Fosi V3 Mono Break-In

I am thinking about trying these. So cheap.

i have a stereo Fosi amp and it sounds great.

if i got a pair of these and used my Cary SLP98 as a preamp would I have any trouble? I sure don’t want to fry my speakers or preamp over 300.00 clads D amp but I am certainly intrigued. Any help would be appreciated.

More money better sound is a thing. Correct. But you need the ears and the means. Some got it some don’t. Nothing snobby about that. Whatever makes you happy.

Being a snobbish audiophile is cool, if that’s your thing.

I’ve got the Fosi currently driving a pair of Magnepan 1.7i with absolutely zero issues.  

Having a pair of what amounts to about sub $600 power amp (op amps/power bricks) that makes me consider selling my other amps is absolutely crazy.  But I think it really shows that one doesn’t need to throw a crap-ton of money at this hobby to get great sound nowadays.

Unless, of course, you want to throw a crap-ton of money at it for bragging rights.

Stories of premature failure and reliability on the web. Not to mention the very low current output. That I see the word "Topping" mentioned is all I need to know. Maybe it’s just high-end for the mid-fiers

No, I won’t be trying them out to replace my Pass amp. Or risk blowing my speakers..

Wow replacing Ayre gear satisfactorily  for a couple hundred bucks says something. 

I've had these for a month or so at this point with the single power supply and Y-shaped connector cord, replacing a huge old Ayre Acoustics V-5xe (at one point Stereophile Class B) - nothing wrong with the Ayre, but I needed the space it took up.  My impressions are overwhelmingly positive; I can't hear the difference between the Ayre and the V3 Monos.  BTW I strongly recommend using the balanced interconnects as opposed to RCA, for reasons explained by Archimago, whose two long quantitative reviews of the Fosis are linked from my blog at https://www.tbray.org/ongoing/When/202x/2024/09/09/Next-Step-Audiophile

Thanks for the info guys. The monos arrived last night and I tried them with the pre-out on my Naim Unitilite but it uses a DIN to RCA cable and the one I have is bad (introducing noise) so the sound was not great. I ordered the Pre90 last night and it should be here today so I can get a better idea of how well these amps perform.

I’m using the Topping Pre90, and am liking the sound quite a bit.  The Fosi, IMO, is a very clean, lean and agile pair of amps.  They are not warm or euphoric in the least.  I feel the same way about the Topping, clean and lean.

Combining the two has given me a rig that is capable of extracting a lot of the subtleties available in any given recording.  

I got the Topping to go with the SMSL VMV class A amp, which I also feel is a great match, provided your speakers aren’t too demanding and uber low in efficiency.  I actually used the 10 watt amp with many speakers in the 86 or so dbl range with absolutely no issues in my small acoustically treated listening room (13x14).

I’ve got to stop watching the reviews by Harley at Pearl Acoustics on YouTube. I got the SMSL because he compared it favorably to the Pass amp (and way less warm - the reason I was interested in it) and the Topping Pre90 also got pretty rave reviews by him.  The best part was that they were both affordable to the common man’s finances.

The Fosi I got into in a roundabout way.  I got one of their older amps that had bluetooth capabilities because I wanted something small, with bluetooth that I could connect to my TV and hide the amp behind it.  I used that one for a few years.

I then came across one of their newer BT integrated amps, which I also liked.  I got tthat one as I was thinking of having some small speakers connected to them in my listening room for some background music when I didn’t want to turn on my main rig (was all tubes then).  Then I came across the V3 monos on that forum where they crowd fund (?) and they seemed pretty interesting

Once I got them, I saw a few reviews about them with the Sparkos on YouTube and decided to pick up four (two each for the XLR inputs).  Kind of crazy that the op amps cost more than the monos, themselves.

Once the temp gets colder I’ll swap the Fosi’s out for probably both the pass gear and tubed gear for some warmth.  But until then, I’m in no hurry to swap out the Topping/Fosi combo.

I’m convinced that if someone put the Fosi into a large, heavy, blinged out, audiophile-approved chassis they would be all the rave.  Provided they were priced at over $10,000 because, as we all know, more money better sound.

Currently a home made, not by me, passive pre with RCA just to start burn in. But will move stuff around and use  Schiit Freya S with XLR

@audiodwebe 

I have a pair of the V3 Mono on the way to try with a set of LRS+.

What preamp are you using with them?

Not sure if they break in much, as I didn’t play my pair too long before swapping out the op amps to the Sparkos (two each in the XLR input).  I did notice an improvement when the op amps were replaced.

Funny, but I mentioned somewhere that the Fosi, with the Sparkos, had better resolution than pretty much any amp I have.  Not by much, mind you, but I noticed some subtle things in my test tracks that I’ve listened to hundreds of times.  And none of the test tracks sounded worse.

I’ve since added a pair of GaN power bricks (48volt/5 amp) and I feel that these made the background more black than with the 48 volt/5 amp power bricks that came with the Fosi.  I didn’t initially hear any difference, but after breaking in the new bricks for a few days, they seemed to sound better.  

Overall, though, the Fosi are quite incredible sounding amps.  They are currently driving a pair of Maggie 1.7i speakers.  

For reference, some of the other amps I have in home;  VTL MB185; Pass Aleph 2; Cary 805B; Marsh A400S; pair of Schiit Aegirs; and a few others.  

The Fosi’s do not make me want to swap in one of the other amps.  I initially got these because most of my other amps generate too much heat in my small listening room during the summer months.  

The Sparkos are your friend.

These amps are terrific. They've been on for 5 days, have played about 50 hours of music - and I"m convinced they do sound better than when new...I did like them cold out of the box, and I did not listen enough along the way so that I "adjusted" to their sound...

 

jasonbourne71

1,133 posts

10-11-2024 at 12:12pm 

Remarkable performance for not much money! Look out all you makers of four and five-figure amps!
 

Yep. Pass Labs, Audio Research, McIntosh, Boulder etc have been locked up in their situation rooms conducting emergency meetings discussing how to combat such a giant killer and survive this threat.

Just buy them from Amazon.

Years ago I bought a stereo amp from Fosi direct and one channel was out. They wanted my to ship it back on my dime. WTF?

PayPal got me a full refund after over a month of much consternation..

Now I have a "mono."

I also was surprised how warm they get 

Yes they need a bit of time to settle in. 

I have a pair with a single 48V/10A supply and splitter.  I am surprised how warm they get for class D, but overall find them excellent.  In my use application I can swap them out with a new- build Dynaco ST35 and they do not sound worse!

Remarkable performance for not much money! Look out all you makers of four and five-figure amps!

Don’t know but I have the Fosi v3 stereo amp in my little desktop system. It is a top performer. I suspect it has output limits that may not cut it with some tougher speakers to drive but have not put it to the test yet.

The Fosi v3 amps are a steal in any case. No harm in trying a pair. If not quite up to snuff, you at least have a capable backup amp in case needed someday. Things break so always nice to have an effective spare around that cost relatively little and take up practically no space.

You might be pleasantly surprised and save a lot of money.  You never know.   Definitely a possibility for many.