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Fosi Audio V3 Mono Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 7 1.4%
  • 2. Not terrible (postman panther)

    Votes: 12 2.4%
  • 3. Fine (happy panther)

    Votes: 100 20.0%
  • 4. Great (golfing panther)

    Votes: 381 76.2%

  • Total voters
    500

SMen

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I'm curious about these Muse02 op amps that Fosi is throwing in with the V3 mono Kickstarter orders. I do believe the Kickstarter hit $500,000, so I believe we get 2 op amps per order (not per amp). Why should getting 2 op amps per order be a reward if, (as some folks have written in other threads), swapping op amps is normally ill advised and even risky in some instances? Are these Muse02 op amps properly matched with the existing V3 Mono amp components? Are these any real noticeable improvement to the amp output or will they be just a hobby test listen where I may get to say things like "detail", "fast", "wider stage", and other neat-o audio descriptive phrases?

By following this thread I think I understand that each V3 mono (I ordered 2), has 2 op amps that may positively affect sound if swapped. Even if I want to try swapping op amps I wouldn't get the full effect without buying another $120 worth of op amps (2 more Muse02s)? I was all ready to give it a try until I figured out I could only do one V3 mono amp without sinking more money. Would swapping one of the op amps in each V3 mono even be worth the labor of opening the case? (Would swapping both be worth it?)

I'll think I'll wait and hopefully some other folks will attempt to determine if their Muse02 op amp offers a real reward vs. just a possible slight change in sound.

But I will say thanks for the XLR cables Fosi, and I would wear an size XL t-shirt if it came with my order.
Now that is a right old can of worms you've opened there :D
:D..

For me never mind all the technical arguments over this - it is the points you raise over the confusions. One per order or one per unit?
Why get people to open up their units for one per order, or for that matter one per unit?!

Can you imagine any manufacturer justifying different op amps on a parallel output stage using two?

There is no icon for "can of worms" available as far as I am aware, but imagine one here: :facepalm:
or here : :eek:
 

DavidM1

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Fosi language around the op amps is careful not to spell out any actual advantage. I don’t think this little accessory market would even exist if it required soldering skills.

People foolishly assume a price-quality relationship in the absence of other information.
 
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Negatywny

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oh shit here we go again....
To put it short, what is the difference with opamp type A costing 5$ with SINAD 100, and opamp type B costing 50$ with SINAD 100?
 

SMen

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oh shit here we go again....
To put it short, what is the difference with opamp type A costing 5$ with SINAD 100, and opamp type B costing 50$ with SINAD 100?
:DIt's such fun.... no Fosi on this single op amp offer for parallel circuit which require two ... and then it might be one op amp offered for four required across the two monoblocks .. this is crazy. It sows disharmony. Confusion. Dare I say it, it is taking the piss! (which in english means "vraiment la merde") :D
 

rgruber

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If you're interested in diving into this particular rabbit op amp hole:


The really interesting thing in this is where he solders together two cheap op amps and is very impressed with the sound. Put on some headphones and see if you come away hearing any differences.
 

GoDawgs

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If you're interested in diving into this particular rabbit op amp hole:


The really interesting thing in this is where he solders together two cheap op amps and is very impressed with the sound. Put on some headphones and see if you come away hearing any differences.
OOhhh, now I don't get it even more o_O. That was some video. I do believe someone here will report on their results eventually and if they are over the top raving about these, maybe I'll do my left channel. ;)
 

DavidM1

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. It sows disharmony. Confusion. Dare I say it, it is taking the piss!
No. It is handing out a sample size in the hope of making sales down the track.

Op amps are the new go to for the scientifically disinclined.
 
Last edited:

gwing

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I an see myself (after checking the forum rules) putting up a post offering either sell one for say £25 or buy 3 for £75. May as well have some fun and one isn't any use.
 

SMen

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No. It is handing out a sample size in the hope of making sales down the track.

Op amps are the new go to for the scientifically disinclined.
This is indeed a slightly politer way of putting it. :) - I think it lets down the rest of their approach which is so constructive, listening to customers etc. One where four are needed (or two depending on interpretation) seems quite cynical.
I an see myself (after checking the forum rules) putting up a post offering either sell one for say £25 or buy 3 for £75. May as well have some fun and one isn't any use.

Seeing your £ sign I'd say Profusion might be the way to go - but yes maybe those of us so inclined could offload to those who might like to try. Good idea. Maybe one for the user thread. https://www.audiosciencereview.com/...v3-mono-user-impressions-owners-thread.54043/
 

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Jon L

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If you're interested in diving into this particular rabbit op amp hole:


The really interesting thing in this is where he solders together two cheap op amps and is very impressed with the sound. Put on some headphones and see if you come away hearing any differences.

