Fosi Audio V3 Mono Amplifier Review

[georgeT]

What type of Class D amp is the V3? because it runs hotter than my inuke 1000 and my Pioneer A10K. matter of fact my A10k runs at room temperature and it has 0 active cooling.
Edit: this is a veiled jab at the fact that Fosi V3 runs hot AF!

 

[john61ct]

Does it matter? The case IS the heat sink

Post the actual internal component temperature.

 

[georgeT]

Does it matter? The case IS the heat sink

Post the actual internal component temperature.

Last winter I used it to warm my hands. Isn't class D supposed to be 90% efficient. it's summer now and the case gets very hot. I also placed 1cm spacers under it to help airflow.

 

[RandomEar]

Last winter I used it to warm my hands. Isn't class D supposed to be 90% efficient. it's summer now and the case gets very hot. I also placed 1cm spacers under it to help airflow.

It's very efficient at full power. Idle losses are still lower than class AB, but at the same time the case and thereby the heat transfer area are much smaller on these units. If you need to constantly dissipate 5-10 W, the case will get warm.

The spacers will help a little bit. If you want to improve convection further without adding a fan, place the amps upright/on their side.

 

[mike70]

Last winter I used it to warm my hands. Isn't class D supposed to be 90% efficient. it's summer now and the case gets very hot. I also placed 1cm spacers under it to help airflow.

Put your class ab amplifier in the same case size, without the internal dissipation and then tell me about the heat.

You can see clearly that thermal management in a class AB is much more powerful and then... you can't compare it as you're doing.

 

[georgeT]

Put your class ab amplifier in the same case size, without the internal dissipation and then tell me about the heat.

You can see clearly that thermal management in a class AB is much more powerful and then... you can't compare it as you're doing.

I have no AB amps the Inuke 1000 and the pioneer A10k are both class D amp, the inuke does have a fan but but the pioneer doesn't and emits almost no heat, the case never gets close to warm.

 

[staticV3]

Last winter I used it to warm my hands. Isn't class D supposed to be 90% efficient. it's summer now and the case gets very hot. I also placed 1cm spacers under it to help airflow.

Here's some discussion on Class D efficiency:

Let's stop calling Class D amplifiers "efficient" when they are not.

Tell me, how much power do your class D amplifiers consume, just idling along, doing nothing, or even playing slightly loudly? Measure it and be shocked. Report back here with your results. Class D "efficiency" is utter and complete bullsh#t.

www.audiosciencereview.com

Also, one counterintuitive thing to keep in mind is that, with two devices of equal size and power draw, whichever is warmer to the touch, has lower internal temperatures as it transfers the heat to the outside more effectively.

You almost never want high-powered electronics that stay cool (case temperature or vented air), as that means the internals are thermally isolated and cooking.

 

[effj]

I have no AB amps the Inuke 1000 and the pioneer A10k are both class D amp, the inuke does have a fan but but the pioneer doesn't and emits almost no heat, the case never gets close to warm.

Is your A10K unit different from the one I Googled? The specs I see are A/B integrated amp with 17” as its longest side and 14 lbs weight. Minimal similarities with the Fosi V3 Mono.

 

[NTK]

Last winter I used it to warm my hands. Isn't class D supposed to be 90% efficient. it's summer now and the case gets very hot. I also placed 1cm spacers under it to help airflow.

Human sensation to temperature changes rapidly around the body temperature. A 30 °C surface feels like an unheated surface at room temperature in summer. 40 °C feels warm, at just above human body temperature. 50 °C can cause burns in about 1 minute, and will feel alarmingly hot to touch. If an amplifier case is warm in winter, an increase in ambient temperature of 10 °C can make it feel too hot to touch.

 

[mike70]

I have no AB amps the Inuke 1000 and the pioneer A10k are both class D amp, the inuke does have a fan but but the pioneer doesn't and emits almost no heat, the case never gets close to warm.

You need to check it out... the Behringer is class D and the Pioneer is class AB but both with big case and internal dissipation.

There's no way to compare it with the Fosi as I said previously.

 

[georgeT]

You need to check it out... the Behringer is class D and the Pioneer is class AB but both with big case and internal dissipation.

There's no way to compare it with the Fosi as I said previously.

It's class D, maximum power draw 135W, outputs 50W x 2 into 4 ohms. It can drive my KEF Q350s with no problem, if you know of an AB amp that draws 135W runs cool and can output 100W let me know!

 

[mike70]

It's class D, maximum power draw 135W, outputs 50W x 2 into 4 ohms. It can drive my KEF Q350s with no problem, if you know of an AB amp that draws 135W runs cool and can output 100W let me know!

This is a deaf conversation, or maybe I'm really bad exposing my point.
In any of both ways is better to leave it as it is. Enjoy your amplifiers.

 

[georgeT]

This is a deaf conversation, or maybe I'm really bad exposing my point.
In any of both ways is better to leave it as it is. Enjoy your amplifiers.

My point is, idle power draw and case temps should be included in reviews. it would help people make buying decisions

 

[mike70]

My point is, idle power draw and case temps should be included in reviews. it would help people make buying decisions

What decision ? There's nothing wrong with the amplifier, at least relative to a smaller case used as thermal solution.
You run on circles.

 

[effj]

My point is, idle power draw and case temps should be included in reviews. it would help people make buying decisions

That seems fair. If the product is hotter than you expected, and that’s a problem in your application, it would be nice to know before buying. I’m not sure it’s the reviewer’s responsibility first, however; I’d say the manufacturer and the company that sells it (if they publish specs). Also, I’m surprised that it’s so hot as to be a problem for you. Mine are noticeably hot, but not concerningly or problematically.

 

[georgeT]

I just found it weird that it doesn't get brought up in the discussions. considering the heatwave in europe it might be useful for interested buyers to know that it runs pretty hot

 

[georgeT]

What decision ? There's nothing wrong with the amplifier, at least relative to a smaller case used as thermal solution.
You run on circles.

buddy, maybe this forum is more up your alley: https://www.audiocircle.com/index.php?board=16.0
just saying!

 

[john61ct]

The fact that the heat is being shed away from the internal components without a fan being required is A. Good. Thing.

Hotter to the touch on the outside, the better!!

 

[staticV3]

Hotter to the touch on the outside, the better!!

*at equal power draw, yes.

100+W of idle draw like some A/B Amps is still bad, even if it'll definitely be hotter to touch

 

[john61ct]

Yes, I meant, within this class, I don't think any draw much at idle.

Personally I power down, even disconnect between usage sessions, especially when running from battery bank