Fosi Audio V3 Amplifier Review

[Guddu]

I dunno about that but I am happy I didn't have to buy a replacement.

Better to clean up softly with something like IP.

 

[mike70]

High end coffee ... you'll listen a more open soundstage like taking off a veil on the speakers

 

[Guddu]

Kudos to Fosi Audio for going above and beyond and including a highly functional spilled coffee safety device on the V3.

What?

 

[motorstereo]

Apparently I spoke too soon about the little Fosi not suffering any damage from the spilt coffee. Late last night after running all day it began to make static noises and then nothing. Today I'll take the cover off and clean things up with a qtip and ip. I'm thinking pull the op amp and clean the legs and reinsert. If that doesn't work it'll be $65 for a replacement unit. Lesson learned.

 

[motorstereo]

A follow up to my spilled coffee mishap. I just finished the reassembly after a good cleaning and it's a no go. The blue light comes on and I can hear a protection circuit click when the volume knob is close to being shut off but no music. Nothing looked out of the ordinary and I couldn't even find a coffee stain. I'm thinking no more than a half teaspoon found it's way to the board but sadly it was enough to ruin it..

 

[Guddu]

A follow up to my spilled coffee mishap. I just finished the reassembly after a good cleaning and it's a no go. The blue light comes on and I can hear a protection circuit click when the volume knob is close to being shut off but no music. Nothing looked out of the ordinary and I couldn't even find a coffee stain. I'm thinking no more than a half teaspoon found it's way to the board but sadly it was enough to ruin it..

Worth trying hair dryer heat up for 10-15 min.

 

[gwing]

Worth trying hair dryer heat up for 10-15 min.

Dried up residue might still be the problem. Before giving up I'd give it a bit of time to make sure all capacitors discharged, thoroughly wash/bath the amp in distilled water, leave it to dry in a warm airing cupboard or warm place for at least 48 hours then give it another try.

You can of course also user 'proper' cleaners but it's a cheap amp to replace

 

[MCH]

I would check the regulators, if you get 15V, 12V and I guess 3.3V (I am guessing the values based on similar amps). If not, you might be able to replace the one failing. If yes, might be dead chip or other dead IC...

 

[motorstereo]

You can of course also user 'proper' cleaners but it's a cheap amp to replace

I'm thinking this is my best option given the price.

 

[rongon]

The V3 is on sale again, so I checked Amazon to see what their user reviews look like. Wow. Lots of comments about unusably low volume, murky sound, 1 and 2 star reviews. Strange for something that measured so well in testing. What gives? Have Fosi been selling thousands of these, so the bad reviews are just the tiny number of defectives shipped out? Or is their QC not so hot?

Amazon.com

 

[KaeliKoo]

The V3 is on sale again, so I checked Amazon to see what their user reviews look like. Wow. Lots of comments about unusably low volume, murky sound, 1 and 2 star reviews. Strange for something that measured so well in testing. What gives? Have Fosi been selling thousands of these, so the bad reviews are just the tiny number of defectives shipped out? Or is their QC not so hot?

Amazon.com

628 global ratings on Amazon -> 94% ratings are 3,4,5 stars -> 2% are 2's & 4% are 1's -> guess I interpret the results different...

 

[cyclo]

Many of those complaining about "low volume" probably need to be pointed to the start of this thread... to understand that the volume pot is using a logarithmic scale. I have 4 x Fosi Audio V3 and all have been working flawlessly... knock on wood.

 

[Toku]

The V3 is on sale again, so I checked Amazon to see what their user reviews look like. Wow. Lots of comments about unusably low volume, murky sound, 1 and 2 star reviews. Strange for something that measured so well in testing. What gives? Have Fosi been selling thousands of these, so the bad reviews are just the tiny number of defectives shipped out? Or is their QC not so hot?

Amazon.com

I think these review articles are the result of ignorance of Chinese products and a lack of technical knowledge. The contents of the reviews are all things I already know and I have no problem with them. However, Fosi should change the expression "PREOUT". It confuses buyers.
As for QC, there are many problems from the perspective of our society. However, these are products of a country whose social system is completely different from ours. Therefore, it is difficult to directly apply our common sense to them. You need to fully understand this before purchasing.

 

[Joe Smith]

The V3's a fine little amp, mine is still working fine, though I have tended to grab the Aiyima A07 Max more of late when using a small amp...

 

[Guddu]

I think these review articles are the result of ignorance of Chinese products and a lack of technical knowledge. The contents of the reviews are all things I already know and I have no problem with them. However, Fosi should change the expression "PREOUT". It confuses buyers.
As for QC, there are many problems from the perspective of our society. However, these are products of a country whose social system is completely different from ours. Therefore, it is difficult to directly apply our common sense to them. You need to fully understand this before purchasing.

Many simply compare it against there old gear and then not finding those advertised power output becomes a concern for a common user.
I have personally recommended these amps to my known ones and a few have simply said the same thing that it isn’t powerful as they say.

 

[rongon]

Many of those complaining about "low volume" probably need to be pointed to the start of this thread... to understand that the volume pot is using a logarithmic scale. I have 4 x Fosi Audio V3 and all have been working flawlessly... knock on wood.

All volume controls use a logarithmic ('audio') taper. Even way back in the days of mono 78s, manufacturers knew that log taper pots were more intuitive to use, more adjustability at lower to medium volume, rather than sounding like the amp's playing nearly full blast with the vol ctrl turned less than half way up.

People also don't understand what 'gain' means. What is the gain (in decibels) of the V3? At what input signal voltage does the amp reach full power?

Good to hear your Fosi V3 amps are working well.

 

[cyclo]

All volume controls use a logarithmic ('audio') taper. Even way back in the days of mono 78s, manufacturers knew that log taper pots were more intuitive to use, more adjustability at lower to medium volume, rather than sounding like the amp's playing nearly full blast with the vol ctrl turned less than half way up.

People also don't understand what 'gain' means. What is the gain (in decibels) of the V3? At what input signal voltage does the amp reach full power?

Good to hear your Fosi V3 amps are working well.

My V3s powering the left, right, and center (bi-amped) channels are set to max when listening to audio (stereo) and/or watching movies (5.2.4 ATMOS). I set the gains on all the speakers/amps on the audio video processor using good old pink noise. Yep I know all about room correction... I have tried them (Audyssey, WiiM Pro's Room Correction on the latest firmware update), but I found setting up the gains using good old pink noise was giving me the best result.

 

[Eric Natural]

... I just leave the Fosi orange vol control turned up to 11 & adjust level with my preamp - plenty loud for my room
best of luck

 

[Subway2400]

Hi,

I've been using a Fosi V3 for 2 about weeks, with the 48V PSU. I'm using it to power a pair of Wharfedale 12.0 speakers for desktop use, connected on a Realtek ALC1220-VB.

I'm pretty satisfied by this little amplifier. I use it at no more than 2 o'clock, the volume control is ensured by the Windows setting. There is no background noise, even with when the GPU is under load. I can't testify about its power, as desktop use isn't really power-demanding and bass below 90 Hz is handled by a subwoofer. Music listening really is enjoyable with the Diamond 12.0 and the Fosi doesn't seem to alter sound in any way. It perfectly fullfils its role. As for temperature, it gets moderately warm to the touch. It runs colder than my Denon X2500H AVR (without Eco mode) and warmer than my ex Yamaha A-S500 (which I really liked).

The only downside to me is the lack of separate power button that forces me to currently use some tape to mark the exact volume pot position. I really wish it had a power button. Plus using the pot when not really needed just add to wear and tear for nothing.

I did some measurements of the frequency response of the speakers using white noise to compare the V3 with my Denon X2500H which uses standard A/B amplifier. Despite a load dependency of the Fosi V3 amplifier, I did not detect any noticeable difference on graphs between the Fosi V3 and the Denon X2500H. The speaker frequency response is the same between the two amplifiers, not showing elevated treble.

I'm pretty happy with this amplifier !

 

[NSacchetti]

No!
Capacitors are glued to the PCB, probably you wouldn't have the same problem with rattling capacitor like @amirm with test example.
Thermal paste is for the metal part on the TPA3255 and the case. Not needed of course, but can be useful in better transfer of heat to the case.


A few more parts and as simple as is proposed from TI.
View attachment 293989
The biggest problem is a gain of (only) 19 dB with PFFB (like with Topping PA5). It will be a lot of complains from customers and @Fosi Audio wouldn't like that, I presume.

@Fosi Audio, you announced a new model after V3 with double XLR inputs, so when we can expect that product?
I hope you will ditch that 32V/5A PSU and you will start with a 36V/6A as a basic PSU.

Hello,

What should I do to replace input opamps by an unbalanced input tube buffer in the Fosi V3? How to find exactly board points to replace opamps outputs by tubes outputs? What is the V3 input impedance?

All help will be much appreciated!
Thank you guys!