TI Data sheet says it can do about 230W (1% THD), Fosi's table quoted above says 280W. The lower figure would need 7.5 amps for each channel into 4 ohm.
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Fosi Audio V3 Mono Amplifier Review
- Thread starter amirm
- Start date
srry for my stupid question...but I want to know if after the 10 mins. without signal it remains hot at around 43° or shuts down completely?
Thank you!Very good post, chock full of ironic truth that many will miss or ignore (doesn't suit their belief system). In the 70s the Japanese made amps that measured perfectly but sounded like shite. It used to be heresy to have bass and treble adjustment, which completely ignores the fact that a lot of listening rooms are made of crap material - single plasterboard walls and ceilings (USA) or hard clay blocks (France,Spain, Italy,Portugal) finished with a hard plaster finish. Just loved the comment - and amazingly the equipment has got better when it was all 'perfect' before.
Re. phono stages - in 2010 I bought at half price because the whole financial system was at the point of meltdown an MC3 Talk Electronics two box phono stage. Adjustable loading and gain via two banks, one for each channel so the jumpers should mirror each other, a warp filter and true mono replay. Not unusual in good phono stages, it caters for virtually all cartridges both MM and MC. So comments made about analogue and digital should be made with details of actual phono stages used. As Parks Audio Puffin and Waxwing are said to neither add or subtract from the analogue signal it should be interesting to do an A/B using one or both to see the digital outcome.
What interests me is when objective tests are born out by subjective (as well as vice versa) - so mutually reinforcing.
The thing about balance it would appear, is that being aware of it does not require you to AB test!
I've noticed a few people here using Schitt pre-amps with switched relays. I'm using a switched relay that I am finding surprisingly good from Ali Express - and I've just bought a Michael Fremer MM Pro - both claim to be very very closely toleranced left and right - and I've appreciated this with many recordings - in combination with the monos. Best thing is the two pre units match in physical width perfectly!
I sure would like M. Fremer or someone to bring out a switched relay with a balance shift - if something like this is possible... and yes ... maybe a few switch settings - little boost around 100hz for example ... or roll off for those 'modern' speakers that are tilted 'up' above 1 or 2khz.
It would appear (reference your comment about measurements in the 70s) that ASR has encouraged not only good manufacturer practice ... but measurement practice also (and general awareness). Gotta be a good thing.
What is your source? If digital, a decent streamer will be able to do all the things you mentioned in the digital domain/in DSP, including balance control and parametric EQ. I do this with a HiBy R6 Pro II.Thank you!
What interests me is when objective tests are born out by subjective (as well as vice versa) - so mutually reinforcing.
The thing about balance it would appear, is that being aware of it does not require you to AB test!
I've noticed a few people here using Schitt pre-amps with switched relays. I'm using a switched relay that I am finding surprisingly good from Ali Express - and I've just bought a Michael Fremer MM Pro - both claim to be very very closely toleranced left and right - and I've appreciated this with many recordings - in combination with the monos. Best thing is the two pre units match in physical width perfectly!
I sure would like M. Fremer or someone to bring out a switched relay with a balance shift - if something like this is possible... and yes ... maybe a few switch settings - little boost around 100hz for example ... or roll off for those 'modern' speakers that are tilted 'up' above 1 or 2khz.
It would appear (reference your comment about measurements in the 70s) that ASR has encouraged not only good manufacturer practice ... but measurement practice also (and general awareness). Gotta be a good thing.
-Ed
I just have a DAC - and the Michael Fremer MMPro now (it was an IFI Zen).
I have to say that tonally for me everything (my latest kit along with the Monos) is following the spirit of getting as close to the source as possible - or that is my impression. Variation between recordings has increased greatly - my sense of the recording itself - or the venue where there is one.
I'm really into my 'vintage' records. Many are simply astonishing, even when compared to 'top' modern recordings. A few could do with just a tweak down in the high frequencies sometimes. Right now I don't need any bass boost, but for low level listening it can be useful.
My context is mostly vinyl with regard to my small 'tweak suggestions' that are non-existent in modern pre-amps.
You have a Freya plus I know... . I'll share a small story. I was thinking of this amplifier myself, and I contacted Schitt and asked them if they had ever considered a balance control. And they replied why?!
But they do have an interesting "eq pre amp".
Still, I really like the Schitt Pre-amps - and I am pretty astonished by the switch relay I am using which surely must be similar in concept to yours.
I reckon they must be a great match for these V3 monos (and Fosi's cousin amps). I went for the MMPro over the Schitt Skoll because conceptually I just did not understand why you would want to roll off bass anywhere remotely close to the audible range to handle low bass issues that can crop up with vinyl. I'm a bit of a vinyl head ... though I love how many of my digital versions are sounding better these days (and even often better better)
DavidM1
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The marketing science that I know of behind this is old and the findings were that in blind tests, using wine or cigarettes, subjects with no other information other than price tended to prefer either the most or least expensive of three options, rarely choosing the mid-priced option. The cheapest was considered exceptional value. Subjects hardly ever stated that they all seemed the same even though the experiment actually used exactly the same wine or cigarettes for each of the three samples.
