Fosi Audio V3 Mono Amplifier Review

[manisandher]

Many in the thread question the point of mono amplifiers, but at least one advantage of small mono amplifiers of this kind is if you want to use active crossover filters and need two or more amplifiers per speaker.

Yep. I use up to 10 amps in an active setup. 5 of these stacked neatly on the side of each speaker would be a very nice solution.

 

[Hipocrates]

When people are watching entire movies at their "worskstations" with headphones, and critically listening to music on their gaming chair in front of a large LCD monitor, you know there is a paradigm shift.

That's me, on last maybe 4 years.
I do have however a dedicated place for music with some gear and big speakers, the other day I grabbed a couple of cds and played them, It was sooo relaxing. I totally forgot how diferent the experience is, just listening a full album without distractions.
That sais I'll get a pair of these llittle things, they sooo inexpensive! I find this little amps very fun!

 

[antcollinet]

I bought a 3e stereo amp board for 134 dollars shipped. Its 6 amp 48 volt power supply was another $40.00. For $174.00 I got 99% of what two of these give me (Not to mention that the 3e has 2 db better SINAD) . If you want to spend $106.00 more to get a bit less than be my guest.

You've only got 3A per channel available rather than 5A. That is less than half the power. Plus you seem to have missed out the cost of the housing, connectors, switches, auto sense/trigger, - and the cost of your time to build the amp.

 

[JSmith]

I bought a 3e stereo amp board for 134 dollars shipped

This really has nothing to do with this review thread... that is a DIY option, this is a built amp. The 2 are not exactly comparable, apples and oranges.


JSmith

 

[Jhify]

Any idea what the longevity of the Fosi Audio V3 Mono amp should be compared to Hypex or Purifi amps? I have always stayed away from external power supplies in the past as they typically have been the weakest link in my experience.

If it’s basic barrel non-proprietary connexion maybe you can replace it with any power supply.

 

[Golf]

Btw ... We have no less than 280 people who »rated« this amplifier?! That’s cute ...

 

[Sokel]

If it’s basic barrel non-proprietary connexion maybe you can replace it with any power supply.

That would defeat the purpose though,wouldn't it?
The sole value of this amp is it's price.
Modding it,replacing stuff etc can get you to a point that you could get a nicer amp.

 

[fatoldgit]

I want a 4 pack!

indeed.

While Fosi have their business plan, a full width package with a decent look and the option of say 2 - 7 boards (if 7 would fit) with IEC plug and increasingly larger internal power supplies as needed for increase in channels would be a killer offering in my opinion.

Price it as a premium offering but it would still undercut all the big boys.

Peter

 

[antcollinet]

If it’s basic barrel non-proprietary connexion maybe you can replace it with any power supply.

Its a £50 item. Not a big deal to replace if it fails.

 

[Golf]

The sole value of this amp is it's price.

So the sole value as well as the price are very, very low, right?

 

[Sokel]

indeed.

While Fosi have their business plan, a full width package with a decent look and the option of say 2 - 7 boards (if 7 would fit) with IEC plug and increasingly larger internal power supplies as needed for increase in channels would be a killer offering in my opinion.

Price it as a premium offering but it would still undercut all the big boys.

Peter

The IEC plug (internal PSU) is not as simple as it looks as the amp would need certification of it;s own so can be sold through USA and EU retailers.
Than would take time+money.

There's a reason for using these pre-certificated PSUs and the ones that don't use them are usually only sold through Ali express and other dubious places.

 

[Sokel]

So the sole value as well as the price are very, very low, right?

Let's say it the other way around,look at the reviews and you'll see Amir stating "good for class" sometimes or similar phrasing.
That's exactly what it means.

 

[Talisman]

The sole value of this amp is it's price.

You say? He would have agreed when we talk about products with load dependence, with audible noise, with RCA only inputs but still with a decent power, then yes, you paid little but you still got something decent with some compromises, but with this Fosi product has entered a different playing field, noise and distortion thrown at -100db, in the category of the best of the best, load dependence almost eliminated, decent power available with loads even at 2ohm, it can drive practically anything, balanced and unbalanced inputs, input signal detection, variable gain....
We maintain an increase in distortion increasing with high frequencies of dubious audibility and in any case quite common to other higher class D designs.
The point of this product is that it is no longer "good for the price" it is simply good, very good in fact, overall and plus it costs very little, but it is an added benefit, it is no longer the heart of the value.
If Fosi confirms the reliability of its products (as has been the case up to now) they are ready to overtake Topping also in the quality amplification sector.

