Fosi Audio V3 Mono Amplifier Review

[louwii]

I think the main 'takeaway' for @louwii , following @jbaumann 's and everyone's comments, is quite a constructive one. Would not have to be Magnepans, but he might need different neighborly conditions!

That's actually my plan. I will only upgrade my speakers once I move into a more suited environment, where I could enjoy them with peace of mind. Which might never happen given the real estate market.
That's also why I'm looking at a few upgrades I could do without blowing the bank. I'm also looking into getting some room correction going, which is probably the best choice, before getting new amp(s).

 

[SMen]

That's actually my plan. I will only upgrade my speakers once I move into a more suited environment, where I could enjoy them with peace of mind. Which might never happen given the real estate market.
That's also why I'm looking at a few upgrades I could do without blowing the bank. I'm also looking into getting some room correction going, which is probably the best choice, before getting new amp(s).

Maybe this the way to go: One of these Wiim's also has a 3255 amp module.

Optimizing Your Audio Experience: The Power of Room Correction & How to Use in the WiiM Home App (Updated - Available now for both Android and iOS users)

Enhance your sound system with room correction: adjust audio to your room's acoustics for clearer, accurate, and immersive listening.

www.blog.wiimhome.com

WiiM Amp Streaming Amplifier Review

This is a review and detailed measurements of the WiiM Amp streaming amplifier. It was sent to me by the company and costs US $299. I was pleasantly surprised by the good bit of weight this small box has. It will help it not slide with the weight of the speaker wires and such. Back panel shows...

www.audiosciencereview.com

 

[Mort]

I got my Fosi monoblocks yesterday and they are a bigger upgrade in power than I expected. I'm not sure why but naturally I'm happy.

Before I was using an AO300 from a Wiim Ultra on 2V as a pre amp. With the AO300 fully opened up to 60 (the top volume on the AO300) the AO300 would clip when the Wiim went over 35 (0-100). Over that 35blevel the AO300 would just shut off, presumably overloaded.

With the Fosi i can get the Wiim well over 60 and into volume territory where there is obvious distortion. I don't know if it would go to 100 (full 2 volts) but I got it over 75 and although it didn't sound good at that high a volume (distortion), the Fosi never shut off like the ao300.

I'm powering Philharmonic audio ceramic minis, large 4ohm bookshelf speakers that are not particularly hard to drive.

I'm not surprised the Fosi is better but I'm surprised by how much. Rated power is 165w for the AO300 and 240w for the Fosi. A 50% increase in power shouldn't more than double the output.

Of course I'm not the best at understanding audio engineering. I'm probably misunderstanding something. Why would the Fosi handle so much more?

 

[EddNog]

I got my Fosi monoblocks yesterday and they are a bigger upgrade in power than I expected. I'm not sure why but naturally I'm happy.

Before I was using an AO300 from a Wiim Ultra on 2V as a pre amp. With the AO300 fully opened up to 60 (the top volume on the AO300) the AO300 would clip when the Wiim went over 35 (0-100). Over that 35blevel the AO300 would just shut off, presumably overloaded.

With the Fosi i can get the Wiim well over 60 and into volume territory where there is obvious distortion. I don't know if it would go to 100 (full 2 volts) but I got it over 75 and although it didn't sound good at that high a volume (distortion), the Fosi never shut off like the ao300.

I'm powering Philharmonic audio ceramic minis, large 4ohm bookshelf speakers that are not particularly hard to drive.

I'm not surprised the Fosi is better but I'm surprised by how much. Rated power is 165w for the AO300 and 240w for the Fosi. A 50% increase in power shouldn't more than double the output.

Of course I'm not the best at understanding audio engineering. I'm probably misunderstanding something. Why would the Fosi handle so much more?

Power is not the only dictator of volume level. Gain is a separate specification. You can amplify with zero gain (unity gain). Your old amplifier and the V3 Monos have different gain based on what you’re saying. Gain is how much volume is increased, and power determines the amplifier’s ability to actually push attached speakers to the volume level you’re asking for. Sort of somewhat like torque versus horsepower.

-Ed

 

[Mort]

Power is not the only dictator of volume level. Gain is a separate specification. You can amplify with zero gain (unity gain). Your old amplifier and the V3 Monos have different gain based on what you’re saying. Gain is how much volume is increased, and power determines the amplifier’s ability to actually push attached speakers to the volume level you’re asking for. Sort of somewhat like torque versus horsepower.

