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AIYIMA A07 TPA3255 Review (Amplifier)

Doodski

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Not to discourage you although any changes you might notice by op amp rolling will be caused by gain differences. Either louder or quieter volume levels if the op amps can affect that otherwise it's just swapping one more than capable op amp for another more than capable op amp. The bandwidth of audio op amps is much higher than required for audio use and so decent op amps are all more than qualified for simple audio use. Is it possible to invest in some EQ/PEQ control?
 

AudioArchitech

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I do look forward to getting miniDSP and DiracLive. would be fun to try a Tube Preamp with the A08, with Tone controls would be a bonus. Maybe try the Aiyima T6 Pro, Douk P1, Shiit Saga+... any ideas?
 

Doodski

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So, op amp roll a DAC makes more sense, not that noticeable in these amps?
Op amp rolling in general is a crap shoot. Sticking in random op aps in place of one that has the peripheral circuitry calculated to be optimized and not exceeding limits is not only risky sometimes but it's just a exercise in swapping stuff and seeing what happens. It is a good way to familiarize oneself with some aspects of electronics like a data sheet or the types of ICs but other than that it doesn't improve anything. If you want to experiment and get some actual improvement get some parametric equalizer happening.
 

Doodski

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Maybe this was already posted? Just in case, here's what Aiyima has to say about Op Amps
https://www.aiyima.com/blogs/aiyima-audio/the-op-chip-can-use-on-aiyima-a04-a07
If you are determined to op amp roll fly at it. If you do op amp roll perhaps investigate what you are changing by reading the data sheets on each op amp and find the differences that will make a change. There won't be much change if anything though. Your best option for increased sound quality is a EQ/PEQ or better speakers and EQ/PEQ. :D
 

AudioArchitech

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Already rebuilt the crossovers in all my speakers to high end parts. Made a big difference for sure, even in my $4000 set. I have a hard time believing that I won't hear a change between Op Amps, too curious, cheap to try. Will be getting DiracLive soon either way.
 

somebodyelse

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Already rebuilt the crossovers in all my speakers to high end parts. Made a big difference for sure, even in my $4000 set. I have a hard time believing that I won't hear a change between Op Amps, too curious, cheap to try. Will be getting DiracLive soon either way.
If you're doing uncontrolled listening tests there's a good chance you'll hear a difference even if the output is the same. That's just how the brain works, similar to seeing optical illusions. If you really want to know if it's audible then change the opamp in one channel only, check the levels are matched, and listen blind.

@ctrl did a three part series on the audibility of crossover component changes. There may have been an audible (and measurable) change, but not because the parts were high end.
 

Zek

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If you really want to know if it's audible then change the opamp in one channel only
It's not possible because audio file is in stereo and you must have mono switch, also one opamp is often for both channels.
 

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somebodyelse

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It's not possible because audio file is in stereo and you must have mono switch,
Am I overestimating the capabilities of our readership? It seems a simple exercise for the reader with multiple options depending on what's at hand.
also one opamp is often for both channels.
Obviously it won't work in that case, but in the examples I've seen recently promoting opamp rolling they're handling one channel per opamp more often than not. Perhaps I've just not seen a representative set of advertising, but at least for that subset it means you can make a meaningful comparison without needing a separate reference amp.
 

Jdunk54nl

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also one opamp is often for both channels.
That depends on amp design if you have one or two op amps in a “2 channel” amp.

If a btl style amp like the a07, it is actually a 4 channel amp with the channels bridged for more power and now only 2 channels of output.
 

AudioArchitech

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would make much more sense to swap op amps in one unit and compare to a stock unit. Anyone have two A08’s or two A07’s?
 
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AudioArchitech

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Aiyima: "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." Then say: " OP275: Better resolution, low frequency and sound field than NE5532 ". Don't you just want to try for fun? Could get 2x OPA275 for $15 easy swap

https://www.aiyima.com/blogs/aiyima-audio/the-op-chip-can-use-on-aiyima-a04-a07
 

Doodski

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Aiyima: "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." Then say: " OP275: Better resolution, low frequency and sound field than NE5532 ". Don't you just want to try for fun? Could get 2x OPA275 for $15 easy swap

https://www.aiyima.com/blogs/aiyima-audio/the-op-chip-can-use-on-aiyima-a04-a07
For fun....
For audio application to 20KHz with a 5 volt output from the op amps a slew rate of ~0.628V/μS is required.
The OP275 has a available slew rate of 22 V/μs and a bandwidth up to 9 MHz.
The NE5532 has a available slew rate of 9 V/μs and a bandwidth up to 10 MHz.
As can be seen the slew rate and bandwidth for any of the two op amps by far exceeds the spec required for 20KHz.
op - 1.png

Op - 2.png
 

Doodski

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may still offer a slightly different flavour
Myself rather than flying blind I like to look at what is occurring during the swap and compare them to see the operating parameters and sometimes the literature goes pretty deep. One can confirm lead leg layouts, the specifics regarding the inputs and outputs, bandwidth/frequency response of ICs, slew rates, gain and other stuff if they divulge more.
 
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