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Fosi Audio V3 Mono Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 13 2.0%
  • 2. Not terrible (postman panther)

    Votes: 21 3.2%
  • 3. Fine (happy panther)

    Votes: 129 19.4%
  • 4. Great (golfing panther)

    Votes: 502 75.5%

  • Total voters
    665
Has anyone worked out a simple way of powering the 12V Fosi fans to turn on and off automatically with amps? The Wiim Ultra has a 3.5mm mono plug trigger which I could use

Also my Elipson XLS 15 speakers are rated 6ohms but reported to drop as low as 3.2ohms. Would the V3 Mono handle this okay?
 
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Also my Elipson XLS 15 speakers are rated 6ohms but reported to drop as low as 3.2ohms. Would the V3 Mono handle this okay?
Yep - if you look at the review (next to last test), Amir took the power cube tests down to 2ohm, and the mono aced it.
 
I don't know about the B200, but Topping implemented the B100 as a bridged pair of single ended amps - hot drives +ve output, cold drives -ve output or vice versa. If you use an RCA to XLR cable, or an impedance balanced output with only one side driven, then you only use one of the two amps, and can't reach rated output. A high performing balanced input to drive a bridged output will need more opamps. See 'The G Word' for details.
Not necessarily,depends on the circuit.It can run as a loop with the right config,key is balancing the output impedance of the pre with a resistor at the cold output.
I don't know how Topping does it but that's how it looks at a bridged icepower:

semi.PNG

Of course the output of the SE pre is usually half,so...
 
Not necessarily,depends on the circuit.It can run as a loop with the right config,key is balancing the output impedance of the pre with a resistor at the cold output.
I don't know how Topping does it but that's how it looks at a bridged icepower:

View attachment 423223

Of course the output of the SE pre is usually half,so...
Of course plenty of amps with balanced inputs do it properly, bridged or not. I draw attention to it because the B200 was mentioned, and @pma found this specific problem with the B100 when testing long term power output. Schiit do the same with the XLR for the Vidar 2, but they at least mention it in their FAQ.
 
Of course plenty of amps with balanced inputs do it properly, bridged or not. I draw attention to it because the B200 was mentioned, and @pma found this specific problem with the B100 when testing long term power output. Schiit do the same with the XLR for the Vidar 2, but they at least mention it in their FAQ.
Yes,I now remember the problem.
Strange choice though.
 
My new setup

PXL-20250126-191046267.jpg
Exactly the same as me! Not running the Fosi cooling fans on the mono’s? I just ordered some fans, will be using the Ultra remote trigger, a 3.5mm TRS cable and 12V automotive relay to get them to auto on/off

IMG_0120.jpeg
 
I added some heatsinks to the top of the amps. Hopefully that will let them dissipate heat better.

PXL-20250129-101358384.jpg
Yes it helps, what's the cd player you have? (sorry for off topic)
 
Can I power Paradigm Sig S8 v3 with these monoblocks? Right now I am using an old Denon 3805 receiver
 
Can I power Paradigm Sig S8 v3 with these monoblocks? Right now I am using an old Denon 3805 receiver
Yes and the efficiency is similar to the Paradigms I’m running at 80 dBA @10 feet away or so. Zero heat issues for my use case (not using any high pass filters, but active sub contributing a bit to overall spl..). Should be good to go.
 
I've been reading this thread since the beginning. I was an early backer for the V3 mono and have been happy with the ones I have in service so far. However, I tried to order another to make it a 5 amp set up. When I added the latest amp, I noticed that when using RCA to RCA, the volume was significantly lower on the speaker hooked to that amp than the others. I switched cables, switched speaker pre-outs on the receiver, but always the speaker connected to the 5th Fosi was lower in volume. I contacted Fosi and here are their replies, see below. It seems they changed the output gain without changing the markings on the case or the specification section on the website. Has anyone else ordered a Fosi V3 Mono lately that might be this "new" version, post Jan. 1, 2025? The gain on the XLR appears to be unchanged.
 

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