Not that I've seen. Just taking Jay's Iyagi's word for it.
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Fosi Audio V3 Mono Amplifier Review
- Thread starter amirm
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I was all set on ordering the Behringer A800 to mount underneath my desk and power 2x subwoofers in my small office, but these Fosi amps sure are tempting me.
Since I plan to mount underneath my desk, does anyone think I'll be risking thermal issues running 4ohm subwoofers with these?
Since I plan to mount underneath my desk, does anyone think I'll be risking thermal issues running 4ohm subwoofers with these?
Thank you, much appreciated!
ninetylol
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No problem i hope you will have a lot fun with them
It seems like a bad idea, the Behringer A800 is a professional amplifier, extremely powerful and robust, perfect for driving passive subs, the Fosi have much better measured performance but useless for subs and lack power compared to the A800 which instead is a characteristic very useful for this task.
Interesting generalization, IRL it all depends on the application. I have DIY 4 ohm passive subs that require 70W max (f3=23Hz, 100dB output each). This Fosi would be much more than adequate for them.
*Simplified V*A=W power per channel calculation with different bricks: (*not power to speakers)
2x V3 Mono & 2x 48V 5A = 240W/channel (or 1x 48V 10A split)
2x V3 Mono & 2x 36V 6A = 216W/channel
2x V3 Mono & 2x 36V 5A = 180W/channel
2x V3 Mono & 2x 32V 5A = 160W/channel
V3 Stereo & 48V 5A = 120W/channel
V3 Stereo & 36V 6A = 108W/channel
V3 Stereo & 36V 5A = 90W/channel
V3 Stereo & 32V 5A = 80W/channel
Interestingly there are a couple of potential sweet spots using the V3 Mono with 36V or 32V power adapters: Smaller & less expensive bricks, less heat, yet still lots of power.
I likely would of opted for a 36V option in the Mono Kickstarter if it were available. Maybe they can still add it to help crack that $500K goal?!
ps. looks like 250 people or so are getting the 2x 48V 10A ... If you're here, what speakers are you driving or what are your reasons for 480W/channel?
pps.: I edited and took out the 2 x 48V 10A line based on feedback.
2x V3 Mono & 2x 48V 5A = 240W/channel (or 1x 48V 10A split)
2x V3 Mono & 2x 36V 6A = 216W/channel
2x V3 Mono & 2x 36V 5A = 180W/channel
2x V3 Mono & 2x 32V 5A = 160W/channel
V3 Stereo & 48V 5A = 120W/channel
V3 Stereo & 36V 6A = 108W/channel
V3 Stereo & 36V 5A = 90W/channel
V3 Stereo & 32V 5A = 80W/channel
Interestingly there are a couple of potential sweet spots using the V3 Mono with 36V or 32V power adapters: Smaller & less expensive bricks, less heat, yet still lots of power.
I likely would of opted for a 36V option in the Mono Kickstarter if it were available. Maybe they can still add it to help crack that $500K goal?!
ps. looks like 250 people or so are getting the 2x 48V 10A
... If you're here, what speakers are you driving or what are your reasons for 480W/channel?pps.: I edited and took out the 2 x 48V 10A line based on feedback.
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How are you getting those calculations? You can't just assume that all the PSU power can be output to speakers.Simplified power per channel calculation with different bricks:
2 x V3 Mono & 2x 48V 10A = 480W/channel
2x V3 Mono & 2x 48V 5A = 240W/channel
V3 Stereo & 48V 10A = 240W/channel
2x V3 Mono & 2x 36V 6A = 216W/channel
2x V3 Mono & 2x 36V 5A = 180W/channel
2x V3 Mono & 2x 32V 5A = 160W/channel
V3 Stereo & 48V 5A = 120W/channel
V3 Stereo & 36V 6A = 108W/channel
V3 Stereo & 36V 5A = 90W/channel
V3 Stereo & 32V 5A = 80W/channel
Interestingly there are a couple of potential sweet spots using the V3 Mono with 36V or 32V power adapters: Smaller & less expensive bricks, less heat, yet still lots of power.
