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Fosi Audio V3 Mono Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 13 2.0%
  • 2. Not terrible (postman panther)

    Votes: 21 3.2%
  • 3. Fine (happy panther)

    Votes: 128 19.3%
  • 4. Great (golfing panther)

    Votes: 501 75.6%

  • Total voters
    663
I had asked Fosi for a splitter cable to operate 2 V3 mono with a 10 A power supply. They sent me the cable but it's not the right one.
Does anyone have a photo of the splitter cable from Fosi?

THX !
I think that’s the right one, between the splitter cable and power supply is a filter with 2 female connections
 
Do you still get hum when you disconnect the tube amp? I am suspecting ground noise from the tube amp.
Nope. No hum with the tube amp disconnected. But then I don't get any hum using the tube amp as an integrated.
I'm using RCA connectors and have twin 48v/5A supplies. I do note that the hum is louder on the higher gain setting though it doesn't increase with volume

Thanks for your suggestions. I do have the V3 stereo but haven't used it in that system. Might give it a try and see if it hums.
 
Do you still get hum when you disconnect the tube amp? I am suspecting ground noise from the tube amp.
So no hum when using the V3s with my vintage Sansui solid state as a preamp, but a loud thump when switching the Sansui on with the V3s attached. Don't like that at all. I think the V3s need to steer clear of vintage amps and vintage technology in modern amps.
Now we need Fosi to bring out a proper, actually useful preamp with multiple inputs and XLR balanced out.
Either that, or time to look again at the Topping Pre90.
I have the P3 but it really doesn't cut it as a proper pre.
 
loud thump when switching the Sansui on with the V3s attached.
Are you saying you are turning on the Sansui (preamp) from off position while Fosi V3's are attached ALREADY powered on? Should never do that with any preamp+amp combinations.
 
a loud thump when switching the Sansui on with the V3s attached.
In the case of several devices connected in series, the switching on procedure should always be followed from the first in the series to the last, also when switching off, it should be done in the reverse order - from the end to the first one.
 
Are you saying you are turning on the Sansui (preamp) from off position while Fosi V3's are attached ALREADY powered on? Should never do that with any preamp+amp combinations.
Ahem... coughs and looks sheepish. Afraid so. Pretty sure the v3s were in the auto position. I'm an integrated amp kind of guy. Probably over 25 years since I had a prepower combo and I was trying a lot of different combinations. Switching on and off and messing with my inputs for other reasons.
Lesson learned. Hopefully not at the expense of my drivers.
 
Just received mine yesterday and have noticeable hum from both midrange drivers at idle which does not increase with volume. I am using the preamp output from my Allnic 300b tube amp.
I have four different amps in my system and have no hum from any of them, so the Fosi does seem to be the culprit. I did swap the polarity of the speaker cables, being aware of the phase issues. This removed the hum from one channel but not the other.
I do have a Fosi P3 preamp and a vintage Sansui with a preamp out so will try it with those and see if the issue remains.
I bought the Fosi out of curiosity to see if it can retain the character of the 300b amp while giving it more oomf when driving my Wharfedale Elysian-4s.
Any thoughts or similar experiences?
What gain are you using? I have no noise on RCAs using the low gain setting.
 
Firstly, my speakers seem to have survived my abuse. So far, anyway. Thanks all for reminding me of the basics.
Secondly, with my P3 as preamp and my Revel speakers in a second system the V3 are silent.
 
I use a boXem Arthur 3409/N2(nc252mp) Poweramp with a pair of KEF R3 Meta.
Would replacing my current amp with two Fossi V3 Mono make any sense? Are there any potential benefits? or I will just add a power supply and some more cables in my living room for no reason?
(specs of my poweramp in the attachments)
 

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I use a boXem Arthur 3409/N2(nc252mp) Poweramp with a pair of KEF R3 Meta.
Would replacing my current amp with two Fossi V3 Mono make any sense? Are there any potential benefits? or I will just add a power supply and some more cables in my living room for no reason?
(specs of my poweramp in the attachments)
The smaller boXem amp has been reviewed on ASR previously. While have not heard it, the specs and internals look superior to the Fosi V3M. I don't see any reason to purchase the V3M. See: https://www.audiosciencereview.com/...-2408-n2-review-stereo-power-amplifier.18710/
 
I use a boXem Arthur 3409/N2(nc252mp) Poweramp with a pair of KEF R3 Meta.
Would replacing my current amp with two Fossi V3 Mono make any sense? Are there any potential benefits? or I will just add a power supply and some more cables in my living room for no reason?
(specs of my poweramp in the attachments)
No benefit at all. The Boxem is a better amp.
 
