Big test of DIP dual op-amps for audio: LM4562, NE5532, OPA2134, TL072 and LM1458

[Gorgonzola]

Not worth much. Thers this BS to start. "However, despite of all these advantages, they are practically devoid of any sonic signature so they require an external input buffer to tuning in a “warm house sound”, customizable according to tastes and requirements."

And get this, $300 for a tiny pair of empty PCBs. And if you want them to add $5 worth of components that will be $450. Add 2 $50 unnecessary discrete opamps and that will be $750.
Is it any surprise there best measurements are for the most expensive option. They probably thru out the NE5532 measurements.

Maybe you're being a bit unfair. atm audio's interest, in the first place, is selling its I/O buffer which allows the permits the user their choice of op amps. Presently they sell their buffers bare or with the choice of a couple of different op amps including the cheap, integrated LM4562.

So let's assume that those testing results are honest, it's entirely up to the buyer to decide what the doubtless very small or even inaudible represent value. Presumably one might decide that NE5532 was the ticket and use that in the buffer bought w/o op amp.

Come to that their buffers are a bit price regardless, (450 Euros w. LM4562's). For cheap I'd go for VTV buffers with OPA1612's for USD 320/pr or Neurochrome buffers that use LM4562's for USD 300/pr

 

[DualTriode]

- in a typical line stage opamps work up to 2Vrms. Balanced 4Vrms are a difference between OUT+ and OUT-, both again up to 2Vrms.
- for higher level I would need to add gain stage behind the DAC, which would lead to increased noise and distortion.

Thanks for sharing your insights. I see now that you are looking at typical pre-amp output levels.

I saw you post over in that A5 Op-Amp rolling thread and followed you over to this measurement thread.

It is interesting to see that the OpAmps actually do not measure the same.

Will you be measuring THD+N for opa1656 op-amps?

Thanks DT

 

[Cbdb2]

Maybe you're being a bit unfair. atm audio's interest, in the first place, is selling its I/O buffer which allows the permits the user their choice of op amps. Presently they sell their buffers bare or with the choice of a couple of different op amps including the cheap, integrated LM4562.

So let's assume that those testing results are honest, it's entirely up to the buyer to decide what the doubtless very small or even inaudible represent value. Presumably one might decide that NE5532 was the ticket and use that in the buffer bought w/o op amp.

Come to that their buffers are a bit price regardless, (450 Euros w. LM4562's). For cheap I'd go for VTV buffers with OPA1612's for USD 320/pr or Neurochrome buffers that use LM4562's for USD 300/pr

At $300 for a pair of small PCBs that cost them $3 there in it for the money. I do not trust there marketing, its to sell you $750 of no audible difference and maybe even worse performance than a $2 NE5532.

 

[pma]

Come to that their buffers are a bit price regardless, (450 Euros w. LM4562's). For cheap I'd go for VTV buffers with OPA1612's for USD 320/pr or Neurochrome buffers that use LM4562's for USD 300/pr

This thread deals with dual op-amps as single components. You are talking about a dedicated implementation in a more complex application that uses op-amps. Those “buffers” cannot be used as an op-amp replacement, so they cannot be directly compared to single components. A special thread comparing those completed boards for Purifi or Hypex, as balanced front ends with balanced outputs, would be needed. Here it confuses the topic.

 

[wwenze]

If we run these op-amps at high gain (and then drop the output voltage later with resistor divider) would the performance be worse?

I'm asking because intentionally running them at worse performance may allow them to be measured by more accessible equipment (i.e. free ones) hence making testing op-amps more accessible to everyone

Because the best way to learn is by doing, and some people are enthusiastic to learn.

 

[pma]

I saw you post over in that A5 Op-Amp rolling thread and followed you over to this measurement thread.

It is interesting to see that the OpAmps actually do not measure the same.

They really do not measure the same and, worse, it strictly depends on the circuit in which they are implemented.

