Fosi Audio V3 Mono Amplifier Review

[quocheiser]

I couldn’t help myself and added 2x V3M and the SP601 speakers to my previous pledge for 3xV3M.

I have a 5.1 setup with a Marantz S6012 as receiver. My speaker setup is as follows:
- Fronts: Monitor Audio GS10 (relatively modest speakers)
- Center: Monitor Audio GSLCR
- Surrounds: the idea is to put the SP601 as surrounds.

Now, with 5 V3 Mono’s to play with, should I go for:
A. Each speaker its own amp
B. Bi-amp the fronts, and drive the surrounds with the S6012’s internal amp?

Of course I’ll experiment, but happy to hear your thoughts on this

If you wanna be a real G then bi-amp the fronts, and give all other speakers their own amp

 

[quocheiser]

I'm saying there is nothing to be heard in the sound waves reaching your ears. If you are hearing what you are saying you are, it is most likely happening in the wetware between them.

There is no physical way for an audible difference to happen - unless in the single amped case, the relatively small amount of power going to the tweeter is pushing the amp over the edge of its power capacity. This seems to me to be a fairly unlikely edge case, and can be solved by using an appropriately rated amp.

I hear you, and even if that is the general consensus on ASR, I respectfully disagree on the first point. Maybe when I'm in my 50s I won't hear a damn difference but for now, I will enjoy the last slivers of my hearing.

On your 2nd point, yeah I personally don't fully understand how it actually works as I am no acoustician/physicist/EE etc. but in my experience, having extra reserves of power often improves dynamics. In the above video, that's not even a proper bi-amping setup (it's somewhere between bi-wiring and bi-amping) as they are using just one (1) AV receiver(!) and yet hey it works. My best guess is that the power demands of each driver are easier to serve with a dedicated channel of power if the speaker's crossover is designed well.

 

[antcollinet]

don't fully understand how it actually works

it is most likely happening in the wetware between them.

Until you've done a properly controlled blind test - this is the only conclusion that can be reached.

 

[Lednek]

I think you might be right on this - especially with 8 ohm speakers. I think that I am right that 8ohm speakers favour amps as a priority? I might be wrong.
I'm using another 3255 happily with 36v. I'm going to do a comparison with matched gain to see when the v3 monos arrive, and see if I detect any difference at up to 14 khz ... my limit I am pretty sure at 57! ...

8ohm speakers need voltage, low impedance speakers, amperes.

 

[quocheiser]

Until you've done a properly controlled blind test - this is the only conclusion that can be reached.

I see what you did there .
I’d prefer to measure and share, rather than rely on my “wetware” . But I don’t have my own bi-amped set up yet.

 

[Rafaille]

The value of time and money is in the ear of the beholder.
Feel free to listen to this video where the poster (ironically) can't hear a difference.

Despite the poor room acoustics and recording quality, to my ears and on my modest listening setup the bi-amping off the same AV receiver (rather than via separate monoblocs etc) is better. There is more depth, separation and weight to the different layers in the music which I'm sure would show up via a FR graph.
In saying that, I'd say most people (80-90%) won't hear the difference or enough of one.
Furthermore, synergy between the different parts of the audio chain will have a big say on the end result.
FWIW I'm definitely planning on a bi-amped system if/when I upgrade my speakers and would happily share measurements of the results when that happens.

I would happily have a look at these measurements, good luck on your quest

 

[Billy Budapest]

Despite the poor room acoustics and recording quality, to my ears and on my modest listening setup the bi-amping off the same AV receiver (rather than via separate monoblocs etc) is better.

Are you using your receiver to power the tweeters (or woofers) and a separate power amp to power the woofers (or tweeters)? Just trying to figure out exactly what you mean by the words “off the same receiver.”

 

[Billy Budapest]

My best guess is that the power demands of each driver are easier to serve with a dedicated channel of power if the speaker's crossover is designed well.

That’s not how electricity works, unfortunately.

 

[Rafaille]

That’s not how electricity works, unfortunately.

Maybe not about power but is there not always a (tiny) bit of crosstalk between channels when powering up both tweeters and woofers off a single amp? (genuine open question)

 

[quocheiser]

I would happily have a look at these measurements, good luck on your quest

Perhaps a fool's errand, dripping in snake oil. I'll still enjoy the quest

 

[quocheiser]

Are you using your receiver to power the tweeters (or woofers) and a separate power amp to power the woofers (or tweeters)? Just trying to figure out exactly what you mean by the words “off the same receiver.”

