Fosi Audio V3 Mono Amplifier Review

[bracko]

How did you do the comparison, if you ensured its truly (not just levelled matched) done in apples to apples way, even in a single blind test you would not likely be able to tell them apart. If you did it sighted, all bets are off. In theory, having the preamp inserted would add THD+N, though the difference should be negligible.

No, unfortunately I didn't do it blind. Even 8300CDQ is a preamplifier so I guess even that component would add THD.

 

[peng]

No, unfortunately I didn't do it blind. Even 8300CDQ is a preamplifier so I guess even that component would add THD.

Yes but adding the preamp will add more THD+N, that’s for sure assuming you connected the CDQ’s line output to the preamp’s analog input.

 

[bracko]

Yes but adding the preamp will add more THD+N, that’s for sure assuming you connected the CDQ’s line output to the preamp’s analog input.

In any case I am not sure if it is my imagination or something else. A proper way would probably be to do a blind test.

 

[Miser_Audioman]

Mine just keep going despite the pointless op amp swap.

 

[ICIETDIYEUR]

Hi.

Look at this ->

 

[stuartkohl]

Hi.

Look at this ->

Could you please at least summarize the content from the video for us, or offer us your own thoughts instead of just linking to some random youtube video? I want to know what you're thinking, not what XYZ Youtuber is thinking.

 

[whazzup]

Hi.

Look at this ->

The case just isn't big enough to dissipate the heat without getting hot.

Physics sucks.
Sure, it's a tone test and not regular music, but man, more than 80°C on the casing is still crazy~

 

[whazzup]

Could you please at least summarize the content from the video for us, or offer us your own thoughts instead of just linking to some random youtube video? I want to know what you're thinking, not what XYZ Youtuber is thinking.

I don't understand why someone needs to do that? Is that a written rule in ASR? Wasn't the title of the video clear enough?

 

[YouDontHaveEnoughBass]

Seems largely unnecessary; music is a much lighter load than a continuous 100W sine wave and you’ll either achieve good enough cooling stock (which mine do with my usage) or with a simple external fan on low rpm

If you’re somehow putting so many continuous watts through the thing that even that isn’t good enough you’re probably best served getting a different amp

 

[Dave TR3A]

I don't understand why someone needs to do that? Is that a written rule in ASR? Wasn't the title of the video clear enough?

I'm with @stuartkohl on this. If the OP wanted to encourage forum members to watch a nearly hour-long video he should explain why.

The video was nearly an hour long and is not edited for either brevity or clarity. The presenter rambles. The whole hour-long video could've been adequately summarized in a few paragraphs.

Also, the presenter (Eddie Aho) gets mixed reviews (e.g., on EEVblog) because of testing oversights and poor procedure.

 

[whazzup]

I'm with @stuartkohl on this. If the OP wanted to encourage forum members to watch a nearly hour-long video he should explain why.

The video was nearly an hour long and is not edited for either brevity or clarity. The presenter rambles. The whole hour-long video could've been adequately summarized in a few paragraphs.

Also, the presenter (Eddie Aho) gets mixed reviews (e.g., on EEVblog) because of testing oversights and poor procedure.

I agree it doesn't look to be properly edited. And the guy himself admitted that he took a long time to edit the video. But that's what the seek function is for. I guess I don't take it for granted that someone owes me something and must summarize things for me on a public forum.

 

[Dave TR3A]

I agree it doesn't look to be properly edited. And the guy himself admitted that he took a long time to edit the video. But that's what the seek function is for. I guess I don't take it for granted that someone owes me something and must summarize things for me on a public forum.

We're approaching this from opposite ends. I don't think I should devote (perhaps waste) an hour of my time just because someone says "look at this".

I think that posters should respect the value of the audience's time. Doing otherwise seems -- to me -- lazy and disrespectful in that the poster seems to value his time far more than that of the audience he wanted to alert.

 

[NTK]

I don't understand why someone needs to do that? Is that a written rule in ASR? Wasn't the title of the video clear enough?

Yes. It is a forum rule.

