Need Power Amp for Subs
I need a power amp to drive a pair of subs. I'll be using it to drive 18" subs, but not in large venues. I'm looking for solid and dependable, and money is an object. What have 'ya got?
kevin-at-shano.mv.com
10/12/2008 4:31:05 PM
Run the subs mono, so they will probably be 4 ohms.
Take whatever the rating of the speakers are at load (probably about 600-800w). Double that get buy that amp.
So, an 800w speaker should have 1600w driving it.
QSC 2450 is a good amp. Stay away from Behirnger amps, they tend to not really be rated at what they say.
If money is an object, better to not use them. If you drive the speakers with an insufficient amp, you'll need to to replace blown speakers, which will also cost $$.
Buy the right amp once.
10/12/2008 4:42:40 PM
We drove these subs for years with a Crown Macro-Tech 1200, which IIRC is ~500 watts a side @ 4 ohms. That's not to say that more power wouldn't be good, but the subs did fine wih the Crown.
That said, the QSC 2450 looks to be available for $700 new, so used we'd be in the right dollar range.
10/12/2008 5:27:39 PM
Kev, I got my QSC 2450 new for $400 four years ago. The price has gone up that much? Check Daddy's used gear inventory.
10/12/2008 7:07:05 PM
Paul, yeah, $700 it is now. I don't see one listed used anywhere in the area at the moment, but they show up ~$400 on Craigslist.
10/12/2008 7:16:19 PM
Workhorse of an amp though.......Very reliable!
10/12/2008 10:07:44 PM
Just to throw in my two cents, If eack speaker is
8 ohms you can parallel them @ 4ohms and bridge the amp,
That should use the amp to it's fullest power and you may not need as beefy of an amp. ya, more kick drum:-)
10/16/2008 6:56:15 PM
Crown Amps are the bomb for driving subs. You really can't get any better. QSC is a great amp but Crowns are just built like tanks for that kind of stuff.
The lower the ohms you drive the tighter the low end will be due to the resistance pressure on the coil. And yes you want double the wattage to speaker rating as Marc stated.
Speakers can actually handle more than they are rated in transients but will not tolerate DC voltage which occurs if you the amp clips from lack of head room. That is the biggest cause of blown speakers. Pushing past the amp's head room.
10/16/2008 7:32:14 PM
I ended up buying a used PV2600, 2x550 watts at 8 ohms. From the manual, it will run in bridged mode @ 4 ohms, but would be happier (run cooler) @ 8 ohms in bridged mode. Our subs are 8 ohms, so I'm inclined to run it in stereo.
I'm not going to pretend that this amp is any replacement for the Crown we used to use (bass-player owner moved...), but for $200 bucks in an SKB rack case it will do the job.
10/17/2008 12:10:35 AM
Bridge Mode-Mono: 8 Ohms: 1800 Watts RMS is the way to go on that amp.
10/17/2008 12:15:32 AM
I don't know how to get to 8 ohms bridged with two 8 ohm subs, besides running just one.
10/17/2008 12:22:44 AM
I think he means 4 ohms mono which is where you will get better performance.
10/17/2008 8:06:18 AM
The specs do say 1800 watts @ 8 ohms, so I'm pretty sure that's what HundredDollarDemo (HDD?) had in mind. But I'll give the 4 ohm bridged mode a shot and see how hot it runs.
10/17/2008 8:23:46 AM
They just word it differently because it's a 4 pin Speakon connector. No more than 8 ohm loads per 2 pin sets. No math involved by just saying 8 ohms. :-)
It's basically 900 watts at 4 ohms X2 / per channel = 1800 watts bridged. 2x 8 ohm connections in parallel will result in 4 ohms.
Running the same two 8 ohm speakers in stereo will result in only 540 watts x2 / per channel = 1080 watts.
10/17/2008 10:30:39 AM
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