Serious Question: How can Op Amp rolling improve the sound of an already well measuring device? Are that many confused? (Master Thread)

[Count Arthur]

Note that as previously expressed elsewhere, I am very suspicious of any results worse than the TL072/M5218... presumably one of the supply pins had poor contact in the socket (oxidized IC pins could be another factor along those lines) or a bad solder joint. It's not like -90ish dBr worth of THD would be a particularly high bar to clear in this day and age.

That's actually just a segment of the chart. If you look at the original post, you can see that those really badly performing op amps, the RC4560 and RC4580, perform just fine in alternative positions and combinations:

Fosi Audio V3 op-amp rolling, has anyone tried it? Snake oil? Or are there actual differences?

A plastic cup holds water. A glass looks better, has better specs in certain areas... but still it just needs to hold water, which it does fine be it crystal, Ikea glass or plastic. And sometimes the "worse" component, a plastic cup, is just what was specified for the job and lasts longer and...

www.audiosciencereview.com

Regardless, it looks like none of the combinations improve on the original NE5532, LME49720 combination in any meaningful way.

 

[007Shorty]

Fosi Audio V3 op-amp rolling, has anyone tried it? Snake oil? Or are there actual differences?

A plastic cup holds water. A glass looks better, has better specs in certain areas... but still it just needs to hold water, which it does fine be it crystal, Ikea glass or plastic. And sometimes the "worse" component, a plastic cup, is just what was specified for the job and lasts longer and...

www.audiosciencereview.com

Thanks for the link! I once swapped the NE5532 for an LM4562 in an Aiyima 07. I couldn't hear any difference. But the sound got really bad with an OPA2604. So bad that I thought I had bought fake OPA2604. With this list, what I heard makes perfect sense!

Edit: I've already posted this

Op Amp Rolling

Lower supply voltage tends to increase sonic differences IMO. What evidence do you have for this? It seems questionable.

audiosciencereview.com

 

[DanielT]

Thanks for the link! I once swapped the NE5532 for an LM4562 in an Aiyima 07. I couldn't hear any difference. But the sound got really bad with an OPA2604. So bad that I thought I had bought fake OPA2604. With this list, what I heard makes perfect sense!

Edit: I've already posted this

Op Amp Rolling

Lower supply voltage tends to increase sonic differences IMO. What evidence do you have for this? It seems questionable.

audiosciencereview.com

Really audible bad? Bad as grandma with no interest whatsoever in HiFi would hear how bad it got? That means absolutely nothing imaginary? In that case, it just shows that you shouldn't replace the op amps because it most likely won't get any better. Worse, however, there is a risk of that.

 

[DanielT]

This op amp switches and get a wonderful sound religion. You can, as I think, be pure nonsense, but don't you think there should be freedom of religion?

Does freedom of religion mean that one has the right to shove one's religion down someone else's throat in any way, at any time? To make it less sensitive, let's say op amp freedom of religion instead.
(For me, freedom of religion is also the freedom not to be subjected to religious pressure)

 

[007Shorty]

Really audible bad? Bad as grandma with no interest whatsoever in HiFi would hear how bad it got? That means absolutely nothing imaginary? In that case, it just shows that you shouldn't replace the op amps because it most likely won't get any better. Worse, however, there is a risk of that.

I can't say whether Grandma would have noticed the difference in sound. It's too late to ask her now, but the voice reproduction suffered significantly with the OPA2604 (as far as I remember). The difference between THD 0.024% (OPA2604) and 0.0028% (NE5532) was clearly audible. And I didn't know this list back then. I must add, however, that I didn't carry out a proper blind test.
If you replace the NE5532 with an LM4562 everything stays the same, at least for me.

Edit: A little spirituality in life is a nice thing but if practiced in the HIFI sector you run the risk of becoming poor without any benefit.

 

[Count Arthur]

Thanks for the link! I once swapped the NE5532 for an LM4562 in an Aiyima 07. I couldn't hear any difference. But the sound got really bad with an OPA2604. So bad that I thought I had bought fake OPA2604. With this list, what I heard makes perfect sense!

Edit: I've already posted this

Op Amp Rolling

Lower supply voltage tends to increase sonic differences IMO. What evidence do you have for this? It seems questionable.

audiosciencereview.com

It seems there isn't a great deal of variance when swapping what's in the PRE AMP socket. As such the NE5532 makes sense, as they are only about 30 or 40 pence each, whereas some if the others are £4.00 to £5.00 each. Although that's individual, retail prices, I'm sure they are much cheaper when you buy them by the thousand.

Also, the difference between the LM4562 and NE5532 is just 0.0001% THD+N, which could be margin of error in the measurement set-up.

Incidentally, I believe LM4562 and LME49720 are in fact the same part:

LME49720 Vs LM4562....

LME49720 The data seems identical to LM4562..is there any difference?

www.diyaudio.com

 

[Jim Taylor]

This op amp switches and get a wonderful sound religion. You can, as I think, be pure nonsense, but don't you think there should be freedom of religion?