-Ed

I can't find the gain numbers for the ao300 but this is probably it, yeah.

 

[harrym13]

Hi all, new user of this forum here. I've got a few Qs on the V3 monos:

I ordered direct from Fosi ($260 for the pair with the 10a supply) on 7th September. Anyone have any ideas when they might arrive? Shipping to the UK.

I'm planning on using both the RCA and XLR inputs (for two different sources) - RCA being driven from the preouts on my Arcam AVR360 (quite curious to see how the v3 monos compare to a reasonably high end AVR which claims 90wpc...). This will cover Film, TV and streamed music use through the AVR. How do people find the manual switches on the front? Robust? Any audible pops or clicks when switching? Should I worry about the RCA noise issue with the single 10a supply? How do people find the auto power switching? Is it useful/works as intended?

For the XLR inputs, I plan to run directly from my Pioneer XDJ-XZ mixer (I DJ as a hobby). Anyone got any experience running directly from a DJ mixer/controller into these monoblocks? I'm hoping I can run them quite loud without pushing the gain on the mixer too hard... As friends (and me!) DJing have a tendency to push towards the red when a party is rocking and they want a bit more oomph from the speakers...

One of the main reasons I ordered these monoblocks is I fairly regualry take my home audio setup (speakers are Tannoy Revolution XT8F - absolutely adore them, 91dB sensitivity and rated power handling up to 200w) and my DJ decks out to parties - but lugging the 16kg Arcam AVR is an extra pain (along with the heavy speakers and decks)... Plus the Arcam has cut out a couple of times due to thermal protection kicking in. So I'm hoping these little monoblocks paired with my Tannoys will provide suitable levels of reliable power to rock a party for extended periods of time. I considered spending similar money on a pro PA power amp for more power output, but the small class D format of the V3 monos appealed for being very portable and living room suitable (I.e. Not ugly and full of cooling fans!)

If anyone else has any experience using these V3 monos driving similar sensitivity 8ohm speakers fairly loudly for extended periods of time, I'd be keen to hear about it!

Cheers all and thanks for providing hours of reading on these forums!

 

[AudioSceptic]

Thanks for the review. Nice results. And a good price indeed.
Now I am waiting for the stereo version.

2 mono ones are small enough!

 

[EddNog]

Hi all, new user of this forum here. I've got a few Qs on the V3 monos:

I ordered direct from Fosi ($260 for the pair with the 10a supply) on 7th September. Anyone have any ideas when they might arrive? Shipping to the UK.

I'm planning on using both the RCA and XLR inputs (for two different sources) - RCA being driven from the preouts on my Arcam AVR360 (quite curious to see how the v3 monos compare to a reasonably high end AVR which claims 90wpc...). This will cover Film, TV and streamed music use through the AVR. How do people find the manual switches on the front? Robust? Any audible pops or clicks when switching? Should I worry about the RCA noise issue with the single 10a supply? How do people find the auto power switching? Is it useful/works as intended?

For the XLR inputs, I plan to run directly from my Pioneer XDJ-XZ mixer (I DJ as a hobby). Anyone got any experience running directly from a DJ mixer/controller into these monoblocks? I'm hoping I can run them quite loud without pushing the gain on the mixer too hard... As friends (and me!) DJing have a tendency to push towards the red when a party is rocking and they want a bit more oomph from the speakers...

One of the main reasons I ordered these monoblocks is I fairly regualry take my home audio setup (speakers are Tannoy Revolution XT8F - absolutely adore them, 91dB sensitivity and rated power handling up to 200w) and my DJ decks out to parties - but lugging the 16kg Arcam AVR is an extra pain (along with the heavy speakers and decks)... Plus the Arcam has cut out a couple of times due to thermal protection kicking in. So I'm hoping these little monoblocks paired with my Tannoys will provide suitable levels of reliable power to rock a party for extended periods of time. I considered spending similar money on a pro PA power amp for more power output, but the small class D format of the V3 monos appealed for being very portable and living room suitable (I.e. Not ugly and full of cooling fans!)

If anyone else has any experience using these V3 monos driving similar sensitivity 8ohm speakers fairly loudly for extended periods of time, I'd be keen to hear about it!

