Fosi Audio V3 Mono Amplifier Review

[Mort]

I love them but decided to return mine. Pops, heat primarily are my concerns.

Bigger, I feel it's just not the right price point (for me.) They might be the worst of both worlds, neither cheap nor refined.

For $200 more I can get a flawless buckeye 2ch nc250mp (which I'm doing) and not really think about it again. For $100 less I can get a ZA3 or similar and be good enough. The Fosi monos are an excluded middle for me.

It's a fun device though. I still want to like the V3 mono.

 

[Bene]

yeah. just bought the Za3 and it has a very good cooling... it's just very little warm, it would have been good to have used the za3 case for better cooling.

 

[strawberry644]

i tried to read over most of the pages here and saw some discussion of the opamps in this Fosi v3 Mono not sure if this has been discussed.

I was wondering how important the op amp is closest to the front panel and if it would make RCA input sound different? i currently have my Fosi v3 Mono's (48v 5A unit. OPA1656 in slot 2 or middle for each) being fed from the RCA of FiiO K7 DAC and was wondering if all 3 matching opamps might sound different since I'm not using XLR input?

either way I'm still really happy with the audio even compared to my Fosi v3 48v stereo i was using before that.

 

[Freezak]

Has anyone found an effective way to turn the AC Infnity fans on automatically when the temperature of these monos goes up? I know there's the AC Infinity Controller 1 available but it's ridiculously expensive in Europe compared to AC Infinity fans, perhaps some cheaper chinese solution that i can't find on AliExpress? Thanks

 

[Sokel]

Has anyone found an effective way to turn the AC Infnity fans on automatically when the temperature of these monos goes up? I know there's the AC Infinity Controller 1 available but it's ridiculously expensive in Europe compared to AC Infinity fans, perhaps some cheaper chinese solution that i can't find on AliExpress? Thanks

Posted again in this thread,it may work on not for you and it will be kind of a Frankenstein solution but do your research:

Fosi v3 Mono - User Impressions | Owner's Thread

If you had the measurement with a 1030 Hz tone I exaggerated it a little so we can see the effect better and I included all values for better visuals. So,at 1030Hz: No fan with fan It's a little horror show. What happens with the harmonics at the other charts are probably canceling,same...

www.audiosciencereview.com

 

[Freezak]

Posted again in this thread,it may work on not for you and it will be kind of a Frankenstein solution but do your research:

Fosi v3 Mono - User Impressions | Owner's Thread

If you had the measurement with a 1030 Hz tone I exaggerated it a little so we can see the effect better and I included all values for better visuals. So,at 1030Hz: No fan with fan It's a little horror show. What happens with the harmonics at the other charts are probably canceling,same...

www.audiosciencereview.com

Thanks for your quick reply, this sounds like the perfect solution, i'm gonna do further research into this.

 

[Killingbeans]

I was wondering how important the op amp is closest to the front panel and if it would make RCA input sound different? i currently have my Fosi v3 Mono's (48v 5A unit. OPA1656 in slot 2 or middle for each) being fed from the RCA of FiiO K7 DAC and was wondering if all 3 matching opamps might sound different since I'm not using XLR input?

First we have to define "different". Is it "performing better" or "sounding better to my taste"? And in the former case, what's your taste?

If you randomly swap in op-amps with different operating parameters, you'd might hit a combo that gives an instability with tons of distortion. Maybe that will be pleasing to you. Most likely it won't be bad enough to actually be audible. You'd also be highly at risk of getting a placebo effect going.

Either way, doing these kind of swaps, without verification through measurements and sensible judgement of the results, is a frivolous exercise, IMO.

 

[SMen]

i tried to read over most of the pages here and saw some discussion of the opamps in this Fosi v3 Mono not sure if this has been discussed.

I was wondering how important the op amp is closest to the front panel and if it would make RCA input sound different? i currently have my Fosi v3 Mono's (48v 5A unit. OPA1656 in slot 2 or middle for each) being fed from the RCA of FiiO K7 DAC and was wondering if all 3 matching opamps might sound different since I'm not using XLR input?

either way I'm still really happy with the audio even compared to my Fosi v3 48v stereo i was using before that.

This might be better over on the Fosi v3 mono user impressions thread . Your RCA input converts to balanced and then progress through the circuit in the same way as the balanced input - so matching your position 3 op amp with your position 2 according to Fosi should bring a change...

Note my italics! I haven't had time but I'm going to write a post on this on the user impressions. Personally, I would not expect an improvement with all OPA1656! But if you already have another pair of OPA1656 them give it a go, and then ask yourself if you really want to keep them there!

The supplied NE5532 in combination with the circuit designed give a nice full natural sound (imso).

 

[burkm]

But nontheless Op amp rolling is is still supported / favored by the manufacturer, because he might sell you some additional (expensive ?) OP amps (to the ones already installed in the power amp) which he makes additional money on them
The arguments against are weighting strongly but "taste" and opinion might favor it the other way. I am still undecided, if OP amp changes are doing any good to SQ

 

[SMen]

First we have to define "different". Is it "performing better" or "sounding better to my taste"? And in the former case, what's your taste?

