Fosi Audio V3 Amplifier Review

[Guddu]

Yup.. Too bad I read their blatant lies, and believed them, when I ordered. heh

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fosiaudioshop.com

Amazon is a safe bet, may be next time!
Thanks for sharing your experience.

 

[Fosi Audio]

I'd be interested in @Fosi Audio opinion about the bass response at low volumes, whether the Frequency Response should be affected by that...

We just confirmed with our R&D team, the frequency response curves are the same under various volume levels.

 

[Stretch2002]

Hi all!

Quick review of V3

First i tried with 48V PSU and amp is clearly overheating!! About 50-60 degrees around whole enclosure. Could be something wrong with PSU (looks like original, but without Fosi inscription)? Then i hooked 32V and temperature dropped almost on ambient temperature around 25 degrees, but sound degraded- much of low listening volume bass was gone, amp lost grip. Boxes are Wharfedale Denton 80, 6 ohm, 86db eff.
So for 100 EUR good amp without sterile class d sound but overheating is clearly issue here. I had similar class d amp Nuforce Icon which is much better sounding and also stone cold in operation.

Hi Mutolay

The whole enclosure is designed to be a heat sink, so the case will heat up by design. 50-60C sounds warm, but may not be abnormal operation for your room's ambient temp and the airflow around the amp. The only way for it to be 'clearly overheating' is if the amp goes into protection mode.

There's a youtube test that found that in their testing their V3 sample went into temp protection at about 66 celsius (see from 8:25):

Waiting for mine to be delivered!
Cheers!

 

[-Jim-]

Hi Mutolay

The whole enclosure is designed to be a heat sink, so the case will heat up by design. 50-60C sounds warm, but may not be abnormal operation for your room's ambient temp and the airflow around the amp. The only way for it to be 'clearly overheating' is if the amp goes into protection mode.

There's a youtube test that found that in their testing their V3 sample went into temp protection at about 66 celsius (see from 8:25):

Waiting for mine to be delivered!
Cheers!

The standard allowable temperature rise most electronics comply to is 40°C above ambient. Ambient is defined as 20°C. So having protection trip near 66°C is prudent.

 

[-Jim-]

I made a comment on the Fosi "The Story Behind Fosi Audio V3 Amplifier" YouTube video about the pre-out and they replied:

"Thank you for your advice. Our team had revised the pre-out port and it will behave like a real pre-out. This revised version will be available in the fourth quarter of the year."

So if this is important to you, I'd hold off until then! Enjoy.

 

[TheBatsEar]

Our team had revised the pre-out port and it will behave like a real pre-out. This revised version will be available in the fourth quarter of the year.

Once again i bought beta hardware.

 

[Zek]

Once again i bought beta hardware.

No, you're actually a beta tester...

 

[Djano]

We just confirmed with our R&D team, the frequency response curves are the same under various volume levels.

Of course, the frequency response was not tuned to lower the bass when high volume is used.

But the design struggles with 45-145Hz when pushed to its limits.

I insist that this seems to be a "worst case scenario". Only 6% of ASR members listen at more than 90dB (see this poll). So this 100dB test is not likely to show what will happen in a real use case, with reasonable listening level.
Everything should be OK at reasonable levels.

A probable explanation is clipping, which is more likely to occur in lower frequency, as shown in Amir's graph

 

[VintageFlanker]

We just confirmed with our R&D team, the frequency response curves are the same under various volume levels.

But certainly not under complex/speaker loads.

 

[Mordor]

I also have this "feeling" sometimes on low volumes there isnt "body" to the sound....can`t explain well.....maybe is my impression.....

 

[Djano]

I also have this "feeling" sometimes on low volumes there isnt "body" to the sound....can`t explain well.....maybe is my impression.....

You should not see any problem at low volume. The issue I show likely only exists when the amp is pushed to its limit, as it is caused by clipping

 

[Matias]

I also have this "feeling" sometimes on low volumes there isnt "body" to the sound....can`t explain well.....maybe is my impression.....