In that video, they're using one AV receiver and then using one speaker output per driver.
I honestly thought it was a pointless idea until I listened to it.
I mean, if there is more power reaching each driver, especially from an underpowered AV receiver, it can't be too hard to imagine that an improvement might be had, surely?

 

[antcollinet]

Maybe not about power but is there not always a (tiny) bit of crosstalk between channels when powering up both tweeters and woofers off a single amp? (genuine open question)

No. When bi amping both amps still amplify all the frequencies, and deliver them as a power signal to the terminals of the speeker. So the terminals of the speaker see the exactly the same regardless of whether it is delivered by one amp, or two.

It is only in the crossover that the frequencies are separated - and it is here that any imperfections exist.

 

[quocheiser]

That’s not how electricity works, unfortunately.

Apparently it is?

Bi-amping 101

This article provides a quick look at how bi-amplification works. The conventional scheme is to split the signal into two frequency bands before the power amplifiers that drive the speakers. The bass (LF) amp sees only LF signals and drives only the LF driver (woofer). The treble (HF) amp sees...

www.audiosciencereview.com

Bi-amp, bi-wire, passive crossover & active crossover interaction

My background is pro audio, where bi/tri-amp is well known. It requires an active crossover, feeding separate amplifiers, such that each speaker (sub/woof/tweet) receives only it's intended frequency range. I see quite a few consumer loudspeakers with two sets of terminals that default to being...

www.audiosciencereview.com

 

[quocheiser]

No. When bi amping both amps still amplify all the frequencies, and deliver them as a power signal to the terminals of the speeker. So the terminals of the speaker see the exactly the same regardless of whether it is delivered by one amp, or two.

It is only in the crossover that the frequencies are separated - and it is here that any imperfections exist.

See previous post.
Even the OPs decline from making too many absolute statements.

 

[antcollinet]

if there is more power reaching each driver,

But there isn't more power reaching each driver, unless the amp is being driven into clipping (the edge case I mentioned above). In which case the correct solution is to use an amp with enough power, rather than bi-amping.

In your case you already (will) have an amp with enough power. Don't waste them by using two per speaker.

 

[antcollinet]

See previous post.
Even the OPs decline from making too many absolute statements.

Those are describing the case I mentioned above - where you remove the speaker crossover, and implement an active crossover filter UPSTREAM of the amps (between source and amp)

You are not proposing to do that.

Here is what the article YOU linked to (I suggest you try reading it) says about the passive bi - amping you are proposing...

 

[quocheiser]

But there isn't more power reaching each driver, unless the amp is being driven into clipping (the edge case I mentioned above). In which case the correct solution is to use an amp with enough power, rather than bi-amping.

In your case you already (will) have an amp with enough power. Don't waste them by using two per speaker.

That usually costs more (which is an important point).
These Fosi V3 Monos are affordable and the user can be as modular with how they build their system as they like.
So easy to get more power with two of these miniblocks on their own power supplies rather than one larger amp
Pretty cool option tbf.

 

[quocheiser]

Those are describing the case I mentioned above - where you remove the speaker crossover, and implement an active crossover filter UPSTREAM of the amps (between source and amp)

You are not proposing to do that.

That's the most optimal solution, but again costs more.
But yeah would be cool to do that with these V3Ms.
Not sure if I'll personally go down that road though, purely based on cost and space factors.

 

[antcollinet]

So easy to get more power with two of these miniblocks on their own power supplies rather than one larger amp
Pretty cool option tbf

Read the passive bi amping section of the article you linked to. It explains why you won't even get more power.

And with that, I'm going to stop playing whack a mole with this discussion, and bow out.

 

[quocheiser]

Read the passive bi amping section of the article you linked to. It explains why you won't even get more power.

And with that, I'm going to stop playing whack a mole with this discussion, and bow out.

Those are describing the case I mentioned above - where you remove the speaker crossover, and implement an active crossover filter UPSTREAM of the amps (between source and amp)

You are not proposing to do that.

Here is what the article YOU linked to (I suggest you try reading it) says about the passive bi - amping you are proposing...

View attachment 368028

Cherry picking a little there, I'll refrain from doing that myself.
The OP tempers their statements really well on the last page, as do many of the commenters.
Don't forget to enjoy the hobby .