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3e Audio A7 [TPA3255 PFFB Stereo] Finished Amplifier - User Impressions | Owner's Thread

for the auto on/off, we are eveluating some change in both HW and FW in next build, to adjust the senstivity higher to support it not turn off faster.

currenttly for some people user case,we suggest below 2 simple way.
  1. adjust higher input cource volume a little bit,this may case by case as the music may diffenent
  2. use volume control on the A5/A7 side
When will the new units be available?
 
but I slightly prefer the ZA3 because the high end is more open and airy.
Maybe because of the Load dependency from the Fosi? If so you could have +1 db from 10 to 20khz but its dependent from your speakers impedance curve. But could have many other reasons like psychoacoustics as example, you have to measure to be shure. Anyway thank you for sharing your experience
 
My speakers are Harbeth M40.1 which have a nominal impedance of 6 Ohm (and a sensitivity of 84 dB). The difference between the 2 amps is very obvious.
 
The difference between the 2 amps is very obvious.
While it might be load dependency, an obvious difference also doesn't rule out perceptive bias.


I replaced the op amps with Sparkos ss3602 which improved the sound significantly.

And the fact you are hearing differences at all from op-amp rolling, let alone significant ones, very strongly suggests perceptive bias is at play.
 
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My speakers are Harbeth M40.1 which have a nominal impedance of 6 Ohm (and a sensitivity of 84 dB). The difference between the 2 amps is very obvious.
If youre interested in more information about this, Stereophile measured this speaker: https://www.stereophile.com/content/harbeth-m401-loudspeaker-measurements
With this information and the review from Erins Audio Corner about the Fosi Za3 you can see a Load dependency is also very probably.
Nice looking speakers. And the za3 is still a very good value for the Money, but the 3e A7 a far bit more "audiophile" :D
 
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Tested out my A5se, I bought it to power some outdoor speakers in our sun room. Had packed things away for the winter but i couldn't resist a testing.

Sounds clean, with enough power at 55% volume from Hiby DAP with volume bypass engaged on the amp.

1000014919.jpg
 
If youre interested in more information about this, Stereophile measured this speaker: https://www.stereophile.com/content/harbeth-m401-loudspeaker-measurements
With this information and the review from Erins Audio Corner about the Fosi Za3 you can see a Load dependency is also very probably.
Nice looking speakers. And the za3 is still a very good value for the Money, but the 3e A7 a far bit more "audiophile" :D
Thank you very much, it's a very informative article :)

I didn't compare the stock amps against each other, but the performance depends a lot on the opamps. With the Sparkos installed, I won't rate the A7 more "audiophile" - at least with my speakers... Maybe the stock OPA1656 inside the A7 performs better than the NE5532 inside the ZA3? Upgrading the ZA3 opamps to Sparkos did make a huge difference...
 
Why does the A7 Mono have a volume control? Surely for nearly all use cases it is completely pointless and adds unnecessary cost.
Matt, I recently bought my first DAC and I wanted to use HDMI-arc port out from my Sony Z9D into my Fosi ZD3 DAC...I began experimenting using the DAC's Preamp-RCAs out, to my pair of AIYIMA A07 MAX both set to Mono Mode. With both amp's volume pots wide open and using the DAC's preamp...It sounds pretty good, but just okay, really. Plus, it's very convenient using the DAC's remote control this way. However: In the Bypass setting on the ZD3 DAC, (no preamp) I sacrificed having Remote HDMI-arc control forced to adjust volume controls on the A07s manually...Amazingly, every input (TV, streaming, CD, Blu-ray) becomes more Transparent, Musically exciting, astonishing in that my system could sound so good set this way. Having to get up to adjust volume on both amps+matching balance by ear...kinds sucks....At this point I'm wondering, am I imagining how good it sounds Direct? I went back and forth from the DAC's preamp to DAC's Bypass...back and forth a few times to make sure. Finally Matt, I'm resigned to the Direct connection...even if I'm being less couch-locked, I'm happy my system improved to a large % .
 
Matt, I recently bought my first DAC and I wanted to use HDMI-arc port out from my Sony Z9D into my Fosi ZD3 DAC...I began experimenting using the DAC's Preamp-RCAs out, to my pair of AIYIMA A07 MAX both set to Mono Mode. With both amp's volume pots wide open and using the DAC's preamp...It sounds pretty good, but just okay, really. Plus, it's very convenient using the DAC's remote control this way. However: In the Bypass setting on the ZD3 DAC, (no preamp) I sacrificed having Remote HDMI-arc control forced to adjust volume controls on the A07s manually...Amazingly, every input (TV, streaming, CD, Blu-ray) becomes more Transparent, Musically exciting, astonishing in that my system could sound so good set this way. Having to get up to adjust volume on both amps+matching balance by ear...kinds sucks....At this point I'm wondering, am I imagining how good it sounds Direct? I went back and forth from the DAC's preamp to DAC's Bypass...back and forth a few times to make sure. Finally Matt, I'm resigned to the Direct connection...even if I'm being less couch-locked, I'm happy my system improved to a large % .
That’s a very strange result. I wonder if there’s some kind of mis-match between the ZD3 output in variable mode and the A07 in direct mode (output impedance, sensitivity, noise, etc).

Also don’t forget sighted/expectation bias plays a huge role in deciding subjective impressions, not to mention that the louder option, even by 0.5dB, is almost always preferred.

