Class AB Audio Amplifiers

[Cristi]

Discussions about class AB audio amplifiers from Connexelectronic

 

[julcat]

Hello Cristi

I'm interested in the 300W LME49810 Audio Amplifier with Heatsink but i have some questions.

How many watts can it ouput in class A??
Does it comes assambled??

 

[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.

 

[butch_vlad]

Hello
What is the supply voltage for the 500w amplifier?
can it run of 2x70 v cc?
thx

 

[Cristi]

to get the full power out of the 500W LME49810 amplifier, each module must be supplied with +-72 to +-76V DC for the power stage and +-75 to +-80V for the driver stage.

 

[marchel]

About the 500W LME49810,

Can it be configured to run 500W class A/B at 2 ohms? What's the supply voltage needed?

Thanks

 

[Cristi]

the supply voltage for 500W at 2 Ohms load impedance should be +-560 to +-60V for the power stage and +-60 to +-67V for the driver stage. if you want to use this SMPS Connexelectronic for the amplifier, can use a single differential voltage for both power stage and driver stage and the output voltage of the smps can be adjusted for +-60V.

 

[butch_vlad]

"Can provide differential output voltage within +-45 to +-55V range"
From the website.....what is the maximum voltage this smps can give? The increased output capacitors help sustaining the maximum wattage better?

 

[Cristi]

the A1000SMPS can provide as i mention before +-45 to +-55V without any change. for different output voltage, in range of +-35 to +-70 V one resistor from the feedback loop must be changed. the same transformer can be used for this voltage range.

 

[TCx]

Hi,
I am looking for a hifi amp module. Output power is not much important, sound quality is of highest priority.
Which of these class AB modules would you recommend?
2x100W LM4702 BPL
2x100W LM4702 MOS
2x100W LM4702 SAP15
300W LME49810 Audio Amplifier
AEM6000 Audio Amplifier with heatsink

And if we add the class T or D amps to this comparison, which one(s) would be most recommended?
Thanks.

 

[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

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]

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.