Fosi Audio V3 Amplifier Review

[OldTimer]

Sound is better if the V3 act as speaker amp using the Line-Out of my old amp. So, it needs pre-amp.
The old amp become pre-amp, receiving bunch of digital and analog input and also headphone connection, etc without any speaker connection. This make the old amp run cooler and reducing electrical power consumption.

 

[Bruce Morgen]

Fosi is having a sale on these for the next couple of days on AliExpress: $48.09 USD with free shipping.

I'm tempted buy a couple, even though I probably won't hear any difference from the two A07s in my particular use case (the four DSP-EQed surround/ambience speakers in a 7.1 configuration).

Fosi Audio V3 Stereo Power Amplifier 300W x2 TPA3255 Class D Mini Speaker Amp 2 Channel Audio Amplifier for Passive Bookshelf

 

[K.Kevin]

Fosi is having a sale on these for the next couple of days on AliExpress: $48.09 USD with free shipping.

I'm tempted buy a couple, even though I probably won't hear any difference from the two A07s in my particular use case (the four DSP-EQed surround/ambience speakers in a 7.1 configuration).

Fosi Audio V3 Stereo Power Amplifier 300W x2 TPA3255 Class D Mini Speaker Amp 2 Channel Audio Amplifier for Passive Bookshelf

That’s without a power supply

 

[Bruce Morgen]

That’s without a power supply

Of course -- many of we "chip amp" owners are well-supplied in that respect, including yours truly.

 

[K.Kevin]

Of course -- many of we "chip amp" owners are well-supplied in that respect, including yours truly.

The way I see it though, even if you have a power supply, what are you going to do with the old amp? It’s a useless paperweight now without a power supply of its own. So you can’t use it anywhere else. The alternative intuitive thing to do is to sell it on a used marketplace, but it will make it a lot harder and more complicated to sell an amp without a power supply. You’re decreasing your prospective buyers exponentially if they have to have a power supply handy themselves.

For that reason, it makes a lot of sense to get one with a power supply included, even if you don’t end up using it. the pricing of the packages with just a 32v psu suddenly make a lot of sense when you look at it that way.

 

[Bruce Morgen]

The way I see it though, even if you have a power supply, what are you going to do with the old amp? It’s a useless paperweight now without a power supply of its own. So you can’t use it anywhere else. The alternative intuitive thing to do is to sell it on a used marketplace, but it will make it a lot harder and more complicated to sell an amp without a power supply. You’re decreasing your prospective buyers exponentially if they have to have a power supply handy themselves.

For that reason, it makes a lot of sense to get one with a power supply included, even if you don’t end up using it. the pricing of the packages with just a 32v psu suddenly make a lot of sense when you look at it that way.

I own two industrial SMPS units nominally rated at 48VDC @ 10A and another rated @ 12.5A -- each capable of powering two typical TPA3255 stereo amplifiers to (something near) their full potential. Moreover, extra amplifiers aren't "paperweights" around here -- they're sub-$50 spares! I've gotten over three trouble-free years out of my A07s, so even if I don't sell them they don't owe me a dime -- thanks for the caveat, but in my case you can feel free to stand down from red alert.

I have a pair in my AliExpress cart -- and a couple of days to decide if I'm actually going to pull the trigger...

 

[antcollinet]

I own two industrial SMPS units nominally rated at 48VDC

I'd be checking those outputs to make sure they are well regulated before using on an amp.

 

[Bruce Morgen]

I'd be checking those outputs to make sure they are well regulated before using on an amp.

Do you believe the sort of generic, sealed "power bricks" generally supplied with these things are particularly "well regulated?"

Moreover, which part of "I've gotten over three trouble-free years out of my A07s" wasn't clear? I've had a fuktonne of "chip amp" experience over the past 4+ years, so I know what works and what doesn't -- and even if there was a volt or two of "sag" under load (in case you're wondering, there isn't), that phenomenon is neither perilous to the gear nor audible to the ear. The one DC power source in my little inventory that developed an issue was -- you guessed it -- a generic sealed CE/UL-rated "power brick" that went a tad wonky on me some time last year, and that didn't cause any problem other than audio noise with no amp damage.

