Fosi Audio V3 Mono Amplifier Review

[wric01]

Youtube reviewers say scorching hot after 3 to 4 hours hits 120 degrees, first 1 to 2 hours 100degrees. Good thing my za3 monos are larger box and just warmer all day loads.

 

[Bleib]

Scorching hot after 3 hours hits 120 degrees. Good thing my za3 monos are larger box and just warmer all day loads.

Fahrenheit obviously, and not as hot as many AVRs
Likely the temperature can be lowered quite a bit by raising them up a bit and allowing a bit more air underneath, and as usually not stacking them one on top of the other.

 

[Doodski]

Youtube reviewers say scorching hot after 3 to 4 hours hits 120 degrees, first 1 to 2 hours 100degrees. Good thing my za3 monos are larger box and just warmer all day loads.

100 F or 120 F are both very low 38 C to 49 C temps and for even a lowly domestic grade of ICs they should sustain @ ~85 C. The electrolytic caps are rated for 105 C <?> So far those temps look good if they are done with accurate metering.

 

[Adrian Parker]

@Fosi Audio:

Have you considered putting two of these amps into a single, 1U rack-mountable chassis?
One set of switches instead of two, most probably better cooling and if the PSU was in the same chassis, a MUCH tidier setup.

Such an amp could become the next Dynaco ST-70 or, if you want, the next NAD 3020 of power amps (yes, I'm that old).

P.S.: I've just checked your Kickstarter page for this product and I've noticed the "V3 Mono*2 + 48V/10A Power Supply*1" bundle, but I've not seen a proper description of it. I'm assuming there is some special cable to link both amp to the same PSU or are we dealing with a PSU that has two output connectors? Thanks for any explanation you can provide.

P.P.S.: I just needed to scroll further down the product's page to stumble onto the mention of a splitter cable that lets the 48V/10A PSU power two V3 Mono amps.

Hello @Fosi Audio one YouTube reviewer is saying that there is cross-talk from the single power supply, "pop and crackle" noises - demonstrated in the video. Suggests avoiding the single power supply, as it goes against "conventional wisdom". Is this a known issue, and will it be fixed, or will Fosi give all backers of the single supply a discount code for a second? I am now concerned at a time when I should be excited. Also I am still not sure how I will connect to my Sub? There is not means to do so, right?

 

[Adrian Parker]

Fahrenheit obviously, and not as hot as many AVRs
Likely the temperature can be lowered quite a bit but raising them up a bit and allowing a bit more air underneath, and as usually not stacking them one on top of the other.

My ignorance, probably, but a small fire gives off less heat than a big fire-yes? Do these amps give off less heat in total than a full sized AB 300W/channel AMP? This is the only reason that I am investing. I get too hot in my Shedquarters (new family name for my man cave - where I work) with my current (pun intended) amp.

 

[ninetylol]

With all the problems with the single supply, I'm glad I've chosen the rationally appropriate option of two separate power supplies.

 

[antcollinet]

My ignorance, probably, but a small fire gives off less heat than a big fire-yes? Do these amps give off less heat in total than a full sized AB 300W/channel AMP? This is the only reason that I am investing. I get too hot in my Shedquarters (new family name for my man cave - where I work) with my current (pun intended) amp.

Yes, much less.

 

[Adrian Parker]

Dear @Fosi Audio

I have pledged, almost sound a religious thing to do. Yesterday was full of excitement. Today however I am now faced with five concerns:

1 Heat - ie total amount of. Videos are now showing amps as running hot. Will total heat output be less than standard A/B amp which runs hot and is large (think baby Krell)?

2 Power Supply crosstalk (noise) - per YouTube review - will this be fixed?
Will Fosi offer second power supplies if not, either free or discounted?

3 Op Amp Rolling - Why does Fosi not simply put the best in to start? (or maybe you do?)
I want flat, my dac/pre-amp does all I need from a musicality perspective. If op amp options are offered, it is not clear how many are needed, nor where to put them, and what difference they make, nor the spec needed to not invalidate warrantee? (unless I missed the small print).

4 I actually needed more amps than I was able to pledge for. 4 amps (2x2) is a start (I actually will need a potential total of 21! for my Kitchen (2), Hall(2), Lounge(7), Lounge II(2), Garage(4), Shedquarters/Office*(4) - and that is before going crazy - (crazy:bi-amping large speakers).
*Thus far, the Office will be the only place I can use them. Unless pledge can be added to? (did I miss something?)

5 There is no Sub out - so what do I do? Anyone, any ideas? (Stereo amp has one, but not the monos?) Or will there be a "Pro" version coming with Sub out?

I look forward to some great feedback.

 

[Adrian Parker]

With all the problems with the single supply, I'm glad I've chosen the rationally appropriate option of two separate power supplies.

