Fosi Audio V3 Amplifier Review

[ddaudio]

Hi Amir,

Maybe add 16 and 32 ohm FR plots, as real world speakers can often go there in the treble?

Don't know if this got lost in the flurry - thoughts, @amirm ?

 

[Krusty09]

Amazon is having a sale I think on this amp. Use the code.

FAV3MKT12

 

[mccririck]

I have the SMSL DA-9 and I'm a complete nerd, so I did some measurement comparisons with Fosi Audio V3.

Setup:

1. Speakers right next to each other
2. UMIK-1 positioned one inch out from each speaker
3. Microphone was positioned between the woofer and tweeter of my ELAC Carina's (strongly recommended!)
4. Level matched using REW "Check Levels" feature. About 90% on the Fosi dial and 52 on the DA-9.
5. Did the listening tests
6. REW ran on each speaker

This is the full picture (20/20k) with 1/48 smoothing. The DA-9 is in green and the Fosi Audio v3:

View attachment 295540

Notice how jagged the SMSL is compared to the Fosi and look at the high frequency boost starting around 16k. We're looking at 6 DB difference from peak to trough. To me, this is an indication of the differences of the TPA 3255 vs the Merus chip in the DA-9.

Zooming in a bit without smoothing applied. This is between 14k and 18k:

View attachment 295542

This really shows the differences in the chips and therefore the amps. The SMSL has wild swings while the Fosi is just drifting down.

Zooming into 20-1k they are basically the same:

View attachment 295544

I would call this run to run variation because they are very close.

Lastly, 1k-5k with 1/48 smoothing applied:

View attachment 295545

They are basically the same but the Fosi seems more well-behaved.

Listening Tests:

I did the listening before the measuring, so I wasn't biased in any way. They were extraordinarily similar but the SMSL was a bit more airy at the top end. To me, it sounded artificial after hearing the Fosi right before or after. It wasn't bad, offensive, or a deal breaker in any way, but there was a minor difference. Ha, I was glad to see the measurements reported the same. I still hear pretty well up to 15k. Bottom line: they are both great units but I think we see the real-world implications of the old Merus chip in the DA-9 vs a top-notch implementation of the TPA 3255 in the measurements and listening tests.

Did you mean the DA-9 is in blue?

 

[brandonhall]

Yes. I'll update the post.

 

[strawberry644]

wondering if anyone tried this DROK 48V 10A SMPS on they're fosi v3, hoping to maybe have more peak power over my 48v 7amp

 

[PiobGuy]

wondering if anyone tried this DROK 48V 10A SMPS on they're fosi v3, hoping to maybe have more peak power over my 48v 7amp

I think you might find that it is more than just a little bit noisy.

 

[maimai]

Got mine.
The box mirrors the price. The foam in the box could have been made from cardboard for environmental reasons. No need to paint the box black either.

The volume knob is fine, but if you want to buy one anyway, the potentiometer shaft is 6mm and it's not a D shape, but round.
View attachment 295590View attachment 295588
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Comparison with a Aiyima 07 with 32v power supply. The power supplies are interchangeable:
View attachment 295593View attachment 295594View attachment 295595
View attachment 295596View attachment 295597

I'll measure the frequency response of a pair of Linton 85 and ATC SCM19v2 at the weekend, compared with a Yamaha A-S301 and A-S1200. I wonder what we will find.

Curious about the measurement results of V3--ATC19V2
I hope the weekend will come soon

 

[dfgoiuj]

operationally that would be weird as you use the knob to set your desired volume and you leave it like that

but then you cant turn it off and so you might add a smart power board with some way to trigger it on via wifi but then does it THUMP on start that way???

or do you just leave it on 24/7? I would do that given they use so little power anyway

I'll experiment with a smart plug, but I think I'll likely just end up leaving it switched on unless I'm tinkering with it, in which case I could just unplug it anyway I guess.