 

[antcollinet]

Do you believe the sort of generic, sealed "power bricks" generally supplied with these things are particularly "well regulated?"

I know they are well regulated enough for the devices with which they are sold. I also know the voltages hold rock steady regardless of mains supply.

Not being experienced with *industrial* UPS systems I dont know the same thing about their DC outputs. So I'd be checking.

Moreover, which part of "I've gotten over three trouble-free years out of my A07s" wasn't clear?

The part that wasn't clear was where you didn't state if those trouble free years were with the stock supply, or with the UPS supply. The implication I understood, was that it was with the stock supply.



Finally - I have no idea of your level of engineering knowledge. My comment was merely meant as a heads up in case you'd not considered the voltage characteristics of the UPS. I'm not assuming you haven't - as stated I simply don't know.

You don't need to take offence as though Ive just called you an idiot. I didn't.

 

[Bruce Morgen]

I know they are well regulated enough for the devices with which they are sold. I also know the voltages hold rock steady regardless of mains supply.

Not being experienced with *industrial* UPS systems I dont know the same thing about their DC outputs. So I'd be checking.



The part that wasn't clear was where you didn't state if those trouble free years were with the stock supply, or with the UPS supply. The implication I understood, was that it was with the stock supply.



Finally - I have no idea of your level of engineering knowledge. My comment was merely meant as a heads up in case you'd not considered the voltage characteristics of the UPS. I'm not assuming you haven't - as stated I simply don't know.

You don't need to take offence as though Ive just called you an idiot. I didn't.

Ah, understood. IIRC, there was no such thing as a "stock supply" from Aiyima several years ago when I bought my first pair of A07s, so what one had to do was to search out something compatible. As per a previous "chip amp" experience, I'd found a "power brick" delivering adequate juice (for the amp I had at the time) to be far inferior in "bang for the buck" to the industrial alternatives, which were (and remain) very plentiful and inexpensive. Going back further, my very first "chip amp" -- a 2.1 TPA3116 gadget with Bluetooth -- did come with a power brick, but it couldn't source anywhere enough current for all three of the amp's channels to perform well, and that's when I spent hours searching out a heftier (and pricier) "power brick," which is the one that eventually manifested the noise issue I mentioned. So, my resort to industrial SMPS units comes from practical, value-conscious experience.

FWIW, I don't think you were calling me an idiot and I'm sorry if I came off offended -- it was just a surprising bit of advice given the thread context. Peace.

 

[Bruce Morgen]

I'd be checking those outputs to make sure they are well regulated before using on an amp.

I have to thank Ant for bringing up the subject of voltage regulation in the power supplies we use for our various chip amps. The sort of "power bricks" supplied with those amps would require building some sort of adapter in order to connect a suitable meter, but industrial SMPS units with their accessible terminals make voltage measurements easy. What I found out when I monitored the DC from the SMPS that runs the two A07s in my system is that its regulation is close to perfect -- going from no load (power switches on both amps off) to idle (both amps powered up, but no signal) to full blast (both amps playing as loud as I could stand, albeit briefly) showed less than one tenth of one volt deviation. There are some significant caveats when using such industrial components in a home audio setting, but if my experience is indicative you can safely cross voltage regulation off your list of concerns.

 

[antcollinet]

Ah, understood. IIRC, there was no such thing as a "stock supply" from Aiyima several years ago when I bought my first pair of A07s, so what one had to do was to search out something compatible. As per a previous "chip amp" experience, I'd found a "power brick" delivering adequate juice (for the amp I had at the time) to be far inferior in "bang for the buck" to the industrial alternatives, which were (and remain) very plentiful and inexpensive. Going back further, my very first "chip amp" -- a 2.1 TPA3116 gadget with Bluetooth -- did come with a power brick, but it couldn't source anywhere enough current for all three of the amp's channels to perform well, and that's when I spent hours searching out a heftier (and pricier) "power brick," which is the one that eventually manifested the noise issue I mentioned. So, my resort to industrial SMPS units comes from practical, value-conscious experience.

