Fosi Audio V3 Mono Amplifier Review

[Guddu]

Sorry for bothering! I'm struggling trying to understand why I haven't gotten the results I was looking for.

Let me try putting it simply.
The amplifier has a certain gain or amplification factor, so now your total output power depends on your input signal strength vs input signal strength needed by amplifier for its optimal operation i.e., input sensitivity.
Fosi v3 mono needs 1.8 - 2 volts which any modern DAC or pre-amp should be able to provide.
Fosi v3 mono is a power amplifier, and its pretty normal for a power amplifier to require about 2v input signal on RCA, and about 4v on XLR/TRS.
Integrated amplifiers might work with lower input signal as well, as normally they have pre-amp in-built to manage input signal strength (volts).

So, it’s just about matching DAC/pre-amp that you need for your Fosi v3 mono for optimal output.

P.E. I saw later that @antcollinet already explained the same

 

[Sokel]

Amir has established the 25dB gain measurement for several reasons,one of them is that is easy to get sources that can drive such an amp.
It depends though,high power ones (>600W) will still need more than 4V for full output at such a gain.

 

[edgar-bcn]

I'm not at home to confirm it but now I realize that I was probably using the miniDSP preset that I use to watch TV at night, and in which I lower all the channels by 10 decibels except the center one ... opening the umbrella...

Thank you very much anyway for your answers, I have learned a lot!

 

[amix]

Worth noting....they are 43 degree C when warmed up, even without anything playing anything, unless you put them into auto mode.

The CPU of my NAS is at 47°C when idling. Just saying...

 

[Nyarlathotep]

The CPU of my NAS is at 47°C when idling. Just saying...

They do run a bit hotter than I would prefer, even with no load. Certainly a bit uncomfortable to an extended touch. I picked up a couple of USB fans, linked earlier in the thread, and at the low setting they keep the case much cooler with the monos under a light load. I haven't pushed my monos under a heavy load yet, so not sure how much warmer these get when driven moderate to hard.

 

[Keauval]

I really dont understand whats the point with the heat... People love to touch their amp while playing music ?

With 120W I do Hope those little monsters get warm

 

[spandy]

I like this passive cooling concept of case=heatsink. Has anyone opened theirs to see if they ended up with thermal compound at the interface?

 

[EddNog]

I like this passive cooling concept of case=heatsink. Has anyone opened theirs to see if they ended up with thermal compound at the interface?

The V3 Mono and stereo V3 do not come from the factory with thermal interface material between the heatsink and the case. The ZA3 does.

-Ed

 

[PJ_Schmidt]

I really dont understand whats the point with the heat... People love to touch their amp while playing music ?

With 120W I do Hope those little monsters get warm

I watched Dune Part 1 with the volume high (reference levels) using my monos and after 3 hours they were only a few degrees warmer (48c) than when set to ON for an extended period (46c). I'm running a 2.1 system so the bass is being shipped off to the subwoofer. Maybe my amps would be warmer if I was running full range towers?

 

[Nyarlathotep]

I really dont understand whats the point with the heat... People love to touch their amp while playing music ?

With 120W I do Hope those little monsters get warm

Lol, no not in my case anyway. I have had consumer electronic slowly cook themselves in the past due to being equipped from the factory with less cooling then they aught to have had. High enough heat is often the enemy of some components, e.g. electrolytic capacitors. I just make sure my equipment is given its best opportunity to survive for years and years.

 

[Cal_Cobra]

I watched Dune Part 1 with the volume high (reference levels) using my monos and after 3 hours they were only a few degrees warmer (48c) than when set to ON for an extended period (46c). I'm running a 2.1 system so the bass is being shipped off to the subwoofer. Maybe my amps would be warmer if I was running full range towers?

I decided to cave and order the Wiim Ultra to use as a preamp, with room correction, PEQ, and a sub out along with bass management. Hell everything else on there's a bonus as far as I'm concerned I'll run optical out to my DAC and then XLR out to the V3 monos for a [semi] balanced setup.

How are you connecting your subwoofer?

 

[antcollinet]

I'll run optical out to my DAC and then XLR out to the V3 monos for a [semi] balanced setup

That's fully balanced as far as I'm concerned.

 

[Cal_Cobra]

That's fully balanced as far as I'm concerned.

I agree. My Oppo 105D Universal Blu Ray player has a balanced XLR and RCA stereo out, I'd like to go end to end full balanced XLR, so I may use a different preamp for that.

 

[EddNog]

That's fully balanced as far as I'm concerned.

Probably single-ended for the subwoofer. Mine is fully balanced except the sub also.

-Ed

 

[PJ_Schmidt]

I decided to cave and order the Wiim Ultra to use as a preamp, with room correction, PEQ, and a sub out along with bass management. Hell everything else on there's a bonus as far as I'm concerned I'll run optical out to my DAC and then XLR out to the V3 monos for a [semi] balanced setup.

How are you connecting your subwoofer?

My preamp is a MiniDSP 2x4 HD. This gives me full EQ/correction/levels/crossover and volume control. I'm using optical input. The outputs are unbalanced, but I have no issues with noise or ground loop hum. Currently it sends L-R to my pair of V3 monos and then also a subwoofer out to a Crown XLS1502 amp. I'm planning on using the last output for a second subwoofer. The EQ capability has been huge for getting really good sound out of my setup.

 

[EddNog]

My preamp is a MiniDSP 2x4 HD. This gives me full EQ/correction/levels/crossover and volume control. I'm using optical input. The outputs are unbalanced, but I've got no issues with noise or ground loop hum. Currently it sends L-R to my pair of V3 monos and then also a subwoofer out to a Crown XLS1502 amp. I'm planning on using the last output for a second subwoofer. The EQ capability has been huge for getting really good sound out of my setup.

Agree on digital domain EQ; I use global PEQ on my streaming source as well (HiBy R6 Pro II).

-Ed

 

[Cal_Cobra]

Probably single-ended for the subwoofer. Mine is fully balanced except the sub also.

-Ed

Don't think it matters for the sub if it's just a line level LFE connection.

 

[EddNog]

Don't think it matters for the sub if it's just a line level LFE connection.

I don’t dispute this at all. Just trying to figure out what the other person meant by partially balanced system.

-Ed

 

[renoxd]

I decided to cave and order the Wiim Ultra to use as a preamp, with room correction, PEQ, and a sub out along with bass management. Hell everything else on there's a bonus as far as I'm concerned I'll run optical out to my DAC and then XLR out to the V3 monos for a [semi] balanced setup.

How are you connecting your subwoofer?

I also would be using Wiim Ultra with with 2x V3 monos. I'm wondering if I should keep my DAC DX7 pro with 9038Pro on the board. I don't think I have to. Any reason u want to keep your DAC?

 

[Cal_Cobra]

I don’t dispute this at all. Just trying to figure out what the other person meant by partially balanced system.

-Ed

I just meant that because the WiiM Ultra isn't balanced out of the box, that I could get it half way there with the optical out to a DAC with balanced XLR out. Then there's the inputs, which will be RCA or digital but no native XLR. I suppose one would simply use the digital inputs negating the need for XLR inputs.