Fosi Audio V3 Mono Amplifier Review

[Sokel]

My assumption is it's rated for 6.3A continuous but 10A for short term peaks (hence the MAX), similar to the continuous/peak ratings for some of the Meanwell models. I looked for a datasheet to confirm, but couldn't find one.

I don't think that this is necessarily bad.
In the crazy case someone runs this amp to it's limit with a true 48V-10A PSU and assuming it's even 90% efficient they will be 40-50 watt of heat to dissipate and its size (total dissipating area) do not inspire it will do so for more than seconds.

Time limited peaks from both sides can come handy sometimes.

 

[Rafaille]

I don't think that this is necessarily bad.
In the crazy case someone runs this amp to it's limit with a true 48V-10A PSU and assuming it's even 90% efficient they will be 40-50 watt of heat to dissipate and its size (total dissipating area) do not inspire it will do so for more than seconds.

Time limited peaks from both sides can come handy sometimes.

Agree, but to run two amps with one 10A, it would be nice if we had 5A for each and not 6.2A to share.
I am thinking about changing my pledge from 1x10A to 2x5A (for a pair of amps), I was initially happy to limit clutter with a single psu but now it feels like I am losing peace of mind instead.

Does anyone know if there is a time order for shipping? If I change my kickstarter pledge, will I go back to the end of the queue? I got an early bird offer, that would be a shame. But then again, peace of mind...

 

[redstang]

Agree, but to run two amps with one 10A, it would be nice if we had 5A for each and not 6.2A to share.
I am thinking about changing my pledge from 1x10A to 2x5A (for a pair of amps), I was initially happy to limit clutter with a single psu but now it feels like I am losing peace of mind instead.

Does anyone know if there is a time order for shipping? If I change my kickstarter pledge, will I go back to the end of the queue? I got an early bird offer, that would be a shame. But then again, peace of mind...

I was torn on which to buy - dual 5A or single 10A - OR dual 10A. I went with single 10A with the thought that if the 10A is limited for two, 5A will be probably be limited for one, so better off having to buy a single extra 10A down the road than wanting to upgrade both the 5A power supplies. Buying a second 10A sort of breaks the value proposition for these, however.

Long term, my intended use for these is likely in a smallish 2ch listening room rather than serving as amps in my HT. Therefore I don't expect to be driving them to their limits so I assume the single 10A will be fine. But who knows - maybe getting 7-9 more for a full monoblock amp array for HT is in the cards

 

[amix]

Where are your devices placed?

In your living room? Beside your TV?

No. Currently they are on a rack between the speakers. No TV here.

 

[Rafaille]

I was torn on which to buy - dual 5A or single 10A - OR dual 10A. I went with single 10A with the thought that if the 10A is limited for two, 5A will be probably be limited for one, so better off having to buy a single extra 10A down the road than wanting to upgrade both the 5A power supplies. Buying a second 10A sort of breaks the value proposition for these, however.

Long term, my intended use for these is likely in a smallish 2ch listening room rather than serving as amps in my HT. Therefore I don't expect to be driving them to their limits so I assume the single 10A will be fine. But who knows - maybe getting 7-9 more for a full monoblock amp array for HT is in the cards

Again I agree totally.
5A for each amp or 10A for two could be limiting but that would be for edge cases.
However, 6.2A to share between two amps could be a real limitation, and since what we really like about these monoblocks is the power they can deliver (for the price) then the value proposition is badly affected here as well.

 

[amix]

@Fosi Audio Could you tell us, which fuses the 10A power supply uses? And how the 10A are specified? Thanks.

 

[drmevo]

I was torn on which to buy - dual 5A or single 10A - OR dual 10A. I went with single 10A with the thought that if the 10A is limited for two, 5A will be probably be limited for one, so better off having to buy a single extra 10A down the road than wanting to upgrade both the 5A power supplies. Buying a second 10A sort of breaks the value proposition for these, however.

This was my thinking as well in choosing the 10A and possibly buying another down the line. Now I’m wondering if just having them as separate 5A to start with would be more beneficial.