Measurement of opamps swapped in the Topping D10s DAC



The dual op-amp makes the DAC output and is emphasized in the yellow oval above. The stock op-amp is LME49720. I have compared it with NE5532, OPA2134 and also LM4562, which is in fact an equivalent to LME49720.

So far, NE5532 was a king in the simple, +6dB gain circuit according to post #1. But now, in the D10s, situation is quite different. The very best is LME49720/LM4562 and the NE5532 is measurably worse in the D10s. Below please find comparisons of THD vs. output voltage at 1kHz and 10kHz, measuring BW 45kHz.

and comparison of LME49720 vs. LM4562:

We may positively conclude that op-amp choice strongly depends on application circuit. And we may positively say that op-amp swapping by laymen people may be a fun, but is incompetent without further measurements.

 

[pma]

If we run these op-amps at high gain (and then drop the output voltage later with resistor divider) would the performance be worse?

It will be different. My test rig has second branch that tests in inverting gain -1x, but with noise gain 86dB. That means, feedback is released of 86 dB and the results reflect situation with 86 dB gain.

Comparing 4562, 5532 and 2134 then, the 4562 works best. This corresponds to datasheet Aol plots.

 

[sabih]

Hey @pma
Can you please perform the test on opa1612 and NJM2068
I think these are also excellent devices just like NE5532

 

[pma]

Hey @pma
Can you please perform the test on opa1612 and NJM2068
I think these are also excellent devices just like NE5532

I can only test the op-amps that I have in my stock.

 

[restorer-john]

I have just measured the noise, using my +30dB measuring amplifier, because the noise of DUT opamps was too low to be measured directly. As a reminder, test circuit is shown in post #1. it has gain +6dB and 10k/10k feedback resistors (important info).

Total 20Hz - 20kHz unweighted noise
LM4562: 3.03 uV
NE5532: 2.70 uV
OPA2134: 3.06 uV
TL072: 4.75 uV
1458: 7.22 uV

Please note that feedback resistors are 10k/10k, this makes 5k seen as a noise resistance. The result of LM4562 is worse than NE5532 due to the fact that input current noise density is 1.6pA/rt(Hz) compared to 0.6pA/rt(Hz) of the NE5532. Again, as in the case of MM preamps, we can see dominance of the current noise above voltage noise, if the feedback total resistance or generator impedance is above 1kohm.

I can conclude that NE5532 is, to me, better universal op-amp design than LM4562/LME49720. The later needs lower values of resistors in the FB net and also lower generator impedance to get any advantage. Almost same applies to OPA1611/12, which has very low voltage noise, but not low current noise. That is the reason why Topping and other manufacturers are pushed to use low input impedance of their preamps, if they are oriented to the lowest distortion.

Great work again Pavel.

The good old NE5532 is hard to beat.

I seem to remember the NE5532AN was an even lower noise version IIRC. ~1.1uV 20-20k, but likely at unity gain?

 

[audio_tony]

Great work again Pavel.

The good old NE5532 is hard to beat.

I seem to remember the NE5532AN was an even lower noise version IIRC. ~1.1uV 20-20k, but likely at unity gain?

Back in the 80's when I was buying 5532's - there was the plain 5532, the slightly lower noise 'N' version, and the super low noise 'AN' version.

The 5534 was available with the same specs / suffix.

Curiously, they mostly just seem to be 'N' or 'P' now.

At least the JRC products are still available in low noise ('D' suffix) and extra low noise ('DD' suffix). I guess that rather being explicitly manufactured to be so - they are probably just selected during final manufacture.

 

[pma]

The parts tested here are NE5532P and they were originally for the SONY CDP-XA2ES Esprit. Manufactured in 1990’s.

Edit: corrected the 5532 sufix to P

 

[sabih]

How is Philips version different from TI version?
Can anybody explain?

 

[AnalogSteph]

How is Philips version different from TI version?
Can anybody explain?

If memory serves, the TI version had higher common-mode distortion than the Philips/Signetics but also a more robust output with less propensity towards oscillation in case of subpar rail bypassing. You can look at Samuel Groner's measurements for the gory details though.

