I own the Aiyima A07 Max and the Fosi V3 amplifiers. When I upgraded to a 48V power supply, I noticed a faint hiss at higher volumes, something that wasn’t present with their original 32V/36V power bricks. After consulting a specialist, I was advised to plug the power supply directly into a wall outlet and position it as far as possible from the amplifier and any nearby devices. Following this simple adjustment, the hiss disappeared entirely, and the system now performs flawlessly.
Thanks for the excellent video. I have both of these amplifiers. I have 3 x ZA3s - one additional with the Sparkos opamp. My first observation is to praise Fosi Audio - over the last two years, I ahve had conversations with them, and they have always been extremely friendly and helpful - they seem to be a company with its heart in the right place. I found it hard to differentiate between the two different types of amps. There are so many variables in hi-fi, with source information being critical. I used these with a tube preamp and was very happy with the product. I am thrilled that Fosi brought out their preamp/DAC - and I own that. However, I persist in using the tube preamp as I prefer it. The heat from the V3s was a bit disconcerting. However, Fosi introduced fans who can be placed on the V3s. I bought these, and they work well! I am no Fosi zealot (!); however, this seems to be a company that is truly 'on the move' and set to introduce some phenomenal products, I strongly suspect. The fabulous thing is that the price means we can buy this equipment and experiment. In the past, this was not something I could do, as products were such huge investments.
Agreed. Fosi iterates extremely fast and they listen to their community’s feedback. I think they also have some tube preamps. They may not be „true” tube preamps as the tubes are only used for buffering signal and not amplifying it, but still…
@NormcoreGreg I am looking forward to seeing your work 😎👍 I am still playing with ZD3 & ZA3 x2 + subwoofer on desktop, near field. I'm comparing this to this other more refined main system... I am enjoying this fun journey 😎👍
According to 'Passion For Sound' he states: This Fosi Audio ZA3 amp has a SECRET weapon! And he says it's a "game changer" in that when you swap the op-amps for the Burson Vivid, it transforms the ZA3 into a "powerhouse" - it causes the ZA3 to surpass the V3 monoblocks. Yes, it also costs more, but the sound apparently greatly increases.
@@theendingmusic I am going to try this opamp rolling thing soon :) However, a pair of those Burson costs around $250, and I think you need do swap at least 2 in each unit. This raises the total cost of those anps quite significantly.
These amps get hot because of the linear voltage regulators. Those regulators regulate the opamps and the chipset 12v circuitry. Linear regulators "burn" the excess voltage, for example if you use a 32V PS, then the regulator needs to burn (32-12)V times the current flowing which also depends on the opamps. Those discrete opamps have a much higher consumption than IC opamps. 20v x0.1A consumes 2W. But 8f you use a 48V PS then (48-12)V x 0.1A =3.6W, this power is burned even when the amp is not playing anything. And you are not considering the power consumed by the actual TPA3255 chip. So, in summary, the higher the PS voltage, the more power the Linear regulators need to burn. And because the case acts as heatsink, the smaller the case the higher the temperature of the case. And the people who are experiencing more with this issue are the ones replacing the opamps with higher power consumption ones.
Thanks for the explanation Miguel! I can see Fosi is selling V3Ms bundled with a cooling fan, so I guess they do acknowledge the problem of overheating. I also noticed some people installing additional radiators on top of the unit.
The temperature problem can be easily avoided with the adjustable fans offered by Fosi Audio. I placed my V3 on one of each and no longer have any problems with heat development.
I am testing the ZA3s in monophonic mode. I have them at maximum volume, I use an Eversolo DMP-A8 as a pre-amplifier and I never heard any hiss or strange noises from having the ZA3s at maximum volume. I have 2 pairs of speakers, a Dynaudio Heritage Special and a Proac Response d2... background noise or hiss with the ZA3s at max volume, nothing at all, no distortion.
@@S.BenditHifi maybe it’s my speakers then. I tested these with two different pairs (wharfedales and elacs) - they both were 6 Ohm, so maybe the impedance is too low.
@@NormcoreGreg Not your speakers, I run the ZA3 (in mono setup) and WD Linton 85th heritage, and absolutely no noise at full throttle. Maybe worth to contact Fosi as you may have a 'faulty' unit.
@@NormcoreGreg I don't think that's it. My ProAc Response speakers have a sensitivity of 8 ohm and 88.5dbs. But the Dynaudio Heritage Special speakers have a sensitivity of 85db and work at 4 ohm. In other words, they are very complicated speakers and I don't have a single noise with the ZA3s at maximum volume in the background. I briefly tried the V3s and found them more analytical and with less bass.
@@34332 they've sent me a replacement unit, but it didn't help. Maybe there's interference somewhere else in my system, but I haven't found it yet and it doesn't happen with other components. I'll keep digging - it's fun anyway :)
Great review, helped a lot, great performance of you, nice jokes, very sympathic. I think we survive 2025 also when we follow our passions, like Audio units and the love for the technic Greatings from Germany / Bavaria
Fosi has quality control problems ur za3 unit is defective ask them to replace the internal board, i have 2 units they sound good at hi volume but my xlr button is defective
I use a pair of Aiyima A07 at maximum volume as a monoblock in a pair of 130W (6 ohm, 87db) speakers and I hear an inconvenient background noise. At 75% it is almost inaudible.
I own the Aiyima A07 Max and the Fosi V3 amplifiers. When I upgraded to a 48V power supply, I noticed a faint hiss at higher volumes, something that wasn’t present with their original 32V/36V power bricks. After consulting a specialist, I was advised to plug the power supply directly into a wall outlet and position it as far as possible from the amplifier and any nearby devices. Following this simple adjustment, the hiss disappeared entirely, and the system now performs flawlessly.
