Fosi v3 Mono - User Impressions | Owner's Thread

[EddNog]

Someone else did point out that reversing cable polarity to the speakers may not necessarily be the best solution due to potential conflict with some speaker crossover components. Although…in my mind, I’m not sure why this would be a problem. Of course, I’m not electrical engineer.

-Ed

 

[antcollinet]

Someone else did point out that reversing cable polarity to the speakers may not necessarily be the best solution due to potential conflict with some speaker crossover components. Although…in my mind, I’m not sure why this would be a problem. Of course, I’m not electrical engineer.

-Ed

The crossovers won't care - in fact they can't "tell" polarity : They just see an ac waveform.

 

[EddNog]

The crossovers won't care - in fact they can't "tell" polarity - especially on a BTL or PBTL amp such as this one.

Thank you. Good thing someone else said it and not I!

-Ed

 

[antcollinet]

Thank you. Good thing someone else said it and not I!

-Ed

Sorry - should I have preceded that statement with a trigger warning?

 

[jbaumann]

I‘m now proud owner of 2 V3Mono amps and I‘m quite happy with them.

My normal setup is a RPi connected to a Topping E70, this is connected to a Rowland Concentra A/B amplifier which drives Magnepan speakers (MG1.6). In addition I have connected an SVS SB1000Pro to the Pre Out (RCA) of the Concentra.

Now to test this I also connected the V3Mono amps to the Pre Out (XLR) of the Concentra and connected them to the Maggies. Interestingly, they have about 4dB less gain than the Concentra, but after reducing the subwoofer volume, the sound is impressive and, with slight deviations (compared using REW), on par with the Concentra. If we take price difference into account this is just short of unbelievable.

But: This morning, when I turned on my system (all of the devices at once using a smart plug), the cirucit breaker got triggered (16A). I find this very strange and a little bit worrying. Has anyone else had similar experiences?

Cheers, Joe

 

[jvdburgt]

I‘m now proud owner of 2 V3Mono amps and I‘m quite happy with them.

My normal setup is a RPi connected to a Topping E70, this is connected to a Rowland Concentra A/B amplifier which drives Magnepan speakers (MG1.6). In addition I have connected an SVS SB1000Pro to the Pre Out (RCA) of the Concentra.

Now to test this I also connected the V3Mono amps to the Pre Out (XLR) of the Concentra and connected them to the Maggies. Interestingly, they have about 4dB less gain than the Concentra, but after reducing the subwoofer volume, the sound is impressive and, with slight deviations (compared using REW), on par with the Concentra. If we take price difference into account this is just short of unbelievable.

But: This morning, when I turned on my system (all of the devices at once using a smart plug), the cirucit breaker got triggered (16A). I find this very strange and a little bit worrying. Has anyone else had similar experiences?

Cheers, Joe

Coincidence, but I just today hooked up my 5 V3 mono's to a smart plug (single plug to control all 5), and runs as smoothly as I could have hoped for:

Furthermore, when I look at the extended graph, there are no power peaks above 51 W (for all 5 combined as mentioned). Standby usage of all 5 together is 20W, so quite happy qwith my smart plug implementation).

 

[Rafaille]

Coincidence, but I just today hooked up my 5 V3 mono's to a smart plug (single plug to control all 5), and runs as smoothly as I could have hoped for:
View attachment 382348
Furthermore, when I look at the extended graph, there are no power peaks above 51 W (for all 5 combined as mentioned). Standby usage of all 5 together is 20W, so quite happy qwith my smart plug implementation).

Is standby 'off' or 'auto' setting on the V3s?
Nice Home Assistant graph

 

[jbaumann]

Ah, Home Assistant. I see the same for my two amps (10W per amp during normal operation) at normal listening volume. I‘ve been using the setup for three days and this was the first time it happened. So, this is something that happens only occasionally.

The challenge in my case is that the circuit breaker got triggered so fast that no telemetry was sent to my MQTT instance, so I don‘t have additional data.

For the moment I have changed the setup so that one of the V3Monos is turned on with a slight delay. I‘m curious whether this approach fixes the problem, but also whether others have the problem also.

Cheers, Joachim

 

[jvdburgt]

Is standby 'off' or 'auto' setting on the V3s?
Nice Home Assistant graph

Based on feedback from another user I set them to auto (haven’t tried to set it to on). HA is programmed to flip the switch on the smart plug 11 minutes after my receiver is turned off.

 

[jvdburgt]

Ah, Home Assistant. I see the same for my two amps (10W per amp during normal operation) at normal listening volume. I‘ve been using the setup for three days and this was the first time it happened. So, this is something that happens only occasionally.

The challenge in my case is that the circuit breaker got triggered so fast that no telemetry was sent to my MQTT instance, so I don‘t have additional data.

For the moment I have changed the setup so that one of the V3Monos is turned on with a slight delay. I‘m curious whether this approach fixes the problem, but also whether others have the problem also.

Cheers, Joachim

If that is a recurring problem, then I’m sure my quintuple setup will experience it soon

I will post here if something unbecoming happens

 

[jvdburgt]

Is standby 'off' or 'auto' setting on the V3s?
Nice Home Assistant graph

Sorry, misread your question: so standby is auto; usage is after the amps go in auto-standby but before (obviously) the smart switch kills the power.

On a side-note: when on, they (together) use 50W on a very very stable level. No matter if I play nothing or quite loud music, power consumption doesn’t really change it seems.