Does freedom of religion mean that one has the right to shove one's religion down someone else's throat in any way, at any time? To make it less sensitive, let's say op amp freedom of religion instead.
(For me, freedom of religion is also the freedom not to be subjected to religious pressure)

People should have the freedom to do whatever they wish ... and in fact, they already do have that freedom. Neither criticism nor disagreement is the same as suppression. If you want to switch out an opamp, go ahead ... just don't expect members here to support your decisions with lies or equivocation.

Think of it this way: if you want to lay your hand on a hot stove, you can do it. But no one here is going to say, "Yeah, go ahead. It won't hurt a bit", and if you expect them to say that you are disconnected from reality.

 

[audio_tony]

Here's some controlled tests I did of various opamps into a 2.7k ohm load. Some of the results surprised me.

At the time, my ADC was limited to around 0.00016% hence the "measurement limit" comment in the notes, so the THD may well have been lower than that.

URL with graphs can be found here: https://gtkc.net/opamp-tests-into-a-2k7-load

 

[antcollinet]

The difference between THD 0.024% (OPA2604) and 0.0028% (NE5532) was clearly audible.

It's extremely difficult to hear even 1% (-40dB) distortion (the majority of people cannot at all). There is no way the difference between 0.003% and 0.02% (-90dB cf -73dB) is going to be "clearly audible"

 

[Doodski]

I can't say whether Grandma would have noticed the difference in sound. It's too late to ask her now, but the voice reproduction suffered significantly with the OPA2604 (as far as I remember). The difference between THD 0.024% (OPA2604) and 0.0028% (NE5532) was clearly audible. And I didn't know this list back then. I must add, however, that I didn't carry out a proper blind test.
If you replace the NE5532 with an LM4562 everything stays the same, at least for me.

Edit: A little spirituality in life is a nice thing but if practiced in the HIFI sector you run the risk of becoming poor without any benefit.

Howdy @007Shorty. This is a great video for demonstrating distortion and what is audible. ~4 minutes of your time for a great test.

 

[DanielT]

I can't say whether Grandma would have noticed the difference in sound. It's too late to ask her now, but the voice reproduction suffered significantly with the OPA2604 (as far as I remember). The difference between THD 0.024% (OPA2604) and 0.0028% (NE5532) was clearly audible. And I didn't know this list back then. I must add, however, that I didn't carry out a proper blind test.
If you replace the NE5532 with an LM4562 everything stays the same, at least for me.

Edit: A little spirituality in life is a nice thing but if practiced in the HIFI sector you run the risk of becoming poor without any benefit.

If we start from the premise that there really was an audible and not imagined difference, then it cannot be due to differences in distortion, as pointed out by others.

Does that OPA2604 fit into the Aiyima 07? I can guess (I'm no electrical engineer) that it should be possible to read from the technical data under which conditions the OPA2604 operates and then compare it with the NE5532.

OPA2604 Datasheet, PDF

OPA2604 Datasheet. Part #: OPA2604. Datasheet: 435Kb/26P. Manufacturer: Texas Instruments. Description: Dual FET-Input, Low-Distortion Operational Amplifier. 22 Results. Datasheet: 214Kb/12P. Manufacturer: Burr-Brown (TI).

www.alldatasheet.com

NE5532 Datasheet, PDF

NE5532 Datasheet. Part #: NE5532. Datasheet: 125Kb/12P. Manufacturer: NXP Semiconductors. Description: Internally-compensated dual low noise operational amplifier. 169 Results. Datasheet: 69Kb/10P. Manufacturer: Texas Instruments.

www.alldatasheet.com

Or there was something wrong with your OPA2604 if you heard clear differences. That on the condition that we can rule out (difficult in practice) the imagination factor.

 

[007Shorty]

Here's some controlled tests I did of various opamps into a 2.7k ohm load. Some of the results surprised me.

At the time, my ADC was limited to around 0.00016% hence the "measurement limit" comment in the notes, so the THD may well have been lower than that.

URL with graphs can be found here: https://gtkc.net/opamp-tests-into-a-2k7-load

View attachment 431467

In your list, the OPA2604 seem to work quite well. That makes me think.

It's extremely difficult to hear even 1% (-40dB) distortion (the majority of people cannot at all). There is no way the difference between 0.003% and 0.02% (-90dB cf -73dB) is going to be "clearly audible"

I can't rule out the possibility that something is wrong with my OPA2604s or the Aiyima 07's circuitry can't handle them. Perhaps they react sensitively to an unclean power supply or they are fake. You may be right, and what I heard was not THD but something else.

Howdy @007Shorty. This is a great video for demonstrating distortion and what is audible. ~4 minutes of your time for a great test.

That's interesting!

 

[Doodski]

That on the condition that we can rule out (difficult in practice) the imagination factor.

Keep in mind we are dealing with a OP amp roller and they are prone to vivid imagination and beliefs of stuff they almost always know nothing about.

 

[antcollinet]

You may be right, and what I heard was not THD but something else.

The most likely of those "something else's" is perceptive bias. As you say - you didn't test blind (Very difficult with an op amp swap)

 

[007Shorty]

If we start from the premise that there really was an audible and not imagined difference, then it cannot be due to differences in distortion, as pointed out by others.

