Fosi M03 / Aiyima 3001 / Nobsound G2 Pro mono sub amp review

[Hendrixon]

maybe it uses PFFB as there seems to be no hump after 20KHz

That's because you only tested it with a 4ohm load.
The hump is created with higher ohm loads as seen on the V3 mini/stereo into 8ohm.

I wonder, how one would go about adding PFFB?
I know how to do that with tube guitar amps, have no clue about SS and D amps

 

[Boredcarrot]

Really sorry to ask this if it's been addressed already, but can anyone confirm if the "sub out" RCA low-level signal is also adjustable via the "sub freq" knob when switched to "sub" mode? Want to run a more powerful Hypex amp to my passive sub with this, so just wanna make sure that it's not only the speaker level outputs that are adjustable. I've been using my Fosi ZP3 for this purpose, but the sub-out is 20hz-200hz, which isn't suiting my system. I would prefer to use the G2 pro for the same purpose, because having that adjust ability all the way down to 40hz is ideal. So only as a preamp using the sub out, but with frequency adjustability.

 

[gaussianmist]

Really sorry to ask this if it's been addressed already, but can anyone confirm if the "sub out" RCA low-level signal is also adjustable via the "sub freq" knob when switched to "sub" mode? Want to run a more powerful Hypex amp to my passive sub with this, so just wanna make sure that it's not only the speaker level outputs that are adjustable. I've been using my Fosi ZP3 for this purpose, but the sub-out is 20hz-200hz, which isn't suiting my system. I would prefer to use the G2 pro for the same purpose, because having that adjust ability all the way down to 40hz is ideal. So only as a preamp using the sub out, but with frequency adjustability.

Yes, it is.

 

[Boredcarrot]

Yes, it is.

Thank you. I thought as much but didn't want to take if for granted. I ordered one anyway in the meantime.

 

[MStan]

I just tried the M03 with a 4 ohm 10" (1 cubic ft enclosure) sealed sub used beside my desk in a small office. Not exactly a demanding application. This thing just barely produced any output and then shutdown. I returned it within the hour to Amazon. I am getting a real amp like this one: https://www.speakerpower.com/products/htb-700?variant=49679777366331. Yes, it costs more than $90 but $90 is expensive for something that doesn't work at all.

 

[AresLuna]

I just tried the M03 with a 4 ohm 10" (1 cubic ft enclosure) sealed sub used beside my desk in a small office. Not exactly a demanding application. This thing just barely produced any output and then shutdown. I returned it within the hour to Amazon. I am getting a real amp like this one: https://www.speakerpower.com/products/htb-700?variant=49679777366331. Yes, it costs more than $90 but $90 is expensive for something that doesn't work at all.

I had the similar problems with the amp going into protection shutdown with the higher voltage power supplies. Using some 19V laptop switching power supplies i could get it running well. Keep in mind that the nominal impedance 4ohm speaker could go well below that value, which may trigger the protection shutdown in those inexpensive sub amps such as the FOSI, AIYIMA and NOBSOUND.

The one you bought is for sure a much more sophisticated and powerful monoblock amp. Which also has a bass boost circuit with a dedicated knob controlling that bass boost. This is very interesting and can help shape a much better bass response.

Unfortunately those inexpensive sub amps sound really flat compared to the plate amplifiers that each subwoofer manufacturer makes since each one is specifically tuned for their respective drivers / enclosures / designs giving them their distinct bass character. When that plate amplifier gets damaged and bypassed using one of those chinese amps the subwoofer loses that distinct sound and bass signature and becomes lifeless and flat. You revive your subwoofer in a way, but it is never the same as it was when it was working with its own plate amp.

 

[Uncola]

ordered a g2 pro with the 48v 5A gan power supply to try out with my super nice passive sub that probably deserves better, but I"m cheap hehe
thanks for the measurements which confirm this is a decent sub amp and not garbo

 

[john61ct]

So is just saving money the reason not to go with 3e A7?

The idea being, get the same power but paying more for higher SQ is just not needed for subwoofers?

I agree the LPF includes is nice, but phase issues?

Compare in my case to CA30, I like multichannel and DC power...

 

[AresLuna]

It's not all about the power output. Those inexpensive digital Class D amplifiers are pretty capable and powerful to drive almost every consumer subwoofer out there, demanding or not, as long as they don't reach low impedance levels to trigger the protection circuit.

They also provide clean and high sound quality BUT as i have written before in my previous posts, don't underestimate the original subwoofer's plate amp's built in equalizer settings, the "voicing" that the manufacturer did to create that specific plate amplifier to match the selected subwoofer driver and enclosure design.

You can always use a multi-band graphic EQ equipment to manually adjust the areas of bass boost you prefer and try to somehow match it to your preferences. Those equalizers create rough rises and dips, so you may need one with 6db/oct which means more smooth slopes. Choose one that has much control over the range of 20-200Hz.

 

[MCH]

It's not all about the power output. Those inexpensive digital Class D amplifiers are pretty capable and powerful to drive almost every consumer subwoofer out there, demanding or not, as long as they don't reach low impedance levels to trigger the protection circuit.

They also provide clean and high sound quality BUT as i have written before in my previous posts, don't underestimate the original subwoofer's plate amp's built in equalizer settings, the "voicing" that the manufacturer did to create that specific plate amplifier to match the selected subwoofer driver and enclosure design.

You can always use a multi-band graphic EQ equipment to manually adjust the areas of bass boost you prefer and try to somehow match it to your preferences. Those equalizers create rough rises and dips, so you may need one with 6db/oct which means more smooth slopes. Choose one that has much control over the range of 20-200Hz.

Agree. I went through the process of "passivating" my inexpensive SVSs and measured the eq applied by the original plate amp here:
https://www.audiosciencereview.com/...e-rumble-of-my-svs-sb-1000.46977/post-1861814

 

[AresLuna]

Agree. I went through the process of "passivating" my inexpensive SVSs and measured the eq applied by the original plate amp here:
https://www.audiosciencereview.com/...e-rumble-of-my-svs-sb-1000.46977/post-1861814

Wow, thanks for sharing!!! And great job you did there!!!! Congrats for all the hard work!!!

 

[Uncola]

Finally received both the nobsound g2 pro and the aayima 48v 5a gan power supply.. very happy with the performance.. it does run a little hot even at average volumes. Great to have my passive sub back in action

 

[dtaylo1066]

 

[AresLuna]

Exactly the same problem that i faced when using the higher voltage power supplies. With 3 different subwoofers!!!! I even tried a second Nobsound G2 PRO in case my first one was defective. It seems some drivers go really low impedance-wise and trigger the protection mode on the amp chip.

 

[dtaylo1066]

Exactly the same problem that i faced when using the higher voltage power supplies. With 3 different subwoofers!!!! I even tried a second Nobsound G2 PRO in case my first one was defective. It seems some drivers go really low impedance-wise and trigger the protection mode on the amp chip.

You kind of get what you paid for. Thinking an amp at the price is going to drive a 2 ohm 12-inch woofer load at high dB may not be realistic. The most upgraded power supply does not really seem worth it. Or you can get a more user friendly woofer, I guess. Hey, for the money, it's not bad.