I do find power a dark art. PS audio video, only yesterday in fact, suggests dedicated power per amp to reduce noise amplification in dual-mono configurations. How is this any different to sharing a power strip, or supply socket? That's what baffles me. Always has. BTW I avoid power amps (and mine are huge) from going anywhere near a power strip.

 

[Adrian Parker]

If you are in the UK ...

(I know where I am )

 

[SMen]

I was looking up power supplies and the AIYIMA 48V10A GaN Power Supply is priced at about 80USD, while the Fosi 'standard' 48V10 is 132USD.

This is a large variation ... particularly when GaN generally commands a premium.

Does anyone have experience of the Aiyima GaN or thoughts on this?

 

[SMen]

(I know where I am )

Well, it could have been Ireland ;-)

 

[ninetylol]

I do find power a dark art. PS audio video, only yesterday in fact, suggests dedicated power per amp to reduce noise amplification in dual-mono configurations. How is this any different to sharing a power strip, or supply socket? That's what baffles me. Always has. BTW I avoid power amps (and mine are huge) from going anywhere near a power strip.

Im no expert, but if you go the route with mono blocks im a bit bewildered you would go with a single power supply. I mean even philosopical - you chose to split each channel for pure bliss and then use a single power supply, that doesnt make any sense to me. Only point that would make sense was for convience reasons, but then i wouldnt go the monoblock path in the first way.

 

[Adrian Parker]

Im no expert, but if you go the route with mono blocks im a bit bewildered you would go with a single power supply. I mean even philosopical - you chose to split each channel for pure bliss and then use a single power supply, that doesnt make any sense to me. Only point that would make sense was for convience reasons, but then i wouldnt go the monoblock path in the first way.

Luckily, I only need to buy more power supplies to fix, and power cables clearly. Then that negates the whole Kickstarter early-bird discount. But it is ok. I guess the same holds for bi-amping, having two power supplies?

 

[Adrian Parker]

Well, it could have been Ireland ;-)

Crazy was the signup-email voucher-link not actually taking you to Kickstarter. I wonder how many people got stuck there! All a bit of fun.

 

[Adrian Parker]

I was looking up power supplies and the AIYIMA 48V10A GaN Power Supply is priced at about 80USD, while the Fosi 'standard' 48V10 is 132USD.

This is a large variation ... particularly when GaN generally commands a premium.

Does anyone have experience of the Aiyima GaN or thoughts on this?

see: https://www.audiosciencereview.com/...48v-power-supplies-for-fosi-aiyima-etc.48373/ - might be out of date but looks a good source.

 

[SMen]

Crazy was the signup-email voucher-link not actually taking you to Kickstarter. I wonder how many people got stuck there! All a bit of fun.

Yes, I made it too from France. I went with the single 10A, but I'm wondering about the much higher price Fosi are charging ... I am presuming they will get these issues fixed with the single 10A power supply before they ship out.

see: https://www.audiosciencereview.com/...48v-power-supplies-for-fosi-aiyima-etc.48373/ - might be out of date but looks a good source.

Thank you - Amir actually reviewed it with the Aiyima here https://www.audiosciencereview.com/forum/index.php?threads/aiyima-a70-stereo-amplifier-review.52830/

This is an example of where I'd love to see a separate measurement for the power supplies provided.

At any rate - this Aiyima GaN 48v 10A is much cheaper than the Fosi 10A, but I remain curious about the ultimate impact these have on the end measurements.

 

[jvdburgt]

An informal survey of how many V3 Mono backers are upgrading from dual ZA3s would be quite interesting. There’s going to be a deluge of used ZA3s on the market in June!

-Ed

I’m actually in the market for a single ZA3. Any dutchies here lookijg to get rid of one?

 

[Fosi Audio]

Do the y-splitter cables come with the 4x amp, 2x power supply backer option or do I have to add them as an extra?

The Y splitter cables will be included in that bundle option.

 

[Fosi Audio]

Hello @Fosi Audio one YouTube reviewer is saying that there is cross-talk from the single power supply, "pop and crackle" noises - demonstrated in the video. Suggests avoiding the single power supply, as it goes against "conventional wisdom". Is this a known issue, and will it be fixed, or will Fosi give all backers of the single supply a discount code for a second? I am now concerned at a time when I should be excited. Also I am still not sure how I will connect to my Sub? There is not means to do so, right?

The noise issue currently occurs when only one V3 Mono is turned on; however, it disappears when another V3 Mono is powered on. Our R&D engineers have been working on resolving this issue over the past two weeks, and we now have a promising solution. Rest assured, we will ensure that this problem does not persist in the final version. If the issue is not perfectly resolved by then, we are prepared to offer a free replacement of two 48V/5A power supplies along with two V3 Monos as a set for you.