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rhythmsandy 30th August 2012 08:58 AM

sound Quality of OPA549 when compared with LM3886
Is OPA549 good quality chip? is it better in terms of sound quality when compared with LM3886?

i saw this thread where 549 compared with Audio note... which is just awesome..

but why its not used much? I see alot of people using LM3886..
I have OPA549 3 units in hand but im thinking of choosing lm3886.
any opinion on audio quality of OPA549..

rhythmsandy 30th August 2012 01:48 PM

did anybody used it?

theAnonymous1 30th August 2012 02:24 PM


Originally Posted by rhythmsandy (
did anybody used it?

Did anybody used the search function?

There are 62 threads on the forum with "OPA549" in the title; try reading a few of them instead of making a new one for every question you have about it.

diyAudio - Search Results

rhythmsandy 30th August 2012 02:53 PM

searched and found few but there is pretty less information. I see more people using LM3886 instead of OPA549. So just thought to start a thread on OPA549.

I found even peter daniel says about it as initially it was not good but after burning for a day it sounded more resolution and good vocals.

Anyway I have the OPA549 ill try myself using that but if i could get any design ideas that makes it better would be a better... like using washers improved some part etc..

jcx 30th August 2012 03:06 PM

the OPA549 datasheet has no useful audio distortion curves

the related OPA541 does - and shows the worst possible distortion profile for audio - the distortion rises at low levels indicating output crossover distortion

most specialized audio chip amps show low distortion at various power levels with much better profile than OPA541

LM3886, other audio chip amps have more loop gain due to decompensation for Av_min >10x compared to these internal unity gain compensated industrial power op amps

likely also have output protection circuitry better tuned to audio demands

there really is no reason to believe that either of the OPA541, 549 have anything special to offer in audio
except that they are different, more expensive - both of which attract some novelty interest

Ray Samuels Aduio gets away with selling a US$3k headphone amp with bridged OPA541

juma 31st August 2012 10:34 PM

I used OPA549 as an audio amp too, in Nelson's Super Symmetry topology. That's the only AB class amp that I kept and still listen to occasionally - it regularly surpasses the expectations.

Here is the sch. (small error - 220p caps should be 5-10 times smaller)

rhythmsandy 1st September 2012 07:59 AM

hi juma the sch is not opening can u attach it somewhere else...

AndrewT 1st September 2012 11:05 AM

The pic is opening to 1000x416.
I can read it easily.

AndrewT 1st September 2012 11:08 AM

what impedance/resistance does the buffer see?

Is the +IN @ PIN8 a virtual earth, due to the cross-coupled feedback?

juma 1st September 2012 12:27 PM


Originally Posted by AndrewT (
what impedance/resistance does the buffer see?



Originally Posted by AndrewT (
Is the +IN @ PIN8 a virtual earth, due to the cross-coupled feedback?

It would be at the same potential even with straight feedback network (simple bridge topology, providing that OPA549 works in NI configuration)

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