Equal-loudness contour - Wikipedia

en.wikipedia.org

 

[Djano]

Equal-loudness contour - Wikipedia

en.wikipedia.org

Yes, I didn't even think about this...
Loudness function is so neat for that reason
Or just use a preset in equalizer apo to make low and high more prevalent

 

[Valvetubehead]

Yes, I didn't even think about this...
Loudness function is so neat for that reason
Or just use a preset in equalizer apo to make low and high more prevalent

Sourcery and switchcraft

 

[Joe Smith]

I'm currently using mine with a Nikko Beta 20 preamp, and can punch up bass and treble slightly at low volumes. It lets me run the Fosi volume at about the 3 o'clock volume level and "dial in" the level I want using the stepped volume control on the Nikko. With the 32v power brick, this gives me a very high amount of volume control, important for this setup as the speakers are pretty close to the space we use for board games, reading etc. No doubt I'm adding some noise into the chain by using an older preamp but that's OK for this purpose.

 

[Djano]

I'm currently using mine with a Nikko Beta 20 preamp, and can punch up bass and treble slightly at low volumes. It lets me run the Fosi volume at about the 3 o'clock volume level and "dial in" the level I want using the stepped volume control on the Nikko. With the 32v power brick, this gives me a very high amount of volume control, important for this setup as the speakers are pretty close to the space we use for board games, reading etc. No doubt I'm adding some noise into the chain by using an older preamp but that's OK for this purpose.

I also think that added noise is worth it considering the features (as tone control) you can get with the preamp.
If you want a new preamp for cheap, Fosi released the SK01. I did not measure it (lack of equipment and knowledge), but can guarantee its functions are numerous and good !
You have tone control, loudness mode, and adjustable gain. I talked about it here, but people seem to not be interested in this device.

 

[Joe Smith]

I also think that added noise is worth it considering the features (as tone control) you can get with the preamp.
If you want a new preamp for cheap, Fosi released the SK01. I did not measure it (lack of equipment and knowledge), but can guarantee its functions are numerous and good !
You have tone control, loudness mode, and adjustable gain. I talked about it here, but people seem to not be interested in this device.

Yeah, I noticed this. Oddly, I don't think that is even on their website yet? I've been accepted into Fosi's testing group but this was not one of the things they offered to send me.

I'm hoping the functionality of this headphone amp that you note is something they could carry into a similar product that would be a preamp to match with the V3 form factor. Maybe just as a high-function equalizer. Having the old style "loudness" button is pretty great. Ideally, I keep hoping Fosi will do V3 style monoblocks (internal power, no volume control) and a matching preamp/equalizer to mate with it...all solid state...

 

[Djano]

Yeah, I noticed this. Oddly, I don't think that is even on their website yet? I've been accepted into Fosi's testing group but this was not one of the things they offered to send me.

It is on their website for sure! You can also find it on eBay (Fosi/neohipo) or Aliexpress (best price, in France at least)
I would also like to be in this group. They are by far my favorite Chi-Fi budget brand. Lucky you!

I'm hoping the functionality of this headphone amp that you note is something they could carry into a similar product that would be a preamp to match with the V3 form factor. Maybe just as a high-function equalizer. Having the old style "loudness" button is pretty great. Ideally, I keep hoping Fosi will do V3 style monoblocks (internal power, no volume control) and a matching preamp/equalizer to mate with it...all solid state...

I like the SK01 form factor a lot, but can understand you would prefer to be able to stack it. I think i read that a V3 monoblock was being worked on. They provided three pictures of different designs. Maybe in this thread ? I don't remember well...

 

[Jeromeof]

Yes the SK01 looks interesting a "middle ground" headphone Pre-amp DAC , it is both "portable" with a battery (yet looks a little bit too big e.g. compared with a Qudelix 5K etc) and so might be better suited to desktop setup, but in that space I think measurements would be key to understanding how good it is, there is lots of competition. Still might have a separate niche.

 

[Djano]

Yes the SK01 looks interesting a "middle ground" headphone Pre-amp DAC , it is both "portable" with a battery (yet looks a little bit too big e.g. compared with a Qudelix 5K etc_ and so might be better suited to desktop setup, but in that space I think measurements would be key to understanding how good it is, there is lots of competition. Still might have a separate niche.

I don't think it is portable at all. It is too bulky, and too heavy. Battery should never have been included, in my opinion. But this is purely subjective, some might find the form factor OK for on the go use.

Beware, it is not a DAC. USB is only used for power. It takes analog 3.5mm jack input.

To me, there is no competition, but I might ignore the existence of some similar products. Who else does cheap a 3 band tone control and loudness function ?

If you want to talk more about it, maybe we should do so in the SK01 thread, to keep this one focused on the V3