 

[TonyJZX]

i'd like to hear how people go with 'min maxing' ie. the V3 and expensive speakers... i consider $1,500 Lintons to be expensive

normally outside of this place a $100 amp + $1,500 speakers isnt a good match but really... i think it should be fine given what we know about the V3.

 

[ddaudio]

i'd like to hear how people go with 'min maxing' ie. the V3 and expensive speakers... i consider $1,500 Lintons to be expensive

normally outside of this place a $100 amp + $1,500 speakers isnt a good match but really... i think it should be fine given what we know about the V3.

I think there's more dependency on the speaker's sensitivity and impedance characteristics than price. I'm using the Fosi's lesser cousin, the Aiyima A07 very happily with my speakers which cost more than that over 20 years ago.

 

[TheBatsEar]

min maxing

I see that all the time, usually used by younger folk, explain what that means to this ESL guy.

i consider $1,500 Lintons to be expensive

So do i, but you can get them for far less, then their value can be considered fair. I got them used at 650€ with stands, a price i would call bonkers.
Anyway, the V3 and A07 have distortion far below that of the speakers at regular listening volume, they have enough power too, so why not.

I think it almost always makes more sense to put more money into speakers than into amps.

 

[Ron Texas]

How does one define "expensive"? If $1500 is expensive, what is the cut off point for not expensive?

 

[TonyJZX]

well you're trying to maximise the performance for minimum cost with other higher cost components like speakers

there's a guy here who is using a V3 on KEF Reference 5s? that absolutely stretching things to the max

to my sensibilites i wouldnt using a Yamaha 701/801 with a set of Lintons. I mean you can and it would fine but I'd spend more on the amp.

 

[Lux_ury]

How does one define "expensive"? If $1500 is expensive, what is the cut off point for not expensive?

In my day if your hifi cost more than your car, your in trouble one way or the other. Laugh emoji

 

[TheBatsEar]

maximise the performance for minimum cost

That doesn't make sense to me, you can't optimize for both.
Either you maximize performance for a target cost, or you minimize cost for a target performance.

 

[Ron Texas]

In my day if your hifi cost more than your car, your in trouble one way or the other. Laugh emoji

That would be a lot of money. The average cost of a new car in the US is just under $50k. Maybe around half of that for a used one.

 

[375HP2482]

Hot air rises via convection... not necessarily heat which can spread in all directions. Here the heat is dissipated through thermal radiation via conduction into the case which acts as a heatsink itself.


JSmith

You have the conducted heat on the bottom of the case. Some of that heat is (slowly) transferred to the constrained amount of air below the case, with minimal convection. It follows that the cooler, non-trapped air above the case will dissipate more readily.

There is a website measuring case temperatures versus power levels. It would be a quick and easy test to simply flip the case upside down and take the measurements again.

 

[ampguy]

I think this Fosi V3 may be the best deal under $200 or so. We haven't seen the SMSL AO200 which is reportedly 2 ohm stable, and has balanced inputs measured here, nor the SMSL A300 which is bridgeable. Those latter 2 have no known (to me) reliability issues and are both in the $200 range. Curious why they haven't been measured here, they are likely high performing bargain amps.

 

[mccririck]

I think this Fosi V3 may be the best deal under $200 or so. We haven't seen the SMSL AO200 which is reportedly 2 ohm stable, and has balanced inputs measured here, nor the SMSL A300 which is bridgeable. Those latter 2 have no known (to me) reliability issues and are both in the $200 range. Curious why they haven't been measured here, they are likely high performing bargain amps.

Fosi V3 might be best under $300 tbh. The 48V power supply gives it extra punch.

 

[ampguy]

Fosi V3 might be best under $300 tbh. The 48V power supply gives it extra punch.

I guest "best" needs to be qualified. It's not 2 ohm stable, it's not bridgeable. It doesn't have balanced inputs. So for folks wanting those features, available well under $300, it wouldn't be better.