Amp Recomendations

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=32976
Printed Date: May 10, 2025 at 7:32 AM

Topic: Amp Recomendations

Posted By: ravenndude
Subject: Amp Recomendations
Date Posted: May 30, 2004 at 11:46 AM

I'm looking for a class D amp that will be able to push about 300watts RMS at 8ohms. Should i just look for a class D amp that pushes 600watts at 4ohms?

I'm partial to Fosgate, MTX, JL...

Replies:

Posted By: DYohn
Date Posted: May 30, 2004 at 11:58 AM

In general that would be correct.

-------------
Support the12volt.com

Posted By: stevdart
Date Posted: May 30, 2004 at 12:17 PM

That will be a large (read expensive) amp. A major benefit of a classD amp is the ability to go to a 2 ohm load. With what you are wanting to do, you will have less in cost by using a 2 channel amp. Same general guidelines as noted above.

-------------
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Posted By: gregfocker77521
Date Posted: May 30, 2004 at 12:19 PM

look at JL audio 450/4 amp, here are the specs

Available: Now
		Channels 1&2 : stereo mode: 150 W RMS x 2 @ 1.5 ohm – 4 ohm (11 – 14.5V) bridged mode: 300 W RMS x 1 @ 3 ohm – 8 ohm (11 – 14.5V)
		Channels 3&4: stereo mode: 75 W RMS x 2 @ 1.5 ohm – 4 ohm (11 – 14.5V) *bridged mode:* 150 W RMS x 1 @ 3 ohm – 8 ohm (11 – 14.5V)
		THD at Rated Power: <0.03% @ 4 ohm (All Channels)
		S/N Ratio* (All Channels): >108.5 dB below rated power
		Frequency Response (All Channels): 5 Hz-30 KHz (+0, -1dB)
		Damping Factor (All Channels): >200 @ 4 ohm/50 Hz
		Slew Rate (All Channels): ±25 V / µS @ 4 ohm per ch.
		Input Range: switchable from 200mV-2V RMS to 800mV-8V RMS
		Dimensions: 19.7"L x 9.25"W x 2.36"H (500 mm x 235 mm x 60 mm)

Posted By: DYohn
Date Posted: May 30, 2004 at 12:24 PM

Actually I'd tend to agree more with stevdart that a 2-channel amp rated at 300 watts per channel into 4-ohms would make a better choice than a 4-channel amp. Bridging 2-channels would be cleaner than bridging 4-channels.

-------------
Support the12volt.com

Posted By: customsuburb
Date Posted: May 30, 2004 at 1:57 PM

Use JL's 300/2 instead. Its has the same specs as the 300/4 except its a 2 channel amp instead.

Posted By: stingercaraudio
Date Posted: May 30, 2004 at 4:48 PM

Pick a 2 channel that's rated at 150 x 2 at 4 ohms, that will give you 300 at 8 ohm bridge. JL or not it should work out just fine. Whut are you trying to power?

Posted By: DYohn
Date Posted: May 30, 2004 at 4:52 PM

stingercaraudio wrote:

Pick a 2 channel that's rated at 150 x 2 at 4 ohms, that will give you 300 at 8 ohm bridge. JL or not it should work out just fine. Whut are you trying to power?

Actually, 150 watts @ 4-ohms stereo will give you 150 watts @ 8-ohms bridged mono.

-------------
Support the12volt.com

Posted By: forbidden
Date Posted: May 30, 2004 at 10:34 PM

Dyohn, take a breather dude, you must have had a long day. My day off. posted_image

300w x 2 @ 2 ohm = 600w x 1 @ 4 ohm

150w x 2 @ 4 ohm = 600w x 1 @ 4 ohm

Thus a single 8 ohm driver in mono will indeed be 300w.

-------------
Top Secret, I can tell you but then my wife will kill me.

Posted By: DYohn
Date Posted: May 31, 2004 at 10:10 AM

Oops. I could lie and say I was posting the value per woofer in a dual setup and look really clever... but the truth is closer to too much Napa Valley wine while posting... posted_image Thanks for the catch.

An amp sould deliver approximately 1/2 its rated output at 4-ohms into an 8-ohm load. Math, duh.

-------------
Support the12volt.com