Okay gang, I actually have a gear question. "Amplifier"

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Hank Davidson

Hank Davidson

Affordable, yet priceless.
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Nov 15, 2006
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Here's the sitch.

I have a pair of the EV Eliminators. I don't use them much unless I have a larger than normal gig. I do however use them for myself during the summer for outdoor family stuff, like 4th of July, etc.

EV_ELIMI.JPG


Anyway, my current amplifier is a QSC-USA900. It's been great for the most part, but lately it's been clipping out on songs with high bass. This particular model is hard to catch before it clips due to the lack of a meter. (the green indicators just turn red when the amp peaks)

View attachment QSCUSA900_transparent.gif

Now, I know these speakers aren't at their limit because they don't even sound like they're breathing heavy. So, what I need is a recommendation for a light, *inexpensive ($300) amp that can handle the new music's higher punch.

Also, could the dip switch settings be the problem?

Any suggestions?

* I have a great new/used dealer near me so I have the potential of getting a good deal. I'm just out of the loop on amps these days.

Thanks!

:tricool:
 
I'm going to tinker with the dip switch settings. I'll try turning the low filter from 30Hz to 50Hz and see if that helps. My neighbors aren't going to be happy when I test it though. LOL!
 
This amp might do the trick.
 
I see the easy answer as being a QSC GX5 and they are all over the used market. $400 MAP, I've seen them for $250-300 used. I saw one for for $200 and pounced on it!

Your USA900 is 270 w/ch @8ohms, 1KHz, 1%THD. The GX5 is 500 w/ch @8ohms, 1KHz but at some magical unknown distortion but before clipping. I'm thinking that's basically 1% as the curve goes vertical. I haven't had coffee yet so my math skills are lacking but I think you should get another 3db out of the Eliminators.
 
I get no distortion or warning. The thing just pops off and comes back up in about 15 seconds. The breaker doesn't trip. That's why I'm thinking it's the limiter.
 
Hank Davidson said:
Now, I know these speakers aren't at their limit because they don't even sound like they're breathing heavy.
Click to expand...

The only way to know how much power the speakers are getting is to measure the voltage across the amp terminals. There is no other reliable method.

Hank Davidson said:
I get no distortion or warning. The thing just pops off and comes back up in about 15 seconds. The breaker doesn't trip. That's why I'm thinking it's the limiter.
Click to expand...

That is not a limter. The amp is overheating and resetting itself. You can try to clean the cooling fans and the heat sinks. That might help a lot. You can also improve the airflow through the amp by making changes to the physical mounting of the amp and associated cables. At that point, you might also consider using a fan to blow more air onto the intake side of the amp.
 
soundinmotiondj said:
That is not a limter. The amp is overheating and resetting itself. You can try to clean the cooling fans and the heat sinks. That might help a lot. You can also improve the airflow through the amp by making changes to the physical mounting of the amp and associated cables. At that point, you might also consider using a fan to blow more air onto the intake side of the amp.
Click to expand...

Thanks for the reply.

That would normally make sense to me, but it only happens when the bass causes the amp to clip into red. Does the clipping raise the heat? The limiter dip switch is set to on (see below) and is supposed to just "lower" the volume. However, it is turning off completely as I mentioned above. The amp is usually outdoors and well ventilated.

It's weird because this amp should be enough power for these speakers.
(I usually run it bridged.)

From the manual....

.............................................................

Limiter
During normal operation, the limiter
does not affect the audio signal and
is, in fact, inaudible. It will allow brief
clipping of peaks and will only
activate when continuous, hard
clipping occurs. The limiter will then
reduce the audio signal enough to
minimize the amount of clipping.
When the signal amplitude
decreases enough that clipping
ends, the limiter will deactivate and
cease its gain reduction.

..................................................................

This is how my dip switches are configured.

dips1.jpg


This is how I am considering them to be (turning off the limiter).

dips2.jpg



Thoughts?
 
Hank those speakers need about 500W rms each to sing properly even more would be better. It is better to have headroom that to push the amp.
 
drzinc said:
Hank those speakers need about 500W rms each to sing properly even more would be better. It is better to have headroom that to push the amp.
Click to expand...

Yeah, that's the ticket. I'm breaking even and need more headroom.
I'm gonna take a ride and see what my man has in stock.

Thanks Dave (and everyone)
 
Soundinmotion makes the point I was gonna make... since it's a relatively new problem, this appears at first glance to be a thermal cutout issue.

