Fosi Audio V3 Mono Amplifier Review

[Nahkarankaisija]

Thinking about these since my Sabaj A30a purchase didn't pan out, I don't really need that many watts ( very efficient DIY 3-way speakers) but the PFFB and the pricing is tempting me. Would I need a RCA-splitter to connect the 2 monoblocks to my SMSL SU-6 DAC?

 

[Talisman]

Thinking about these since my Sabaj A30a purchase didn't pan out, I don't really need that many watts ( very efficient DIY 3-way speakers) but the PFFB and the pricing is tempting me. Would I need a RCA-splitter to connect the 2 monoblocks to my SMSL SU-6 DAC?

Of course not, they are monoblocks, each one has only one channel, therefore only one RCA cable

 

[Nahkarankaisija]

Of course not, they are monoblocks, each one has only one channel, therefore only one RCA cable

You are correct, now that I thought about it properly I can just connect the monoblocks to the R-L RCA channels of the DAC, should not ask such stupid questions in the morning. Order placed for 2xMono V3 with 2x 48/5V PSU.

 

[Psinet]

FYI, you may already have seen this, but Fosi has this to say regarding the amps performance with the different power supplies:

Based on our measurement, using a 48V/10A power supply does not significantly increase power output compared to a 48V/5A power supply. Other parameters, such as signal-to-noise ratio, THD, and frequency response, are also virtually identical. Therefore, there is no noticeable difference between the two options in terms of your user experience. We are offering this one-to-two power configuration option for more flexible system building. Of course, by using one less power supply unit, you can save space and achieve a neater system setup.

$20 bet: One of these amps on a single 48v 5A power supply provided by FOSI, will score a higher power rating at >1% distortion and 2 Ohms on a dyno, than it does when two are connected to the 48v "10A(Max)" power supply provided by FOSI (also, it will have a lower noise floor).

 

[Sokel]

$20 bet: One of these amps on a single 48v 5A power supply provided by FOSI, will score a higher power rating at >1% distortion and 2 Ohms on a dyno, than it does when two are connected to the 48v "10A(Max)" power supply provided by FOSI (also, it will have a lower noise floor).

No doubt if the 10A one is 6.3A after all as suspected by some previous posts.

 

[Talisman]

No doubt if the 10A one is 6.3A after all as suspected by some previous posts.

I'm still waiting for @Fosi Audio 's response on this matter, if so I think it would be correct to allow those who chose the option with only 48V 10A to be able to have the combo with double 48V 5A instead

 

[Psinet]

I'm still waiting for @Fosi Audio 's response on this matter, if so I think it would be correct to allow those who chose the option with only 48V 10A to be able to have the combo with double 48V 5A instead

They are already pretty cheap. And it is a bit nit-picky - but it matters to me, because I like to run 8-ish Ohm industrially built DIY "audiophile" two-way bookshelf speakers, and big-a** 2-ish Ohm subwoofer, all nicely crossed over - at too loud volumes. Without distortion. Very efficiently. Because I also run them off batteries. When camping.

Also, I am insane.

*Edit: To be fair to me, listening to audiophile quality sound systems outdoors without any physical walls or sonic reflections, in the middle of nowhere, under a starry sky, is other-worldly.

*Edit edit: Do not try this with your McIntosh/Musical Fidelity/Luxman/Denafrips amplifiers. Fosi Audio is fine.

 

[Talisman]

They are already pretty cheap. And it is a bit nit-picky - but it matters to me, because I like to run 8-ish Ohm industrially built DIY "audiophile" two-way bookshelf speakers, and big-a** 2-ish Ohm subwoofer, all nicely crossed over - at too loud volumes. Without distortion. Very efficiently. Because I also run them off batteries. When camping.

Also, I am insane.

*Edit: To be fair to me, listening to audiophile quality sound systems outdoors without any physical walls or sonic reflections, in the middle of nowhere, under a starry sky, is other-worldly.

*Edit edit: Do not try this with your McIntosh/Musical Fidelity/Luxman/Denafrips amplifiers. Fosi Audio is fine.

I wouldn't make it a question of fussiness but of correctness, if it declares a value of 48V 10A I trust the company but if it were instead a disguised 6.3A I would be very disappointed for a question of transparency.
The product is cheap and very good, but the reason why I finance Fosi projects (and for example non-topping which has potentially even better products at very close prices) is because they have often demonstrated correctness and desire to collaborate with users as well as attention to criticism and customer care (as opposed to Topping)
For this reason it is very important for me to understand what they are actually providing

 

[Psinet]

I wouldn't make it a question of fussiness but of correctness, if it declares a value of 48V 10A I trust the company but if it were instead a disguised 6.3A I would be very disappointed for a question of transparency.
The product is cheap and very good, but the reason why I finance Fosi projects (and for example non-topping which has potentially even better products at very close prices) is because they have often demonstrated correctness and desire to collaborate with users as well as attention to criticism and customer care (as opposed to Topping)
For this reason it is very important for me to understand what they are actually providing

It does say "10A(MAX)". But to steel-man your position - if it can reach 10A even for 10ms I will eat a Fosi Audio monoblock and stream it.

 

[antcollinet]

It does say "10A(MAX)". But to steel-man your position - if it can reach 10A even for 10ms I will eat a Fosi Audio monoblock and stream it.