FWIW, I don't think you were calling me an idiot and I'm sorry if I came off offended -- it was just a surprising bit of advice given the thread context. Peace.

Peace back.

 

[Bruce Morgen]

I have a pair in my AliExpress cart -- and a couple of days to decide if I'm actually going to pull the trigger...

I've decided against the purchase. In my particular use case, IMO the better SINAD and -- possible, since Amir didn't measure the A07 with a 48V/5A power supply we don't know for sure -- extra available power of the V3 vs. the A07 won't have any audible impact at all. Both have the same load dependency, but that's a non-issue here because the DSP-based EQ I use accounts for it.

 

[CauliflowerEars]

I expected was to get close to the performance of the pa5 topping, but we're not there.

How much better did you find the Topping PA5? How did the load dependency difference affect the sound?

I’m looking for a new amp for my (hard to drive, 8 ohm) Elac DBR62 speakers.
Due to the upcoming holidays and V3’s return window I kind of have to decide, if the PA5 II could be a worthy upgrade.

Atm, wondering about V3 vs PA5 vs SMSLS A300 …

 

[Talisman]

How much better did you find the Topping PA5? How did the load dependency difference affect the sound?

I’m looking for a new amp for my (hard to drive, 8 ohm) Elac DBR62 speakers.
Due to the upcoming holidays and V3’s return window I kind of have to decide, if the PA5 II could be a worthy upgrade.

Atm, wondering about V3 vs PA5 vs SMSLS A300 …

If you continue reading the thread you will notice that it also talks about the impedance curve of the dbr62 which really isn't a problem with the fosi V3, plus the V3 definitely has more power reserve than the pa5 and I wouldn't trade any FR variations lower than 1db on frequencies that you might not hear with a nice energy reserve that is useful for dbr62s. Basically, keep the V3

 

[CauliflowerEars]

Basically, keep the V3

Ah, OK. From your initial comment, I understood that the V3 isn't as good as the PA5:
'What I expected was to get close to the performance of the pa5 topping, but we're not there. [...] A little disappointed (I say this as an owner)'.

Doesn't the PA5's 20% better SINAD over V3 (106 vs 88) make it sound better?
If the power reserve is the issue, there seems to be Topping PA5 PLUS ...

 

[K.Kevin]

Ah, OK. From your initial comment, I understood that the V3 isn't as good as the PA5:
'What I expected was to get close to the performance of the pa5 topping, but we're not there. [...] A little disappointed (I say this as an owner)'.

Doesn't the PA5's 20% better SINAD over V3 (106 vs 88) make it sound better?
If the power reserve is the issue, there seems to be Topping PA5 PLUS ...

You need to pick one: either you have “hard to drive” speakers (you really don’t) or you need ultra premium sinad (you probably don’t unless you listen very loud). To get both you need to pay a lot more.

Do you have cauliflower ears or godly ears? Are you going to hear the difference between 88db sinad and 106 at the majority of the usage at reasonably low to moderate listening volumes? There’s three possible answers to that question: option 1 is “No”, option 2 is “Yes”, and option 3 is “I like to think I can hear the difference, because I call myself an audiophile, and it mentally bothers me to suggest I can’t hear it, even though statistically and probability theory would dictate that I am overwhelmingly unlikely to be in the highest percentile of human ears that are capable of discerning these differences”

If you are more worried about the prospect that your speakers are hard to drive, no amount of increased sinad fancy amplifier will make up for an underpowered amplifier that could possibly clip or distort at high output, or be incapable of driving bass drivers at full potential. If this is a concern (which I doubt your speakers are actually that extremely hard, probably some random guy online spouted this nonsense once and the train chugged away), then the V3 makes more sense.

