Fosi Audio V3 Amplifier Review

[Talisman]

He made an important note to a suspect looking difference and luckily Fosi is transparent and carries out excellent communication and the worries were in vain. But absolutely not unfounded critique. We need to be able to criticize and scrutinize without being burnt by the stake.

And you're bringing in some kind of racist motive as well?!

The post I referred to has been deleted, along with others, including mine.
Adam warned us not to go back to the same controversy, and he's right, so now let's just get back to talking about the Fosi V3

 

[KaeliKoo]

Fosi sells the 48V 5A power supply standalone for $60 on their website, my thinking is it must be quite decent
(they don't seem to be a company chasing high profit margins). I read a review on Amazon where someone
replaced their Aiyama power supply with the Fosi 48V and found it had more "clarity" and sounded much better.

 

[Fosi Audio]

I hint on my TB10D review to use the casing

Yes, we are truly grateful for your excellent suggestion of utilizing the casing as a heatsink. It has proven to be a remarkable solution in enhancing heat dissipation. Thank you for your valuable contribution!

 

[Biagiod]

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.

Excellent test showing REAL behavior of different chips in real-life usage

6db difference is HUGE

Just to make sure since you are talking about SMSL response being jagged compared to Fosi

SMLS -> green
FOSI -> blue

Blue trace seems less jagged than green..

Would be interesting to test as well a class AB amplifier vs class D of FOSI and SMSL. Do you have the chance/availability of running such a test and show comparative results?

Thanks
Marco

 

[brandonhall]

Excellent test showing REAL behavior of different chips in real-life usage

6db difference is HUGE

Just to make sure since you are talking about SMSL response being jagged compared to Fosi

SMLS -> green
FOSI -> blue

Blue trace seems less jagged than green..

Would be interesting to test as well a class AB amplifier vs class D of FOSI and SMSL. Do you have the chance/availability of running such a test and show comparative results?

Thanks
Marco

Fosi is definitely green. I was trying to consider the whole picture when talking about the variations. Some jaggedness is completely expected since this is coming out of a speaker. The waves just appear larger with the SMSL. Of course, that's just how I interpret it and others may see things differently. Similar to reading a stock chart. I may get out my old receiver tomorrow night

 

[375HP2482]

Yes, we are truly grateful for your excellent suggestion of utilizing the casing as a heatsink. It has proven to be a remarkable solution in enhancing heat dissipation. Thank you for your valuable contribution!

Given that hot air rises, it may be a little better to mount the power chip to the top of the case instead of the bottom. Would reduce the temperature inside the case. OTOH there may be considerations of accidental chip access that don't present when the chip is mounted to the bottom; strategic venting may avoid that.

 

[Talisman]

Per me, questa è un'indicazione delle differenze tra il TPA 3255 e il chip Merus nel DA-9.

I hope a ti3255 implementation without load dependency is possible.
The only Infineon measured so far is the topping pa3s, with double 12070, and actually it would seem not to suffer from load dependence, but I don't know if it is due to the chip or the implementation of Topping, other amplifiers with double 12070 like sabaj a 20a , smsl da9 or smsl ao200 weren't measured, so we can't be sure.
The thing we do know is that the 3255 appears to be able to generate much more horsepower than the Infineons, and that's a huge plus. A possible 3255 implementation with its typical power characteristics, with the noise and distortion levels of this V3 and with a filter implementation to minimize load dependence would be the holy grail of budget amplifiers.

 

[JSmith]

Given that hot air rises

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

 

[Alex.san]

Hi all.
At first I ordered Topping PA3s, but the seller, after three days of waiting, told me that the amplifiers would be only in a week. I canceled the order and ordered Fosi V3 32V for my vintage paper three-band Siemens RL171 in bedroom (1972, sensitivity 96+dB, custom tube amplifier is working now, Soviet tubes 6P14P-EV, two-stage amplification (not PP), 2*6W).
The next day, after some thought, I decided to order another Fosi V3 48V for the living room, where I have a Bryston 3B-ST and a Jamo Concert 11 (D870). I feel that little Fosi will put the Bryston monster on both shoulder blades.
Then I decided to order a third Fosi for my cabinet, for the German "I.Q .Trend 1" floor standings (82dB sensitivity due to SEAS passive bass drivers inductively coupled to the VIFA midrange section + SEAS tweeter). Hopefully in two weeks I'll have Fosi family with three V3 amplifiers and make a big comparison!

 

[AdamG]

The post I referred to has been deleted, along with others, including mine.
Adam warned us not to go back to the same controversy, and he's right, so now let's just get back to talking about the Fosi V3

Good call Sir. Those that could not contain themselves were given a helping hand. Multiple Warnings issued, posts deleted and permanent reply bans handed out. We tried the nice way first.

This is the final warning to move on from this false narrative about counterfeit parts. Any further comments about this will earn the posters a Forum Ban. All Stop!

Thank you for your cooperation and support.

 

[TheBatsEar]

B&Ws CDM2

awfully bright top

The ferrofluid might have dried out and what you hear are undampened resonances.

 

[Lux_ury]

I have heard about speaker with the fluid in the drivers but that was another brand that suffered with this. All I know is the metal tweeters of that time all had bright top ends. Not even sure how to refluidise them tbf.Its the same with my AR98s harsh top end, but with a Dac they sound more balance. On another note i do like the A07 with the cdm2 regardless of performance I still prefer decent 3 ways speakers as mids are usually missing on old Bookshelf Speakers which coming back really want to use the v3 for comparison.(Smile emoji)

The ferrofluid might have dried out and what you hear are undampened resonances.

 

[ClassicGuy]

Are Fosi's 32V power supply identical to Aiyima's 32V power supply? They look very similar.

 

[Lux_ury]

Are Fosi's 32V power supply identical to Aiyima's 32V power supply? They look very similar.

This is my A07s 32v different manufacturing on outside input lead in middle fosi one to the side.

 

[TheBatsEar]

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.




Comparison with a Aiyima 07 with 32v power supply. The power supplies are interchangeable:



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.

 

[LeeRoy]

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
View attachment 295589View attachment 295592
View attachment 295591

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.

I had Linton and found them find, curious to see the outcome of your measures.

 

[Ron Texas]

I'm glad that I missed the kerfuffle.

 

[TheBatsEar]

I'm glad that I missed the kerfuffle.

Either @AdamG247 deleted faster than light or there wasn't much of a kerfuffle.
Most dramatic thing was me, playing songs of hurt feelings and eternal pain in the background, on this instrument:

I had Linton and found them find, curious to see the outcome of your measures.

I also have a pair of Mission LX-3 MKII and a pair of Canton Plus GXL.3, both measured by @amirm. That gives us at least three speakers with known impedance curves.

 

[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