 

[Lednek]

This was my thinking as well in choosing the 10A and possibly buying another down the line. Now I’m wondering if just having them as separate 5A to start with would be more beneficial.

I am "patiently"-ish waiting for Fosi to respond, but I'm thinking I'll change my two 10A supplies to two 5A. I don't have or plan to get any low impedance speakers. I like the idea of having more and not needing it, but if it's only 1.3A additional output, I can't see spending double for it, when it won't be used anyway.

 

[Chrispy]

Just saw a bit on Erin's FB posting about he was going to give two of these away but only has one now due to one going up in flames....might have to do with a 1 ohm load?

 

[TonyJZX]

Just saw a bit on Erin's FB posting about he was going to give two of these away but only has one now due to one going up in flames....might have to do with a 1 ohm load?

fosi should consider this '3rd party authorised destructive testing'

also what speaker is he using thats going down to 1 ohm?

 

[Daverz]

fosi should consider this '3rd party authorised destructive testing'

also what speaker is he using thats going down to 1 ohm?

It's not a speaker, it's a "complex reactive load" he uses for testing. Erin himself makes the point that you are unlikely to have the same problem unless you are testing the amps in the same way.

 

[TonyJZX]

oh the infamous amp dyno like williston

yeah that would do it

 

[Sokel]

fosi should consider this '3rd party authorised destructive testing'

also what speaker is he using thats going down to 1 ohm?

That's his reactive loads.

Far from 1 Ohm,not even close to 2 Ohm,it's more like a 3 Ohm one.
But hard,nevertheless.

 

[galego100]

Agree, but to run two amps with one 10A, it would be nice if we had 5A for each and not 6.2A to share.
I am thinking about changing my pledge from 1x10A to 2x5A (for a pair of amps), I was initially happy to limit clutter with a single psu but now it feels like I am losing peace of mind instead.

Does anyone know if there is a time order for shipping? If I change my kickstarter pledge, will I go back to the end of the queue? I got an early bird offer, that would be a shame. But then again, peace of mind...

The pledge with one 10A includes the splitter cord or we have to add it?

 

[SMen]

The pledge with one 10A includes the splitter cord or we have to add it?

it is included

 

[Deleted member 72219]

Looks like Erin from Erin’s Audio Corner has ascertained that there is, in fact, a measurable improvement using two separate 48V/5A power supplies rather than a single 48V/10A supply for two amps at once:

-Ed

 

[kemmler3D]

Looks like Erin from Erin’s Audio Corner has ascertained that there is, in fact, a measurable improvement using two separate 48V/5A power supplies rather than a single 48V/10A supply for two amps at once:
View attachment 367282

-Ed

He also ascertained that you can fry one by pushing it into protection repeatedly... so I guess the lesson is don't do that.

 

[Deleted member 72219]

He also ascertained that you can fry one by pushing it into protection repeatedly... so I guess the lesson is don't do that.

Yes that just seems very…extra.

-Ed

 

[drmevo]

Looks like Erin from Erin’s Audio Corner has ascertained that there is, in fact, a measurable improvement using two separate 48V/5A power supplies rather than a single 48V/10A supply for two amps at once:
View attachment 367282

-Ed

Welp, I changed my pledge to two 5A power supplies. Not just because of this - I was on the fence already. There’s too much uncertainty with the single 10A power supply for me. The cords will be hidden anyways in my set up so it’s just a matter of taking up an extra outlet.

 

[Negatywny]

it's very mediocre review, much needed measurements, but overally mostly irrational complains (this amp has 200W, oh i like 500W! Thats how quirky I'am - might be the stupidest thing said by the reviewer i've heart this year) Also measurements without any comments or context: oh the graph look like this, now f*ck off. And also Fosi stop sending mi these i don't like to review this amps (Wtf?). Oh, and one got fried, haha, so funny. I haven't seen such an unfair review in a long time.

But apart from the diva reviewer, looks like two power supplies is the way to go (5A or more).