Fosi Audio V3 Mono Amplifier Review

[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)

 

[burkm]

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.

View attachment 393358

On Amazon there are some really quiet fans (inaudible) from i.e. "upHere" N1204 or U1204, both are 120 mm USB DC-fans with standoffs and black protective grills, which provide 3 speeds each plus an USB splitter for combining them for 1 USB power supply connection. The lowest speed should be sufficient for cooling the V3 Mono amps. Depending on the model ordered they have 2 or 4 pole cables with USB connectors. Others (like SCCCF, Marame, Eluteng, AC Infinity, NewHail etc., some might be OEMs ) at almost the same price are also offered: it's your choice. They are really quiet at 18db/19db each (inaudible) at their lowest settings and feature dual ball bearings. Two fans for two amps then would add up to ~22 db of fan noise ? They fit comfortably underneath the amp(s) and need about 0.336 A each... If wanted You might add some higher ruibber feet to those amps (for further clearance).

They are also inexpensive at 17$-18$ (€) for two fans (complete sets), delivery would be free of charge for Amazon Prime customers. These should be much cheaper than those ordered from Fosi Audio...
I got those and I am more than satisfied with them...
I also ordered some cheap self adhesive rubber feet for the V3 Monos to have the amps firmly positionend above each fan for additional clearance.

 

[EddNog]

In case anyone has a single 48V/10A power supply and wants to change to separate 5A units, I am giving away some power supplies (you pay shipping).

Thread 'FREE (But You Pay Shipping): 48V Power Supplies for Power Amplifiers (Fosi, Aiyima, Douk, etc.)'
https://audiosciencereview.com/foru...-power-amplifiers-fosi-aiyima-douk-etc.57103/

-Ed

EDIT: All spoken for now.

 

[Mort]

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

I was more curious about my math. Was it correct?

I didn't do RCA because I couldn't find the input sensitivity. If we assume it's 2v then

(1.6^2)/(2^2) = 2.56 / 4 * 230W = 147w

 

[Brian Hall]

I'm using a Wiim Ultra as the preamp for a pair of V3 monos driving Klipsch Heresy IVs. They have way more power than needed for these speakers. Sounds great.

The Wiim Ultra needs an option to do volume steps by 1 instead of 4 or whatever it is now when using the remote. That was one thing the Eversolo DMP-A6 did better. It had an option for the volume step.

 

[galego100]

@Fosi Audio The worst customer experience i had!! Everything is getting more worse.

 

[ninetylol]

@Fosi Audio The worst customer experience i had!! Everything is getting more worse.

I have to agree. One of my V3 monos Was damaged, I sent pictures, they ask for a video. I sent them a video no response. When I write them again, they tell me to send them a video again.

The are completly clueless, helpless and useless. Terrible!

 

[galego100]

I still don´t have the monos i pledged on May! On September 3 they said they have re-send it. They send me a tracking number , the product is still stuck on their warehouse , the carrier haven't collected the packaging yet
They´ve send me a tracking number just to shut up me , because probably they don´t have stock... They don´t answers the emails or give any explanation ...
@Fosi Audio if there a option to refund my money or my pledge, i want to proceed . I don´t want anymore any of your products.
I will give feedback and advise potential buyers of your customer support on regular foruns , as AV forum , AVS foruns .

 

[burkm]

@ninetylol
Just one thing to tell: Every company has once-in-a-while problems with some of their stuff (and items). It is not unusual, that even expensive items are defective, That is main reason warranty is for. Just check, if their wish of sending a video has been satisfied (suggested URl used ?), because they might expect ist at another place ? Often service is handled by several people working in parallel, which don't know, what is going on, if You - as an example - changed the message title somehow, because many customer support systems look for identical titels...

@galego100
You have to be patient. even if they might not have any stock currently. They probalby sent You the new tracking ID for Your address (and problems with spanish customs) even if they currently don't have any stock... That item and its tracking ID is now reserved for You... but delivery will only take place if they have the corresponding goods available. There might be a longer list of people waiting for their orders, and You are in line for that but not the 1st...
Its not their "fault" to not have any goods for that item You are waiting for.

 

[galego100]

@galego100
You have to be patient. even if they might not have any stock currently. They probalby sent You the new tracking ID for Your address (and problems with spanish customs) even if they currently don't have any stock... That item and its tracking ID is now reserved for You... but delivery will only take place if they have the corresponding goods available. There might be a longer list of people waiting for their orders, and You are in line for that but not the 1st...
Its not their "fault" to not have any goods for that item You are waiting for.

I pledge their product, after that ,many buyers from Amazon per example bought and receive their monos , and i was an early adopter , have no monos , no money , and i have to be patient ??!!!!
Sorry , but i don´t agree with you... Terrible and awful support.

 

[burkm]

You don't have to agree to my position and opinion

My opinion: It's not Fosi Audio's fault but that of the Spanish Customs. Thus I don't know what You are complaining about because Fosi Audio is going to sent another set to Your address. Fosi can't probably sent Your V3 monos because they don't have any available currently, thus Your official address and the trackin ID is placed on the waiting list. Nobody is going to conjure up because of this, You just have to wait, don't You, although patience doesn't seem to be Your primary motion ?

Sorry, neither I can't help You nor - at least it seems to me - Fosi Audio right away...

 

[galego100]

You don't have to agree to my position and opinion

My opinion: It's not Fosi Audio's fault but that of the Spanish Customs. Thus I don't know what You are complaining about because Fosi Audio is going to sent another set to Your address. Fosi can't probably sent Your V3 monos because they don't have any available currently, thus Your official address and the trackin ID is placed on the waiting list. Nobody is going to conjure up because of this, You just have to wait, don't You, although patience doesn't seem to be Your primary motion ?

Sorry, neither I can't help You nor - at least it seems to me - Fosi Audio right away...

LOL , 5 months waiting i don´t have patience ? It´s easy to talk when is everything ok... I ´m not a rich person, of course i have to be upset with all this situation... The main error here, is i´m customer who became from the kickstarter project.. After that customers from other stores as Amazon receive their monos... Fosi wait to much to try to solve the problem, which in fact not solve , yet.