I likely would of opted for a 36V option in the Mono Kickstarter if it were available. Maybe they can still add it to help crack that $500K goal?!
ps. looks like 250 people or so are getting the 2x 48V 10A
staticV3
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Green is confirmed with measurements.
Yellow is corrected power numbers (as measured by Amir).
Everything else is yet-to-be confirmed.
If there are measurements that I've missed, then please tell me.
Really? 480 watts per channel? This can't be right...Simplified power per channel calculation with different bricks:
2 x V3 Mono & 2x 48V 10A = 480W/channel
2x V3 Mono & 2x 48V 5A = 240W/channel
V3 Stereo & 48V 10A = 240W/channel
2x V3 Mono & 2x 36V 6A = 216W/channel
2x V3 Mono & 2x 36V 5A = 180W/channel
2x V3 Mono & 2x 32V 5A = 160W/channel
V3 Stereo & 48V 5A = 120W/channel
V3 Stereo & 36V 6A = 108W/channel
V3 Stereo & 36V 5A = 90W/channel
V3 Stereo & 32V 5A = 80W/channel
Interestingly there are a couple of potential sweet spots using the V3 Mono with 36V or 32V power adapters: Smaller & less expensive bricks, less heat, yet still lots of power.
I likely would of opted for a 36V option in the Mono Kickstarter if it were available. Maybe they can still add it to help crack that $500K goal?!
ps. looks like 250 people or so are getting the 2x 48V 10A
Thanks for getting back to me.
I think I will take your advice and stick to getting the A800 for my use case. I will probably be driving the subs hard at times and would hate to overheat the Fosi.
Still a really interesting little amp, crazy what you get for the money.
It's not, and covered in the thread already. Fosi has already confirmed the 48V10A supply does not result in any appreciable power output increase over the 48V/5A supply (in a single amp/single power supply scenario).
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My goal was 'simplified' power from the power supplies, not actual power to the speakers.
I get even that's theoretical. The comparison may still be useful in relative terms...
Then you shouldn't state per channel power, and should clearly state you are only talking about PSU power output.
It isn't - it is misleading.
Both are the same power supply. The Model number (HKA30048063-7D which means 300W, 48V 6.3A) is the same, the input current is the same. The actual output power is the same. I think it's a little dishonest/misleading to state that the second PS provides 10A(max), people may believe this is a 480W power supply.intersting.
Top: this ebay listing https://www.ebay.co.uk/itm/275540643117
Bottom: Guddu's review here in ASR:
most (all?) huntkey models, the three figures after the letters denote power in watts
View attachment 366964
have seen worse made though
View attachment 366969
The real question is , do we really need all that power? With the 4Vrms input signal we provide at -12dBFS or even -14dBFS attenuation(x0.2 to x0.25) , and the total amplifier gain of 20.5dB or x10.6, the output voltage the amp can produce is 4V x0.20 x10.5= 8.4V, at 4Ohm we have 8.4^2 / 4= 17.64W
This means that a 8.4V DC/0.707 = 12V DC Power supply with 2A is more than capable of providing power for this particular use case. This is in "theory" because we know the TPA3255 needs at least 18V and 10.8V for the other digital circuitry:
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Am I missing something here? Fosi have kindly shown on this forum that their supply is indeed capable of the claimed 48V 10A output, have you not read those posts or are you suggesting the supplied evidence and results are false/faked?
Before drawing this kind of conclusion it would be useful to continue reading....
Here!ps. looks like 250 people or so are getting the 2x 48V 10A
Though it's not about the 480W/channel, especially since Fosi doubts, the 10A will give much more output power.
I did so, since I suffer from bad synergy of my speakers and my amplifier (QUAD 66 Pre + QUAD 306 PA) for far too long. The speakers are Dynaudio Contour 1.3 SE. It is generally believed, all across the forums I visited so far, that Dynaudios want not so much power as they want current. I still don't understand the technical aspects behind it, but I had enough and took the chance to get the higher current supplies.
Dynaudio's customer support recommended an amp with high reserves.
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