Fosi Audio V3 Mono Amplifier Review

[echt]

There is only one channel in a monoblock, as you may have realised.

Yes mono blocks are one channel but you run two sumultaneouly for stereo.

a. Fosi offers the unusual option of a shared 10A power supply via a spliiter cable. Independenttly testing to see how the shared 10A compares to the separate 5A power supplies would be of interest to some.

b. More importantly to me, if you only test a single channel, you won't know if beat frequencies are generated.

My follow up questions to Amir were intended to see if there was a way to test for beat frequencies or if he considered them non-issues and/or not worth the effort to test (if a test was possible).

 

[Down South]

Yes I lost money on a record cleaner project called VinylSonic. They never produced a product but collected over 600,000 dollars

This happens on Indiegogo - lost money on a no-show and on a crap product - caveat emptor.

 

[Sokel]

Measurements would be good. But no harm in those who don't want them to offload them.

I think visuals are more convincing sometimes:

I really-really wonder if any of Fosi's engineers had a look at the way this pic shows an op-amp change.
And I really-really hope friends here who will go to the despair or replacing the op-amps don't do it this way.

 

[Down South]

Some valid points about the benefit of mono amps have been raised. It would be good if Amir was to check out Rod Elliot's site. He's a no B/S Australian.

He destroys the b/s of bi-wiring - if you really want to improve the sound try his rec. not just bi-amping but use one amp for bass and another for mids and treble. It's the bass that uses most of the juice.

One other point - I paid for the hex set and a set of cables. Now it appears we get these for free. I'm not interested in the Muse o-amps but I would like to have the 3.5mm to RCAs. I've sent an email to Jocelyn to sort this out. Hs anyone else paid for what appears will now come for free?

 

[Lednek]

I picked up an SMSL D-6s (DAC with 2 rca outs, 2 balanced XLR outs).
I did this specifically so that I'd have something with volume control and balanced outs that I could then use with my V3 monos for 2-channel listening.

Seemed like a great idea, until I realized just now that I'll have no way to retain the room correction from my Denon X3700H, as this AVR doesn't have balance pre-outs!

Oh well, looks like I'll be using the RCA pre-outs on the Denon into the Mono V3's. The benefit of room-correction far outweighs the benefits of balanced vs unbalanced in my scenario.

I have asimilar setup and plan. Using a Dennon 3400. I'll be using the LCR single ended preout to drive 3 V3 mono for the front stage. Additionally the balanced output from the DAC can be used for a pure 2 channel experience. I Imagine I'll use the RCA pre-outs more often than not, as I like having the bass management and dual subs. The monos have plenty of power to drive my towers straight from the DAC. I am interested to hear it. And, Fosi is sending you cables anyway. Might as well give it a try and have both options available.

 

[Kayshot]

Or you could see this as an opportunity and embark on the journey to DSP and room correction

Oh I am! I've ran Audyssey before, but today I'm going to attempt sub alignment and EQ with REW and MiniDSP 2x4 HD. Wish me luck! Going to follow the video from Home Theater Guru.

 

[Trasam Audio]

Yes, several people replied to me and explained this. Including Amir himself. I finally know what "PreAmps" are for.
Always wondered what the purpose of this was and why you would need a volume control that goes into an amp when Amps have volume control.
I apologize for my ignorance because I only live in the headphone world. I have no powered speakers outside of powered monitors.

Yeah, why do you need a volume control when your amps already have volume control?

 

[redstang]

I went with 2 op amps but we need 4 for stereo. The 2 op muses will likely end up in my BT20APRO if I can’t source 2 more.

Well, you can just swap one of them in each, but you need to do both to make it more noticeable, I guess. I didn't know this and figured I'd get the two op amps since I got two amps and at least have something to try. But now if you really want to go whole hog you're in for another 50+ bucks for two more.

The cost of those Sparkos op amps destroys the value proposition for these (and really any other inexpensive) amps. The fact that you need 4 for the full effect is dumb since each pair of those cost more than the amp itself. Every reviewer I've ever watched always blathers on about how much better the Sparkos op amps are, so it makes me curious, yet suspicious. How is there no one that just outright states that they make no difference? Don't want to go off topic in this thread - anyone familiar with another thread on here that discusses op-amp rolling?

 

[Deleted member 72219]

Well, you can just swap one of them in each, but you need to do both to make it more noticeable, I guess. I didn't know this and figured I'd get the two op amps since I got two amps and at least have something to try. But now if you really want to go whole hog you're in for another 50+ bucks for two more.

The cost of those Sparkos op amps destroys the value proposition for these (and really any other inexpensive) amps. The fact that you need 4 for the full effect is dumb since each pair of those cost more than the amp itself. Every reviewer I've ever watched always blathers on about how much better the Sparkos op amps are, so it makes me curious, yet suspicious. How is there no one that just outright states that they make no difference? Don't want to go off topic in this thread - anyone familiar with another thread on here that discusses op-amp rolling?

People who insist they make no difference either won’t bother testing or attest that measurements show nothing. People who insist they do make a difference will tell you they hear it and what those differences are. Your options are either try to make measurements and search for your own objective answer or just, “trust your ears,” and listen for your subjective differences.

-Ed

 

[Nopiano]

Yes mono blocks are one channel but you run two sumultaneouly for stereo.

a. Fosi offers the unusual option of a shared 10A power supply via a spliiter cable. Independenttly testing to see how the shared 10A compares to the separate 5A power supplies would be of interest to some.

b. More importantly to me, if you only test a single channel, you won't know if beat frequencies are generated.

My follow up questions to Amir were intended to see if there was a way to test for beat frequencies or if he considered them non-issues and/or not worth the effort to test (if a test was possible).