FYI, Fosi V3 Mono Kickstarter is ending in 5 days. I could not resist and placed an order.
I do plan to "parallel" 5532 op-amps, partly because I have many of them laying around already and the discrete op-amps would double the amp price, as two op-amps per monoblock need to be changed.
To my ears, parallel 5532 did sound significantly better than single 5532 in that youtube video.

BTW, does anyone know if the third op-amp is used only if XLR input is used? In that case, I would just use RCA input and not change the 3rd op-amp.
 

SMen

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FYI, Fosi V3 Mono Kickstarter is ending in 5 days. I could not resist and placed an order.
I do plan to "parallel" 5532 op-amps, partly because I have many of them laying around already and the discrete op-amps would double the amp price, as two op-amps per monoblock need to be changed.
To my ears, parallel 5532 did sound significantly better than single 5532 in that youtube video.

BTW, does anyone know if the third op-amp is used only if XLR input is used? In that case, I would just use RCA input and not change the 3rd op-amp.
The third op-amp is used to convert the RCA input to balanced I understand.
 

EddNog

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FYI, Fosi V3 Mono Kickstarter is ending in 5 days. I could not resist and placed an order.
I do plan to "parallel" 5532 op-amps, partly because I have many of them laying around already and the discrete op-amps would double the amp price, as two op-amps per monoblock need to be changed.
To my ears, parallel 5532 did sound significantly better than single 5532 in that youtube video.

BTW, does anyone know if the third op-amp is used only if XLR input is used? In that case, I would just use RCA input and not change the 3rd op-amp.
The third op-amp on V3 Mono is only used for RCA/single-ended input. It is only used for balanced input (XLR/TRS) on ZA3.

You don’t need to change the third op-amp on V3 Mono if you’re using balanced input.

-Ed
 

Jon L

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The third op-amp on V3 Mono is only used for RCA/single-ended input. It is only used for balanced input (XLR/TRS) on ZA3.

You don’t need to change the third op-amp on V3 Mono if you’re using balanced input.

-Ed
That's strange things are opposite on ZA3 vs V3 mono. That's too bad because I currently use RCA signal and had hoped to bypass that third op-amp on V3 op-amp.
I would buy ZA3, but I really need an actual on-off switch, not on-off by volume knob.
 

EddNog

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That's strange things are opposite on ZA3 vs V3 mono. That's too bad because I currently use RCA signal and had hoped to bypass that third op-amp on V3 op-amp.
I would buy ZA3, but I really need an actual on-off switch, not on-off by volume knob.
Apparently V3 Mono is internally balanced due to PFFB, because ZA3 is internally not balanced.

-Ed
 

Matt F

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The third op-amp on V3 Mono is only used for RCA/single-ended input. It is only used for balanced input (XLR/TRS) on ZA3.

You don’t need to change the third op-amp on V3 Mono if you’re using balanced input.

-Ed
Thank you, I popped in to ask that specific question.
 

Jon L

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Apparently V3 Mono is internally balanced due to PFFB, because ZA3 is internally not balanced.

-Ed
I suppose internally balanced design is a good thing, but this means full potential is realized when feeding the amp true balanced signal. If using RCA input, one needs to upgrade THREE op-amps per mono. Six discrete op-amps, we are looking at around $500-600!
 

Talisman

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I suppose internally balanced design is a good thing, but this means full potential is realized when feeding the amp true balanced signal. If using RCA input, one needs to upgrade THREE op-amps per mono. Six discrete op-amps, we are looking at around $500-600!
My god these are amplifiers costing 230 euros per pair, but how do you think of spending such ridiculously high amounts to replace the operational amplifiers? It's ridiculous to even think about it.
230 euros plus 600 euros are 830 euros with which you can buy many more powerful and high-performance versions of Hypex.
And then who knows why the discussion returns to these damned operational amplifiers again and again as if they were the most important thing in the project.
I'm heartbroken.
 

Guddu

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My god these are amplifiers costing 230 euros per pair, but how do you think of spending such ridiculously high amounts to replace the operational amplifiers? It's ridiculous to even think about it.
230 euros plus 600 euros are 830 euros with which you can buy many more powerful and high-performance versions of Hypex.
And then who knows why the discussion returns to these damned operational amplifiers again and again as if they were the most important thing in the project.
I'm heartbroken.
This OPamp rolling to going totally through the sky in this thread, how can one make any sense out if it!
 

SMen

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I suppose internally balanced design is a good thing, but this means full potential is realized when feeding the amp true balanced signal. If using RCA input, one needs to upgrade THREE op-amps per mono. Six discrete op-amps, we are looking at around $500-600!
I'm not sure about your math(s) except maybe for some extremely expensive solutions ... you can try with much cheaper alternatives to hear / not hear ... but I think this whole op amp discussion (regarding swapping) was closed here, and maybe belongs with users' experiences when we get them on the user impressions thread. https://www.audiosciencereview.com/...v3-mono-user-impressions-owners-thread.54043/
 
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