Cheers all and thanks for providing hours of reading on these forums!

I don’t recommend changing inputs while powered up—turn it off to switch inputs.

XLR input gain is the lowest, +20dB, compared to the two RCA options.

-Ed

 

[SMen]

Hi all, new user of this forum here. I've got a few Qs on the V3 monos:

I ordered direct from Fosi ($260 for the pair with the 10a supply) on 7th September. Anyone have any ideas when they might arrive? Shipping to the UK.

I'm planning on using both the RCA and XLR inputs (for two different sources) - RCA being driven from the preouts on my Arcam AVR360 (quite curious to see how the v3 monos compare to a reasonably high end AVR which claims 90wpc...). This will cover Film, TV and streamed music use through the AVR. How do people find the manual switches on the front? Robust? Any audible pops or clicks when switching? Should I worry about the RCA noise issue with the single 10a supply? How do people find the auto power switching? Is it useful/works as intended?

For the XLR inputs, I plan to run directly from my Pioneer XDJ-XZ mixer (I DJ as a hobby). Anyone got any experience running directly from a DJ mixer/controller into these monoblocks? I'm hoping I can run them quite loud without pushing the gain on the mixer too hard... As friends (and me!) DJing have a tendency to push towards the red when a party is rocking and they want a bit more oomph from the speakers...

One of the main reasons I ordered these monoblocks is I fairly regualry take my home audio setup (speakers are Tannoy Revolution XT8F - absolutely adore them, 91dB sensitivity and rated power handling up to 200w) and my DJ decks out to parties - but lugging the 16kg Arcam AVR is an extra pain (along with the heavy speakers and decks)... Plus the Arcam has cut out a couple of times due to thermal protection kicking in. So I'm hoping these little monoblocks paired with my Tannoys will provide suitable levels of reliable power to rock a party for extended periods of time. I considered spending similar money on a pro PA power amp for more power output, but the small class D format of the V3 monos appealed for being very portable and living room suitable (I.e. Not ugly and full of cooling fans!)

If anyone else has any experience using these V3 monos driving similar sensitivity 8ohm speakers fairly loudly for extended periods of time, I'd be keen to hear about it!

Cheers all and thanks for providing hours of reading on these forums!

Just a few of your questions:
I'm using 91 db Triangle speakers, 8ohm - the V3 monos are not 'forward' in anyway so this will depend on your mixer.

Balanced inputs going to full volume will depend very much on the maximum output of your mixer - whatever that is on full - I think 4v is enough balanced - both my balanced sources are 5v.

They will certainly go loud ... but partying "punch" ... I'm afraid you will have to report back on that one!

The manual switches are robust enough - feel good as expected - I don't mind the small clicking sound when the amps click on from standby. This feature works very effectively for me. As far as I know having both amps plugged in and on at the same time should be fine with the 10A. You will need decent lengths xlr I'd imagine and short speaker cables to tuck these monos in behind those Tannoys .... so no one steps on them while dancing or whatever!

You should have tracking with your order - mine took about a week from Fosi.

I think these are probably more 'hi fi' than you expect!

 

[LSPhil]

Hi all, new user of this forum here. I've got a few Qs on the V3 monos:

I ordered direct from Fosi ($260 for the pair with the 10a supply) on 7th September. Anyone have any ideas when they might arrive? Shipping to the UK.

I'm planning on using both the RCA and XLR inputs (for two different sources) - RCA being driven from the preouts on my Arcam AVR360 (quite curious to see how the v3 monos compare to a reasonably high end AVR which claims 90wpc...). This will cover Film, TV and streamed music use through the AVR. How do people find the manual switches on the front? Robust? Any audible pops or clicks when switching? Should I worry about the RCA noise issue with the single 10a supply? How do people find the auto power switching? Is it useful/works as intended?

For the XLR inputs, I plan to run directly from my Pioneer XDJ-XZ mixer (I DJ as a hobby). Anyone got any experience running directly from a DJ mixer/controller into these monoblocks? I'm hoping I can run them quite loud without pushing the gain on the mixer too hard... As friends (and me!) DJing have a tendency to push towards the red when a party is rocking and they want a bit more oomph from the speakers...

