Fosi Audio V3 Mono Amplifier Review

[Hunter Mike]

Really nice looking (measuring) wee amp, and tremendous value. Looking forward to seeing how it performs in the wild, in real use.

One question: what's the thinking on stacking these? @amirm has commented that they are stackable and some of the promotional pictures show that too. Any concerns about overheating (appreciate that there's no practical experience possible yet)

I contacted Fosi about stacking four ZA-3’s and they said it was fine. I would think there are no issues but reach out to them directly if you’re concerned.

I currently have three ZA-3’s stacked and they’re barely warm. The top of all the amps is 88-90F with an infrared thermometer. Combined power consumption is 22W for all three at idle so not much heat. That includes losses in the power supply too, although they don’t feel warm.

 

[billymac]

Ah - understood - so then I assume you have set the SONOS sub settings to maximum output level?

If so then an alternative to a new amp with higher gain would be to put a simple preamp in front of the 502. Something like:

preamp

Thank you again. Yes, +15 on Sonos sub level in app. Thought about a line amplifier, but was slightly skeptical. May try that path, but gosh, I think I want to pick one of these up!

 

[jayapple]

This amp is pure Science Fiction. This level of power and performance for less than $140 per channel? Wow.

Thanks for this delightful review Boss. The budget guys are cheering in the background. Look at that 4 and 2 ohm numbers. Real doubling for a Buck Fifty?

If I didn’t know better I would think this is a well done April Fools joke. But Amir doesn’t joke!

And don't forget that there is also a discount, which can be less than $260 for two together! unbelievable！

 

[antcollinet]

Thank you again. Yes, +15 on Sonos sub level in app. Thought about a line amplifier, but was slightly skeptical. May try that path, but gosh, I think I want to pick one of these up!

Just checked the two amps - as far as I can see they both have the same gain (26dB) in RCA** mode. Even if you get this you are still going to need a preamp.


**EDIT - as measured by @Amir - though there does seem to be a 31dB option in the pictures.

 

[Rottmannash]

The other characteristic of the Cancel culture is that its brave members need to act in packs. You just can't resist, can you?

In your eagerness to bite you just missed this post: https://www.audiosciencereview.com/...o-v3-mono-amplifier-review.53474/post-1933746

Go and see that post. You don't even need to apologize.

So, once again: "Be conservative in what you do, be liberal in what you accept from others."

Sorry-speaking of another member-not you. No need to apologize.

 

[YesChickenNuggets]

And don't forget that the single 10A supply also leaves you the opportunity to waste more money further improve your system later on with a second 10A supply added whereas two 5A supplies don't have that flexibility.

Has Fosi said anything about getting 2x 10A ? Does it increase output at all or is the 250watt the absolute max?

 

[dpuopolo]

I suppose you're going to lay the board and power supply on your desk for all to see? Factor in the cost of casework, binding posts, etc and your labor and then give us a total.

Actually, yes! Been running great for months! Nice and cool too.

 

[antcollinet]

Actually, yes! Been running great for months! Nice and cool too.

Great - but I'm sure you can understand that is not how most people want to use their amplifiers.

 

[olieb]

Great - but I'm sure you can understand that is not how most people want to use their amplifiers.

Would not be my preferred setup either, but considering that some here advertise the V3mono for multichannel use and stashing away the multiple power bricks "somewhere" for "neatness", this might not be so outrageous as it looks like.

 

[antcollinet]

Would not be my preferred setup either, but considering that some here advertise the V3mono for multichannel use and stashing away the multiple power bricks "somewhere" for "neatness", this might not be so outrageous as it looks like.

I'd say it's even worse if you are trying to hide multiple amps. Nothing to stop them tripping over each other and shorting out.

 

[dpuopolo]

I'd say it's even worse if you are trying to hide multiple amps. Nothing to stop them tripping over each other and shorting out.

How will they short each other out? All the connections to this board are by insulated connectors and very tight push on terminals (ones that go to power and speakers are both crimped and silver/tin soldered).

If you put this in a cabinet then you have two input and speaker connections and I only have one.

 

[antcollinet]

How will they short each other out? All the connections to this board are by insulated connectors and very tight push on terminals (ones that go to power and speakers are both crimped and silver/tin soldered).

If you put this in a cabinet then you have two input and speaker connections and I only have one.

just try chucking a few of them in a drawer or on a shelf uncased to "hide them" and wait for them to move such that the PCB's are in contact.

It's not going to end well.

 

[Hunter Mike]

Has Fosi said anything about getting 2x 10A ? Does it increase output at all or is the 250watt the absolute max?

Same output whether you use two 48v5A or one 48v10A split.

 

[echt]

@Fosi Audio

Have you tested and/or do you have any comments on whether their is any performance benefit to using a 10amp power supply for each monoblock.

Understand the "value proposition" may be debatable, so just asking about pure performance. Thanks.

 

[Cal_Cobra]

Just to clarify the use-case with this amp, I'm not quite sure what you're saying here. When using the Oppo's analogue outputs - as one would with this Fosi amp - the Oppo's built-in volume control will work fine, no matter what input you use into the Oppo, with no need to use a second volume control in any device or software upstream of the Oppo. The Oppo is a digital preamp, and its volume control is disabled only at its own digital outputs. Same goes for any DAC or other source device with a built-in volume control.

That's how I'm using the Oppo now, with it's RCA analog stereo out to my tube amp, and can use either the volume control on the Oppo or the amp. I'm planning to purchase the Fosi mono-blocks to go with the Oppo and will probably switch to XLR as the SINAD increases significantly vs RCA.

I wanted tone controls, and tried a Douk Audio EQ pre amp, but didn't care for it.

 

[mike70]

SINAD increases significantly vs RCA

That SINAD difference is inaudible.
You won't recognize any amp with more than 80dB SINAD (and flat FR ... tubes aren't valid ) with a blind test in domestic situations.

 

[wyup]

What's interesting about XLR having lower gain and distortion is that you can still use it with unbalanced by means of a simple adapter.

20db gain is still ideal for home use and you don't have to attenuate the input signal that much and get lower noise.
This convinces me.

 

[Fosi Audio]

Does anyone know the actual dimensions of the V3 mono? @Fosi Audio ? In cm or inches? Sorry if I am staring blindly and missing this! The v3 stereo looks different but is 6.5x4.1x1.4 inches

V3 mono's dimensions are 5.6x4.2x1.6 inches. Actually, it has the same chassis as the v3 stereo.

 

[billymac]

V3 mono's dimensions are 5.6x4.2x1.6 inches. Actually, it has the same chassis as the v3 stereo.

So the upcoming preamp (ZD3) will be same form factor/width as ZA3 and not V3 variants?

 

[DavidM1]

V3 mono's dimensions are 5.6x4.2x1.6 inches. Actually, it has the same chassis as the v3 stereo.

In other words...tiny! I think these might have to become known as "miniblocks".