This sort of conversation comes up so often on this forum that I must see if I can find the original articles or any work done more recently.
DavidM1
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I would just like to say, hand on heart, that I choose hifi gear because it measures well. I don’t have the time or inclination to cycle through gear looking for things I think I might prefer and I care little for brand reputation.
Give me hard data from a reliable source and I’m there.
Lux_ury
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I can't comment, I have no control over @Fosi Audio. All I can do is listen to my music and enjoy the two brick solutions I created for myself.Are You sure they would supply a 2nd (improved) filter at no further cost ?
You might have to pay for it...
Monetary values are just another solution to more worldy problems (Wink emoji)
Sometimes that works, sometimes it doesn’t. The stellar numbers for KEF LS50 Meta are what drew me to them and I couldn’t possibly be happier with them (after pairing them with an SVS SB-3000 subwoofer), but at one point I tried an SMSL SA400 to drive them and I didn’t enjoy it one bit despite that amplifier’s stellar measurements. I’ve enjoyed all three Fosi amps that I’ve auditioned (V3, ZA3 in a pair, and V3 Monos), and even a Douk H7 (also TPA3255-based) much more than that SA400, so good measurements are only half of the equation.
-Ed
By my observations it cools down a bit in "Auto"-mode. It does not shut down "completely"...
Pulkass
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Nice. I wish they had internal power supply, not that bulky box outside, considering you need two. Oh yes. Or one 10 A. Btw can l change the op amps inside ? What s the best solution?This is a review and detailed measurements of the Fosi Audio V3 Mono class D amplifier. It was sent to me by the company. The price with the power supply I tested is US $139.99.
View attachment 360697
I must say the concept of a "monoblock" amplifier in such a small size runs foul of any expectation a longtime audiophile would have! But monblock it is even though it is a very small block. Controls are on/off/trigger audio and selection of XLR vs RCA inputs -- just like the big boys!
View attachment 360698
The power supply as noted, is quite beefy with 48 volts at 5 amps on tap (240 watts). The amplifier is stated to have PFFB implementation which for a class D amplifier means it should have no load dependency together with lower distortion. Let's see if we get these with our measurements.
Fosi Audio V3 Mono Amplifier Measurements
Let's start with XLR input:
View attachment 360699
Wow, I did not expect this class of amplifier to break through the 100 dB SINAD barrier but the V3 Mono does exactly that, placing it in our prestigious category of "excellent:
View attachment 360700
View attachment 360701
RCA input costs you some performance but I was relieved to not see any mains interference:
View attachment 360702
Distortion is still at provably inaudible -115 dB. I like that the gain is nominal 25 which is my new recommendation for amplifiers.
Noise performance is excellent and at full power, darn near approaches sate of the art:
View attachment 360703
Now the all important frequency response and load dependency test:
View attachment 360704
There is essentially no impact up to 20 kHz between the 4 and 8 ohm indicating very low output impedance, albeit with a bit of peaking. Compare that to non-PFFB amps such as Fosi Audio V3 stereo Amp:
Above we have 2 dB differential at 20 kHz.
Distortion is very low and only increases with frequency:
View attachment 360706
View attachment 360707
Let's see how much power we can get out of this little box:
View attachment 360709
View attachment 360710
Efficiency must be quite high as we get essentially the power we put in (the power supply likely has some headroom).
There is decent amount of power even with 8 ohm and with very low noise:
View attachment 360712
As note though, distortion does rise at higher frequencies:
View attachment 360713
Fortunately it is good where our hearing is very sensitive (below 5 kHz).
I also threw my suite of my punishing reactive loads at it:
View attachment 360717
Translating into watts:
View attachment 360716
Amazing that this little amplifier can handle even 2 ohm load! Note that these are short term power ratings.
There may be a bit of power on noise:
View attachment 360718
Conclusions
All I can say is wow! It is incredible how far these small amplifiers have come. It is the result of a manufacturer listening to our needs, implementing features such as balanced and trigger inputs, and proper feedback mechanism to essentially eliminate load dependency. I can't imagine asking for more from Fosi when it comes to such an amplifier. Everything is as good as you could possibly want.
It is my pleasure to recommend Fosi Audio V3 Mono amplifier.
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Killingbeans
Major Contributor
Yes.
In terms of op-amps? Probably to leave the factory ones alone.
All of the measurements I've seen from different op-amps in products with sockets have shown sometimes marginal improvement (with doubtful audibilty), sometimes a sh¤tfest of added distortion, but mostly practically zero change. There's absolutely no correlation between performance and price/fancyness of the op-amps, since stability mostly rely on other factors. It's a complete dice throw, unless somebody has taken the time to actually verify the effect of a specific swap with measurements. And considering the data we see in this review, the chance of it being worth the trouble is slim to say the least.