One of the main reasons I ordered these monoblocks is I fairly regualry take my home audio setup (speakers are Tannoy Revolution XT8F - absolutely adore them, 91dB sensitivity and rated power handling up to 200w) and my DJ decks out to parties - but lugging the 16kg Arcam AVR is an extra pain (along with the heavy speakers and decks)... Plus the Arcam has cut out a couple of times due to thermal protection kicking in. So I'm hoping these little monoblocks paired with my Tannoys will provide suitable levels of reliable power to rock a party for extended periods of time. I considered spending similar money on a pro PA power amp for more power output, but the small class D format of the V3 monos appealed for being very portable and living room suitable (I.e. Not ugly and full of cooling fans!)

If anyone else has any experience using these V3 monos driving similar sensitivity 8ohm speakers fairly loudly for extended periods of time, I'd be keen to hear about it!

Cheers all and thanks for providing hours of reading on these forums!

If you're seeking more power for your speakers, I'm afraid I have to inform you that there won't be a significant difference. The increase is only around +2.5dB. Your speakers have a sensitivity of 91dB at 1 meter, and with the AVR amplifier providing an additional 19dB, you’re already achieving 110dB at 1 meter, which is quite substantial. To double the perceived volume (a +10dB increase), you would need to reach 120dB at 1 meter. To achieve that, you'd require an 800W amplifier, compared to the current 80W.

 

[antcollinet]

you would need to reach 120dB at 1 meter.

And some ear defenders if they value their hearing

 

[harrym13]

Just a few of your questions:
I'm using 91 db Triangle speakers, 8ohm - the V3 monos are not 'forward' in anyway so this will depend on your mixer.

Balanced inputs going to full volume will depend very much on the maximum output of your mixer - whatever that is on full - I think 4v is enough balanced - both my balanced sources are 5v.

They will certainly go loud ... but partying "punch" ... I'm afraid you will have to report back on that one!

The manual switches are robust enough - feel good as expected - I don't mind the small clicking sound when the amps click on from standby. This feature works very effectively for me. As far as I know having both amps plugged in and on at the same time should be fine with the 10A. You will need decent lengths xlr I'd imagine and short speaker cables to tuck these monos in behind those Tannoys .... so no one steps on them while dancing or whatever!

You should have tracking with your order - mine took about a week from Fosi.

I think these are probably more 'hi fi' than you expect!

Thanks for the reply - all sounds good. Glad to hear positive experiences from people with (similar-ish) spec speakers.

Just did some reading and it seems the XLR outputs are pro-audio spec on the Pioneer mixer; capable of outputting high signals around (and above!) 5V - so I will have to make sure to keep an eye on that at parties, but by the sounds of it the V3 monos will be plenty loud - will happily report back on how effective they are for getting things going. If all goes to plan they'll be driving the Tannoys at a friend's wedding reception in under a month!

I'll order some decent length XLRs but yeah was planning on having the monos tucked away nicely too. Getting pretty excited to hear them now!

 

[harrym13]

If you're seeking more power for your speakers, I'm afraid I have to inform you that there won't be a significant difference. The increase is only around +2.5dB. Your speakers have a sensitivity of 91dB at 1 meter, and with the AVR amplifier providing an additional 19dB, you’re already achieving 110dB at 1 meter, which is quite substantial. To double the perceived volume (a +10dB increase), you would need to reach 120dB at 1 meter. To achieve that, you'd require an 800W amplifier, compared to the current 80W.

I'm not looking for particularly more power - the Arcam can drive the Tannoys pretty loud already...

My main issues with the AVR are it being awkward to move out of the living room/transport to other venues and suitably locate it at said party (safe from not-sober folk!)... Also, giving it enough space to prevent it from going into thermal protection can be a pain (which I think means I often hold back on pushing the full power envelope of the amp, so i'm probably rarely getting most of the power handling capability out of it anyway - perhaps my unit is generating mroe heat than it should do.... It also has no XLR/balanced inputs which are preferred when outputting audio from the Pioneer mixer.

Anyhow, yes, i'm well versed in the power requirements for proper party volume levels (I go to a fair few clubs/parties with huge multi-kw soundsystems) so i'm not expecting to break physics with these little V3 monos. But hoping they can put in a good shift for a relatively low cost!

 

[SMen]

I'm not looking for particularly more power - the Arcam can drive the Tannoys pretty loud already...