I use a boXem Arthur 3409/N2(nc252mp) Poweramp with a pair of KEF R3 Meta.
Would replacing my current amp with two Fossi V3 Mono make any sense? Are there any potential benefits? or I will just add a power supply and some more cables in my living room for no reason?
(specs of my poweramp in the attachments)
If you do then you would get many potential buyers here if you decide to sell boxem… pls count me the first, I am always interested in trying a boxem amp and put it against all these tpa3255 amps I have got.
 
If you do then you would get many potential buyers here if you decide to sell boxem… pls count me the first, I am always interested in trying a boxem amp and put it against all these tpa3255 amps I have got.
The Boxem is quite a bit more expensive?
No benefit at all. The Boxem is a better amp.
Yes, just looking here on ASR it is not 'cut and dry' looking at the Buckeye nc252mp reviewed here that 'better' is a 'given'.

In fact many would "chip" in on here that measurement wise hearing a difference would not be a 'given' either ;)
 
I use a boXem Arthur 3409/N2(nc252mp) Poweramp with a pair of KEF R3 Meta.
Would replacing my current amp with two Fossi V3 Mono make any sense? Are there any potential benefits? or I will just add a power supply and some more cables in my living room for no reason?
(specs of my poweramp in the attachments)
I have that boxem Arthur amp. Some differences with the Fosi based on comments in this thread:
- Power consumption in stand by (audio sense) mode < 0.5 W
- does not goes on when I switch on the light as someone reported a few posts back
- stays at room temperature in normal usage
 
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In fact many would "chip" in on here that measurement wise hearing a difference would not be a 'given' either
Not a given - but 16 bits vs 11 bits of distortion free range may (albeit unlikely) be audible for some. (IMD test)

Plus - a little more power.

More importantly - better build quality and established track record of the modules.
Nicer Aesthetics (subjective, I know)
Built in PSU and consequent larger rear panel with more space for the binding posts.
Clipping indicator

And the lower heat and auto power on stability mentioned by @MCH.

All adds up to quite a bit.
 
Not a given - but 16 bits vs 11 bits of distortion free range may (albeit unlikely) be audible for some. (IMD test)

Plus - a little more power.

More importantly - better build quality and established track record of the modules.
Nicer Aesthetics (subjective, I know)
Built in PSU and consequent larger rear panel with more space for the binding posts.
Clipping indicator

And the lower heat and auto power on stability mentioned by @MCH.

All adds up to quite a bit.
Looking these up I think it is 800euros vs much much less for these monos on kickstarter. Perhaps this is not a fair comparison.
Someone I am sure has listened to both these and the more expensive hypex NC252MP modules.

Probably this is a bit of a diversion / distraction ... but a worthwhile comparison by someone who has both.
 
Perhaps this is not a fair comparison.
Of course not - it is not intended to be.

The person I was replying to already has the Boxem. He was asking if he should "upgrade" to the Monos.

So in this case, the "upgrade" for lower objective performance, plus all the other differences discussed would cost additional money. It would clearly make no sense.

He has the better amp already.
 
Indeed.
I bought the Fosi because I wanted a flavour of Class D without the big price tag. If I could justify it I would get a Purifi Eigentakt based amp from someone like Boxem.
Unfortunately (or fortunately) I have a wide selection of Class A and AB amps I am very attached to.
Of course not - it is not intended to be.

The person I was replying to already has the Boxem. He was asking if he should "upgrade" to the Monos.

So in this case, the "upgrade" for lower objective performance, plus all the other differences discussed would cost additional money. It would clearly make no sense.

He has the better amp already.
D
 
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