Class AB Audio Amplifiers

[Cristi]

if the output power is not very important, i recommend the LM4702MOS or the SAP15 version then AEM6000. if higher output power is needed, i recommend to use the 300W LME49810 modules. this modules and the 500W version have the best S/N ratio, >120dB and linearity from all of the above modules.
from the switching amplifiers, i recommend the TA3020v3c amplifier.

[CharlieLaub]

Can you provide a little more info on your 500W LME49810 amp with heatsink. Can this amp operate with a load that dips down to about 2.2 ohms minimum? What are the power supply requirements? I don't see much info on the product page - it looks like the description ends abruptly. Maybe there was more you wanted to post about it?

-Charlie

Originally Posted by Cristi

if the output power is not very important, i recommend the LM4702MOS or the SAP15 version then AEM6000. if higher output power is needed, i recommend to use the 300W LME49810 modules. this modules and the 500W version have the best S/N ratio, >120dB and linearity from all of the above modules.
from the switching amplifiers, i recommend the TA3020v3c amplifier.

[bobodioulasso]

Originally Posted by Cristi

the 300LME49810 module is complete assembled, and is class AB amplifier but can be adjusted to work as a class A amplifier with derrated output power to about 50-100W depending on cooling method. i recommend to use it in class AB, since the sound quality is quite high to not justify the class A operation with the inherent disadvantages.

It would be a nonsense to run a 49810 based amplifier into class A since the last stage of the chip is class AB.

[Cristi]

the 500W version of the LME49810 amplifier can work with lower impedances, if the supply voltage is reduced, and the maximum output power will not exceed 700W. for 2 Ohms which is close to 2.2 Ohms, the supply voltage should be max. +-63V for the power stage and max. +-68V for the driver stage. also, the power supply should be able to provide at least 10A. i recommend this supply board: Connexelectronic or the A1000SMPS.
the amplifier can work in class A, i tried before, but, i don't recommend to use it. the output power is low, and the power dissipation is huge, and the differences in sound are not that significant to change the operation class.

[bobodioulasso]

the amplifier can work in class A

I agree about the external output stage, though the built in pre drivers are internally biased in AB.( see Audioman thread "National opamp inflation")
For class A operation, i would go for a lme49811, where the built-in pre drivers do not exist.
Anyway, as you said, there would be no advantage.

[sangram]

Hi Cristi - are the power supply and power output capabilities of the SAP version of the LM4702 the same as the MOS and BPL versions, or is there a difference? Since you offer three versions of the same amplifier, it would be good to know some illustrative differences between the three before I order.

[Cristi]

The main difference between the modules, is the type of the ouptut transistors used, as you pointed out. i have tried all 3 possible implementation (BPL version), with normal bipolar transistors, with thermal-track transistors, (SAP15 version) and MOSFET transistors. the main advantage in using the SAP transistors instead a normal pair of bipolars is that the current bias is more precise and the THD is less dependent on the output transistors temperature, music volume or supply voltage as in a normal amplifier with bipolar transistors. the sonic performance of the SAP amplifier module is better than the BPL version, and i cosider at least as good as the MOSFET version.

[sangram]

Thanks - I assume this means the MOSFET version has the best sonic performance, followed by the SAP version? Good to know.

[Bratislav]

Cristi,

can you confirm that from sonic (and engineering) point of view, MOSFET version is the one to go for ? Or is it SAP version ? I know this is nitpicking, but price differences aren't that significant, might as well go for the best.

Thanks,
Bratislav

[Cristi]

Alhtough most of the ppls tend to say that the MOS-FET sounds better, i still believe (and i look at the measurements too) that the SAP version is on the first place then followed by the MOS-FET and after the plain Bipolar version.