FOSI AMP Mono V3: cooling it down :)

[pjorgenunes]

I have two Fosi Amp Mono V3 Amp to feed my B&W 805S and, although not that disturbing, they run a bit hot for my taste

So I tweak them, after some investigation around how to do it, and came up with this solution (not expensive and bought all, except the feet on amazon.es).





Under around three hours of listening music at a generous volume, pressing hard with my hand on top:

Before: after some seconds I had to get my hand of. It started to be unconfortable.

Now: I can keep my hand. It's warm+ but not unconfortable.

Sorry I don't have the means to measure "scientificaly".
The initial test was with one of them like this and the other not. The difference was obvious on touch. I believe that some 10ºC or more less (but no way to measure).

PS - If anyone is interested I can put the links of the materials . The feet are from Leroy Merlin (solid metal drawer pushers and the rubber end are the original feet from the amps: I removed them and resticked them on the metal ones).

 

[Leonidas_k]

Interesting idea. I was thinking about doing something similar, by adding a heat sink on the top of the V3.
This solution looks much better, though I wonder if it is as effective as putting them on top of the device.
Perhaps I can try both when I get the time, and see if there is any significant difference.

 

[pjorgenunes]

Interesting idea. I was thinking about doing something similar, by adding a heat sink on the top of the V3.
This solution looks much better, though I wonder if it is as effective as putting them on top of the device.
Perhaps I can try both when I get the time, and see if there is any significant difference.

I’ve read about this and since the chip is at the bottom putting heat sink on bottom with some air circulating space seemed the best way ( and aesthetically much better imho).
Meanwhile I got a laser temperature meter “gun” and, after 3 hours of rock listening at very respectable levels medium-high, feeding my B&W 805S I get a stable 43-43,3 degrees Celsius (measured it several times during the 3 hours) on both amps.

I don’t have the reading without this cooling but someone might have this and share it (but it’s much cooler on hand touch).

 

[Leonidas_k]

I’ve read about this and since the chip is at the bottom putting heat sink on bottom with some air circulating space seemed the best way ( and aesthetically much better imho).
Meanwhile I got a laser temperature meter “gun” and, after 3 hours of rock listening at very respectable levels medium-high, feeding my B&W 805S I get a stable 43-43,3 degrees Celsius (measured it several times during the 3 hours) on both amps.

I don’t have the reading without this cooling but someone might have this and share it (but it’s much cooler on hand touch).

I do have access to a thermal camera, so at some point I will check give it a shot to see what is the temperature, before & after.
I had not thought about the chip placement, to be honest, just had in mind that having the heatsink on the top, would let hot air escape easier.
But completely agree on the aesthetic part, of having the heatsinks under the amp. And that would also be better to avoid getting too much dust on it.

 

[pjorgenunes]

I do have access to a thermal camera, so at some point I will check give it a shot to see what is the temperature, before & after.
I had not thought about the chip placement, to be honest, just had in mind that having the heatsink on the top, would let hot air escape easier.
But completely agree on the aesthetic part, of having the heatsinks under the amp. And that would also be better to avoid getting too much dust on it.

Nice! If you can then share the results it would be great.

 

[machacream]

Sharing what I did to keep mine cool, hoping this could help some people.
Each monoblock is run on a separate 48V10A, and passive cooling alone was not enough to cool it down (I also repasted the internal heatsink).
The solution was: I flipped the bottom up, put external heatsink over, then a 12V regular PC fan blowing into the heatsink. Now they never get warm even over long listening sessions. (I previously had 2 fans, but it was unneccesary).

Credit to Clipperjay for showing me how to do this. (Don't forget to give him a thumbs-up!)