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Can any EBS HD350 be run at 2 ohms?

gimmeagig

gimmeagig

Feb 25, 2004
2,891
1,198
Coeur D'Alene,Idaho
#1
Hi,
I have an EBS HD350. I recently switched to a couple of Avatar 112 4 ohm cabinets.
The amp sounds great with one of them but I'm not sure if I can go down to two ohms with the HD350 so that I can use both Avatars.
I saw somewhere that yes it's possible but only on newer models of that amp.Other articles on the web just say that the amp goes down to two ohms.
On the back of my amp it says 4-8 ohms.
So my question is, how can I be sure that my amp is indeed able to go to 2 ohms without blowing it up. What would the wattage be at 2 ohms.
If there are newer models that are capable to do 2 ohms, is it possible to modify the older model?
At what serial number was the change made?
 
#4
The HD350 head, for example, is rated at 350 watts output. What will be the output at 2 ohms with two cabinets connected to the amp and what would be the output at 4 ohms if I use only one cab?

The continuous output power would still be 350W, even if you load the amp with one or two 4 ohms cabinets. One difference though, the total peak power increases by nearly 20% if you load the amp down to 2 ohms
 
#5
I don't know a whole lot about electronics and impedances. I'm so used to the normal way where a 350W amp into 4 ohms would have maybe 450 into 2, right?
Why is that not so with the EBS. Is the poweramp section completely different from say my Eden WT 550?
I'm actually going back and forth with the Eden and the EBS in my house right now( one cab only)
Both sound good. The Eden is warmer,but the EQ has always been kind of complex for me. They say the Eden is designed to sound great flat but it's much too dark sounding for my taste.The EBS really does sound great flat and is much easier to dial in but I don't think it has the power of my WT550. Haven't tried it with 2 of my Avatars yet..
So If you guys think it's safe I'll give it a shot.
I did send out a message to EBS directly about that but have not received an answer yet.
 
#6
Pretty easy to find the answer via google ....

Link Removed

Minimum speaker impedance 2 ohms
Dynamic Output Power 350 W RMS
Continuous Output Power 300 W RMS

You can also use your WT550 with both 4 ohm cabs = 2 ohms (750W)
 
#7
nashman said:
Pretty easy to find the answer via google ....

Link Removed

Minimum speaker impedance 2 ohms
Dynamic Output Power 350 W RMS
Continuous Output Power 300 W RMS

You can also use your WT550 with both 4 ohm cabs = 2 ohms (750W)
Click to expand...

I read somewhere that older HD350 amps cannot handle 2 ohms.
I don't know if that information is correct.
I bought mine used it's serial # 261202 I don't know how old it is.
 
#8
gimmeagig said:
Hi,
I have an EBS HD350...

...So my question is, how can I be sure that my amp is indeed able to go to 2 ohms without blowing it up. What would the wattage be at 2 ohms.
If there are newer models that are capable to do 2 ohms, is it possible to modify the older model?
At what serial number was the change made?
Click to expand...
The "very first" HD350s could only go down to 4 ohms. The documentation on the EBS web site isn't very explicit about when they cut over, but they started shipping HD350s in 2001, so anything within the past 7 years is almost certainly OK for 2 ohm operation. Write to EBS via their web site with your serial number if you think there's any doubt. I've always found their support outstanding.
 
#9
Sid Fang said:
The "very first" HD350s could only go down to 4 ohms. The documentation on the EBS web site isn't very explicit about when they cut over, but they started shipping HD350s in 2001, so anything within the past 7 years is almost certainly OK for 2 ohm operation. Write to EBS via their web site with your serial number if you think there's any doubt. I've always found their support outstanding.
Click to expand...

I just tried to send them my serial number and this question, but the support page does not have a send button, just a reset button. Seems like they don't want to hear from me.....:confused:
 
#10
I just found the FAQs on EBS .
This is what it says
What impedances do the EBS bass heads operate at?
All EBS heads operate at 2-8 ohms except some early HD350:s that operates at 4-8 ohms (check the back panel of the bass head) and the new T90 Tube Head that operates at 4-8 ohms.
My Head says 4-8 ohms so I guess it's not capable of 2 ohms.
Which brings me back to my question : Can my amp be upgraded to 2 ohm capability?
Or do you guys think I should just chance it? Is there some type of protection circuit or will the thing just blow up?
 
#13
The oldest HD350s are not 2 ohm rated. They made them 2 ohm capable at some point. Read the label on back. If it says 2-8 ohm you are fine like mine that I bought around 2003. If it does not have 2 ohm on the back you probably have an older one and SHOULD NOT run it at 2 ohm.
 
#14
OK, I was able to send an e-mail to EBS afterall and they got back to me.
So or anyone who's interested here's what they wrote:

Dear Roxy,
The 2 ohms versions were introduced from serial number 261501.
Now, best way to know is to open up the amp and check the number of output devices that are assembled on the main heatsink.
If there are only 6 ones installed, you may have the option of installing another 2 pcs for complying with 2 ohms load.

-- Best Regards

--------------------
Mats Kristoffersson
Technical Director


On my circuit board there are already mounting holes for the chips and the cooling grilll has mounting holes as well. So I'm hoping they will sell me those chips and I'll try to find someone in my area to put them in for me.I'm in northern Idaho near the Canadian border so it's easier to find someone to fix a tractor here than an amp from Sweden.
Wish me luck!
 
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#15
Update:
I did get the parts and a local technician was able to install them.I played a few gigs with the two Avatar 112 cabs that i use now and I'm really happy with the sound.On rehearsals I just use one cab and again I couldn't be happier. In fact I retired my Eden WT550 that's how good the EBS works out.
I asked Mats at EBS if the two extra output transistors would give me more power and the answer was "NO" but I could swear this amp has never had the punch that it has now.
Usually when I use my Eden head I catch myself tweaking the tone knobs quite often, if it is a gig or a rehearsal, it doesn't matter. Something is always missing for me. With the EBS head I had the sound I wanted in 5 minutes and I got through whole gigs without even looking back at the amp once. That has never happened to me with any amp I have ever owned.
 
#16
gimmeagig said:
Update:
I did get the parts and a local technician was able to install them.I played a few gigs with the two Avatar 112 cabs that i use now and I'm really happy with the sound.On rehearsals I just use one cab and again I couldn't be happier. In fact I retired my Eden WT550 that's how good the EBS works out.
I asked Mats at EBS if the two extra output transistors would give me more power and the answer was "NO" but I could swear this amp has never had the punch that it has now.
Usually when I use my Eden head I catch myself tweaking the tone knobs quite often, if it is a gig or a rehearsal, it doesn't matter. Something is always missing for me. With the EBS head I had the sound I wanted in 5 minutes and I got through whole gigs without even looking back at the amp once. That has never happened to me with any amp I have ever owned.
Click to expand...
It's a popular misconception that more watts equates to higher output.
What it will give you is increased headroom.
 

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