 

[MCH]

indeed.

While Fosi have their business plan, a full width package with a decent look and the option of say 2 - 7 boards (if 7 would fit) with IEC plug and increasingly larger internal power supplies as needed for increase in channels would be a killer offering in my opinion.

Peter

You stole my idea

 

[Sokel]

You say? He would have agreed when we talk about products with load dependence, with audible noise, with RCA only inputs but still with a decent power, then yes, you paid little but you still got something decent with some compromises, but with this Fosi product has entered a different playing field, noise and distortion thrown at -100db, in the category of the best of the best, load dependence almost eliminated, decent power available with loads even at 2ohm, it can drive practically anything, balanced and unbalanced inputs, input signal detection, variable gain....
We maintain an increase in distortion increasing with high frequencies of dubious audibility and in any case quite common to other higher class D designs.
The point of this product is that it is no longer "good for the price" it is simply good, very good in fact, overall and plus it costs very little, but it is an added benefit, it is no longer the heart of the value.
If Fosi confirms the reliability of its products (as has been the case up to now) they are ready to overtake Topping also in the quality amplification sector.

Agree for the overall performance but as we are used to value engineering more than audibility here these "flaws" (as the rising distortion,19+20Khz tests,etc) stand out.
I would argue about thermals also in such a small case but it will be probably fine for most uses.

(fine tunning of PFFB as shown by Fosi maybe improved it some more and that's nice)

 

[holbob]

Why don't they set full power for 4 volts instead, so we don't have to attenuate and amplify noise at the same time? Most music today is maximized and has a few db of dynamic range, and hardly ever we reach for full potentiometer at home, so that we don't ever reach clipping.

I bypassed the input buffer stage on a Hypex NC122MP amp, for a total of 13db gain, perfect for my needs. (26db default was too much, I found hard to regulate volume in the first degrees, too much gain for nothing. That amp reached full power at 1.17V at 4 ohms for balanced inputs!)

Because youtubers create bespoke tests to describe amplifiers with less gain as "anemic" because it doesn't fit their very narrow usage requirement. With the Fosi v3 I still have 20db of headroom even at the loudest mark I ever listen at. Usual volume it's 28-30db headroom and that's with turning the Fosi v3 volume knob down to the 2/3 mark. A gain switch solves all these problems - wonder what the cost to manufacturers actually is adding a gain switch.

 

[Jhify]

That would defeat the purpose though,wouldn't it?
The sole value of this amp is it's price.
Modding it,replacing stuff etc can get you to a point that you could get a nicer amp.

I was saying in case the one provided fails in few years.

 

[Jhify]

Let's say it the other way around,look at the reviews and you'll see Amir stating "good for class" sometimes or similar phrasing.
That's exactly what it means.

There’s way better on the market for sure but even with a worst amp than this Fosi the weakest link in the chain will be our ears

 

[gwing]

This looks like a tacky Walmart alarm clock ...

It has a sort of bizarre appeal though, just the thing to have in use on your main system when an old-school audiophile friend comes round

 

[mdsimon2]

Because youtubers create bespoke tests to describe amplifiers with less gain as "anemic" because it doesn't fit their very narrow usage requirement. With the Fosi v3 I still have 20db of headroom even at the loudest mark I ever listen at. Usual volume it's 28-30db headroom and that's with turning the Fosi v3 volume knob down to the 2/3 mark. A gain switch solves all these problems - wonder what the cost to manufacturers actually is adding a gain switch.

There is certainly a balance here. Don’t want gain too high to unnecessarily amplify noise (and also hurt ASR ranking) but also want enough gain / voltage from the DAC to account for lower level recordings if needed. I think this is a somewhat modern issue as many people no longer run preamps and use DACs for volume control.

At 20.5 dB gain and 100 W in to 8 ohm you still have the ability to overdrive the amp with a typical 4 V output DAC by about 3.5 dB. I personally prefer a bit more gain as I use lower sensitivity speakers but I am sure this amp is fine for 99% of source material / speakers.

Michael