 

[Negatywny]

I have a slightly sad and reflective story for you, relating to the use of V3M in a surprising way...

Over the weekend, I decided to organize the cables in my rather complicated set
(stereo amplifier, Fosi V3M power amplifiers, home theater receiver, DAC, amplifier switch, tuner and turntable, PC, TV).

Well, it turns out that the power supply plugs of the Fosi power amplifiers, unless you are very careful, do not differ much from the plug of the power supply cable of my DAC.
So it turns out that there are absolutely no obstacles to inserting the plug from a 48V power supply into a DAC powered by 5V USB.

As you might expect, I only saw a small flash, followed by the typical smell of burning electronics.

State of the art, $200 DAC went to heaven in a blink of the eye.

Watch your plugs people...

 

[EddNog]

Sorry to hear, my friend. That is really sad to hear.

-Ed

 

[gwing]

I have a slightly sad and reflective story for you, relating to the use of V3M in a surprising way...

Over the weekend, I decided to organize the cables in my rather complicated set
(stereo amplifier, Fosi V3M power amplifiers, home theater receiver, DAC, amplifier switch, tuner and turntable, PC, TV).

Well, it turns out that the power supply plugs of the Fosi power amplifiers, unless you are very careful, do not differ much from the plug of the power supply cable of my DAC.
So it turns out that there are absolutely no obstacles to inserting the plug from a 48V power supply into a DAC powered by 5V USB.

As you might expect, I only saw a small flash, followed by the typical smell of burning electronics.

State of the art, $200 DAC went to heaven in a blink of the eye.

Watch your plugs people...

I feel your pain, thanks for the warning.

 

[Basstölpel]

Ah, Home Assistant. I see the same for my two amps (10W per amp during normal operation) at normal listening volume. I‘ve been using the setup for three days and this was the first time it happened. So, this is something that happens only occasionally.

The challenge in my case is that the circuit breaker got triggered so fast that no telemetry was sent to my MQTT instance, so I don‘t have additional data.

For the moment I have changed the setup so that one of the V3Monos is turned on with a slight delay. I‘m curious whether this approach fixes the problem, but also whether others have the problem also.

Cheers, Joachim

The problem you are experiencing is most probably based on the inrush-current drawn by the simultaniusly starting devices. For a short moment that does far exceed the current drawn during normal operation. You can either swap the circuitbreaker to a b-type (slower reacting) or put a current limiting NTC (Anlaufstrombegrenzer) adapter in front of your powerstrip.

Your solution of delaying the start of one device should in all probability solve the issue, too

 

[audioguy272727]

On a whim, I was on Amazon.ca yesterday and noticed they had V3 mono units available so I bought 2 with 48v/5amp supplies. Arrived at lunch time today and playing as we speak. Comparing, in my very non scientific manner, to my PA7. Very comparable but to my user impression, “seems” to have more - and the same level of heat emerging from the unit.

Will continue to audition- I was happy with the PA7 but seemed like supply chain good fortune dared me to take a chance ….. so I did.

 

[SMen]

I have a slightly sad and reflective story for you, relating to the use of V3M in a surprising way...

State of the art, $200 DAC went to heaven in a blink of the eye.

Watch your plugs people...

Unfortunately state of the art but without overload protection.

This mistake is so easy for us to make I wish overload protection was one of the essential requirements of all modern kit ...

However, may I reflect as a glass half full kind of chap... the same thing happened to me with a little Trichord amp called the Amptastic ... still being sold.

So I got an Allo Volt ... better ... and then an Aiyima A07 ... better, well certainly more powerful ... and then I discovered ASR because of the review on the A07...

And now I have a pair of lovely V3 monos... (post edit ... much much much better)

Just think of how best to spoil yourself with a new state of the art $200 DAC ...

I hope my counseling proves beneficial
!

 

[jvdburgt]

If that is a recurring problem, then I’m sure my quintuple setup will experience it soon

I will post here if something unbecoming happens

Yup, just happened to me now as well

So one smart plug to rule them all is not the way forward, unfortunately?

Any trick to circumvent this, other than using 5 smart plugs? Maybe there’s a device that can be put in between to limit the inrush or something?

 

[jbaumann]

My current approach is to use a master-slave-powerstrip that is turned on via the smart plug. You can plug in one of the V3Mono as the master and the other as slave, and that should stagger them just enough. Another approach would be (and that was my original idea, before I found the powerstrip in my storage) to have a power strip turned on via the smart plug, one V3Mono connected directly, the other via a second smart plug. In the best case the boot time for the second smart plug should already be enough, otherwise program it with a 1 second delay…

 

[jvdburgt]

My current approach is to use a master-slave-powerstrip that is turned on via the smart plug. You can plug in one of the V3Mono as the master and the other as slave, and that should stagger them just enough. Another approach would be (and that was my original idea, before I found the powerstrip in my storage) to have a power strip turned on via the smart plug, one V3Mono connected directly, the other via a second smart plug. In the best case the boot time for the second smart plug should already be enough, otherwise program it with a 1 second delay…

Thank you for the suggestion, will try something similar: put the mono's for front speakers on one smart plug, and the mono's for the surrounds on another (and the center without smart plug); with a one second delay between powering them on. Let's see of that does the trick.

I also found a inrush current limiter plug (H-Tronic 1114730) that should do the trick, but that would be another $35-40 down the drain