My main issues with the AVR are it being awkward to move out of the living room/transport to other venues and suitably locate it at said party (safe from not-sober folk!)... Also, giving it enough space to prevent it from going into thermal protection can be a pain (which I think means I often hold back on pushing the full power envelope of the amp, so i'm probably rarely getting most of the power handling capability out of it anyway - perhaps my unit is generating mroe heat than it should do.... It also has no XLR/balanced inputs which are preferred when outputting audio from the Pioneer mixer.

Anyhow, yes, i'm well versed in the power requirements for proper party volume levels (I go to a fair few clubs/parties with huge multi-kw soundsystems) so i'm not expecting to break physics with these little V3 monos. But hoping they can put in a good shift for a relatively low cost!

What I find most interesting about your post, is the quality of the speakers you are bringing to these gigs!

And some ear defenders if they value their hearing

It's in situations like this people lose their hearing!

If you're seeking more power for your speakers, I'm afraid I have to inform you that there won't be a significant difference. The increase is only around +2.5dB. Your speakers have a sensitivity of 91dB at 1 meter, and with the AVR amplifier providing an additional 19dB, you’re already achieving 110dB at 1 meter, which is quite substantial. To double the perceived volume (a +10dB increase), you would need to reach 120dB at 1 meter. To achieve that, you'd require an 800W amplifier, compared to the current 80W.

Yes, it's kind of why I used the word 'punch'!

@harrym13 I would very much like to hear how you get on with those Tannoys and the Fosi v3 monos.

Whatever your mixer is outputting is key (and your mix).

Back in my (vinyl) day I suspect we would have been relying on something from Stanton! That's my world!

Post edit : to provide the "punch".

 

[TimF]

A company develops a product that becomes popular, how do they produce tens of thousands of them? I am stupid about high volume production.

I am twentieth century and not equipped to comprehend twenty first century. I cannot comprehend how to produce fifty million Apple watches in a year. That seems an impossible task. It requires production of about 160,000 Apple watches each day. How do you even box 160,000 watches in one day? And as you are working on boxing today's 160,000 watches, have you completely dispatched yesterday's 160,000?

You people know these things. Explain it to me.

The Apple watch is by volume mostly the battery and the case, and then the electronic display on the visible surface. And there is a small amount of miniaturized electronic circuitry. It is largely, though, a battery and a metal case. There must be many, many, many suppliers across Asia. Moving the goods is an industry in itself. 50 million watches in one year. What a production problem.
So much for scale and realities of Apple watch production. A bigger question, how do you produce 230 million Apple phones each year. That requires producing over 700,000 each production day.

1.2 million people are employed by Foxconn that manufactures Apple phones. Apple I phone production is moving to or expanding to India from China. Clearly, armies of people are involved in mass production for products sold globally.

 

[Mort]

I have a basic math question about power.

I got the 10 amp version and using with a Wiim Ultra into 4ohm speakers. The Wiim puts out 2Vrms and the Fosi has a ~2.4Vrms input sensitivity at 4ohm.

Amir measured the Fosi output at 4 ohms in the 230 Watts range. If I have the Wiim at full 100 / 2Vrms the Fosi should be delivering around (2/2.4)*240 or 200w? Is that approximately and conceptually right?

 

[antcollinet]

I have a basic math question about power.

I got the 10 amp version and using with a Wiim Ultra into 4ohm speakers. The Wiim puts out 2Vrms and the Fosi has a ~2.4Vrms input sensitivity at 4ohm.

Amir measured the Fosi output at 4 ohms in the 230 Watts range. If I have the Wiim at full 100 / 2Vrms the Fosi should be delivering around (2/2.4)*240 or 200w? Is that approximately and conceptually right?

No, because power is proportional to the square of the voltage (P=V^2/R)

So you need (2^2)/(2.4^2) = 4 / 5.76 * 230W = 160W

 

[Mort]

Ah I knew it couldn't be that simple, ty.

And if I put a 4v DAC in between, I would see something close to the 230w?

I don't need this for any reason although I have the equipment to do it so I might.

 

[antcollinet]

I don't need this for any reason....

Exactly - if you already have the gear, you can obviously try it. But I wouldn't spend much money for it.

The difference between 160W and 230W is only 1.6dB (Or approx 16% perceived volume increase)

 

[Mort]

I don't think I really understand 'headroom' but that would be the 'reason'?