 

[CauliflowerEars]

You need to pick one: either you have “hard to drive” speakers (you really don’t) or you need ultra premium sinad (you probably don’t unless you listen very loud). To get both you need to pay a lot more.

Yes
1) I saw PA5’s SINAD in the blue ‘excellent’ area (in the top 20 of ASR measured amps), so was curious to have an affordable near ‘end game’ amp and call it a day. Especially as many said a V3 without load dependency would be a game changer.
I haven’t experienced +16 SINAD difference before, so have no clue how/if that’d sound. But so far most other upgrades I went with were mostly in the +20% area. I suppose better soundstage, imagining, detail and separation would be some of the most noticeable differences.

2) What bothers me with my Elac DBR62 is that they feel ‘slow’, not as dynamic with the sound. Does sheer Watt-per-channel mitigate that?

To summarise, from what you are saying, the differences in pt 2 have more influence than the differences in pt 1?
Then, doesn’t PA5 II Plus answer both points? Just gonna try to order one when I’m back from holidays.

probably some random guy online spouted this nonsense

Might have been Amir in the DBR62 measurements: ‘So you better have a beefy amplifier to drive this speaker.’

 

[king0188]

Atm, wondering about V3 vs PA5 vs SMSLS A300 …

I also want to know

 

[K.Kevin]

Yes
1) I saw PA5’s SINAD in the blue ‘excellent’ area (in the top 20 of ASR measured amps), so was curious to have an affordable near ‘end game’ amp and call it a day. Especially as many said a V3 without load dependency would be a game changer.
I haven’t experienced +16 SINAD difference before, so have no clue how/if that’d sound. But so far most other upgrades I went with were mostly in the +20% area. I suppose better soundstage, imagining, detail and separation would be some of the most noticeable differences.

2) What bothers me with my Elac DBR62 is that they feel ‘slow’, not as dynamic with the sound. Does sheer Watt-per-channel mitigate that?

To summarise, from what you are saying, the differences in pt 2 have more influence than the differences in pt 1?
Then, doesn’t PA5 II Plus answer both points? Just gonna try to order one when I’m back from holidays.


Might have been Amir in the DBR62 measurements: ‘So you better have a beefy amplifier to drive this speaker.’

I just saw his review. I don’t think what he said was nonsense, so I want to qualify my earlier statement.

However, I think what he’s talking about is a very limited area of the speaker, it is around the 125hz region that may be problematic. I also think you shouldn’t take everything he says in isolation and without context. How loud do you listen? That is the number one variable that matters most. The impedence of the speaker doesn’t actually drop below 4 ohms. It’s just the phase angle that may make the amplifier work harder and hotter, but it will still work.

The cheapest way to solve some of this “problem” (arguably it’s not a big deal in the first place) is to buy the 48v 5A power supply. It will deliver more current than the stock 32v one.


In regards to your earlier points: no, I don’t think you will necessarily notice 20% better sound experience. The higher Sinad, you won’t get better soundstage or imaging with higher sinad. You MAY get better detail if you have very good ears, listen very close to the speakers like a desktop setup, or listen very loud where distortion may be present in. but that’s not because the Amp is making your speaker produce higher detail, it’s just because there will be less noise and distortion alongside the sound. If you can’t hear the noise and distortion as is, already, then having less noise and distortion won’t really do anything to improve what you hear. If you CAN hear the noise and distortion already, right now with your V3, then what are you doing? You have your answer. It’s a simple case closed.

You may get better soundstage/imagine separation if the crosstalk is better on the PA5. But the V3 is already “very good” tier of crosstalk. It’s hard to hear further improvements past it.

If you want to spend more money on an amp that has higher power and high sinad, then there’s nothing wrong with that. Just as long as it’s an informed decision on what you do and don’t need and that you’re not expecting miracles by spending the premium will get you audibly superior experiences. It goes back to my earlier point: Everyone thinks they’re the special one, when statistically they aren’t.