Also, see:

Notification about “External YouTube Video Link Dropping”

Forum Wide Notification: NOTE: The updated version of this policy is posted in the site Terms and Rules See the above before posting any comments or reporting. ====== below is maintained for reference ====== We are strongly discouraging random YouTube and similar “Video links” being posted...

www.audiosciencereview.com

 

[whazzup]

Yes. It is a forum rule.
View attachment 555352

Also, see:

Notification about “External YouTube Video Link Dropping”

Forum Wide Notification: NOTE: The updated version of this policy is posted in the site Terms and Rules See the above before posting any comments or reporting. ====== below is maintained for reference ====== We are strongly discouraging random YouTube and similar “Video links” being posted...

www.audiosciencereview.com

Ok, thanks I stand corrected.

 

[stuartkohl]

I agree it doesn't look to be properly edited. And the guy himself admitted that he took a long time to edit the video. But that's what the seek function is for. I guess I don't take it for granted that someone owes me something and must summarize things for me on a public forum.

I don't so much need it to be summarized for me as to let me know why I should leave ASR and watch a video on youtube. I also meant what I said as far as wanting to hear what my fellow ASRians think. I'm here because of what people here write and post, not for links to youtube videos. I can find stuff on youtube myself thank you very much.


I also wasn't aware that it was a forum rule. Thank you @NTK for pointing that out.

 

[ICIETDIYEUR]

Hi.

It is true that this video is rather hard to digest and should have been summarized, so excuse me

I highlighted it simply to emphasize the importance of the supply voltage used with TPA3255-based chips, as they generate a great deal of heat—even at idle.

I will also focus on the importance of the enclosure's volume and material (including thickness), as well as the care taken in selecting the heat dissipation method.

We worked extensively on this aspect with Alexander Lin (O-NOORUS) for the D3 Pro model; here is the principle that was used ->

You will note that the heatsink covers almost the entire surface of the PCB; while it would have been preferable for it to be in full contact with the amplifier casing—which itself could benefit from being slightly larger and made of thicker material—cost constraints are tight in order to keep the product within a price range acceptable to consumers.

I do not claim that this is the ultimate solution or approach, but rather one that should be explored for future refinement—aiming for even greater efficiency—by the various manufacturers of Class D amplifiers using Texas Instruments power chips (in this case, the TPA3255).

Furthermore, based on my extensive testing, I maintain that a 42V power supply voltage offers the best compromise between heat dissipation at idle and available power for driving speakers, whether 4-ohm or 8-ohm models.

I think it would be interesting to hear FOSI's perspective on this, as well as that of other manufacturers and technicians with solid DIY experience regarding this type of amplifier.

Of course, I am not overlooking—since it is the most important factor—user feedback regarding the heat generated by (or felt on) the amplifier's casing, the acceptable size for the unit, and the available power output.

Design ideas would also be welcome, and who knows—perhaps we will soon discover an amplifier that meets all these criteria

 

[bracko]

At the end I decided to return my Fosi V3 Monos. I got a 3E Audio A7 instead and I am happy so far. It is much cooler, can be used as an integrated amplifier and hopefully has better reliability.

 

[wilcaz]

I got a pair of these +ZD3 and while the sound is fine the heat is bloody ridiculous. Is it safe to run these without fans? I even left them in standby mode overnight and they were still pretty warm in the morning.

 

[MajorTom]

It's been almost one year with the v3 monos. Nothing to complain about. They drive my floorstand speakers very well. And yes, they run hot, at least with the 48V psu. So I've just add the fosi fan (15euros), it works in silence and the fosi are not warm any more. (I add a same fan on my internet box too because it was as hot as the v3s!) . I barely use the standby mode, as I prefer switch off my stuff when not using them.
Anyway, fosi v3 monos are one of my best bargain ever

 

[Mirus100]

Is there any visual marking on the packaging (shipping box) of the Fosi Audio V3 mono amplifier that would inform me of the version?
Older - Gain 31dB-25dB
Newer - Gain 25dB-19dB