Fosi Audio V3 Mono Amplifier Review

[DavidM1]

I believe they try to circumvent any "turbulences" among (potential) users due to those "rumors" of high temperatures generated by the V3 monos during use.
They are beeing sold (sometimes) on several marketplaces for similar ones at almost 1/2 the Fosi Audio price, but their size is somewhat special: 125 mm.
A 120 mm fan with USB connection should be fine too...
Note: No info about the additional noise generated and amperage needed by those fans.... An external USB power supply must be used.

This is very funny. You can't blame some Ali Express retailer for supplying a market of panicky audiophiles.

 

[jboyer]

Should I store icepacks?
As a programmer I pay attention to the temperature of my workstation. My multi fan box barely starts these. But if you read the PC literature, modern CPU'S and video cards need tons of fresh air.
For some reasons, it seems that Class D amps generate the same panicking as the Intel 14th gen CPUs.
Before it becomes a problem, it will create death ears.
There is always a customer for a extra fan.

 

[Lux_ury]

I defend the right for people to go through the OP amps, it's a process and it's my right to highlight it's the way your perspective is always gonna be subjective. TBf I'm popping in and surprised OP amps are still a thing?
My understanding is there would be no professional ladies of the night, if there wasn't a demand for the ladies too soon?
My amps have completely cooled nicely with time used on the amps hardly no heat, but ambient has dropped. (Passive cooling is cheap and free)
Fosi still have no production date on the new DC filter My guess it will have two jacks at one end to split the issues.

 

[Freezak]

Should I store icepacks?
As a programmer I pay attention to the temperature of my workstation. My multi fan box barely starts these. But if you read the PC literature, modern CPU'S and video cards need tons of fresh air.
For some reasons, it seems that Class D amps generate the same panicking as the Intel 14th gen CPUs.
Before it becomes a problem, it will create death ears.
There is always a customer for a extra fan.

Intel 13th and 14th gen is defective in its "core", here the potential problem with the V3 Mono is most likely just the heat.

 

[burkm]

This is very funny. You can't blame some Ali Express retailer for supplying a market of panicky audiophiles.

This is not an "Ali Exspress retailer thing", but comes from the manufacturer Fosi Audio itself.
Naturally it is a "new" offering, because the article has not been offered before.
You have to look through their offerings especially "Accessories" (?) to find it...
Fosi Audio is just supplying what their (potential) customers might eventually want
It's the same thing as those different (expensive) OP amps suggested, because the original ones are made replacable ...

 

[amix]

Any numbers for inner resistance? Does someone know the damping factor?

 

[Sokel]

Any numbers for inner resistance? Does someone know the damping factor?

Typically 30-40x for the TPA3255 chip.
It's fine.

 

[burkm]

Is their any value (range) listed in their complex data sheet ?

 

[Sokel]

Is their any value (range) listed in their complex data sheet ?

Here's a real measurement by Archimago,seems like fosi did it better than average:

More than enough,nice and smooth till 10kHz or so.
Is not a DF champion though.

 

[burkm]

For pure "8 Ohm speakers" or resistors it doubles it damping factor value to almost 300 (267 to be exact) ?

 

[ninetylol]

Anyone paired these with the Lintons? I jumped on the wagon now and ordered a pair replacing a Wiim Amp, which is great for it, but with the Lintons i dont actually need a sub anymore so i wanted to give them some new amplifier toys to play with

 

[Sokel]

For 8 Ohm speakers it doubles it damping factor value to almost 300 ?

Yes,but finding true 8 Ohm speakers these days...

 

[burkm]

It did change that to a power-resistor measurement, because most manufacturer defined "8 Ohm speakers" vary wildly in their real impedance
The real damping value at a given impedance varies the same ...

 

[ninetylol]

can someone give me an TLDR of the phase issue? My Monos only got one QC sticker

using 2 monos with inverted phase = no issue?

you should just connect speaker terminals inverted:
+ goes to -
and - goes to + ?

how can i measure correct/inverted phase this using RWE?

 

[burkm]

Both inputs (XLR + RCA) cause phase inversion, thus only a simple reversal of the speaker connection (only on amp side) is needed for all cases. This has been checked by Fosi Audio.
If this setup is used only for stereo (2x V3 mono) than nothing has to be done...
Action has to be taken only for an existing mixture with active subwoofers, AVRs with more channels than V3 Mono amps used etc.
For your case no action has to be taken, because phase inversion as might be, is not audible to human hearing, thus no changes are needed for "normal" (non-inverted) or inverted phase.

 

[Ziroz]

I experienced an issue with one of my amps. While I was listening to music, I heard a loud pop coming from one of the amp enclosures. When I went to check it out, I noticed a burnt rubber smell. I tried rebooting the amp, but only the light turned on and there was no sound at all. I tested different power supplies, audio sources, and speakers, but nothing worked. The amp appears to be completely dead. I am currently seeking a refund for this product.

 

[amix]

Typically 30-40x for the TPA3255 chip.
It's fine.

Thanks. Meanwhile I found this information. According to it, it is >100, I even read 140, but it escapes me as to where.

 

[Freezak]

For anyone interested: i am extremely happy with AC Infinity MULTIFAN S7-P 120mm fans. I am using them together with some extremely cheap chinese temperature controller with its probe put on top of the v3 mono case. It reads the temperature of the case without fans at about 50C, with AC Infinity fans it goes down to 32C after solid 2 hours of music playing, which is outstanding, not something i'd expect. Set the temperature controller to turn the fans on at 35C and turn them off at 31C.

 

[Mort]

Monoblocks are cost effective for HT, one amp per channel and easy to upgrade. The Fosi has a lot of power for the money. Is it good for home theater applications when the preout voltage is often quite low?

Specifically I'm trying to figure out the penalty I'll take using a V3 mono when I have a 'maximum' preout of 1.6v?

I think power is proportional to the square of the voltage (P=V^2/R). My Denon X4800H has a preout voltage that can approach 1.6v. at 4 ohm. The Fosi is about 230w at 2.6v 4 Ohm.

(1.6^2)\ (2.6^2) = 2.56/ 6.76 * 230W = 87W

87w? That seems like a very step penalty. I'm likely very wrong somewhere.

 

[ninetylol]

Monoblocks are cost effective for HT, one amp per channel and easy to upgrade. The Fosi has a lot of power for the money. Is it good for home theater applications when the preout voltage is often quite low?

Specifically I'm trying to figure out the penalty I'll take using a V3 mono when I have a 'maximum' preout of 1.6v?

I think power is proportional to the square of the voltage (P=V^2/R). My Denon X4800H has a preout voltage that can approach 1.6v. at 4 ohm. The Fosi is about 230w at 2.6v 4 Ohm.

(1.6^2)\ (2.6^2) = 2.56/ 6.76 * 230W = 87W

87w? That seems like a very step penalty. I'm likely very wrong somewhere.

Use rca then, only need 1.7 or 0.x volt (with 31db gain)