Yes, more bass in your sound will cause the amp to work harder, thus dissipating more heat. If the heat isn't removed from the heat sinks properly, you'll have a thermal shutdown. Clipping alone won't necessarily cause thermal shutdown; a clip indication simply means that the amp is at its power output limit. However, at peak output your amp will be producing more heat than usual.

Another cause could be a thermal sensor on the heat sink going bad. That doesn't happen often but it can happen.

I agree ~ remove the cover and give the amp a good D&C, or dusting and cleaning first. Be sure to clean the fan(s) and venturi completely. Just a little dirt on the fan blade will reduce air movement by a considerable margin.
 
Love my P7000 :)
 
Hank Davidson said:
Thanks for the reply.

That would normally make sense to me, but it only happens when the bass causes the amp to clip into red. Does the clipping raise the heat?
Click to expand...

First, "clipping" sounds bad...but is not otherwise dangerous to woofers or amps.

Clipping does present some danger to compression drivers and other high frequency elements...as they tend to have lower power handling and are built in a way that makes them vulnerable to high voltage.

Clipping will raise the applied RMS signal level. This will result in a higher average voltage differential, with an associated increase in the supplied current. Sourcing that current will cause the amplifier power supply to produce more heat.

Hank Davidson said:
It's weird because this amp should be enough power for these speakers.
(I usually run it bridged.)
Click to expand...

STOP! Do NOT run the amp bridged with more than one speaker cabinet connected as a load. This is what is "causing" the overheating problem.

Switch to running the amp in "stereo" with each channel driving one of your two speakers. There is no such thing as a "free lunch" and putting one speaker on each channel will deliver the same power to each cabinet, and will allow the amp to run cooler.

There are Very Few situations where amps should be run bridged...and if you do not fully understand what bridging does, and what those situations are...you should just stick to running the amp with two independent channels.

Next, setup a proper hard limiter in your system, and properly setup the gain structure of your system. If you do, you will run the amp cooler, and have more SPL in the room.
 
soundinmotiondj said:
STOP! Do NOT run the amp bridged with more than one speaker cabinet connected as a load. This is what is "causing" the overheating problem.

Switch to running the amp in "stereo" with each channel driving one of your two speakers. There is no such thing as a "free lunch" and putting one speaker on each channel will deliver the same power to each cabinet, and will allow the amp to run cooler.

There are Very Few situations where amps should be run bridged...and if you do not fully understand what bridging does, and what those situations are...you should just stick to running the amp with two independent channels.

Next, setup a proper hard limiter in your system, and properly setup the gain structure of your system. If you do, you will run the amp cooler, and have more SPL in the room.
Click to expand...

Thank you sir. That is valuable information. :tricool:
That's the kind of stuff that manuals don't tell you.
 
Hank Davidson said:
Thank you sir. That is valuable information. :tricool:
That's the kind of stuff that manuals don't tell you.
Click to expand...
Hank,
I know you run your stuff in Mono. So all you have to do to "fake" stereo is set the amp to stereo operation and use a "Y" cord from your source to the amps. Singe end connects to your source output and each of the other ends goes to the amp input. You should try and get a more powerful amp though.
DJ Sazon has a bunch of stuff that he is selling including an amp, see if you can get him to sell it to you separate. Crown XTI 2000 Rated at 475W per Channel.
Sells for around $450.00 Brand new. http://www.amazon.com/Crown-Digital-Power-Amplifier-Watts/dp/B000FL3QGY

Here is the Posthttp://ourdjtalk.com/threads/41096-...-case-and-Behringer-mixer?p=468803#post468803

Check with Ben to see if he has any open box/used amps.
 
ahoustondj said:
Hank,
I know you run your stuff in Mono. So all you have to do to "fake" stereo is set the amp to stereo operation and use a "Y" cord from your source to the amps. Singe end connects to your source output and each of the other ends goes to the amp input. You should try and get a more powerful amp though.
DJ Sazon has a bunch of stuff that he is selling including an amp, see if you can get him to sell it to you separate. http://ourdjtalk.com/threads/41096-...-case-and-Behringer-mixer?p=468803#post468803
Click to expand...
Or hit the parallel input selector ;) Single XLR to channel 1 and you'll get the same output on both speakers no need for the "Y" unless your amp does not offer that option.
 
DJ SVO said:
Or hit the parallel input selector ;) Single XLR to channel 1 and you'll get the same output on both speakers no need for the "Y" unless your amp does not offer that option.
Click to expand...

+1

Always prefer balanced over unbalanced....if there is a choice.
 
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