Either way, I don’t think your experience is a justification for using two separate volume controls which no doubt leads to volume imbalances (that itself could be a factor in your experience) between channels and definitely is extremely inconvenient.

Appreciate your thoughts though. Why do you think you heard the improvement?
 
It's amazing that even after staggering amounts of measured and scientific evidence, that empirical myths such as op amp swaps significantly affecting actual sound quality exist. When its really a between the ears phenomenon :) .
for you empirical myths, for others reality that OPAMPS have sound signatures
 
... Finally Matt, I'm resigned to the Direct connection...even if I'm being less couch-locked, I'm happy my system improved to a large % .
That’s a very strange result. I wonder if there’s some kind of mis-match between the ZD3 output in variable mode and the A07 in direct mode (output impedance, sensitivity, noise, etc).

Also don’t forget sighted/expectation bias plays a huge role in deciding subjective impressions, not to mention that the louder option, even by 0.5dB, is almost always preferred.

Either way, I don’t think your experience is a justification for using two separate volume controls which no doubt leads to volume imbalances (that itself could be a factor in your experience) between channels and definitely is extremely inconvenient.

Appreciate your thoughts though. Why do you think you heard the improvement?
It is very interesting when one experiments with balance.

0.5dB is a very obvious shift left or right on the sound stage, and also 'mixes' where instruments are placed 'back' in the soundstage can improve.

0.5dB can be all it takes. People invest in digital room adjustment equipment also. A wall significantly further away on one side, or a staircase opening up to a duplex on one side, can make a difference.

It also depends on the digital volume control. I find that once the digital attenuation gets significant the dynamics decrease, but small changes I don't notice. Obviously a lot of juggling is involved so no blind A/B testing realistic here. ... or not worth the faff.

Broadcasts don't necessarily get it right ... balance shifts.

So can having a cold (your ears' balance can shift)!

Then there is the equipment used in the studio to mix (interesting review by Erin's Audio Corner - OK not balance related ... but at the end of the day a 0.5 shift in balance can be all it takes.
 
for you empirical myths, for others reality that OPAMPS have sound signatures
Maybe they have, maybe Not, i personally cant Tell because i have Not tested and did not seen a review with two amps, one with Stock and one with Special OP amps directly compared. Time between to Swap them in one Amp and Test, will not end in a result anybody can Trust. And a A/B Switch and blind Test with 10 repeats would be the Minimum. If there are diffenrences, i bet they are minor.
And OP Amps dont fix the Load dependency from the Fosi Za3.
 
Matt, I recently bought my first DAC and I wanted to use HDMI-arc port out from my Sony Z9D into my Fosi ZD3 DAC...I began experimenting using the DAC's Preamp-RCAs out, to my pair of AIYIMA A07 MAX both set to Mono Mode. With both amp's volume pots wide open and using the DAC's preamp...It sounds pretty good, but just okay, really. Plus, it's very convenient using the DAC's remote control this way. However: In the Bypass setting on the ZD3 DAC, (no preamp) I sacrificed having Remote HDMI-arc control forced to adjust volume controls on the A07s manually...Amazingly, every input (TV, streaming, CD, Blu-ray) becomes more Transparent, Musically exciting, astonishing in that my system could sound so good set this way. Having to get up to adjust volume on both amps+matching balance by ear...kinds sucks....At this point I'm wondering, am I imagining how good it sounds Direct? I went back and forth from the DAC's preamp to DAC's Bypass...back and forth a few times to make sure. Finally Matt, I'm resigned to the Direct connection...even if I'm being less couch-locked, I'm happy my system improved to a large % .
Something else

I don't know if you tried this, but you could keep your Fosi ZD3 in pre-amp mode, but have the volume attenuated in analogue using the Aiyima's. You may find that 95% to 100% on the digital control don't make such a difference ... and then you can dial in your two analogue controls ... enjoy that couch 10 % more :)
 
for you empirical myths, for others reality that OPAMPS have sound signatures
The consensus amongst most qualified engineers on this site, based on understanding how op amps work, and backed up by measurements - is that swapping op amps is a pointless waste of time and money. At best it will make no audible difference, at worst it might destabilise an amp and cause it to oscillate.

People might think they are hearing real differences but this will almost certainly be because they are not testing blind (not typically possible when swapping op amps) and are hearing the effect of perceptive bias. Alternatively they may be hearing the effect of a destabilised amp oscillating. This is never a good thing.

tl:dr - don't waste your effort. :p
 
The consensus amongst most qualified engineers on this site, based on understanding how op amps work, and backed up by measurements - is that swapping op amps is a pointless waste of time and money. At best it will make no audible difference, at worst it might destabilise an amp and cause it to oscillate.

People might think they are hearing real differences but this will almost certainly be because they are not testing blind (not typically possible when swapping op amps) and are hearing the effect of perceptive bias. Alternatively they may be hearing the effect of a destabilised amp oscillating. This is never a good thing.

tl:dr - don't waste your effort. :p
of course I'm not able and willing to argue against the qualified engineers here! I simply wonder why so many different equivalent OPAMP's are on the market? please give me a qualified hint.
 
of course I'm not able and willing to argue against the qualified engineers here! I simply wonder why so many different equivalent OPAMP's are on the market? please give me a qualified hint.
For exactly the same reason that there are a million audiophile cables available. Snake oil sales for the scientifically ignorant obsessive audiophile.
 
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