Does that OPA2604 fit into the Aiyima 07? I can guess (I'm no electrical engineer) that it should be possible to read from the technical data under which conditions the OPA2604 operates and then compare it with the NE5532.

Or there was something wrong with your OPA2604 if you heard clear differences. That on the condition that we can rule out (difficult in practice) the imagination factor.

I'm really hesitant to post the Aiyima link below because I don't believe the content and it unnecessarily fires up this op-amp-rolling stuff but the OPA2604 is strongly recommended here. My experience was different.

The OP Chip Can Use on AIYIMA A04 & A07

Currently, the op chip used on AIYIMA A04 & A07 is NE5532. Although NE5532 performs well, many audiophiles still want to improve the sound quality by replacing the OP chip. Here we recommend some replaceable OP chips. NE5532: The resolution is average, the high frequency is relatively dry, and...

www.aiyima.com

 

[007Shorty]

The most likely of those "something else's" is perceptive bias. As you say - you didn't test blind (Very difficult with an op amp swap)

But shouldn't I have heard a difference to the LM4562? The whole thing is slowly becoming a mystery to me.

 

[Doodski]

I'm really hesitant to post the Aiyima link below because I don't believe the content and it unnecessarily fires up this op-amp-rolling stuff but the OPA2604 is strongly recommended here. My experience was different.

Without blind testing and proof of the claims on that web page it's all hogwash.

 

[antcollinet]

But shouldn't I have heard a difference to the LM4562? The whole thing is slowly becoming a mystery to me.

The differences are too small to hear. The chances of the opamp or the amp itself being faulty in such a way is very small.

That leaves perceptive bias.

Just to be clear - we (humanity) are always hearing the results of perceptive bias - it is how our hearing works. If you don't compare controlled and blind, and differences you hear not not a result of an obvious change (faulty gear, or use of tone controls, eq etc)** then it is impossible to know if what you are hearing comes from the sound waves reaching your ears, or is generated in the wetware between them.


**even then you can't be certain.

 

[DanielT]

I'm really hesitant to post the Aiyima link below because I don't believe the content and it unnecessarily fires up this op-amp-rolling stuff but the OPA2604 is strongly recommended here. My experience was different.

The OP Chip Can Use on AIYIMA A04 & A07

Currently, the op chip used on AIYIMA A04 & A07 is NE5532. Although NE5532 performs well, many audiophiles still want to improve the sound quality by replacing the OP chip. Here we recommend some replaceable OP chips. NE5532: The resolution is average, the high frequency is relatively dry, and...

www.aiyima.com

Holy shit, this is what Aiyima themselves have to say about what it sounds like with different op amps in their A04 & A07!

NE5532: The resolution is average, the high frequency is relatively dry, and the low frequency is relatively muddy and fat.

OP275: Better resolution, low frequency and sound field than NE5532.

EL2244: The timbre is neutral, the sound field is relatively wide, the high frequency is okay, and the mid-frequency music tastes poor. Some people say that the resolution is very high. In fact, it is because the low-frequency volume is less, the mid-frequency is thin, and the high-frequency is prominent. It is more difficult to use well.

LT1057: The two ends extend well, and the speed, dynamics and resolution are also quite good, but it is a cool tone.

AD827: The extension is very good, the resolution is high, the high frequency is gorgeous, the intermediate frequency is pure and thick, the low frequency dive and the strength are good, the sound field expands forward and backward, the speed is good, the dynamics are good, and it feels very exciting. It feels refreshing. But after listening for a long time, I found many problems. 1 Although the three-frequency band, the sound field is very wide, the momentum is strong, and the opening is wide, but the structure is a bit loose and not tight enough. 2 The vocal part is average, sometimes large In the dynamic state, the vocals are submerged by the soundtrack. 3 It is not detailed enough, which is more than passion but not tender enough.

OPA2604: It feels like an upgraded version of NE5532, with great improvements in all aspects, good resolution, better musical taste, courageous, solid sound bottom and a bit rigid, and the overall quality is very good.

DY649: Compared with OPA2604, the resolution is better. The high frequency part is slender and soft and rich in overtones. The sound bottom is not thicker than OPA2604. It has a clear and detailed feeling. The music picture is very clear. The vocal part is round and transparent, and sweet. The sweet feeling, human voice (especially female voice) is its strong point.

DY639: The overallity is slightly weaker than DY649, but it has the characteristics of tube amplifier.

DY669: Not too different from OPA2604, pure and thick voice.

AD712: The resolving power is very good, the sound is clear and without coloration, a very transparent feeling, the sound bottom is detailed, and the low frequency is slightly less.

The OP Chip Can Use on AIYIMA A04 & A07

Currently, the op chip used on AIYIMA A04 & A07 is NE5532. Although NE5532 performs well, many audiophiles still want to improve the sound quality by replacing the OP chip. Here we recommend some replaceable OP chips. NE5532: The resolution is average, the high frequency is relatively dry, and...

www.aiyima.com

 

[Doodski]

Holy shit, this is what Aiyiama themselves have to say about what it sounds like with different op amps in their A04 & A07!

It's pandering to the base of OP amp rollers. That's all.