This is a great review (I think someone posted the part 1 here or on the user impressions thread)
archimago.blogspot.com
"The Fosi V3 Mono sounds well balanced and "rich". Some people claim that Class D can sound excessively "thin". Well, maybe years ago this could have been the case but not with modern Class D amplifiers capable of hi-fi performance (low noise, full frequency response, low distortion, excellent transient response); they're just neutral-sounding these days".
Well put (you get down to this after all the measurements). Could not have put it any better.
Part II: Fosi Audio V3 Mono Amp; Class D + PFFB, TI TPA3255 - Retail box with single 48V/10A power supply and filter. [Power, Distortion, and Subjective Impressions.] And on rejoicing over "Solved Problems" in audio.
A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.
archimago.blogspot.com
"The Fosi V3 Mono sounds well balanced and "rich". Some people claim that Class D can sound excessively "thin". Well, maybe years ago this could have been the case but not with modern Class D amplifiers capable of hi-fi performance (low noise, full frequency response, low distortion, excellent transient response); they're just neutral-sounding these days".
Well put (you get down to this after all the measurements). Could not have put it any better.
Sokel
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What's worth saying is how gain reflects in it's measurements,specially with RCA input and how a totally decent 91.4dB SINAD at 1kHz/1W goes down to either 79dB for 25dB gain or 77dB SINAD at 1kHz/1W for 31dB gain.This is a great review (I think someone posted the part 1 here or on the user impressions thread)
Part II: Fosi Audio V3 Mono Amp; Class D + PFFB, TI TPA3255 - Retail box with single 48V/10A power supply and filter. [Power, Distortion, and Subjective Impressions.] And on rejoicing over "Solved Problems" in audio.
A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.
"The Fosi V3 Mono sounds well balanced and "rich". Some people claim that Class D can sound excessively "thin". Well, maybe years ago this could have been the case but not with modern Class D amplifiers capable of hi-fi performance (low noise, full frequency response, low distortion, excellent transient response); they're just neutral-sounding these days".
Well put (you get down to this after all the measurements). Could not have put it any better.
SINAD almost takes the same penalty as the numerical gain increase.
And it's worth noting that every time we see a review we should pay close attention to gain and compare with amp's results of similar gain.
It's extremely rare to see an amp that takes no penalty with higher gain.
This whole V3 Mono story is a true debacle.
First, noise issues, then reversed polarities. What next?
ninetylol
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Ouch at that introduced distortion with rca. Probably still below speaker thd, but that kinda makes the selling point for some of us invalid.
You get more power too yes, but in total to another TPA3255 thats more or less +2db more Max volume.
I still think its a great amp, but I think its not much better than any cheap TPA3255 like a V3 stereo for 1/4 of the price.
You get more power too yes, but in total to another TPA3255 thats more or less +2db more Max volume.
I still think its a great amp, but I think its not much better than any cheap TPA3255 like a V3 stereo for 1/4 of the price.
And did you reverse the test also?
@JBL321GO
Noise issues ? I never heard of any with my 2x 48VDC / 5A power supplies for 2 amps. Some "noise issues" have been introduced with that 48VDC / 10A power supply for two amps because of users trying to "save money and space" for the power supply. The supplied filter and ist siblings are nullifying this advantage now anyways.
Polarity issues ? I just reversed the speaker connections (banana plugs) which cured any "phase reversals" They will change - probably - the female banana colors on the back plate and the corresponding printing for the next batch. I did this already... It will be only a "real issue" when mixing different amps or systems, otherwise there is "none".
Never mind, aren't You exaggerating a bit ???
Noise issues ? I never heard of any with my 2x 48VDC / 5A power supplies for 2 amps. Some "noise issues" have been introduced with that 48VDC / 10A power supply for two amps because of users trying to "save money and space" for the power supply. The supplied filter and ist siblings are nullifying this advantage now anyways.
Polarity issues ? I just reversed the speaker connections (banana plugs) which cured any "phase reversals"
They will change - probably - the female banana colors on the back plate and the corresponding printing for the next batch. I did this already... It will be only a "real issue" when mixing different amps or systems, otherwise there is "none".Never mind, aren't You exaggerating a bit ???
I'm just being objective.
DavidM1
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Funny, I don’t see it that way. I guess it met and maybe exceeded my expectations. I always planned to use balanced inputs and I did what I thought was the obvious thing and chose two 5A power supplies. It is silent, it has heaps of juice, the auto functions without any issue and I feel like it does justice to my equally impressive and affordable SMSL DAC.
It seems every 6 months there is another amp on the market so if you sit tight there will be something new to fuss over. I won’t be changing these though.
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