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  Loudspeaker Amplifier: Four Channel

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Author Topic:   Loudspeaker Amplifier: Four Channel
TransAm posted 06-09-2009 09:35 PM ET (US)   Profile for TransAm   Send Email to TransAm  
I an considering adding a 4 channel amplified to my head unit and need some recommendations. Idealy, I would like to have a compact unit, however, I am aware of the general relationship of size to power and want a quality unit. I have looked at the offerings from JL Audio and Clarion and am considering both in one of their 45 +/-watt per channel offerings, however would prefer something a little more compact. In terms of power output, 40 watts RMS per channel of clean power would be plenty as I am not seeking to advertise my music; just want good clean output. Budget would be about $300.
jimh posted 06-09-2009 09:45 PM ET (US)     Profile for jimh  Send Email to jimh     
I suggest getting four older Macintosh tube amplifiers. They may be a little over your budget.
TransAm posted 06-09-2009 09:58 PM ET (US)     Profile for TransAm  Send Email to TransAm     
I think the tubes may be too sensitive to aquatic life. But I have a few Bryston mono-blocks and another 4-channel beast that I could that I could bridge into 2 channels that will certainly do the trick though.
SC Joe posted 06-09-2009 10:24 PM ET (US)     Profile for SC Joe  Send Email to SC Joe     
I recently (last week) purchased a Sony XM-604M, a 4 channel 60 watt/channel amplifier, but it is kind of large. It was $200 from Best Buy; a price you could certainly beat on line.

In the past I have used a JBL MA6004 4 channel marine amplifier that was also 60 watts/channel that I think sounded better and was louder. JBL also makes a smaller version that is the same power but only 2 channel and smaller (MA-6002). I would recomend either one of those depending on your needs. Thee are available on Ebay from several vendors for around $130 and <$100, respectively.

davej14 posted 06-11-2009 06:19 PM ET (US)     Profile for davej14  Send Email to davej14     
http://www.polyplanar.com/productsingle.aspx?prt=ME-400
jimh posted 06-11-2009 08:02 PM ET (US)     Profile for jimh  Send Email to jimh     
Why do you need a four channel amplifier, if I may ask? Most recorded music is recorded in two-channel stereophonic mode.
TransAm posted 06-11-2009 09:15 PM ET (US)     Profile for TransAm  Send Email to TransAm     
While I have not thought this through, and do realize I could wire 4 speakers in parallel to a 2-channel amp, I believe I would loose the ability to fade sound between the 2 sets of speakers (which is a necessity) and I may increase the distortion a bit. The speakers would then be operating at 2 ohms, would they not?
jimh posted 06-11-2009 09:42 PM ET (US)     Profile for jimh  Send Email to jimh     
It sounds like (pardon the pun) you are going to feed a stereo signal to your four channel amplifier with two channels running in parallel for stereo-left and stereo-right. If you have independent gain controls for all four channels you could set a balance as desired among the four loudspeakers.
TransAm posted 06-11-2009 10:07 PM ET (US)     Profile for TransAm  Send Email to TransAm     
I am seeking an amplifier that produces the cleanest possible sound, allow for independent operation of each speaker and to be operated in a manner in which it was specifically designed. I assumed the easiest way to accomplish this was to consider adding a 4 channel amplifier. If this can be accomplished by adding a 2-channel amplifier, it is something I would certainly consider. Since I am a novice when it comes to technical aspects of audio equipment, I would need to be convinced of this with a complete list of pro's and con's of using a 2-channel amp for my application. I welcome you input.
SC Joe posted 06-12-2009 08:50 PM ET (US)     Profile for SC Joe  Send Email to SC Joe     
Just get a loud one. On a boat, <1 THD won't matter.
Dan posted 06-14-2009 09:58 AM ET (US)     Profile for Dan  Send Email to Dan     
I have the JBL 6002 and am happy with it. I agree you need a loud amp while underway.
TransAm posted 06-14-2009 12:09 PM ET (US)     Profile for TransAm  Send Email to TransAm     
I sea-trialed my new speakers (JL Audio M650's) only using the 21 watt/channel Clarion CMD5 head unit and was surprised at the service. We were able to hear relatively clear music at 90% of the volume's potential and no problem hearing music traveling at 40 MPH. I am not looking to announce my arrival anywhere, and would seldom listen to music while on plane. I'm convinced 40-45 watts/channel RMS of clean power would be plenty.
davej14 posted 06-18-2009 09:54 AM ET (US)     Profile for davej14  Send Email to davej14     
If all you want is independent "fader" control for each speaker then you can accomplish this with a two channel amplifier and a quality volume control that allows for selectable impedance matching. Just set the volume controls for 2x on each channel and you are all set.

A properly designed control will present a pure resistive load to the amplifier and therefore have no effect on audio quality.

http://www.nilesaudio.com/product.php?prodID=MVC100& recordID=Weatherproof%20Volume%20Controls&categoryID=Volume%20Controls& catcdID=6&prdcdID=FG00972

SC Joe posted 06-18-2009 11:08 AM ET (US)     Profile for SC Joe  Send Email to SC Joe     
Wouldn't it be easier to just install a four channel amp?
TransAm posted 06-18-2009 11:11 AM ET (US)     Profile for TransAm  Send Email to TransAm     
Cheaper too, those control units seem to be priced well over $100 and would at least double the installation effort. I think they are designed for larger, more complex applications.
SC Joe posted 06-18-2009 11:24 AM ET (US)     Profile for SC Joe  Send Email to SC Joe     
Again,I think the JBL is probably your best bet. At ~$100, it's hard to lose. If it stinks, sell it on Ebay at half off and get another one.

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