Fosi Audio V3 Mono Amplifier Review

[antcollinet]

Thanks for the clarification. I've come across audio equipment that inverts polarity for decades. In the case of the V3 Mono, it is an issue in my intended application in that I will be using them to drive woofers in a large, multi-way DIY speaker in conjunction with different amplifiers driving other drivers in the speaker, and crossing over to a subwoofer below the frequencies those woofers will be handling. In such an instance, I would have observed the polarity reversal in tests and simply swapped wires accordingly, no big deal. Still, it's nice to know what to expect ahead of time. I've actually seen a few manufacturers' product information/specifications sheets indicate whether or not a device inverts polarity. Usually you're left to discover it on your own. Looking forward to my four V3 Monos arriving in a few days time!

Did you mean to reply to me?

 

[DavidMcRoy]

Did you mean to reply to me?

Sorry, I convoluted Fosi Audio's quote which was within your post!

 

[Borland]

I really wouldn't worry. Amps give off heat, it's one of their charms. Fosi has posted a video on the V3 monos and they point out that the entire case is a heat sink and it's going to be warm to touch. Not a problem and a good sized heat sink is a wonderful thing.

At room temperature 24 degrees (C):

After 3 hours (background music, German = Zimmerlautstärke) 45 degrees on the surface with the door of the lowboard closed. The lowboard has active ventilation.

After a further 2 hours 42 degrees with the lowboard door open.

This looks different in the video.

I will now try passive cooling of the V3 monos.

 

[EJK]

Looks like I had some movement since getting tracking info on July 11th. It is at the airport in China. Doesn't look like 1 to 2 weeks to receive the amps.

 

[Endibol]

See this paper

E-library page - AES

AES E-Library ← Back to search

aes2.org

and this article in Audio (Dec 1993 issue) by the same authors.

https://acmebass.com/archive_files/mag_articles/audio_magazine/polarity_quest_for_audibility_12-1993.pdf

Thanks a lot for these links, very interesting. It shows that it’s worthwhile to keep absolute polarity intact in the entire recording- processing-playback chain.

 

[Nopiano]

Thanks a lot for these links, very interesting. It shows that it’s worthwhile to keep absolute polarity intact in the entire recording- processing-playback chain.

I think in practice that’s well nigh impossible if you use LPs, radio or streaming as there’s no easy way to know how the source was recorded.

Some years ago I had a Meridian CD player-preamp with a polarity switch, and best of all it worked from the remote. But after a few trials, although I could hear a minute change, it was nigh on impossible to express a preference, so in the end I rarely touched it.

There used to be tables of absolute phase used by popular record labels, and these are probably just a Google away.

 

[gwing]

Thanks a lot for these links, very interesting. It shows that it’s worthwhile to keep absolute polarity intact in the entire recording- processing-playback chain.

Thanks for the links, very interesting. In practice though polarity is likely to be completely inaudible for actual music as opposed to isolated specially designed wave forms, and even if it were there will likely be a 50:50 chance of polarity in the recorded music being inverted or not so we wouldn't know which way to set up our system. Actually that's probably a best case, in practice the recording is likely to be a mismatched mess of phase/polarity inconsistencies for different instruments and mikes so there is no polarity that we could select to improve the mess. Good job it's likely to be inaudible in the first place

 

[audioguy272727]

I have seen some people just remove that orange-colored strip from the sides of the chassis for better ventilation, which sounds like a good idea, especially during these super hot summer months.
View attachment 382593

In my “testing” I found the V3M devices to be 10 to 11 degrees hotter than the PA7 (112 deg F for the V3M vs 102 degrees F for the PA7) with the devices being situated standalone - no other devices contributing ambient to heat. When I stacked the PA7 and the V3Ms on a Teac Dac I have that throws off quite a bit more heat, the V3Ms got to 118 degrees F while the PA7 only got to 105 degrees F. So the V3Ms seem to really like being solitary and I would expect cooled. And the PA7 just lived its life without reacting too much to the world around it. So I returned the V3Ms since there was little to no “audio pleasure benefit” vs the PA7 and it of course uses two supplies and two chassis so not really a tidy minimalist solution that I was hoping for as well. And for reference, I bought the PA7 used for about the same price as the V3Ms with the 20% discount from Amazon.

 

[Supernono]

Hello everyone,
I need advice on the fosi audio v3 mono amp
I want to connect it to the pre-out output of my home cinema amp.
Is this possible?
Thanks in advance

 

[EddNog]

Hello everyone,
I need advice on the fosi audio v3 mono amp
I want to connect it to the pre-out output of my home cinema amp.
Is this possible?
Thanks in advance

Pre out is line level with volume controlled by the preamp, right? That’s exactly where you would hook it up to.

-Ed

 

[antcollinet]

Hello everyone,
I need advice on the fosi audio v3 mono amp
I want to connect it to the pre-out output of my home cinema amp.
Is this possible?
Thanks in advance

Yes.

 

[LukeA]

How on Earth is this the V3 mono?!? Unbelievable to receive this in the post today. Angry.

Let’s see how Fosi responds via ebay….

 

[wybe]

How on Earth is this the V3 mono?!? Unbelievable to receive this in the post today. Angry.

Let’s see how Fosi responds via ebay….

I understand you are angry, but hey, it’s work done by people, and yes people make mistakes. Besides, this is not a Fosi company review thread.

Relax and maybe complain somewhere else.

I really like all the interaction about how the mono is used and in which setup.

The moaning, not my cup of tea.

 

[antcollinet]

How on Earth is this the V3 mono?!? Unbelievable to receive this in the post today. Angry.

Let’s see how Fosi responds via ebay….

Holy crap. That is a bad stock mixup when you end up sending out a completely different product.

All manuafacturers make mistakes though. The sign of a good one is in how they respond - as you say, let's see.

 

[Kimbrough Xu]

How on Earth is this the V3 mono?!? Unbelievable to receive this in the post today. Angry.

Let’s see how Fosi responds via ebay….

I think it's a gift, I just saw pre-order on Ebay.

 

[antcollinet]

The moaning, not my cup of tea.

I think @LukeA has the right in this case.

 

[Bleib]

I think it's a gift, I just saw pre-order on Ebay.

Could be, but a whole amp?

 

[SMen]

How on Earth is this the V3 mono?!? Unbelievable to receive this in the post today. Angry.

Let’s see how Fosi responds via ebay….

Might be useful to post the link to the ebay shop you bought it from to alert other possible purchasers from there ...

 

[LukeA]

D’oh. My bad. It’s a gift from the ebay shop…

Idiot I am.

 

[wybe]

D’oh. My bad. It’s a gift from the ebay shop…

Idiot I am.

Congrats! Hopefully the angry feeling slips away and we all can talk V3 mono audio again!

Still waiting for the delivery? Or already hooked them up?

What’s going to be your setup?