contact EBS directly via https://ebssweden.com , they have a pretty good record for supplying spare drivers and other cab components.

Thanks for the advice. I’ll do that after the holidays.