You'd better get your streamer ready.

If the limit is purely thermal, then it can probably output significantly more than rated power for a significant time.

 

[Psinet]

You'd better get your steamer ready.

If the limit is purely thermal, then it can probably output significantly more than rated power for a significant time.

Depends on the regulation, but such a device simply cannot deal with the thermal load of a 480w output.

 

[drmevo]

I wouldn't make it a question of fussiness but of correctness, if it declares a value of 48V 10A I trust the company but if it were instead a disguised 6.3A I would be very disappointed for a question of transparency.
The product is cheap and very good, but the reason why I finance Fosi projects (and for example non-topping which has potentially even better products at very close prices) is because they have often demonstrated correctness and desire to collaborate with users as well as attention to criticism and customer care (as opposed to Topping)
For this reason it is very important for me to understand what they are actually providing

Agreed. If we're paying essentially double for a 10A vs. 5A then the power of the 10A should match 2x5A. That may be the case here, hopefully @Fosi Audio chimes in soon to confirm.

Also, regarding my previous comment wondering why testing here didn't indicate the same discrepancy, I just realized Amir was provided with a single 5A power supply (and I suppose just one amp?), so the 10A supply was not tested.

 

[SMen]

Agreed. If we're paying essentially double for a 10A vs. 5A then the power of the 10A should match 2x5A. That may be the case here, hopefully @Fosi Audio chimes in soon to confirm.

Also, regarding my previous comment wondering why testing here didn't indicate the same discrepancy, I just realized Amir was provided with a single 5A power supply (and I suppose just one amp?), so the 10A supply was not tested.

Good point.

The difference between the two seems to be
116 / 111 watts into 8ohm at 1% vs 122 watts in Amirm's test
224 and 217 watts into 4ohm at 1% vs 236 watts in Amirm's test. I guessing the 0 resistive is the correct comparison.
and 255 and 239 watts int 2ohm at 1% vs 348 watts " " ".

So this might explain why one early user was reporting it shutting off into his bass speaker. And actually someone with a difficult load would need to know this to have made an informed choice. So hopefully those users will indeed be able to switch to the 2x5A option. Or @Fosi Audio can say if the power supplies distributed in June are 10A for sure

 

[oldloder]

There’s no reason not to include it other than cost so long as there is a bypass for people who don’t have a need/run a subwoofer. Although I would personally use that feature for sure. I eyed Emotiva BasX PT2 and Parasound NewClassic 200 preamps with bass management for a long time seriously considering buying one of them because of the bass management features but part of the reason I passed on them is a refusal to give up balanced interconnects.

Frankly if either of them had balanced inputs and outputs, I’d already have bought it. Unfortunately, neither of them do.

This is a good opportunity for Fosi for market-making for sure, a BALANCED preamp WITH bass management for a reasonable price would be truly killer and have basically zero competition anywhere at or under $1,000.

-Ed

Have you seen the Parasound P5?

 

[Toasted]

Would my X3500H be a suitable pre-amp for use with these Fosi V3's?

 

[EddNog]

Have you seen the Parasound P5?

Looks like it was replaced by P6. Looking at the manual for P6, the high-pass crossover does work on balanced output and the low-pass crossover will work also as long as subwoofer is kept as monoraul. This is pretty good! Too bad I’ve already settled in quite happily with my current preamp.

-Ed

 

[EddNog]

Would my X3500H be a suitable pre-amp for use with these Fosi V3's?

Looking at the back of the Denon AVR-X3500H, it has line level (Pre) outputs for all channels, so yes, it should work as a preamp for V3 Monos.

-Ed

 

[rvsixer]

Have you seen the Parasound P5?

The P5 has analog high/low pass crossovers. However most would consider true bass management to include delays at the very very least as well. Fortunately miniDSP already has ~$1K USD and under market for such types of preamps covered (all with comprehensive bass management solutions), but it would be nice to have competition like Fosi step in.

 

[oldloder]

Looks like it was replace by P6. Looking at the manual for P6, the high-pass crossover does work on balanced output and the low-pass crossover will work also as long as subwoofer is kept as monoraul. This is pretty good! Too bad I’ve already settled in quite happily with my current preamp.

-Ed

I was looking at the Emo's as well and stumbled on a mint used P5 for $500 ... I was surprised at the similarities and when I saw the XLR connectivity was ... well, I wished I had the cash. Glad you found something you're happy with. I'm looking forward to what Fosi comes up with too.

 

[jdg78]

Quick question for those that may have more technical/engineering knowledge than me...

For the past couple of years I've been using an Aiyima A07 essentially as a power amp to run the main L and R speakers in my home theater setup, using my HT receiver as a preamp to control volume, etc. I keep volume knob of the A07 set at around 75% of total output, and this gets my speakers as loud as I would want to hear them without any obvious distortion, noise, etc.

Given that these new Fosi V3 monoblocks are based around the same amp chip, would there be any audible benefit to swapping out my A07 with a pair of these (increased punchiness, better channel separation, etc)? A higher SINAD score and/or power output is meaningless to me unless it actually translates into audibly better sound at low to moderate listening levels.

One practical consideration that does attract me to the V3 monoblocks is the inclusion of a standby mode, but I'm not sure if this alone would justify making the switch.