If you randomly swap in op-amps with different operating parameters, you'd might hit a combo that gives an instability with tons of distortion. Maybe that will be pleasing to you. Most likely it won't be bad enough to actually be audible. You'd also be highly at risk of getting a placebo effect going.

Either way, doing these kind of swaps, without verification through measurements and sensible judgement of the results, is a frivolous exercise, IMO.

We replied at the same time... My findings with these is that there is distortion ... but I can't measure it, just hear it on things like violins. But I'll expand when I have a moment over on the user impressions.

 

[SMen]

But nontheless ist is still favored by the manufacturer, because he might sell you some (expensive ?) additional OP amps (to the ones already installed in the power amp) he makes additional money on them

Yes - it is seriously getting out of hand IMO. At this rate I'll have written my post!
We need measurements from the manufacturers to justify these diversions.

Post edit: I posted this request from 3e audio on their PFFB thread and received a very positive response.
Now what they suggest would be really good ... and we should start demanding all, including Fosi start doing the same!

 

[burkm]

It is getting out of hand because "evidence" about any negative or positive effects are hard to get at, if there exists any The problem seems to be, that usually no one can provide "real" measurements one way or the other about the "goods" of each position. The question comes up then, why the manufacturer didn't choose the "best sounding" op amps (objective and subjective) for the job to be done if not for cost reason...

 

[SMen]

It is getting out of hand because "evidence" about any negative or positive effects are hard to get at, if there exists any The problem seems to be, that usually no one can provide "real" measurements one way or the other about the "goods" of each position. The question comes up then, why the manufacturer didn't choose the "best sounding" op amps (objective and subjective) for the job to be done if not for cost reason...

Exactly.

Instead we get lots of NE5532 for cost reason (when in fact there is a very valid reason to design a circuit with this opamp for sound reason). And then, quite possibly, untested expensive opamps proposed as swaps for profit reason ...

I was pleased with the 3e response because it looks like they are trying OPA16xx op amps for an optimized circuit. Whether it measures better (or subjectively sounds) better is to be seen and heard.

But the latter "spirit" is one to encourage!

Post edit: if you look here https://fosiaudio.com/pages/fosi-audio-zd3-balanced-dac and go down to the op amp section, it seems that this circuit does not need to be optimized for any particular op amp ... Is this really the case? A question for the engineers here.

 

[kingkoolkris]

I'm sure someone asked this before but: is there any advantage in using RCA<->XLR cables because my Onkyo AVR doesn't have XLR outs.

 

[Freezak]

I'm sure someone asked this before but: is there any advantage in using RCA<->XLR cables because my Onkyo AVR doesn't have XLR outs.

I did - and was told other than slightly lower gain with XLR there's hardly any audible difference, which is probably true. Still, i went with XLR for that placebo effect and peace of mind, lol.

 

[kingkoolkris]

Placebo and peace of mind is something you should never underestimate in hifi matters, lol.
I'll follow your idea and do the same

 

[harrym13]

She probably did, what she was told, and read it of the screen and didn't tell You that there are no V3 Monos in the warehouse right now...

I ordered some on 7th September and they sent them out start of this week - just gone through customs today I think. So Fosi do have stock it seems!

 

[DavidM1]

I am bamboozled by consumers tempted by op amps. To me, hifi components are about transparency with levels of distortion and noise ideally below the level of human perception. Show me an op amp swap with better measurements and I might be interested but swapping blindly makes zero sense.

On the other hand, I understand completely the motivation for selling op amps.

 

[EddNog]

I am bamboozled by consumers tempted by op amps. To me, hifi components are about transparency with levels of distortion and noise ideally below the level of human perception. Show me an op amp swap with better measurements and I might be interested but swapping blindly makes zero sense.

On the other hand, I understand completely the motivation for selling op amps.

Op-amp rolling is the new tube rolling. You’re looking for your preferred flavor of distortion coloring, not a perfect signal.

Take a Big Mac and then put something else in it—BBQ sauce, fried onions, ranch dressing, banana peppers, whatever…it’s no longer a, “perfect Big Mac,” it’s your own twist.

ASR crowd doesn’t understand anything other than the perfect Big Mac, but these people want it their way; they’re the Burger King types.

-Ed

 

[SMen]

Op-amp rolling is the new tube rolling. You’re looking for your preferred flavor of distortion coloring, not a perfect signal.

Take a Big Mac and then put something else in it—BBQ sauce, fried onions, ranch dressing, banana peppers, whatever…it’s no longer a, “perfect Big Mac,” it’s your own twist.

ASR crowd doesn’t understand anything other than the perfect Big Mac, but these people want it their way; they’re the Burger King types.

-Ed

The thing though is, this V3 Mono does not seem to particularly like the op amps suggested by Fosi!! Well, the Muses02's anyway, certainly x4. I do not have the Sparkos SS3602 - and I am not sure anyone has raved about any of these choices, or the opa1656 (with the Monos). I have the impression a good job was achieved optimizing them for the NE5532s (as per previous posts) on this page. I've got one more thing to try, and then I'll pop my head above the parapet over on the user impressions!

I am not in anyway saying other circuits are the same case examples ...