Sure, and I see that you’re ideally seeking tests on a pair, as that’s how most of us will use them. Good idea about seeking a comparison between the split 10A -v- 2x5A because again that’s the decision most buyers face. (I chose the higher powered option on my v3)

 

[Guddu]

People who insist they make no difference either won’t bother testing or attest that measurements show nothing. People who insist they do make a difference will tell you they hear it and what those differences are. Your options are either try to make measurements and search for your own objective answer or just, “trust your ears,” and listen for your subjective differences.

-Ed

One can always agree to disagree.

 

[SMen]

One can always agree to disagree.

People who insist they make no difference either won’t bother testing or attest that measurements show nothing. People who insist they do make a difference will tell you they hear it and what those differences are. Your options are either try to make measurements and search for your own objective answer or just, “trust your ears,” and listen for your subjective differences.

-Ed

Yes, one can always agree to disagree. There are some who have tried, and some who have not, but have (strong) opinions based on measurement or theory.
But let people try if they want to and come to their own conclusions, but be self aware, especially if you have come to your own conclusions, having done the same...

I just don't get the half measures here with op amp 'mixes' in parallel. Anyway! Be safe etc. I think one needs 4 the same 2x2 really, in parallel.

 

[Guddu]

Yes, one can always agree to disagree. There are some who have tried, and some who have not, but have (strong) opinions based on measurement or theory.
But let people try if they want to and come to their own conclusions, but be self aware, especially if you have come to your own conclusions, having done the same...

I just don't get the half measures here with op amp 'mixes' in parallel. Anyway! Be safe etc. I think one needs 4 the same 2x2 really, in parallel.

I am in category of those who have tried, fried the brain to limit to find any difference.
But I am still hopeful….. may be one day

 

[gwing]

Yeah, why do you need a volume control when your amps already have volume control?

If you are using a pre-amp you would ideally drive power amps, without volume controls from your pre- amp. However even if you have to use integrated amps, complete with their own volume control, you might still want to use the preamp vol control so their is a single one to adjust rather than one on each of your integrated amps.

 

[SMen]

I am in category of those who have tried, fried the brain to limit to find any difference.
But I am still hopeful….. may be one day

But you have tried... ! I have too, because a kind fellow member here shared a few (and another sold me a couple), and then I got so hacked off at being told what I could and could not hear I bought a couple more!... but that is for another time and place and context!

If someone says "I can't hear a difference" I say, good, because then, when they say they do, I might believe them!

 

[DavidM1]

Op amps can be switched without soldering skills and that would be the reason a hifi accessory market has emerged. People like to make a buck and it is far easier to sell these through the post than most things. Electronic components generally cost very little in bulk.

The marketing of op amps is the same as for hifi interconnects and power cables. It relies on convincing people that their ears are the only thing that matters and no further information is provided apart from price. Human psychology does the rest, attaching imagined benefits to either the most expensive or the one considered best value. Rarely will anyone admit to wasting time and money on imagined improvements.

If you want to test yourself then start with only the audio track from demonstration videos and see whether you are able to identify which op amps are in use and when they change.

 

[SMen]

Op amps can be switched without soldering skills and that would be the reason a hifi accessory market has emerged. People like to make a buck and it is far easier to sell these through the post than most things. Electronic components generally cost very little in bulk.

The marketing of op amps is the same as for hifi interconnects and power cables. It relies on convincing people that their ears are the only thing that matters and no further information is provided apart from price. Human psychology does the rest, attaching imagined benefits to either the most expensive or the one considered best value. Rarely will anyone admit to wasting time and money on imagined improvements.

If you want to test yourself then start with only the audio track from demonstration videos and see whether you are able to identify which op amps are in use and when they change.

I very nearly used cables as a comparison myself. I think there is a threshold of quality that is rapidly reached, and not at a high price. With op amps there is mass production and scale too (regarding price).

I'm not sure about those demonstration videos though. With the V3 monos it should be possible to use a mono track and put two Muses02 in one v3 mono and switch between speakers (in the same place) with the unchanged second v3 mono... Not sure if it would be possible to also use the same speaker, or even power both speakers in mono and switch. Plenty of power...

 

[DavidM1]

I very nearly used cables as a comparison myself. I think there is a threshold of quality that is rapidly reached, and not at a high price. With op amps there is mass production and scale too (regarding price).

I'm not sure about those demonstration videos though. With the V3 monos it should be possible to use a mono track and put two Muses02 in one v3 mono and switch between speakers (in the same place) with the unchanged second v3 mono... Not sure if it would be possible to also use the same speaker, or even power both speakers in mono and switch. Plenty of power...

I really wouldn’t bother. I’m sure the Texas Instruments op amps are absolutely fine. I think op amp fans are listening with their imaginations fully engaged.

 

[SMen]

I really wouldn’t bother. I’m sure the Texas Instruments op amps are absolutely fine. I think op amp fans are listening with their imaginations fully engaged.

No I know, but where I am coming from is a proper blind A/B test for anyone who wants to, and establish for themselves / challenge their perceptions etc.
Those who already have great. Saves the debating.

As in the goal could indeed be to not hear a difference.

 

[Roland68]

No I know, but where I am coming from is a proper blind A/B test for anyone who wants to, and establish for themselves / challenge their perceptions etc.
Those who already have great. Saves the debating.

As in the goal could indeed be to not hear a difference.

There are differences in OPAmps, but firstly they are marginal and secondly they are not to be found in the area of sound. There are very subtle differences in the area of reproduction of details, bass precision etc., but they are really small, because each OPAmp does its job.
The often heard differences in sound are very often due to a mismatch between the circuit and the OPAmp, which is why OPAmp rolling without background knowledge, experience and adaptation of the circuit is nonsense in most cases.