Fosi Audio V3 Amplifier Review

[antcollinet]

so in my environment the v3 would not cause problems?

i doubt it. but we can't tell from the measurement you posted.

 

[totti1965]

Can it be, that the Fosi V3 gets hotter inside with the 48 Volt 5 ampere Power supply, than with the 32 Volt power supply, even if you just use 0.1 Watt (which is realistic with normal music listening) or there is no music playing at all?
I doubt it. With my 48 Volt 5 Ampere power supply, the Fosi stays pretty cool (perhaps 37 degree Celsius).
Did anyone made a propper measurement?

 

[antcollinet]

Can it be, that the Fosi V3 gets hotter inside with the 48 Volt 5 ampere Power supply, than with the 32 Volt power supply, even if you just use 0.1 Watt (which is realistic with normal music listening) or there is no music playing at all?
I doubt it. With my 48 Volt 5 Ampere power supply, the Fosi stays pretty cool (perhaps 37 degree Celsius).
Did anyone made a propper measurement?

It is quite likely to get hotter with the higher voltage.

Most of the losses in the output transistors (in the chip) will be switching losses. These increase (roughly) proportionally to the voltage being switched. These losses are independent of output power - so form part of the idle losses.

 

[gwing]

this is the frequency response with the Fosi v3 at maximum and the Denon at 9.30 o'clock there are no increases in the high frequencies

How does the frequency response of your speakers tell us anything about the transitory boom you are hearing at power up?

 

[musica]

I took the frequency response not for the boom, but to check the variation at high frequencies with my speakers. Are there always no problems?

 

[antcollinet]

I took the frequency response not for the boom, but to check the variation at high frequencies with my speakers. Are there always no problems?

As I said above - you can't see problems from an amp by measuring through speakers with a mic in room. The speaker/room interaction dominates the measurement results.

 

[musica]

As I said above - you can't see problems from an amp by measuring through speakers with a mic in room. The speaker/room interaction dominates the measurement results.

I say, that in real listening in my environment there are no exaggerated highs, so the Fosi v3 is good for my listening or am I wrong?

 

[antcollinet]

I say, that in real listening in my environment there are no exaggerated highs, so the Fosi v3 is good for my listening or am I wrong?

If it sounds good to you, that is all you have to worry about.

The load dependency is not going to be audible to most people in most situations. Even if it is, it is easily fixed with a little EQ.

 

[musica]

sorry, but can the boom when turning on and off break the speakers or is it just a nuisance?

 

[NTK]

sorry, but can the boom when turning on and off break the speakers or is it just a nuisance?

To the loudspeakers, the turn on and off pops are just signals, no different from the music you play. As long as the pop sound output is comfortably less than the max output SPL level of the speakers, everything should be just fine.

One thing I would like to confirm, however, is that the amp is not outputting DC during the pops, which can cause large excursions of the woofers that we can't hear. You can verify that by looking at the woofer diaphragms. If they don't move considerably during the on-off pops, then there is no DC problem.

 

[musica]

Can Fosi stay there or not?

 

[musica]

To the loudspeakers, the turn on and off pops are just signals, no different from the music you play. As long as the pop sound output is comfortably less than the max output SPL level of the speakers, everything should be just fine.

One thing I would like to confirm, however, is that the amp is not outputting DC during the pops, which can cause large excursions of the woofers that we can't hear. You can verify that by looking at the woofer diaphragms. If they don't move considerably during the on-off pops, then there is no DC problem.

It sounds like the boom when the needle of a record player hits the record

 

[antcollinet]

View attachment 388626Can Fosi stay there or not?

you've got is sat direction on the vents of the device below. If that is switched on at the same time as the FOSI I'd not recommend it.

 

[CBdicX]

Hi, will this Fosi V3 give a speaker "pop" when power Up and Down used on a Master/Slave power socket ?

The receiver will be the "Master" and the V3 will be the "Slave" and will be turned on and off by the power socket when the receiver powers up and down.
The power knob on the V3 will be aways ON.
Think using a Master/Slave power socket works the same as pulling the power cord to tun on and off, intade of using the power knob on the V3.

Maybe someone can check by pulling the the power cord of the extrenal powerblock if the speakers pop ?

 

[antcollinet]

Hi, will this Fosi V3 give a speaker "pop" when power Up and Down used on a Master/Slave power socket ?

The receiver will be the "Master" and the V3 will be the "Slave" and will be turned on and off by the power socket when the receiver powers up and down.
The power knob on the V3 will be aways ON.
Think using a Master/Slave power socket works the same as pulling the power cord to tun on and off, intade of using the power knob on the V3.

Maybe someone can check by pulling the the power cord of the extrenal powerblock if the speakers pop ?

You have the answer in this review - the very first post in this thread:

 

[musica]

Does the sound improve if I power it with 48V 5A GaN power supply?

 

[Jimbob54]

Does the sound improve if I power it with 48V 5A GaN power supply?

No. It will be able to go louder but I don't think you are running at max output?

 

[musica]

Is it normal that when I set the volume of the Fosi v3 to maximum I hear a lot of mid-highs, even if the volume of the Denon preamp is at minimum?

 

[musica]

Is it normal that when I set the volume of the Fosi v3 to maximum I hear a lot of mid-highs, even if the volume of the Denon preamp is at minimum?

is it better to set the volume of the Fosi v3 to 3 o'clock or to maximum?

 

[antcollinet]

is it better to set the volume of the Fosi v3 to 3 o'clock or to maximum?

What I would do:

1 - Turn your V3 down to zero.
2 - SLOWLY Turn your Denon up to max.
3 - Now SLOWLY raise the volume of the V3 so it is a little bit louder than you will ever want to listen to. This is the volume you should leave the V3 at. Mark it with a small bit of tape or similar.
4 - Now you can control the volume DOWN from there using the Denon volume control. With the Denon volume control at the higher end of the range, and the gain in the amp minimised, you will optimise SNR.