...but I have a couple questions. First of all, what are the rated power output ratings of these three amps:
LM3886
LM3875
LM4780
And second, is there any one particular that stands out, or that I should stay away from? Any opinions on these amps would be useful, and much appreciated. Thanks,
-Justin
LM3886
LM3875
LM4780
And second, is there any one particular that stands out, or that I should stay away from? Any opinions on these amps would be useful, and much appreciated. Thanks,
-Justin
LM3886 1 x 68 W @ 8 Ohm
LM3875 1 x 56 W @ 8 Ohm
LM4780 2 x 60 W @ 8 Ohm
Datasheets are available from http://www.national.com/apnotes/AudioProducts.html
LM3875 sounds (ever so slightly) warmer, due to (ever so slightly) higher 2nd harmonics, but is not officially produced anymore.
LM4780 is two LM3886 on one chip. Advantages of the LM4780 are better thermal coupling between the channels, more compact layouts possible for stereo, parallel or bridged applications. Disadvantages are lower output power due to higher heat sink requirements (you won't notice the difference under normal listening conditions), worse channel separation, layout requires usually two layer boards, soldering is more difficult, due to very little spacing between the pins.
You won't find significant differences in sound quality or character. The differences you will find, depend rather on the external components and the layout than on the chip model.
LM3875 1 x 56 W @ 8 Ohm
LM4780 2 x 60 W @ 8 Ohm
Datasheets are available from http://www.national.com/apnotes/AudioProducts.html
LM3875 sounds (ever so slightly) warmer, due to (ever so slightly) higher 2nd harmonics, but is not officially produced anymore.
LM4780 is two LM3886 on one chip. Advantages of the LM4780 are better thermal coupling between the channels, more compact layouts possible for stereo, parallel or bridged applications. Disadvantages are lower output power due to higher heat sink requirements (you won't notice the difference under normal listening conditions), worse channel separation, layout requires usually two layer boards, soldering is more difficult, due to very little spacing between the pins.
You won't find significant differences in sound quality or character. The differences you will find, depend rather on the external components and the layout than on the chip model.
My input:
lm3886 is only 50 W into 8ohm with +-35V rails (according to datasheet)
and 68W into 4ohm with 28V rails. (according to datasheet)
I would go for the 3886 if you want to drive 4 ohm loads since it has the highest current capability.
In simple terms.
for lm3886
25-0-25 (minimum 160VA for stereo application ) for 8ohm loads
20-0-20 (minimum 160VA for stereo application) for 4ohm loads (18-0-18) might be easier to get )
lm3886 is only 50 W into 8ohm with +-35V rails (according to datasheet)
and 68W into 4ohm with 28V rails. (according to datasheet)
I would go for the 3886 if you want to drive 4 ohm loads since it has the highest current capability.
In simple terms.
for lm3886
25-0-25 (minimum 160VA for stereo application ) for 8ohm loads
20-0-20 (minimum 160VA for stereo application) for 4ohm loads (18-0-18) might be easier to get )
Ok so if the amp I'm looking at based on the LM4780 is a dual mono format, that means that it has a separate LM4780 per amplifier board. Does that mean it is utilizing both of it's internal LM3886 chips in a bridge form for more output? Maybe Peter Daniel can chime in as I believe that is his site.
-Justin
-Justin
I'm pretty sure those boards are designed to be easily configurable into paralell, stereo or bridged operation by simply moving a few components.
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