Fosi Audio V3 Mono Amplifier Review

[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.

 

[RCL162]

i forgot to turn on my small fan on the side of the fosi v3 mono amplifier, and only half of the album is playing and it's very hot.

i'm using SB acoustics full range 8 inch speakers and discrete blameless preamp (DIY, no opamps no headache), i like the sound and and yes the heat generated by these little amps is also good. i have a V3 stereo 32v and it doesn't get as hot as this.

 

[RCL162]

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.

bought mine from a local store, and received it in 4 days. there may be something wrong with your shipping service.

 

[RCL162]

Is there a reason I need to turn the preamp volume up higher for the v3 monos to get the same loudness as a single ZA3?

My preamp volume never reach 10 o'clock, sir. But maybe different speakers.

 

[RCL162]

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

i use 24v fan with P1 PSU 12v, and stack v3 mono, and put that fan beside it. no noise sir.

 

[burkm]

I checked the amperage of the "upHere" 120 mm USB fan (switchable 3 speeds) at those 3 speeds with my USB measuring instrument: at "Low" it needs 0.14A, at "Medium" it needs 0.17A and at "High"its amperage is 0.20A. Fan noise is very low to inaudible, but haven't tested the highest speed. Even at the lowest speed the V3 Mono temperature (placed underneath the horizontally mounted amp) in idle state (continously ON for about 8 hours) is appr. 30.8°C / 87.08°F. Under full load it's probably somewhat higher...

I then turned on both fans and the amperage measurements shown were 0.35A at "Low", 0.38A at "Medium" and 0,41A at "High" speed. USB-Voltage indicated was 5.22VDC.
Thus a simple 1A USB power supply is needed. This would still work for 3 fans min, if the amperage would add up further as expected. Given the low cost of those instruments those measurements should be OK...

 

[Stoutblock]

I have eight V3M amps now. Use two in my office (balanced) and 6 in my HT system (SE). I bought all direct from Fosi (first two on kickstarter) with totally seamless transactions and quick shipping (to PNW USA). I did have a problem with one but I think it was caused by user error in that I may have hot swapped it with an RCA connection. Fosi had great customer service with response within 24 hours and no language problems. Replacement amp was sent and all they asked was for me to ship the old one back so they could analyse the problem. They reimbursed my shipping. Based on my experience with Fosi I can’t say I have ever had better experience with a direct marketed product.

I did add two passive (finned) heat sinks to the office amps because they are in a cabinet. The 6 HT amps are out in the open so heat is not really a problem.

Oh yeah, the amps work and sound fine for my application in these two systems.

 

[drmevo]

After having these amps since the KS launch I am mostly quite happy with them. In terms of sound and power, I’m completely satisfied.

The one area where they are a bit frustrating is the Auto-On function. Just turning on lights on the same circuit seems to trip it. I unplugged the speaker cable in case it was poor power filtering from my preamp but that wasn’t the issue - the amps still turn on with just power connected.

This wouldn’t bother me that much except for that a) the relay click is fairly loud - someone not used to it thinks they’ve done something wrong by flipping the light switch and b) they do seem to use a decent amount of power while on. It also begs the question, how good is the power filtering if simply using other things on the same circuit trips the Auto function?

 

[burkm]

It depends what You mean by "...other things...", because a) the function is been activated by some "electronic dirt" coming through by the chosen input or b) some spikes on the power supply input has triggered it. As long, as nobody has identified it with some trustworthy idea or measurements, it is hard to tell, what really had triggered that function...
Depending on the outcome, I would be reluctant to provide an opinion on this right now...

 

[burkm]

I checked the amperage of the "upHere" 120 mm USB fan (switchable 3 speeds) at those 3 speeds with my USB measuring instrument: at "Low" it needs 0.14A, at "Medium" it needs 0.17A and at "High"its amperage is 0.20A. Fan noise is very low to inaudible, but haven't tested the highest speed. Even at the lowest speed the V3 Mono temperature (placed underneath the horizontally mounted amp) in idle state (continously ON for about 8 hours) is appr. 30.8°C / 87.08°F. Under full load it's probably somewhat higher...

I then turned on both fans and the amperage measurements shown were 0.35A at "Low", 0.38A at "Medium" and 0,41A at "High" speed. USB-Voltage indicated was 5.22VDC.
Thus a simple 1A USB power supply is needed. This would still work for 3 fans min, if the amperage would add up further as expected. Given the low cost of those instruments those measurements should be OK...

I checked the temperatures of both V3 Mono amps after about 4 hours in "idle state" (fans setting for "Low"): 30.4°C. I re-checked them after more than 10 hours running (XLR input) and they are at about 30°C. I might try it lateron with some content playing endlessly (loop)