There's even a third version by Fairchild, not to forget the JRC implementation NJM5532.

 

[007Shorty]

If the NE5532 cost $50, everyone would want it. That's the psychology of audio enthusiasts. Something that costs only 60 cents can't be good.

Actually, we need a thread to pay homage to the NE5532 and its developers. If there were a Nobel Prize in audio, the NE5532 would deserve it.

 

[Scytales]

OPA2134 was introduced by Burr-Brown in the nineties as a lower noise and lower distortion improvement of TL072.

A great many thanks to you, PMA, for the innumerable practical and down-to-earth experimentation you share on this forum! They are most enlightening.

A quick note about OPA2134. From what I understand, I suspect OPA2134 and OPA2132 are the same chip, just differently named after factory test. The OPA2132 specifies a much better high-frequency linearity than OPA2134 on low loads (600 ohms). It may be that OPA2132 is a better chip than the audio specified OPA2134. Perhaps putting on the market OPA2134 as an audio specified op-amp is just a way to obtain a better yield rate by being able to sell chips that have failed factory test to meet some OPA2132 target specifications. Just a thought. In fact, from what I have gathered, Sony has consistently used OPA2132 instead of OPA2134 in its audio gears, for instance.

 

[pma]

From what I understand, I suspect OPA2134 and OPA2132 are the same chip

Yes. AFAIK Burr-Brown have admitted this back in 1990’s.

BTW, I am just testing with gain 11x and up to 10Vrms output.

 

[Gorgonzola]

This thread deals with dual op-amps as single components. You are talking about a dedicated implementation in a more complex application that uses op-amps. Those “buffers” cannot be used as an op-amp replacement, so they cannot be directly compared to single components. A special thread comparing those completed boards for Purifi or Hypex, as balanced front ends with balanced outputs, would be needed. Here it confuses the topic.

In that case I apologize; it wasn't my intention to "hijack" the thread. I take your point that talking about one particular application of op amps in beyond the intended scope of this thread.

I/O so-called "buffer" boards for Hypex and Purifi amps is only one of innumerable applications of op amps but discrete and/or tube based options are possible. These boards happen to be topical these days and deserve their own, separate thread.

 

[pma]

I am a bit puzzled by limiting the Op-Amp output voltage to 3 volts. What is the reasoning?

The typical Op-Amp with 15 volt + / - rails will output close to 10 volts 10 volts + / -.

To follow your comment and my previous explanation (DAC output stage rated SE voltage is 2Vrms), I have modified my test circuit from post #1, changing R2 from 10k to 1k

The gain is now 11x, or +20.83dB, as you like it. Load is 2kohm now. Please note that R5 creates a voltage divider with 2k load impedance. Output voltage is measured behind the R5. Right at the op-amp output the voltage is 1.1 x higher.

Now I stand corrected and cannot fully support this previous post of mine:

I can conclude that NE5532 is, to me, better universal op-amp design than LM4562/LME49720. T

Though the NE5532P was a better performer in the +6dB test circuit (with 10k/10k feedback) than LM4562, it is not so in case of the test in Topping D10s socket and also not the case with gain 11x and output up to clipping.

The result with gain 11x (+20.83dB) for NE5532P, LM4562 and Burr-Brown OPA2134 can be seen below:

The LM4562 dominates above NE5532 and OPA2134 at higher output voltages and gain 11x. NE5532 is still very good performer, but LM4562 is excellent here.

THD vs. output voltage at 10kHz, LM4562 dominates again.

Note: This E1DA Cosmos ADC is an excellent thing, thank you @IVX for making it available to us engineering audio hobbyists. I wished I had something like this 20 years ago, when it was not possible to reveal such differences between the op-amps without having at least AP2 or SYS-2722.

 

[pma]

In that case I apologize; it wasn't my intention to "hijack" the thread. I take your point that talking about one particular application of op amps in beyond the intended scope of this thread.

It is no problem .