The Best Sounding DUAL opamps

Dear Andrea,
what I think to ascertain is, that You have come across an application less suitable for the OPA627. There is IMHO absolutely nothing wrong with this chip for other applications, where it certain does not behave in the fashion You are trying to describe.
It does not surprise me, since chips with j-fet LTP inputs are (again IMHO) better applicated in other circuit's than the by You described one. Bipolar LTP input chips, again 'as a rule of at least my thumb', is better used here, just as you have come to like the LT1028 as an example.
regards
a1greatdane
Hmm, as I see it, it's generally better to use a bipolar wherever it's not forbidden by its input currents...meaning that to me the bipolars have always sounded better... take for instance the OPA211 and the OPA827 (and I'm not claiming that either is perfect). The OPA211 can sound more transparent, yet smoother at the same time. Lower distortion...
 
Dear Andrea,
that latest remark/statement of Yours is IMHO completely 'on You' as a for You personal observation.

Kind regards
a1greatdane
Yes... I met with people that generally preferred FET opamps... presumably, I don't know, for their more forward reproduction of transients? This might give an idea of better detail, although I don't believe it's the case.
 
I just did a very careful comparison of OPA827 and OPA627BP on the output stages of 3 different cd players. I preferred OPA627 throughout the comparison. OPA827 is a very very good opamp, better than OPA2107. It is musical and balanced, but in front of OPA627, I found it to be slightly congested. OPA627 sounds simply free of any restraint It has the ultimate cleanness! Listening to it is a refreshing experience. I say hah every time I switched to OPA627, because I felt that the last bit of detail has just been released. OPA827 is the second best, with OPA2107 following slightly behind. All of these, of course, is regarding applications in output stages. For the I/V stage, I normally prefer a few harder sounding AD, Linear, and National chips.
 
I don't discuss that the OPA627 is clear sounding... (though a bit less than the LT1028ACN8 and the OPA1611 and OPA211)

It's something else what it lacks, and makes me prefer maybe less clear but more musically enjoyable opamps like the OPA132UA. Try it...


OPA827, OPA627 and OPA2107 all have the same kind of flaws...

Try the OPA1611. :)
 
Last edited:
Hi All,

Please advise what would be the best bet for a modern replacement of the NJM353 in my 12-15 years old vintage 4X60W Class A Zero Feedback car amplifier?

Tried dual OPA627AU on adaptor but the sound is of reduced volume, of loss details and PCB is warmer than before ... and the noob in me did not realized the input current of 7mA X 2 or 14mA for the each of 4 dual adaptor as compared to 3.6mA each for the NJM353. Not sure if "oscillation" is happening due to the increased bandwidth in older PCB design or the input current drawn is just too much for the PSUs to handle and I am not knowledgeable enuff to mod PSUs or other parts.

I have also received the LME49720HA but with 10mA and not good for repeated desoldering, I hope for other recommendations in addition to the OPA2107 at input current of 4.5mA which seems to be most compatible for the final try or can I push it a little to 6-7mA requirement of the AD8620 since the slower and warmer nature of these Class A amplifiers may be helped by reported "faster' AD op amps.

Thanks in advance.

Regards,

Richard
Singapore
 
Last edited:
Hi,

Forget the OPA627, it's a very much overrated opamp, which I don't even like.

Since the NJM353 is FET input, try the new OPA1642. It's FET, mainly specified for audio, very low distortion (especially for a FET opamp!), low supply current (1.8mA per channel = 3.6mA), not even overly fast... It looks perfect for your case.
 
Otherwise, if you can use low input current bipolars, try the LME49723 (slower and lower supply current than the LME49720HA, just 6 mA total; and it sounds better than the plastic DIP LM4562). If multiple opamp stages are involved, try combining LME49723 and OPA1642 for a better balanced (than whenever a single opamp type is 'repeated') sonic presentation.
 
Hi Andrea,

Thanks for the recommendation on OPA1642 and LME49723 !

While I understand schematic is required for more accurate prediction, should I still go for 6mA requirement of LME49723 instead of just OPA1642 with exactly the same input current requirement.

In the realm of Op Amp, is 3.6mA in original NJM353 considered significantly different compared to 6mA for the LME49723 i.e. just 2.4mA to cause potential problem like in the case of 14mA for dual OPA627 although I read that sound is usually better with BJT?

I know I should try it to find out the answer but soldering/desoldering for me itself is already a challenge and hope to zoom in with the best bet for at least some improvement against NJM353 and live with it.

BTW, op amps are only in the preamp (4 pcs for 4 channels) and there is one stage without any buffer etc.

Thanks again.

Richard
 
In the realm of Op Amp, is 3.6mA in original NJM353 considered significantly different compared to 6mA for the LME49723 i.e. just 2.4mA to cause potential problem like in the case of 14mA for dual OPA627 although I read that sound is usually better with BJT?
Actually they're more like minute differences... they may matter only if a conspicuous series resistance is used in the opamps' power lines (causing a voltage drop with the higher quiescent current opamp types). Anyway 6 mA isn't that much more than 3.6 mA, and even if there was a voltage drop, the LME49723 is specified starting from +/- 2.5V ..
 
There are no such thing, as a "good sounding op-amp". All op-amps sound like an op-amp. Yes, they do have different sonic performance, but you will ALWAYS know it as an op-amp.

People who have the guts to do real "blind tests", normally will point out NE5532 as the best, even though in theory it's not nearly the best. But then again.... In theory op-amps are perfect due to the nice specifications, but real life they aren't that good for audio.
 
There are no such thing, as a "good sounding op-amp". All op-amps sound like an op-amp. Yes, they do have different sonic performance, but you will ALWAYS know it as an op-amp.

People who have the guts to do real "blind tests", normally will point out NE5532 as the best, even though in theory it's not nearly the best. But then again.... In theory op-amps are perfect due to the nice specifications, but real life they aren't that good for audio.

Hahah, I'm sure you don't know much apart from the "good old NE5534/NE5532". So much for all opamps sounding like opamps. ;)
 
Hi Andrea,

Thanks again for the comments for my understanding on extend on input mA difference but guess 14mA on the dual OPA627 was still too significant or indeed the higher speed in causing some chaos or perhaps needing buffer as mentioned by some for preamp implementation?

Googled on OPA1642 and did not managed to find any review or even casual comments from any users ... can you advise comparable sound of some other op amps to this? I also looked at the LME49723 and the current stated is typical at 6.7mA and max of 7.5amp.

One more concern is that OPA1642 are surface mounted which means adaptor in my case ... sigh ..

Don't mean to be ungrateful but OPA2107 seems to be an easier option now especially still not sure how others rate the sound quality of OPA1642.

Regards,

Richard
 
Last edited: