Fosi Audio V3 Mono Amplifier Review

[igfarm]

Quick question: connecting the Fosi V3 Mono to a Motu M4 interface using XLR. Should I add some attention to the input signal on the digital domain not to overdrive the amp, say -5db?

 

[DavidM1]

Quick question: connecting the Fosi V3 Mono to a Motu M4 interface using XLR. Should I add some attention to the input signal on the digital domain not to overdrive the amp, say -5db?

Check the voltage output of the interface. If it is 4v or less I wouldn’t worry.

 

[Deleted member 71304]

Sorry if this has already been asked (couldn't read the whole 102 pages of this thread) but is there any advantage at all on using two v3 monos with two independent 48/10 power supplies?
I mean, as opposed to the splitting psu unit?

 

[Deleted member 72219]

Sorry if this has already been asked (couldn't read the whole 102 pages of this thread) but is there any advantage at all on using two v3 monos with two independent 48/10 power supplies?
I mean, as opposed to the splitting psu unit?

Using separate PSUs avoids known noise issues. Using a 10amp PSU yields no known benefit over a 5amp PSU on a single amp basis, so the optimal cost/performance setup is dual separate 48V/5A units.

-Ed

 

[Deleted member 71304]

Using separate PSUs avoids known noise issues. Using a 10amp PSU yields no known benefit over a 5amp PSU on a single amp basis, so the optimal cost/performance setup is dual separate 48V/5A units.

-Ed

Thanks a lot

 

[SMen]

Thanks a lot

Except down at 2ohms ... there was one review on youtube which measured that

Check it out . it's quite fun (or skip straight to the end)

 

[LeMiki]

I had a really notable hum when using the RCA connections (from my Onkyo AVR preouts) now I'm using RCA->XLR cables and it's gone. At least they made some sense now

Hi,
Yesterday I installed three v3 mono units for the LRC channels on my Denon 4800. Unfortunately, all three channels are constantly humming. If i remove the rca cable, silence on that channel, the others continue to hum in the same way.
Did it do the same to you? Did i understand you have the rca jack in the onkyo and the xlr in the fosi?

Thanks

 

[jazzboy]

Thanks for the info!

 

[Rajvbs]

I have a custom built (Drivers and electronics purchased from Madisound USA. Built the speaker boxes myself with a trained carpenter as per the design specs given by Zaph Audio itself) MTM bookshelf speakers always connected to Fiio DAC BTR5 +Ayima A03 Pro Tube Pre+Marantz PM6006 UK Edition acting as Power Amp or Fiio DAC + Ayima A3Pro Pre and Ayima A07 Power alternatively. All these connected to my Dell G15 Laptop as this is my Personal music listening station via Type C. So, this is a nearfield listening setup. I do not like powered setups.

Somehow, I like the Ayima combo more than the PM6006 combo. Recently, I have been enjoying the Ayima combo more as they really reveal the quality of Zaph Audio Speakers' capabilities. I am also 90% happy with the low end from these bookshelves. I have planned to add a Sub but I need to figure out a way to do that as Ayima does not have a Sub out. I recently started to feel the itchiness to upgrade or introduce something new to this small and compact audio setup and I just purchased 2 numbers of V3 Mono blocks after spending long hours quietly in the ASR Forum and watching Amir's videos and review posts.

The ASR's high ratings on Fosi V3 gave me confidence and I pulled the trigger yesterday night. I connected the V3s via RCA only and not balanced etc. But somehow, I am not feeling the same punch/power what I used to get from the Ayima A03/A07 combo. Somehow, the sound from this new setup is a bit mellowed and lacks punch. I feel the separation and staging has improved but the lack of power especially after the swap is kind of irking me. I feel like returning the V3s.

 

[Deleted member 72219]

PFFB vs non-PFFB, perhaps?

-Ed

 

[Roland68]

I have a custom built (Drivers and electronics purchased from Madisound USA. Built the speaker boxes myself with a trained carpenter as per the design specs given by Zaph Audio itself) MTM bookshelf speakers always connected to Fiio DAC BTR5 +Ayima A03 Pro Tube Pre+Marantz PM6006 UK Edition acting as Power Amp or Fiio DAC + Ayima A3Pro Pre and Ayima A07 Power alternatively. All these connected to my Dell G15 Laptop as this is my Personal music listening station via Type C. So, this is a nearfield listening setup. I do not like powered setups.

Somehow, I like the Ayima combo more than the PM6006 combo. Recently, I have been enjoying the Ayima combo more as they really reveal the quality of Zaph Audio Speakers' capabilities. I am also 90% happy with the low end from these bookshelves. I have planned to add a Sub but I need to figure out a way to do that as Ayima does not have a Sub out. I recently started to feel the itchiness to upgrade or introduce something new to this small and compact audio setup and I just purchased 2 numbers of V3 Mono blocks after spending long hours quietly in the ASR Forum and watching Amir's videos and review posts.

The ASR's high ratings on Fosi V3 gave me confidence and I pulled the trigger yesterday night. I connected the V3s via RCA only and not balanced etc. But somehow, I am not feeling the same punch/power what I used to get from the Ayima A03/A07 combo. Somehow, the sound from this new setup is a bit mellowed and lacks punch. I feel the separation and staging has improved but the lack of power especially after the swap is kind of irking me. I feel like returning the V3s.

What does the current device chain with the V3 Monos look like?

 

[Rajvbs]

What does the current device chain with the V3 Monos look like?

The current setup
Dell G15 Laptop -> Fiio BTR5 USB Type-C -> Ayiyima Tube A3 Pro -> Fosi V3 Monoblocks - Bookshelf speakers. All RCA connections up until the speakers.

Somehow, I am not getting the depth/low end with this setup which I used to get with the earlier setup:
the same as above except the Aiyima Stereo Power Amp instead of the 2 Fosi Mono blocks.

Should I return the V3s? I am a bit confused even though I like the V3's wide soundstage and cleaner stereo separation. This only lacks the punch.

Sharing the photos of the Pre and Mono blocks, just for info.

 

[Rajvbs]

PFFB vs non-PFFB, perhaps?

-Ed

PFFB ones. The link is here : Fosi V3 Monoblocks for the specifications.

 

[Deleted member 72219]

PFFB ones. The link is here : Fosi V3 Monoblocks for the specifications.

Sorry, I meant the audible difference may be due to the Fosi having PFFB but the older setup does not.

-Ed

 

[SMen]

The current setup
Dell G15 Laptop -> Fiio BTR5 USB Type-C -> Ayiyima Tube A3 Pro -> Fosi V3 Monoblocks - Bookshelf speakers. All RCA connections up until the speakers.

Somehow, I am not getting the depth/low end with this setup which I used to get with the earlier setup:
the same as above except the Aiyima Stereo Power Amp instead of the 2 Fosi Mono blocks.

Should I return the V3s? I am a bit confused even though I like the V3's wide soundstage and cleaner stereo separation. This only lacks the punch.

Sharing the photos of the Pre and Mono blocks, just for info.

The thing about using something like the A07, is that you can 'reach high volume' quickly. Also, the rest of your gear - your sources - might be 'lower bandwidth' than you think, but the combination with the Aiyima gives a sense of 'punch' as you wind the volume up - could be a kind of 'nice compression' you are getting.

Too many variables, but it sounds to me that the Fosi's are requiring wholescale changes ... see if you can get a hold of a different balanced DAC - maybe from a mate - or on trial with amazon - with a lossless volume control and good output, and see how it sounds with your speakers ... or return the Fosi's as they are not a match for your set up (but I would not hold it against them - just a synergy thing ).

 

[Roland68]

The current setup
Dell G15 Laptop -> Fiio BTR5 USB Type-C -> Ayiyima Tube A3 Pro -> Fosi V3 Monoblocks - Bookshelf speakers. All RCA connections up until the speakers.

Somehow, I am not getting the depth/low end with this setup which I used to get with the earlier setup:
the same as above except the Aiyima Stereo Power Amp instead of the 2 Fosi Mono blocks.

Should I return the V3s? I am a bit confused even though I like the V3's wide soundstage and cleaner stereo separation. This only lacks the punch.

Sharing the photos of the Pre and Mono blocks, just for info.

Which power supplies exactly?

 

[Rajvbs]

48v/5a that comes with the Fosi. For Aiyima, I went for a power brick DC48V from Aiyima itself. Btw, I returned the Fosis today and ordering Aiyima A70 mono blocks. I will try these and decide which one is for my liking. Also, I like the sub out in the Aiyima with the volume control. But at the end of the day, I will only keep it if the sound signature meets my taste.

 

[kingkoolkris]

Hi,
Yesterday I installed three v3 mono units for the LRC channels on my Denon 4800. Unfortunately, all three channels are constantly humming. If i remove the rca cable, silence on that channel, the others continue to hum in the same way.
Did it do the same to you? Did i understand you have the rca jack in the onkyo and the xlr in the fosi?

Thanks

Yep, I used some cheap RCA male (Onkyo AVR preout) to XLR male (V3 input) cables from ebay and it 100% eliminated my humming.

 

[ArturroD]

Hello everyone!

I apologize for my English right away.

Nice measurements, but one of my V3 monos burned out on the first day. I know there are more cases like that.

V3 mono has poor heat dissipation. It is a poorly designed device and probably not carefully assembled. Fast mass production. Too small a safety margin. It has too small a radiator. With such a small space inside, it boils inside.

First of all, there should be thermal protection. The amplifier should turn off and work after cooling down. This morning I connected it cold to test. One works and the other is dead, only the indicator light is on and the relay clicked.

In my case, the cooler one failed. So it probably gave off less heat. Underneath there is a radiator connected to the housing with thermal paste, like in a computer processor. The housing should give off heat because it is also a radiator. Apparently there was too little paste or poor adhesion.

- I would disassemble it as if I were replacing opamps. I would buy the best processor paste possible, remove the old one and carefully install the new one.

- Second thing, the feet are too low. Air should flow underneath. I would install some small metal spikes to make some air space. Alternatively, I would place the amplifier on a nice black radiator as a base, gluing it to the bottom with a thermal pad.

- Or indeed, put some slow-running, quiet fan under the amplifier. Of course, there has to be air flow. The manufacturer knows about overheating, because they sell fans for $37. They should be included with every V3 mono.

But it will all ruin the design, which is quite nice in a way. That's all you can do I'm calling the seller right now and saying goodbye to Fosi.
My rating - a headless panther.

 

[somebodyelse]

Hello everyone!

Hello, and welcome.

Nice measurements, but one of my V3 monos burned out on the first day. I know there are more cases like that.

This sounds like typical 'bathtub curve' early device failure, or possibly a manufacturing fault. A failure like this should be a simple replacement by the seller. There have certainly been others as you say. What we don't know is whether the early failure rate is unusually high or typical for consumer electronics.

V3 mono has poor heat dissipation. It is a poorly designed device and probably not carefully assembled. Fast mass production. Too small a safety margin. It has too small a radiator. With such a small space inside, it boils inside.

It's not great, but it's better than most TPA325x based amps. It should manage more sustained output than the A07, but I doubt it'll sustain full output for long. I hope they keep improving, but it'll probably push the price up. That may take it uncomfortably close to budget nCore based competition.

First of all, there should be thermal protection.

There is. It's built into the TPA325x amp chip and I see no way to bypass it in the datasheet. This is why overheating of the amp chip seems an unlikely cause of failure.