Replace OP amps. Completely pointless, or not?

[Tangband]

Tangbands graphs show a low level power frequency spike, this comes down likely to poor implementation, though a better amp may alleviate. Then there is what looks like a power supply spike. Looks like the unit was powered by 60hz bench supply but used in a 50hz environment. Who knows what ground loops are there.

Its PMA:s measurements on the Aiyima a07 with ne5532 and lm4562. Its the same power supply used.

 

[audio2design]

Unless you have very sophisticated equipment simple measurement don't detect op amp clones.

 

[audio2design]

Here are some measurements. EG up to 20dB difference in SINAD:

Objective Guide to Op-Amp Rolling - Part 1

As per moderator, here is full article from the site: Objective Guide to Op-Amp Rolling - Part 1 July 30, 2021 Op-Amp Test Board This blog article/post is a deep dive into currently available 8-pin DIP dual op-amps, for those that like to swap op-amps in their designs and/or DIY projects. The...

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Closer to 12db the other was the AP loopback. Constant across signal level suggesting purely noise or poorer PSRR. There is no decoupling between the caps and external supply so quite possible. It's a poor implementation and not representative of what may happen in a proper circuit.

 

[antcollinet]

Closer to 12db the other was the AP loopback. Constant across signal level suggesting purely noise or poorer PSRR. There is no decoupling between the caps and external supply so quite possible. It's a poor implementation and not representative of what may happen in a proper circuit.

well spotted. I missed that one was loopback

 

[DanielT]

Aiyima themselves now recommends and offers replacement of ne5532 to lm4562 in the a07 model.
View attachment 156697View attachment 156698

My counter-question. If so, why do not Aiyima themselves put in lm4562 from the beginning?

 

[DanielT]

Tangbands graphs show a low level power frequency spike, this comes down likely to poor implementation, though a better amp may alleviate. Then there is what looks like a power supply spike 3x50. Looks like the unit was powered by 50hz bench supply but used in a 50hz environment. Who knows what ground loops are there.

Well now the Aiyima A07 is not an expensive amplifier but poor implementation, not so good amp ... do you think so?

 

[Tangband]

My counter-question. If so, why do not Aiyima themselves put in lm4562 from the beginning?

Because of cost . The ne5532 is almost for free. They are offering LM4562 for an additional cost .
a07 is a very cheap amplifier.

 

[DanielT]

Because of cost . The ne5532 is almost for free. They are offering LM4562 for an additional cost .

Well, hm ..Do you think that buying X number of LM4562 for Aiyima would mean such a big extra cost for them? Note I mean that: Why does Aiyima not design its amplifier with just LM4562 if they now think it is better?

 

[oldsysop]

Tangband : Come back when you have blind evidence​

 

[Honken]

Many non- believers has been on visit and they all can hear the sound differences.

Would you be willing to demonstrate the difference to another skeptic? Where in SE are you located? I'm in NW Scania.

 

[levimax]

Because of cost . The ne5532 is almost for free. They are offering LM4562 for an additional cost .

Cost difference is pennies... both are dirt cheap and preform well. Put me down as a skeptic... a few dB difference in SINAD at low frequency but still more than -100 dB down is not audible.

 

[audio2design]

My counter-question. If so, why do not Aiyima themselves put in lm4562 from the beginning?

Cause they can charge more for an upgrade ...

 

[audio2design]

Well now the Aiyima A07 is not an expensive amplifier but poor implementation, not so good amp ... do you think so?

I was speaking to the implementation of the op-amp in the circuit and why the two were different at 50hz and 150hz (if not measurement error).

 

[Tangband]

Well, hm ..Do you think that buying X number of LM4562 for Aiyima would mean such a big extra cost for them? Note I mean that: Why does Aiyima not design its amplifier with just LM4562 if they now think it is better?

counterquestion: Why do expensive amplifiers sometimes use TL 072 Op:s ?

In Aiyimas case: Probably it would have done the amplifier more expensive. After all, - lm4562 is 20 times more expensive. Thats the way all companies works- cut the costs where you can.
And maybe 90% of the buyers dont care much about soundquality also….. not for 70 dollars for a whole amplifier.
As I said earlier - Aiyima themselves recommends lm4562 as an upgrade and you can buy the amplifier from them with lm4562 , for an additional cost.

 

[Tangband]

Cause they can charge more for an upgrade ...

Thats true!

 

[Tangband]

I just want to say that my Aiyima a04 with a meanwell 30 v 6 A power supply outperforms every class A/B amplifier up to about 500 dollars we have found (tested 5 amplifiers ) and done comparisons with, listening to music. Thats an achivement , and Amirms up-writing of the bigger brother a07 is entirely true.
Those amplifiers and the topping d10s are incredibly bargains, and a perfect beginning for audiophile students and such..
I also think that op-amp rolling is rather fun, even if the only op I found to be sounding clearly better than ne5532, was the lm4562 ( the others I tried: opa1642 opa2134 and opa1612 )

 

[DanielT]

Okay, I'm quitting the speculation about why Aiyima chooses OP amp X. It can be due to a lot of different technical and or business decisions.

 

[Tangband]

Okay, I'm quitting the speculation about why Aiyima chooses OP amp X. It can be due to a lot of different technical and or business decisions.

Yes, the thing that they have the option to swap the OP:s they have incommon with many other chinese amplifier or dac-makers like topping. Maybe the cause is to start an interest in modifying and starting a cult like a07 or d10s ?

 

[DanielT]

I just want to say that my Aiyima a04 with a meanwell 30 v 6 A power supply outperforms every class A/B amplifier up to about 500 dollars we have found (tested 5 amplifiers ) and done comparisons with, listening to music. Thats an achivement , and Amirms up-writing of the bigger brother a07 is entirely true.
Those amplifiers and the topping d10s are incredibly bargains, and a perfect beginning for audiophile students and such..
I also think that op-amp rolling is rather fun, even if the only op I found to be sounding clearly better than ne5532, was the lm4562 ( the others I tried: opa1642 opa2134 and opa1612 )

Very affordable. The question is in any case at the price Aiyima is sold for if it is possible to find someone with better performance? . In the case of a two-channel amplifier (apart from the missing remote and only one input).

When it comes to comparing sounds. Tangband, well. I guess in my case I will not hear any differences, if I were to roll, switch up amps.
Went completely to he...l (or it went well as it went, as you might expect) when I was going to detect differences here:

What is this? No golden ears!

Got an idea last week. Connected a Blu-ray, Sony BDP-S570, and a CD- player Marantz CD5001 to the pre amp. It has line selectors. Went to the local flea market and managed to find duplicates, CDs. Exactly the same CDs, the same recording on the discs. Same master. Enter with the discs in the...

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[oldsysop]

I just want to say that my Aiyima a04 with a meanwell 30 v 6 A power supply outperforms every class A/B amplifier up to about 500 dollars we have found (tested 5 amplifiers ) and done comparisons with, listening to music.