@@samirbegovic7107 interesting. I’ll try that. Thanks.
Thanks for the excellent video. I have both of these amplifiers. I have 3 x ZA3s - one additional with the Sparkos opamp. My first observation is to praise Fosi Audio - over the last two years, I ahve had conversations with them, and they have always been extremely friendly and helpful - they seem to be a company with its heart in the right place. I found it hard to differentiate between the two different types of amps. There are so many variables in hi-fi, with source information being critical. I used these with a tube preamp and was very happy with the product. I am thrilled that Fosi brought out their preamp/DAC - and I own that. However, I persist in using the tube preamp as I prefer it. The heat from the V3s was a bit disconcerting. However, Fosi introduced fans who can be placed on the V3s. I bought these, and they work well! I am no Fosi zealot (!); however, this seems to be a company that is truly 'on the move' and set to introduce some phenomenal products, I strongly suspect. The fabulous thing is that the price means we can buy this equipment and experiment. In the past, this was not something I could do, as products were such huge investments.
Agreed. Fosi iterates extremely fast and they listen to their community’s feedback. I think they also have some tube preamps. They may not be „true” tube preamps as the tubes are only used for buffering signal and not amplifying it, but still…
You did a good job comparing these two. Very similar to my evaluation.
@@Grooverski, thanks!
Nicely done 😎👍
I'm lucky to get "no hiss" at full ZA3 Monoblock volume. Feeding them with FOSI ZD3 XLR.
ZD3 review comming up ;)
@NormcoreGreg I am looking forward to seeing your work 😎👍
I am still playing with ZD3 & ZA3 x2 + subwoofer on desktop, near field.
I'm comparing this to this other more refined main system...
I am enjoying this fun journey 😎👍
According to 'Passion For Sound' he states: This Fosi Audio ZA3 amp has a SECRET weapon! And he says it's a "game changer" in that when you swap the op-amps for the Burson Vivid, it transforms the ZA3 into a "powerhouse" - it causes the ZA3 to surpass the V3 monoblocks. Yes, it also costs more, but the sound apparently greatly increases.
@@theendingmusic I am going to try this opamp rolling thing soon :) However, a pair of those Burson costs around $250, and I think you need do swap at least 2 in each unit. This raises the total cost of those anps quite significantly.
These amps get hot because of the linear voltage regulators. Those regulators regulate the opamps and the chipset 12v circuitry. Linear regulators "burn" the excess voltage, for example if you use a 32V PS, then the regulator needs to burn (32-12)V times the current flowing which also depends on the opamps. Those discrete opamps have a much higher consumption than IC opamps. 20v x0.1A consumes 2W. But 8f you use a 48V PS then (48-12)V x 0.1A =3.6W, this power is burned even when the amp is not playing anything. And you are not considering the power consumed by the actual TPA3255 chip. So, in summary, the higher the PS voltage, the more power the Linear regulators need to burn. And because the case acts as heatsink, the smaller the case the higher the temperature of the case. And the people who are experiencing more with this issue are the ones replacing the opamps with higher power consumption ones.
Thanks for the explanation Miguel! I can see Fosi is selling V3Ms bundled with a cooling fan, so I guess they do acknowledge the problem of overheating. I also noticed some people installing additional radiators on top of the unit.
The temperature problem can be easily avoided with the adjustable fans offered by Fosi Audio. I placed my V3 on one of each and no longer have any problems with heat development.
I am testing the ZA3s in monophonic mode. I have them at maximum volume, I use an Eversolo DMP-A8 as a pre-amplifier and I never heard any hiss or strange noises from having the ZA3s at maximum volume. I have 2 pairs of speakers, a Dynaudio Heritage Special and a Proac Response d2... background noise or hiss with the ZA3s at max volume, nothing at all, no distortion.
@@S.BenditHifi maybe it’s my speakers then. I tested these with two different pairs (wharfedales and elacs) - they both were 6 Ohm, so maybe the impedance is too low.
@@NormcoreGreg
Not your speakers, I run the ZA3 (in mono setup) and WD Linton 85th heritage, and absolutely no noise at full throttle. Maybe worth to contact Fosi as you may have a 'faulty' unit.
@@NormcoreGreg I don't think that's it. My ProAc Response speakers have a sensitivity of 8 ohm and 88.5dbs. But the Dynaudio Heritage Special speakers have a sensitivity of 85db and work at 4 ohm. In other words, they are very complicated speakers and I don't have a single noise with the ZA3s at maximum volume in the background. I briefly tried the V3s and found them more analytical and with less bass.
@@34332 they've sent me a replacement unit, but it didn't help. Maybe there's interference somewhere else in my system, but I haven't found it yet and it doesn't happen with other components. I'll keep digging - it's fun anyway :)
Thanks Greg,, 🌟
Cheers from Sweden,, 🍻😎👍
Cheers Iren :)
@@NormcoreGreg 💖
Great review, helped a lot, great performance of you, nice jokes, very sympathic.
I think we survive 2025 also when we follow our passions, like Audio units and the love for the technic
Greatings from Germany / Bavaria
Thanks for your kind words and greetings to you too @DocHouse-f8w
Fosi has quality control problems ur za3 unit is defective ask them to replace the internal board, i have 2 units they sound good at hi volume but my xlr button is defective
I use a pair of Aiyima A07 at maximum volume as a monoblock in a pair of 130W (6 ohm, 87db) speakers and I hear an inconvenient background noise. At 75% it is almost inaudible.
@@AlexandreBiciati mine are also 6 ohm, so maybe that’s the problem.
None of them. Go for class ab mono. Topping is offering.
@@tamayaytam maybe one day. I fear it will come sooner than my wife would want to ;)
@NormcoreGreg it is contagious, long lasting disease you know. You can't run from it.